drm/msm/a2xx: support loading legacy (iMX) firmware

Support loading A200 firmware generated from the iMX firmware header
files. The firmware lacks protection support, however it allows GPU to
function properly while using the firmware files with clear license
which allows redistribution.

Cc: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/516443/
Link: https://lore.kernel.org/r/20230101155753.779176-1-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/a2xx_gpu.c

@@ -53,6 +53,8 @@ static void a2xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 
 static bool a2xx_me_init(struct msm_gpu *gpu)
 {
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a2xx_gpu *a2xx_gpu = to_a2xx_gpu(adreno_gpu);
 	struct msm_ringbuffer *ring = gpu->rb[0];
 
 	OUT_PKT3(ring, CP_ME_INIT, 18);
@@ -84,15 +86,20 @@ static bool a2xx_me_init(struct msm_gpu *gpu)
 	/* NQ and External Memory Swap */
 	OUT_RING(ring, 0x00000000);
 	/* protected mode error checking (0x1f2 is REG_AXXX_CP_INT_CNTL) */
-	OUT_RING(ring, 0x200001f2);
+	if (a2xx_gpu->protection_disabled)
+		OUT_RING(ring, 0x00000000);
+	else
+		OUT_RING(ring, 0x200001f2);
 	/* Disable header dumping and Header dump address */
 	OUT_RING(ring, 0x00000000);
 	/* Header dump size */
 	OUT_RING(ring, 0x00000000);
 
-	/* enable protected mode */
-	OUT_PKT3(ring, CP_SET_PROTECTED_MODE, 1);
-	OUT_RING(ring, 1);
+	if (!a2xx_gpu->protection_disabled) {
+		/* enable protected mode */
+		OUT_PKT3(ring, CP_SET_PROTECTED_MODE, 1);
+		OUT_RING(ring, 1);
+	}
 
 	adreno_flush(gpu, ring, REG_AXXX_CP_RB_WPTR);
 	return a2xx_idle(gpu);
@@ -101,6 +108,7 @@ static bool a2xx_me_init(struct msm_gpu *gpu)
 static int a2xx_hw_init(struct msm_gpu *gpu)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a2xx_gpu *a2xx_gpu = to_a2xx_gpu(adreno_gpu);
 	dma_addr_t pt_base, tran_error;
 	uint32_t *ptr, len;
 	int i, ret;
@@ -221,6 +229,17 @@ static int a2xx_hw_init(struct msm_gpu *gpu)
 	len = adreno_gpu->fw[ADRENO_FW_PM4]->size / 4;
 	DBG("loading PM4 ucode version: %x", ptr[1]);
 
+	/*
+	 * New firmware files seem to have GPU and firmware version in this
+	 * word (0x20xxxx for A200, 0x220xxx for A220, 0x225xxx for A225).
+	 * Older firmware files, which lack protection support, have 0 instead.
+	 */
+	if (ptr[1] == 0) {
+		dev_warn(gpu->dev->dev,
+			 "Legacy firmware detected, disabling protection support\n");
+		a2xx_gpu->protection_disabled = true;
+	}
+
 	gpu_write(gpu, REG_AXXX_CP_DEBUG,
 			AXXX_CP_DEBUG_MIU_128BIT_WRITE_ENABLE);
 	gpu_write(gpu, REG_AXXX_CP_ME_RAM_WADDR, 0);

drivers/gpu/drm/msm/adreno/a2xx_gpu.h

@@ -15,6 +15,7 @@
 struct a2xx_gpu {
 	struct adreno_gpu base;
 	bool pm_enabled;
+	bool protection_disabled;
 };
 #define to_a2xx_gpu(x) container_of(x, struct a2xx_gpu, base)