clocksource/drivers/spreadtrum: Add timer driver for the Spreadtrum SC9860 platform

The Spreadtrum SC9860 platform will use the architected timers as local
clock events, but we also need a broadcast timer device to wake up the
CPUs when the CPUs are in sleep mode.

The Spreadtrum timer can support 32-bit or 64-bit counters, as well as
supporting period mode or one-shot mode.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-8-git-send-email-daniel.lezcano@linaro.org
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index c729a88..0359812 100644 (file)
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -441,6 +441,13 @@ config MTK_TIMER
        help
          Support for Mediatek timer driver.
 
+config SPRD_TIMER
+       bool "Spreadtrum timer driver" if COMPILE_TEST
+       depends on HAS_IOMEM
+       select TIMER_OF
+       help
+         Enables support for the Spreadtrum timer driver.
+
 config SYS_SUPPORTS_SH_MTU2
         bool
 

diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 72711f1..d6dec44 100644 (file)
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_CLKSRC_TI_32K)   += timer-ti-32k.o
 obj-$(CONFIG_CLKSRC_NPS)       += timer-nps.o
 obj-$(CONFIG_OXNAS_RPS_TIMER)  += timer-oxnas-rps.o
 obj-$(CONFIG_OWL_TIMER)                += owl-timer.o
+obj-$(CONFIG_SPRD_TIMER)       += timer-sprd.o
 
 obj-$(CONFIG_ARC_TIMERS)               += arc_timer.o
 obj-$(CONFIG_ARM_ARCH_TIMER)           += arm_arch_timer.o

diff --git a/drivers/clocksource/timer-sprd.c b/drivers/clocksource/timer-sprd.c
new file mode 100644 (file)
index 0000000..ef9ebea
--- /dev/null
+++ b/drivers/clocksource/timer-sprd.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+
+#include "timer-of.h"
+
+#define TIMER_NAME             "sprd_timer"
+
+#define TIMER_LOAD_LO          0x0
+#define TIMER_LOAD_HI          0x4
+#define TIMER_VALUE_LO         0x8
+#define TIMER_VALUE_HI         0xc
+
+#define TIMER_CTL              0x10
+#define TIMER_CTL_PERIOD_MODE  BIT(0)
+#define TIMER_CTL_ENABLE       BIT(1)
+#define TIMER_CTL_64BIT_WIDTH  BIT(16)
+
+#define TIMER_INT              0x14
+#define TIMER_INT_EN           BIT(0)
+#define TIMER_INT_RAW_STS      BIT(1)
+#define TIMER_INT_MASK_STS     BIT(2)
+#define TIMER_INT_CLR          BIT(3)
+
+#define TIMER_VALUE_SHDW_LO    0x18
+#define TIMER_VALUE_SHDW_HI    0x1c
+
+#define TIMER_VALUE_LO_MASK    GENMASK(31, 0)
+
+static void sprd_timer_enable(void __iomem *base, u32 flag)
+{
+       u32 val = readl_relaxed(base + TIMER_CTL);
+
+       val |= TIMER_CTL_ENABLE;
+       if (flag & TIMER_CTL_64BIT_WIDTH)
+               val |= TIMER_CTL_64BIT_WIDTH;
+       else
+               val &= ~TIMER_CTL_64BIT_WIDTH;
+
+       if (flag & TIMER_CTL_PERIOD_MODE)
+               val |= TIMER_CTL_PERIOD_MODE;
+       else
+               val &= ~TIMER_CTL_PERIOD_MODE;
+
+       writel_relaxed(val, base + TIMER_CTL);
+}
+
+static void sprd_timer_disable(void __iomem *base)
+{
+       u32 val = readl_relaxed(base + TIMER_CTL);
+
+       val &= ~TIMER_CTL_ENABLE;
+       writel_relaxed(val, base + TIMER_CTL);
+}
+
+static void sprd_timer_update_counter(void __iomem *base, unsigned long cycles)
+{
+       writel_relaxed(cycles & TIMER_VALUE_LO_MASK, base + TIMER_LOAD_LO);
+       writel_relaxed(0, base + TIMER_LOAD_HI);
+}
+
+static void sprd_timer_enable_interrupt(void __iomem *base)
+{
+       writel_relaxed(TIMER_INT_EN, base + TIMER_INT);
+}
+
+static void sprd_timer_clear_interrupt(void __iomem *base)
+{
+       u32 val = readl_relaxed(base + TIMER_INT);
+
+       val |= TIMER_INT_CLR;
+       writel_relaxed(val, base + TIMER_INT);
+}
+
+static int sprd_timer_set_next_event(unsigned long cycles,
+                                    struct clock_event_device *ce)
+{
+       struct timer_of *to = to_timer_of(ce);
+
+       sprd_timer_disable(timer_of_base(to));
+       sprd_timer_update_counter(timer_of_base(to), cycles);
+       sprd_timer_enable(timer_of_base(to), 0);
+
+       return 0;
+}
+
+static int sprd_timer_set_periodic(struct clock_event_device *ce)
+{
+       struct timer_of *to = to_timer_of(ce);
+
+       sprd_timer_disable(timer_of_base(to));
+       sprd_timer_update_counter(timer_of_base(to), timer_of_period(to));
+       sprd_timer_enable(timer_of_base(to), TIMER_CTL_PERIOD_MODE);
+
+       return 0;
+}
+
+static int sprd_timer_shutdown(struct clock_event_device *ce)
+{
+       struct timer_of *to = to_timer_of(ce);
+
+       sprd_timer_disable(timer_of_base(to));
+       return 0;
+}
+
+static irqreturn_t sprd_timer_interrupt(int irq, void *dev_id)
+{
+       struct clock_event_device *ce = (struct clock_event_device *)dev_id;
+       struct timer_of *to = to_timer_of(ce);
+
+       sprd_timer_clear_interrupt(timer_of_base(to));
+
+       if (clockevent_state_oneshot(ce))
+               sprd_timer_disable(timer_of_base(to));
+
+       ce->event_handler(ce);
+       return IRQ_HANDLED;
+}
+
+static struct timer_of to = {
+       .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
+
+       .clkevt = {
+               .name = TIMER_NAME,
+               .rating = 300,
+               .features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
+                       CLOCK_EVT_FEAT_ONESHOT,
+               .set_state_shutdown = sprd_timer_shutdown,
+               .set_state_periodic = sprd_timer_set_periodic,
+               .set_next_event = sprd_timer_set_next_event,
+               .cpumask = cpu_possible_mask,
+       },
+
+       .of_irq = {
+               .handler = sprd_timer_interrupt,
+               .flags = IRQF_TIMER | IRQF_IRQPOLL,
+       },
+};
+
+static int __init sprd_timer_init(struct device_node *np)
+{
+       int ret;
+
+       ret = timer_of_init(np, &to);
+       if (ret)
+               return ret;
+
+       sprd_timer_enable_interrupt(timer_of_base(&to));
+       clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
+                                       1, UINT_MAX);
+
+       return 0;
+}
+
+TIMER_OF_DECLARE(sc9860_timer, "sprd,sc9860-timer", sprd_timer_init);