[PATCH 2/8] drm/amdgpu: add a generic fb accessing helper function

[Alex Deucher]

From: "Tianci.Yin" <tianci.yin at amd.com>

add a generic helper function for accessing framebuffer via MMIO

Change-Id: I4baa0aa53c93a94c2eff98c6211a61f369239982
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Tianci.Yin <tianci.yin at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h           |  2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    | 42 +++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 13 +-----
 3 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 17ccb9015141..0d60c2e6c592 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -985,6 +985,8 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 void amdgpu_device_fini(struct amdgpu_device *adev);
 int amdgpu_gpu_wait_for_idle(struct amdgpu_device *adev);
 
+int amdgpu_device_vram_access(struct amdgpu_device *adev, loff_t pos,
+		       uint32_t *buf, size_t size, bool write);
 uint32_t amdgpu_mm_rreg(struct amdgpu_device *adev, uint32_t reg,
 			uint32_t acc_flags);
 void amdgpu_mm_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index f25275abf408..53ce227f759c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -153,6 +153,48 @@ bool amdgpu_device_is_px(struct drm_device *dev)
 	return false;
 }
 
+/**
+ * VRAM access helper functions.
+ *
+ * amdgpu_device_vram_access - read/write a buffer in vram
+ *
+ * @adev: amdgpu_device pointer
+ * @pos: offset of the buffer in vram
+ * @buf: virtual address of the buffer in system memory
+ * @size: read/write size, sizeof(@buf) must > @size
+ * @write: true - write to vram, otherwise - read from vram
+ *
+ * Returns 0 on success or an -error on failure.
+ */
+int amdgpu_device_vram_access(struct amdgpu_device *adev, loff_t pos,
+		       uint32_t *buf, size_t size, bool write)
+{
+	uint64_t end = pos + size;
+	unsigned long flags;
+
+	if (IS_ERR_OR_NULL(buf) ||
+	    (adev->gmc.mc_vram_size > 0 &&
+	     end > adev->gmc.mc_vram_size)) {
+		DRM_ERROR("parameter error! pos:%llx, buf:%llx, size:%zx.\n",
+			  pos, (u64)buf, size);
+		return -EINVAL;
+	}
+
+	while (pos < end) {
+		spin_lock_irqsave(&adev->mmio_idx_lock, flags);
+		WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)pos) | 0x80000000);
+		WREG32_NO_KIQ(mmMM_INDEX_HI, pos >> 31);
+		if (write)
+			WREG32_NO_KIQ(mmMM_DATA, *buf++);
+		else
+			*buf++ = RREG32_NO_KIQ(mmMM_DATA);
+		spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
+		pos += 4;
+	}
+
+	return 0;
+}
+
 /*
  * MMIO register access helper functions.
  */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index db2dab3a6dff..324c2d605f54 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -134,21 +134,10 @@ static int hw_id_map[MAX_HWIP] = {
 
 static int amdgpu_discovery_read_binary(struct amdgpu_device *adev, uint8_t *binary)
 {
-	uint32_t *p = (uint32_t *)binary;
 	uint64_t vram_size = (uint64_t)RREG32(mmRCC_CONFIG_MEMSIZE) << 20;
 	uint64_t pos = vram_size - BINARY_MAX_SIZE;
-	unsigned long flags;
-
-	while (pos < vram_size) {
-		spin_lock_irqsave(&adev->mmio_idx_lock, flags);
-		WREG32_NO_KIQ(mmMM_INDEX, ((uint32_t)pos) | 0x80000000);
-		WREG32_NO_KIQ(mmMM_INDEX_HI, pos >> 31);
-		*p++ = RREG32_NO_KIQ(mmMM_DATA);
-		spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
-		pos += 4;
-	}
 
-	return 0;
+	return amdgpu_device_vram_access(adev, pos, (uint32_t *)binary, BINARY_MAX_SIZE, false);
 }
 
 static uint16_t amdgpu_discovery_calculate_checksum(uint8_t *data, uint32_t size)
-- 
2.20.1