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Subject[PATCH v2 2/3] drm/panfrost: add amlogic reset quirk callback
Date
The T820, G31 & G52 GPUs integratewd by Amlogic in the respective GXM, G12A/SM1 & G12B
SoCs needs a quirk in the PWR registers at the GPU reset time.

Since the Amlogic's integration of the GPU cores with the SoC is not
publicly documented we do not know what does these
values, but they permit having a fully functional GPU running with Panfrost.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
drivers/gpu/drm/panfrost/panfrost_gpu.c | 11 +++++++++++
drivers/gpu/drm/panfrost/panfrost_gpu.h | 2 ++
drivers/gpu/drm/panfrost/panfrost_regs.h | 4 ++++
3 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index a6de78bc1fa8..e1b2a3376624 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -76,6 +76,17 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev)
return 0;
}

+void panfrost_gpu_amlogic_quirk(struct panfrost_device *pfdev)
+{
+ /*
+ * The Amlogic integrated Mali-T820, Mali-G31 & Mali-G52 needs
+ * these undocumented bits in GPU_PWR_OVERRIDE1 to be set in order
+ * to operate correctly.
+ */
+ gpu_write(pfdev, GPU_PWR_KEY, GPU_PWR_KEY_UNLOCK);
+ gpu_write(pfdev, GPU_PWR_OVERRIDE1, 0xfff | (0x20 << 16));
+}
+
static void panfrost_gpu_init_quirks(struct panfrost_device *pfdev)
{
u32 quirks = 0;
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.h b/drivers/gpu/drm/panfrost/panfrost_gpu.h
index 4112412087b2..468c51e7e46d 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.h
@@ -16,4 +16,6 @@ int panfrost_gpu_soft_reset(struct panfrost_device *pfdev);
void panfrost_gpu_power_on(struct panfrost_device *pfdev);
void panfrost_gpu_power_off(struct panfrost_device *pfdev);

+void panfrost_gpu_amlogic_quirk(struct panfrost_device *pfdev);
+
#endif
diff --git a/drivers/gpu/drm/panfrost/panfrost_regs.h b/drivers/gpu/drm/panfrost/panfrost_regs.h
index ea38ac60581c..eddaa62ad8b0 100644
--- a/drivers/gpu/drm/panfrost/panfrost_regs.h
+++ b/drivers/gpu/drm/panfrost/panfrost_regs.h
@@ -51,6 +51,10 @@
#define GPU_STATUS 0x34
#define GPU_STATUS_PRFCNT_ACTIVE BIT(2)
#define GPU_LATEST_FLUSH_ID 0x38
+#define GPU_PWR_KEY 0x50 /* (WO) Power manager key register */
+#define GPU_PWR_KEY_UNLOCK 0x2968A819
+#define GPU_PWR_OVERRIDE0 0x54 /* (RW) Power manager override settings */
+#define GPU_PWR_OVERRIDE1 0x58 /* (RW) Power manager override settings */
#define GPU_FAULT_STATUS 0x3C
#define GPU_FAULT_ADDRESS_LO 0x40
#define GPU_FAULT_ADDRESS_HI 0x44
--
2.22.0
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