ARC: [axs10x] Specify reserved memory for frame buffer

Allocation of a frame buffer memory in a special memory region
allows bypassing of so-called IO Coherency aperture
which is typically set as a range 0x8z-0xAz.

I.e. all data traffic to PGU bypasses IO Coherency block
and saves its bandwidth for other peripherals.

Even though for AXS101 (which sorts ARC770 CPU) IOC is not
an option for a sake of keeping one DT description for the
base-board (axs10x_mb.dtsi) we're still defining reserved
memory location in the very end of DDR.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Cc: devicetree@vger.kernel.org

diff --git a/arch/arc/boot/dts/axc001.dtsi b/arch/arc/boot/dts/axc001.dtsi
index 420dcfd..262496a 100644 (file)
--- a/arch/arc/boot/dts/axc001.dtsi
+++ b/arch/arc/boot/dts/axc001.dtsi
@@ -93,8 +93,26 @@
        memory {
                #address-cells = <1>;
                #size-cells = <1>;
-               ranges = <0x00000000 0x80000000 0x40000000>;
+               ranges = <0x00000000 0x80000000 0x20000000>;
                device_type = "memory";
-               reg = <0x80000000 0x20000000>;  /* 512MiB */
+               reg = <0x80000000 0x1b000000>;  /* (512 - 32) MiB */
+       };
+
+       reserved-memory {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+               /*
+                * We just move frame buffer area to the very end of
+                * available DDR. And even though in case of ARC770 there's
+                * no strict requirement for a frame-buffer to be in any
+                * particular location it allows us to use the same
+                * base board's DT node for ARC PGU as for ARc HS38.
+                */
+               frame_buffer: frame_buffer@9e000000 {
+                       compatible = "shared-dma-pool";
+                       reg = <0x9e000000 0x2000000>;
+                       no-map;
+               };
        };
 };

diff --git a/arch/arc/boot/dts/axc003.dtsi b/arch/arc/boot/dts/axc003.dtsi
index f90fadf..35ece04 100644 (file)
--- a/arch/arc/boot/dts/axc003.dtsi
+++ b/arch/arc/boot/dts/axc003.dtsi
@@ -100,4 +100,18 @@
                device_type = "memory";
                reg = <0x80000000 0x20000000>;  /* 512MiB */
        };
+
+       reserved-memory {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+               /*
+                * Move frame buffer out of IOC aperture (0x8z-0xAz).
+                */
+               frame_buffer: frame_buffer@be000000 {
+                       compatible = "shared-dma-pool";
+                       reg = <0xbe000000 0x2000000>;
+                       no-map;
+               };
+       };
 };

diff --git a/arch/arc/boot/dts/axc003_idu.dtsi b/arch/arc/boot/dts/axc003_idu.dtsi
index 06a9f29..df9ddb6 100644 (file)
--- a/arch/arc/boot/dts/axc003_idu.dtsi
+++ b/arch/arc/boot/dts/axc003_idu.dtsi
@@ -123,4 +123,18 @@
                device_type = "memory";
                reg = <0x80000000 0x20000000>;  /* 512MiB */
        };
+
+       reserved-memory {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               ranges;
+               /*
+                * Move frame buffer out of IOC aperture (0x8z-0xAz).
+                */
+               frame_buffer: frame_buffer@be000000 {
+                       compatible = "shared-dma-pool";
+                       reg = <0xbe000000 0x2000000>;
+                       no-map;
+               };
+       };
 };

diff --git a/arch/arc/boot/dts/axs10x_mb.dtsi b/arch/arc/boot/dts/axs10x_mb.dtsi
index 823f15c..64b063d 100644 (file)
--- a/arch/arc/boot/dts/axs10x_mb.dtsi
+++ b/arch/arc/boot/dts/axs10x_mb.dtsi
@@ -283,7 +283,7 @@
                        encoder-slave = <&adv7511>;
                        clocks = <&pguclk>;
                        clock-names = "pxlclk";
-
+                       memory-region = <&frame_buffer>;
                        port {
                                pgu_output: endpoint {
                                        remote-endpoint = <&adv7511_input>;