spi: pxa2xx: Set controller->max_transfer_size in dma mode

In DMA mode we have a maximum transfer size, past that the driver
falls back to PIO (see the check at the top of pxa2xx_spi_transfer_one).
Falling back to PIO for big transfers defeats the point of a dma engine,
hence set the max transfer size to inform spi clients that they need
to do something smarter.

This was uncovered by the drm_mipi_dbi spi panel code, which does
large spi transfers, but stopped splitting them after:

commit e143364b4c1774f68e923a5a0bb0fca28ac25888
Author: Noralf Trønnes <noralf@tronnes.org>
Date:   Fri Jul 19 17:59:10 2019 +0200

    drm/tinydrm: Remove tinydrm_spi_max_transfer_size()

After this commit the code relied on the spi core to split transfers
into max dma-able blocks, which also papered over the PIO fallback issue.

Fix this by setting the overall max transfer size to the DMA limit,
but only when the controller runs in DMA mode.

Fixes: e143364b4c17 ("drm/tinydrm: Remove tinydrm_spi_max_transfer_size()")
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Andy Shevchenko <andriy.shevchenko@intel.com>
Reported-and-tested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-spi@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20191017064426.30814-1-daniel.vetter@ffwll.ch
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-qspi: Clear TDH bits in FLSHCR register

Later versions of the QSPI controller (e.g. in i.MX6UL/ULL and i.MX7)
seem to have an additional TDH setting in the FLSHCR register, that
needs to be set in accordance with the access mode that is used (DDR
or SDR).

Previous bootstages such as BootROM or bootloader might have used the
DDR mode to access the flash. As we currently only use SDR mode, we
need to make sure the TDH bits are cleared upon initialization.

Fixes: 84d043185dbe ("spi: Add a driver for the Freescale/NXP QuadSPI controller")
Cc: <stable@vger.kernel.org>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/20191007071933.26786-1-frieder.schrempf@kontron.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Always use the TCFQ devices in poll mode

With this patch, the "interrupts" property from the device tree bindings
is ignored, even if present, if the driver runs in TCFQ mode.

Switching to using the DSPI in poll mode has several distinct
benefits:

- With interrupts, the DSPI driver in TCFQ mode raises an IRQ after each
  transmitted word. There is more time wasted for the "waitq" event than
  for actual I/O. And the DSPI IRQ count can easily get the largest in
  /proc/interrupts on Freescale boards with attached SPI devices.

- The SPI I/O time is both lower, and more consistently so. Attached to
  some Freescale devices are either PTP switches, or SPI RTCs. For
  reading time off of a SPI slave device, it is important that all SPI
  transfers take a deterministic time to complete.

- In poll mode there is much less time spent by the CPU in hardirq
  context, which helps with the response latency of the system, and at
  the same time there is more control over when interrupts must be
  disabled (to get a precise timestamp measurement): win-win.

On the LS1021A-TSN board, where the SPI device is a SJA1105 PTP switch
(with a bits_per_word=8 driver), I created a "benchmark" where I read
its PTP time once per second, for 120 seconds. Each "read PTP time" is a
12-byte SPI transfer. I then recorded the time before putting the first
byte in the TX FIFO, and the time after reading the last byte from the
RX FIFO. That is the transfer delay in nanoseconds.

Interrupt mode:

  delay: min 125120 max 168320 mean 150286 std dev 17675.3

Poll mode:

  delay: min 69440 max 119040 mean 70312.9 std dev 8065.34

Both the mean latency and the standard deviation are more than 50% lower
in poll mode than in interrupt mode. This is with an 'ondemand' governor
on an otherwise idle system - therefore running mostly at 600 MHz out of
a max of 1200 MHz.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: stm32-qspi: Fix kernel oops when unbinding driver

spi_master_put() must only be called in .probe() in case of error.

As devm_spi_register_master() is used during probe, spi_master_put()
mustn't be called in .remove() callback.

It fixes the following kernel WARNING/Oops when executing
echo "58003000.spi" > /sys/bus/platform/drivers/stm32-qspi/unbind :

------------[ cut here ]------------
WARNING: CPU: 1 PID: 496 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x9c/0xa4
kernfs: can not remove 'uevent', no directory
Modules linked in:
CPU: 1 PID: 496 Comm: sh Not tainted 5.3.0-rc1-00219-ga0e07bb51a37 #62
Hardware name: STM32 (Device Tree Support)
[<c0111570>] (unwind_backtrace) from [<c010d384>] (show_stack+0x10/0x14)
[<c010d384>] (show_stack) from [<c08db558>] (dump_stack+0xb4/0xc8)
[<c08db558>] (dump_stack) from [<c01209d8>] (__warn.part.3+0xbc/0xd8)
[<c01209d8>] (__warn.part.3) from [<c0120a5c>] (warn_slowpath_fmt+0x68/0x8c)
[<c0120a5c>] (warn_slowpath_fmt) from [<c02e5844>] (kernfs_remove_by_name_ns+0x9c/0xa4)
[<c02e5844>] (kernfs_remove_by_name_ns) from [<c05833a4>] (device_del+0x128/0x358)
[<c05833a4>] (device_del) from [<c05835f8>] (device_unregister+0x24/0x64)
[<c05835f8>] (device_unregister) from [<c0638dac>] (spi_unregister_controller+0x88/0xe8)
[<c0638dac>] (spi_unregister_controller) from [<c058c580>] (release_nodes+0x1bc/0x200)
[<c058c580>] (release_nodes) from [<c0588a44>] (device_release_driver_internal+0xec/0x1ac)
[<c0588a44>] (device_release_driver_internal) from [<c0586840>] (unbind_store+0x60/0xd4)
[<c0586840>] (unbind_store) from [<c02e64e8>] (kernfs_fop_write+0xe8/0x1c4)
[<c02e64e8>] (kernfs_fop_write) from [<c0266b44>] (__vfs_write+0x2c/0x1c0)
[<c0266b44>] (__vfs_write) from [<c02694c0>] (vfs_write+0xa4/0x184)
[<c02694c0>] (vfs_write) from [<c0269710>] (ksys_write+0x58/0xd0)
[<c0269710>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x54)
Exception stack(0xdd289fa8 to 0xdd289ff0)
9fa0:                   0000006c 000e20e8 00000001 000e20e8 0000000d 00000000
9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000
9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6
---[ end trace 1b15df8a02d76aef ]---
------------[ cut here ]------------
WARNING: CPU: 1 PID: 496 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x9c/0xa4
kernfs: can not remove 'online', no directory
Modules linked in:
CPU: 1 PID: 496 Comm: sh Tainted: G        W         5.3.0-rc1-00219-ga0e07bb51a37 #62
Hardware name: STM32 (Device Tree Support)
[<c0111570>] (unwind_backtrace) from [<c010d384>] (show_stack+0x10/0x14)
[<c010d384>] (show_stack) from [<c08db558>] (dump_stack+0xb4/0xc8)
[<c08db558>] (dump_stack) from [<c01209d8>] (__warn.part.3+0xbc/0xd8)
[<c01209d8>] (__warn.part.3) from [<c0120a5c>] (warn_slowpath_fmt+0x68/0x8c)
[<c0120a5c>] (warn_slowpath_fmt) from [<c02e5844>] (kernfs_remove_by_name_ns+0x9c/0xa4)
[<c02e5844>] (kernfs_remove_by_name_ns) from [<c0582488>] (device_remove_attrs+0x20/0x5c)
[<c0582488>] (device_remove_attrs) from [<c05833b0>] (device_del+0x134/0x358)
[<c05833b0>] (device_del) from [<c05835f8>] (device_unregister+0x24/0x64)
[<c05835f8>] (device_unregister) from [<c0638dac>] (spi_unregister_controller+0x88/0xe8)
[<c0638dac>] (spi_unregister_controller) from [<c058c580>] (release_nodes+0x1bc/0x200)
[<c058c580>] (release_nodes) from [<c0588a44>] (device_release_driver_internal+0xec/0x1ac)
[<c0588a44>] (device_release_driver_internal) from [<c0586840>] (unbind_store+0x60/0xd4)
[<c0586840>] (unbind_store) from [<c02e64e8>] (kernfs_fop_write+0xe8/0x1c4)
[<c02e64e8>] (kernfs_fop_write) from [<c0266b44>] (__vfs_write+0x2c/0x1c0)
[<c0266b44>] (__vfs_write) from [<c02694c0>] (vfs_write+0xa4/0x184)
[<c02694c0>] (vfs_write) from [<c0269710>] (ksys_write+0x58/0xd0)
[<c0269710>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x54)
Exception stack(0xdd289fa8 to 0xdd289ff0)
9fa0:                   0000006c 000e20e8 00000001 000e20e8 0000000d 00000000
9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000
9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6
---[ end trace 1b15df8a02d76af0 ]---
8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 00000050
pgd = e612f14d
[00000050] *pgd=ff1f5835
Internal error: Oops: 17 [#1] SMP ARM
Modules linked in:
CPU: 1 PID: 496 Comm: sh Tainted: G        W         5.3.0-rc1-00219-ga0e07bb51a37 #62
Hardware name: STM32 (Device Tree Support)
PC is at kernfs_find_ns+0x8/0xfc
LR is at kernfs_find_and_get_ns+0x30/0x48
pc : [<c02e49a4>]    lr : [<c02e4ac8>]    psr: 40010013
sp : dd289dac  ip : 00000000  fp : 00000000
r10: 00000000  r9 : def6ec58  r8 : dd289e54
r7 : 00000000  r6 : c0abb234  r5 : 00000000  r4 : c0d26a30
r3 : ddab5080  r2 : 00000000  r1 : c0abb234  r0 : 00000000
Flags: nZcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: dd11c06a  DAC: 00000051
Process sh (pid: 496, stack limit = 0xe13a592d)
Stack: (0xdd289dac to 0xdd28a000)
9da0:                            c0d26a30 00000000 c0abb234 00000000 c02e4ac8
9dc0: 00000000 c0976b44 def6ec00 dea53810 dd289e54 c02e864c c0a61a48 c0a4a5ec
9de0: c0d630a8 def6ec00 c0d04c48 c02e86e0 def6ec00 de909338 c0d04c48 c05833b0
9e00: 00000000 c0638144 dd289e54 def59900 00000000 475b3ee5 def6ec00 00000000
9e20: def6ec00 def59b80 dd289e54 def59900 00000000 c05835f8 def6ec00 c0638dac
9e40: 0000000a dea53810 c0d04c48 c058c580 dea53810 def59500 def59b80 475b3ee5
9e60: ddc63e00 dea53810 dea3fe10 c0d63a0c dea53810 ddc63e00 dd289f78 dd240d10
9e80: 00000000 c0588a44 c0d59a20 0000000d c0d63a0c c0586840 0000000d dd240d00
9ea0: 00000000 00000000 ddc63e00 c02e64e8 00000000 00000000 c0d04c48 dd9bbcc0
9ec0: c02e6400 dd289f78 00000000 000e20e8 0000000d c0266b44 00000055 00000cc0
9ee0: 000000e3 000e3000 dd11c000 dd11c000 00000000 00000000 00000000 00000000
9f00: ffeee38c dff99688 00000000 475b3ee5 00000001 dd289fb0 ddab5080 ddaa5800
9f20: 00000817 000e30ec dd9e7720 475b3ee5 ddaa583c 0000000d dd9bbcc0 000e20e8
9f40: dd289f78 00000000 000e20e8 0000000d 00000000 c02694c0 00000000 00000000
9f60: c0d04c48 dd9bbcc0 00000000 00000000 dd9bbcc0 c0269710 00000000 00000000
9f80: 000a91f4 475b3ee5 0000006c 000e20e8 b6f87da0 00000004 c0101204 dd288000
9fa0: 00000004 c0101000 0000006c 000e20e8 00000001 000e20e8 0000000d 00000000
9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000
9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6 600e0030 00000001 00000000 00000000
[<c02e49a4>] (kernfs_find_ns) from [<def6ec00>] (0xdef6ec00)
Code: ebf8eeab c0dc50b8 e92d40f0 e292c000 (e1d035b0)
---[ end trace 1b15df8a02d76af1 ]---

Fixes: a88eceb17ac7 ("spi: stm32-qspi: add spi_master_put in release function")
Cc: <stable@vger.kernel.org>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Link: https://lore.kernel.org/r/20191004123606.17241-1-patrice.chotard@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: lpspi: fix memory leak in fsl_lpspi_probe

In fsl_lpspi_probe an SPI controller is allocated either via
spi_alloc_slave or spi_alloc_master. In all but one error cases this
controller is put by going to error handling code. This commit fixes the
case when pm_runtime_get_sync fails and it should go to the error
handling path.

Fixes: 944c01a889d9 ("spi: lpspi: enable runtime pm for lpspi")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Link: https://lore.kernel.org/r/20190930034602.1467-1-navid.emamdoost@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: gpio: prevent memory leak in spi_gpio_probe

In spi_gpio_probe an SPI master is allocated via spi_alloc_master, but
this controller should be released if devm_add_action_or_reset fails,
otherwise memory leaks. In order to avoid leak spi_contriller_put must
be called in case of failure for devm_add_action_or_reset.

Fixes: 8b797490b4db ("spi: gpio: Make sure spi_master_put() is called in every error path")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Link: https://lore.kernel.org/r/20190930205241.5483-1-navid.emamdoost@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: orion: fix runtime PM initialization

The current initialisation of runtime PM in the orion-spi.c driver is
incorrect, because calling pm_runtime_put_autosuspend before calling
pm_runtime_get leads to a negative value of the reference count and
therefore it sometimes causes suspend during a transmission.

Signed-off-by: Tomas Paukrt <tomaspaukrt@email.cz>
Link: https://lore.kernel.org/r/E2A.ZWgn.6sH16TohXKE.1TYpoi@seznam.cz
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Add call to spi_slave_abort() function when spidev driver is released

This change is necessary for spidev devices (e.g. /dev/spidev3.0) working
in the slave mode (like NXP's dspi driver for Vybrid SoC).

When SPI HW works in this mode - the master is responsible for providing
CS and CLK signals. However, when some fault happens - like for example
distortion on SPI lines - the SPI Linux driver needs a chance to recover
from this abnormal situation and prepare itself for next (correct)
transmission.

This change doesn't pose any threat on drivers working in master mode as
spi_slave_abort() function checks if SPI slave mode is supported.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Link: https://lore.kernel.org/r/20190924110547.14770-2-lukma@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20190925091143.15468-2-lukma@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mxic: Fix DMAS_CTRL register layout

Fix the current layout which only matches early non-public revisions
of the IP. Since its official distribution, two bytes of the SPI
controller DMAS_CTRL register have been inverted.

Suggested-by: Mason Yang <masonccyang@mxic.com.tw>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20190919202504.9619-4-miquel.raynal@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mxic: Select SPI_NOR type by default

The SPI_NAND bit is a (wrongly named) placeholder that is intended
to be used in the future. Right now SPI_NOR (which is currently
identical to SPI_NAND in this version of the IP) should be used in
both cases.

Suggested-by: Mason Yang <masonccyang@mxic.com.tw>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20190919202504.9619-3-miquel.raynal@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mediatek: support large PA

Add spi large PA(max=64G) support for DMA transfer.

Signed-off-by: luhua.xu <luhua.xu@mediatek.com>
Link: https://lore.kernel.org/r/1568195731-3239-4-git-send-email-luhua.xu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mediatek: add spi support for mt6765 IC

This patch add spi support for mt6765 IC.

Signed-off-by: luhua.xu <luhua.xu@mediatek.com>
Link: https://lore.kernel.org/r/1568195731-3239-3-git-send-email-luhua.xu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

dt-bindings: spi: update bindings for MT6765 SoC

Add a DT binding documentation for the MT6765 soc.

Signed-off-by: luhua.xu <luhua.xu@mediatek.com>
Link: https://lore.kernel.org/r/1568195731-3239-2-git-send-email-luhua.xu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: Speed up RX-only DMA transfers by zero-filling TX FIFO

The BCM2835 SPI driver currently sets the SPI_CONTROLLER_MUST_TX flag.
When performing an RX-only transfer, this flag causes the SPI core to
allocate and DMA-map a dummy buffer which is copied to the TX FIFO.
The dummy buffer is necessary because the chip is not capable of
automatically clocking out null bytes.

Avoid the overhead induced by the dummy buffer by preallocating a
reusable DMA transaction which fills the TX FIFO by cyclically copying
from the zero page.  The transaction requires very little CPU time to
submit and generates no interrupts while running.  Specifics are
provided in kerneldoc comments.

[Nathan Chancellor contributed a DMA mapping fixup for an early version
of this commit, hence his Signed-off-by.]

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Link: https://lore.kernel.org/r/f45920af18dbf06e34129bbc406f53dc9c5d1075.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: Speed up TX-only DMA transfers by clearing RX FIFO

The BCM2835 SPI driver currently sets the SPI_CONTROLLER_MUST_RX flag.
When performing a TX-only transfer, this flag causes the SPI core to
allocate and DMA-map a dummy buffer into which the RX FIFO contents are
copied.  The dummy buffer is necessary because the chip is not capable
of disabling the receiver or automatically throwing away received data.
Not reading the RX FIFO isn't an option either since transmission is
halted once it's full.

Avoid the overhead induced by the dummy buffer by preallocating a
reusable DMA transaction which cyclically clears the RX FIFO.  The
transaction requires very little CPU time to submit and generates no
interrupts while running.  Specifics are provided in kerneldoc comments.

With a ks8851 Ethernet chip attached to the SPI controller, I am seeing
a 30 us reduction in ping time with this commit (1.819 ms vs. 1.849 ms,
average of 100,000 packets) as well as a 2% reduction in CPU time
(75:08 vs. 76:39 for transmission of 5 GByte over the SPI bus).

The commit uses the TX DMA interrupt to signal completion of a transfer.
This interrupt is raised once all bytes have been written to the
TX FIFO and it is then necessary to busy-wait for the TX FIFO to become
empty before the transfer can be finalized.  As an alternative approach,
I have explored using the SPI controller's DONE interrupt to detect
completion.  This interrupt is signaled when the TX FIFO becomes empty,
avoiding the need to busy-wait.  However latency deteriorates compared
to the present commit and surprisingly, CPU time is slightly higher as
well:

It turns out that in 45% of the cases, no busy-waiting is needed at all
and in 76% of the cases, less than 10 busy-wait iterations are
sufficient for the TX FIFO to drain.  This was measured on an RT kernel.
On a vanilla kernel, wakeup latency is worse and thus fewer iterations
are needed.  The measurements were made with an SPI clock of 20 MHz,
they may differ slightly for slower or faster clock speeds.

Previously we always used the RX DMA interrupt to signal completion of a
transfer.  Using the TX DMA interrupt now introduces a race condition:
TX DMA is always started before RX DMA so that bytes are already clocked
out while RX DMA is still being set up.  But if a TX-only transfer is
very short, then the TX DMA interrupt may occur before RX DMA is set up.
If the interrupt happens to occur on the same CPU, setup of RX DMA may
even be delayed until after the interrupt was handled.

I've solved this by having the TX DMA callback clear the RX FIFO while
busy-waiting for the TX FIFO to drain, thus avoiding a dependency on
setup of RX DMA.  Additionally, I am using a lock-free mechanism with
two flags, tx_dma_active and rx_dma_active plus memory barriers to
terminate RX DMA either by the TX DMA callback or immediately after
setting it up, whichever wins the race.  I've explored an alternative
approach which temporarily disables the TX DMA callback until RX DMA
has been set up (using tasklet_disable(), local_bh_disable() or
local_irq_save()), but the performance was minimally worse.

[Nathan Chancellor contributed a DMA mapping fixup for an early version
of this commit, hence his Signed-off-by.]

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Link: https://lore.kernel.org/r/874949385f28251e2dcaa9494e39a27b50e9f9e4.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

dmaengine: bcm2835: Avoid accessing memory when copying zeroes

The BCM2835 DMA controller is capable of synthesizing zeroes instead of
copying them from a source address. The feature is enabled by setting
the SRC_IGNORE bit in the Transfer Information field of a Control Block:

"Do not perform source reads.
 In addition, destination writes will zero all the write strobes.
 This is used for fast cache fill operations."
https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf

The feature is only available on 8 of the 16 channels. The others are
so-called "lite" channels with a limited feature set and performance.

Enable the feature if a cyclic transaction copies from the zero page.
This reduces traffic on the memory bus.

A forthcoming use case is the BCM2835 SPI driver, which will cyclically
copy from the zero page to the TX FIFO. The idea to use SRC_IGNORE was
taken from an ancient GitHub conversation between Martin and Noralf:
https://github.com/msperl/spi-bcm2835/issues/13#issuecomment-98180451

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Kauer <florian.kauer@koalo.de>
Link: https://lore.kernel.org/r/b2286c904408745192e4beb3de3c88f73e4a7210.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: Cache CS register value for ->prepare_message()

The BCM2835 SPI driver needs to set up the clock polarity in its
->prepare_message() hook before spi_transfer_one_message() asserts chip
select to avoid a gratuitous clock signal edge (cf. commit acace73df2c1
("spi: bcm2835: set up spi-mode before asserting cs-gpio")).

Precalculate the CS register value (which selects the clock polarity)
once in ->setup() and use that cached value in ->prepare_message() and
->transfer_one().  This avoids one MMIO read per message and one per
transfer, yielding a small latency improvement.  Additionally, a
forthcoming commit will use the precalculated value to derive the
register value for clearing the RX FIFO, which will eliminate the need
for an RX dummy buffer when performing TX-only DMA transfers.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Link: https://lore.kernel.org/r/d17c1d7fcdc97fffa961b8737cfd80eeb14f9416.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

dmaengine: bcm2835: Document struct bcm2835_dmadev

Document the BCM2835 DMA driver's device data structure so that upcoming
commits may add further members with proper kerneldoc.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Kauer <florian.kauer@koalo.de>
Link: https://lore.kernel.org/r/78648f80f67d97bb7beecc1b9be6b6e4a45bc1d8.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Guarantee cacheline alignment of driver-private data

__spi_alloc_controller() uses a single allocation to accommodate struct
spi_controller and the driver-private data, but places the latter behind
the former.  This order does not guarantee cacheline alignment of the
driver-private data.  (It does guarantee cacheline alignment of struct
spi_controller but the structure doesn't make any use of that property.)

Round up struct spi_controller to cacheline size.  A forthcoming commit
leverages this to grant DMA access to driver-private data of the BCM2835
SPI master.

An alternative, less economical approach would be to use two allocations.

A third approach consists of reversing the order to conserve memory.
But Mark Brown is concerned that it may result in a performance penalty
on architectures that don't like unaligned accesses.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/01625b9b26b93417fb09d2c15ad02dfe9cdbbbe5.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

dmaengine: bcm2835: Allow reusable descriptors

The DMA engine API requires DMA drivers to explicitly allow that
descriptors are prepared once and reused multiple times. Only a
single driver makes use of this functionality so far (pxa_dma.c,
to speed up pxa_camera.c).

We're about to add another use case for reusable descriptors in
the BCM2835 SPI driver, so allow that in the BCM2835 DMA driver.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Kauer <florian.kauer@koalo.de>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Link: https://lore.kernel.org/r/bfc98a38225bbec4158440ad06cb9eee675e3e6f.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

dmaengine: bcm2835: Allow cyclic transactions without interrupt

The BCM2835 DMA driver currently requests an interrupt from the
controller regardless whether or not the client has passed in the
DMA_PREP_INTERRUPT flag. This causes unnecessary overhead for cyclic
transactions which do not need an interrupt after each period.

We're about to add such a use case, namely cyclic clearing of the SPI
controller's RX FIFO, so amend the DMA driver to request an interrupt
only if DMA_PREP_INTERRUPT was passed in. Ignore the period_len for
such transactions and set it to the buffer length to make the driver's
calculations work.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Cc: Florian Kauer <florian.kauer@koalo.de>
Link: https://lore.kernel.org/r/73cf37be56eb4cbe6f696057c719f3a38cbaf26e.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: Drop dma_pending flag

The BCM2835 SPI driver uses a flag to keep track of whether a DMA
transfer is in progress.

The flag is used to avoid terminating DMA channels multiple times if a
transfer finishes orderly while simultaneously the SPI core invokes the
->handle_err() callback because the transfer took too long.  However
terminating DMA channels multiple times is perfectly fine, so the flag
is unnecessary for this particular purpose.

The flag is also used to avoid invoking bcm2835_spi_undo_prologue()
multiple times under this race condition.  However multiple *concurrent*
invocations can no longer happen since commit 2527704d8411 ("spi:
bcm2835: Synchronize with callback on DMA termination") because the
->handle_err() callback now uses the _sync() variant when terminating
DMA channels.

The only raison d'être of the flag is therefore that
bcm2835_spi_undo_prologue() cannot cope with multiple *sequential*
invocations.  Achieve that by setting tx_prologue to 0 at the end of
the function.  Subsequent invocations thus become no-ops.

With that, the dma_pending flag becomes unnecessary, so drop it.

Tested-by: Nuno Sá <nuno.sa@analog.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Link: https://lore.kernel.org/r/062b03b7f86af77a13ce0ec3b22e0bdbfcfba10d.1568187525.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi-gpio: Use PTR_ERR_OR_ZERO() in spi_gpio_request()

Simplify this function implementation by using a known function.

Generated by: scripts/coccinelle/api/ptr_ret.cocci

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/b2dd074a-1693-3aea-42b4-da1f5ec155c4@web.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Use an abbreviated pointer to ctlr->cur_msg in __spi_pump_messages

This helps a bit with line fitting now (the list_first_entry call) as
well as during the next patch which needs to iterate through all
transfers of ctlr->cur_msg so it timestamps them.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: npcm-fiu: remove set but not used variable 'retlen'

drivers/spi/spi-npcm-fiu.c: In function npcm_fiu_read:
drivers/spi/spi-npcm-fiu.c:472:9: warning:
 variable retlen set but not used [-Wunused-but-set-variable]

It is never used, so remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190905072436.23932-1-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-spi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-37-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: zynq-qspi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-36-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: zynqmp: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-35-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: xlp: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-34-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: uniphier: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-33-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: tegra: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-32-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sun6i: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-31-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sun4i: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-30-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: st-ssc4: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-29-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sirf: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-28-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sifive: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-27-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: s3c24xx: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-26-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: rb4xx: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-25-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-qcom-qspi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-24-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: pic32-sqi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-23-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: oc-tiny: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-22-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: nuc900: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-21-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: npcm: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-20-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mxs: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-19-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: mt7621: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-18-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-meson-spifc: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20190904135918.25352-17-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: meson-spicc: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20190904135918.25352-16-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: lp-8841: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-15-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-geni-qcom: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-14-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: dw-mmio: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-13-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: coldfire-qspi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-12-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: clps711x: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-11-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: octeon: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-10-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: cadence: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-9-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm63xx-hsspi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-8-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-7-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835aux: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-6-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-axi: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-5-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: ath79: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-4-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: a3700: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-3-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: altera: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-2-yuehaibing@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: npcm-fiu: fix spelling mistake "frequancy" -> "frequency"

There is a spelling mistake in a dev_warning message. Fix it. Also
break line to clear up checkpatch warning.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190903122812.3986-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix race condition in TCFQ/EOQ interrupt

When the driver is working in TCFQ/EOQ mode (i.e. interacts with the SPI
controller's FIFOs directly) the following sequence of operations
happens:

- The first byte of the tx buffer gets pushed to the TX FIFO (dspi->len
  gets decremented). This triggers the train of interrupts that handle
  the rest of the bytes.

- The dspi_interrupt handles a TX confirmation event. It reads the newly
  available byte from the RX FIFO, checks the dspi->len exit condition,
  and if there's more to be done, it kicks off the next interrupt in the
  train by writing the next byte to the TX FIFO.

Now the problem is that the wait queue is woken up one byte too early,
because dspi->len becomes 0 as soon as the byte has been pushed into the
TX FIFO. Its interrupt has not yet been processed and the RX byte has
not been put from the FIFO into the buffer.

Depending on the timing of the wait queue wakeup vs the handling of the
last dspi_interrupt, it can happen that the main SPI message pump thread
has already returned back into the spi_device driver. When the rx buffer
is on stack (which it can be, because in this mode, the DSPI doesn't do
DMA), the last interrupt will perform a memory write into an rx buffer
that has been freed. This manifests as stack corruption.

The solution is to only wake up the wait queue when dspi_rxtx says so,
i.e. after it has processed the last TX confirmation interrupt and
collected the last RX byte.

Fixes: c55be3059159 ("spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190903105708.32273-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: uniphier: introduce polling mode

Introduce new polling mode for short size transfer. Either the estimated
transfer time is estimated to exceed 200us, or polling loop actually exceeds
200us, it switches to irq mode.

Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Link: https://lore.kernel.org/r/1567488661-11428-4-git-send-email-hayashibara.keiji@socionext.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: uniphier: remove unnecessary code

This commit removed if() because priv->is_save_param is always true.

Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Link: https://lore.kernel.org/r/1567488661-11428-3-git-send-email-hayashibara.keiji@socionext.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: ep93xx: Repair SPI CS lookup tables

The actual device name of the SPI controller being registered on EP93xx is
"spi0" (as seen by gpiod_find_lookup_table()). This patch fixes all
relevant lookup tables and the following failure (seen on EDB9302):

ep93xx-spi ep93xx-spi.0: failed to register SPI master
ep93xx-spi: probe of ep93xx-spi.0 failed with error -22

Fixes: 1dfbf334f1236 ("spi: ep93xx: Convert to use CS GPIO descriptors")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Link: https://lore.kernel.org/r/20190831180402.10008-1-alexander.sverdlin@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm-qspi: Make BSPI default mode

The spi-nor controller defaults to BSPI mode, hence switch back
to its default mode after MSPI operations (write or erase)
are completed.

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kamal Dasu <kdasu.kdev@gmail.com>
Link: https://lore.kernel.org/r/1567139325-7912-1-git-send-email-rayagonda.kokatanur@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: npcm-fiu: add NPCM FIU controller driver

Add Nuvoton NPCM BMC Flash Interface Unit(FIU) SPI master
controller driver using SPI-MEM interface.

The FIU supports single, dual or quad communication interface.

the FIU controller can operate in following modes:
- User Mode Access(UMA): provides flash access by using an
  indirect address/data mechanism.
- direct rd/wr mode: maps the flash memory into the core
  address space.
- SPI-X mode: used for an expansion bus to an ASIC or CPLD.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20190828142513.228556-3-tmaimon77@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

dt-binding: spi: add NPCM FIU controller

Added device tree binding documentation for Nuvoton BMC
NPCM Flash Interface Unit(FIU) SPI master controller
using SPI-MEM interface.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20190828142513.228556-2-tmaimon77@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm2835: Convert to use CS GPIO descriptors

This converts the BCM2835 SPI master driver to use GPIO
descriptors for chip select handling.

The BCM2835 driver was relying on the core to drive the
CS high/low so very small changes were needed for this
part. If it managed to request the CS from the device tree
node, all is pretty straight forward.

However for native GPIOs this driver has a quite unorthodox
loopback to request some GPIOs from the SoC GPIO chip by
looking it up from the device tree using gpiochip_find()
and then offseting hard into its numberspace. This has
been augmented a bit by using gpiochip_request_own_desc()
but this code really needs to be verified. If "native CS"
is actually an SoC GPIO, why is it even done this way?
Should this GPIO not just be defined in the device tree
like any other CS GPIO? I'm confused.

Cc: Lukas Wunner <lukas@wunner.de>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Chris Boot <bootc@bootc.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190804003852.1312-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl: Convert to use CS GPIO descriptors

This converts the Freescale SPI master driver to use GPIO
descriptors for chip select handling.

The Freescale (fsl) driver has a lot of quirks to look up
"gpios" rather than "cs-gpios" from the device tree.
After the prior patch that will make gpiolib return the
GPIO descriptor for "gpios" in response to a request for
"cs-gpios", this code can be cut down quite a bit.

The driver has custom handling of chip select rather
than using the core (which may be possible but not
done in this patch) so it still needs to refer directly
to spi->cs_gpiod to set the chip select.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190804003539.985-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing

On platforms like LS1021A which use TCFQ mode, an interrupt needs to be
processed after each byte is TXed/RXed. I tried to make the DSPI
implementation on this SoC operate in other, more efficient modes (EOQ,
DMA) but it looks like it simply isn't possible.

Therefore allow the driver to operate in poll mode, to ease a bit of
this absurd amount of IRQ load generated in TCFQ mode. Doing so reduces
both the net time it takes to transmit a SPI message, as well as the
inter-frame jitter that occurs while doing so.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove impossible to reach error check

dspi->devtype_data is under the total control of the driver. Therefore,
a bad value is a driver bug and checking it at runtime (and during an
ISR, at that!) is pointless.

The second "else if" check is only for clarity (instead of a broader
"else") in case other transfer modes are added in the future. But the
printing is dead code and can be removed.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Exit the ISR with IRQ_NONE when it's not ours

The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.

Fixes: 13aed2392741 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Reduce indentation level in dspi_interrupt

If the entire function depends on the SPI status register having the
interrupt bits asserted, then just check it and exit early if those bits
aren't set (such as in the case of the shared IRQ being triggered for
the other peripheral). Cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Merge branch 'spi-5.3' into spi-5.4

spi: spi-fsl-dspi: Exit the ISR with IRQ_NONE when it's not ours

The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.

Fixes: 13aed2392741 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822212450.21420-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

spi: spi-fsl-qspi: Add ls2080a compatibility string to bindings

There are 2 version of QSPI-IP, according to which controller registers sets
can be big endian or little endian.There are some other minor changes like
RX fifo depth etc.

The big endian version uses driver compatible "fsl,ls1021a-qspi" and
little endian version uses driver compatible "fsl,ls2080a-qspi"

Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Signed-off-by: Ashish Kumar <ashish.kumar@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/1565691791-26167-1-git-send-email-Ashish.Kumar@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fsl-qspi: Enhance binding to extend example for flash entry

Add example for adding flash entry on various boards' dts
using flash manufacture spansion/cypress.

Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Link: https://lore.kernel.org/r/1565691791-26167-3-git-send-email-Ashish.Kumar@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Move dspi_interrupt above dspi_transfer_one_message

The two functions are loosely coupled through dspi->waitq, but
logically, dspi_transfer_one_message depends on dspi_interrupt in order
to complete. Move its definition above it so the I/O functions are
grouped closer together.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-13-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix typos

mask of -> mask off
at and -> and

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-12-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use reverse Christmas tree declaration order

This patch puts variable declaration in the reverse order of their
length for cosmetic purposes.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Replace legacy spi_master names with spi_controller

This adapts the spi-fsl-dspi driver to the API changes introduced in
commit 8caab75fd2c2 ("spi: Generalize SPI "master" to "controller"").

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove pointless assignment of master->transfer to NULL

Introduced in commit 9298bc727385 ("spi: spi-fsl-dspi: Remove
spi-bitbang") for less than obvious reasons, this assignment is
confusing and serves no purpose.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove unused initialization of 'ret' in dspi_probe

There is no code path for reaching 'return ret;' without it first being
assigned to an error code. Therefore the initialization with 0 is
pointless.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-8-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Reduce indentation in dspi_release_dma()

There is no point in surrounding an entire function block in an if
condition. Rather, exit early if the condition is false.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Change usage pattern of SPI_MCR_* and SPI_CTAR_* macros

These are macros that accept 0 or 1 as argument (a boolean value). Their
use encourages the abuse of complex ternary operations inside their
argument list, which detracts from the code readability. Replace these
with simple if-else statements.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Demistify magic value in SPI_SR_CLEAR

This patch adds the field definitions for the SPI_SR register. The SPI
status register is write-1-to-clear and this value is written at init
time.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Use BIT() and GENMASK() macros

Switch to using more idiomatic register field definitions, which makes
it easier to look them up in the datasheet. Cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Remove unused defines and includes

This is a cosmetic patch.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-fsl-dspi: Fix code alignment

This is a cosmetic patch that changes nothing except makes sure the code
is aligned to the same column, which makes it easier to the eye.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Fix the number of CS lines documented as an example

The number of CS lines is mentioned as 2 in the spi-controller binding
but however in the example, 4 cs-gpios are used. Hence fix that to
mention 4.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20190820115000.32041-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: zynq-qspi: Fix missing spi_unregister_controller when unload module

Use devm_spi_register_controller to fix missing spi_unregister_controller
when unload module.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20190818095113.2397-1-axel.lin@ingics.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: dw-pci: Add support for Intel Elkhart Lake PSE SPI

Add support for Intel(R) Programmable Services Engine (Intel(R) PSE) SPI
controller in Intel Elkhart Lake when interface is assigned to the host
processor.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20190812101344.3975-1-jarkko.nikula@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Rename of_spi_register_master() function

Rename this function to of_spi_get_gpio_numbers() as this
is what the function does, it does not register a master,
it is called in the path of registering a master so the
name is logical in a convoluted way, but it is better to
follow Rusty Russell's ABI level no 7:
"The obvious use is (probably) the correct one"

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190808150321.23319-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: sh-msiof: Use devm_platform_ioremap_resource() helper

Use the devm_platform_ioremap_resource() helper instead of open-coding
the same operation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190807085213.24666-1-geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: bcm-qspi: Fix BSPI QUAD and DUAL mode support when using flex mode

Fix data transfer width settings based on DT field 'spi-rx-bus-width'
to configure BSPI in single, dual or quad mode by using data width
and not the command width.

Fixes: 5f195ee7d830c ("spi: bcm-qspi: Implement the spi_mem interface")

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Link: https://lore.kernel.org/r/1565086070-28451-1-git-send-email-rayagonda.kokatanur@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: atmel: add tracing to custom .transfer_one_message callback

Driver specific implementations for .transfer_one_message need to call
the tracing stuff themself. This is necessary to make spi tracing
actually useful.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20190801204710.27309-1-uwe@kleine-koenig.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-42-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Reduce kthread priority

The SPI thingies request FIFO-99 by default, reduce this to FIFO-50.

FIFO-99 is the very highest priority available to SCHED_FIFO and
it not a suitable default; it would indicate the SPI work is the
most important work on the machine.

Cc: Benson Leung <bleung@chromium.org>
Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20190801111541.917256884@infradead.org
Signed-off-by: Mark Brown <broonie@kernel.org>