drm/amdgpu: add helper function for indirect reg access (v3)

Add helper function in order to remove RREG32/WREG32
in current pcie_rreg/wreg function for soc15 and
onwards adapters.
PCIE_INDEX/DATA pairs are used to access regsiters
outside of mmio bar in the helper functions.
The new helper functions help remove the recursion
of amdgpu_mm_rreg/wreg from pcie_rreg/wreg and
provide the oppotunity to centralize direct and
indirect access in a single function.

v2: Fixed typo and refine the comments

v3: Remove unnecessary volatile local variable

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 142 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index befef3b60547..bc921c83aad7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1032,6 +1032,19 @@ uint8_t amdgpu_mm_rreg8(struct amdgpu_device *adev, uint32_t offset);
 u32 amdgpu_io_rreg(struct amdgpu_device *adev, u32 reg);
 void amdgpu_io_wreg(struct amdgpu_device *adev, u32 reg, u32 v);
 
+u32 amdgpu_device_indirect_rreg(struct amdgpu_device *adev,
+				u32 pcie_index, u32 pcie_data,
+				u32 reg_addr);
+u64 amdgpu_device_indirect_rreg64(struct amdgpu_device *adev,
+				  u32 pcie_index, u32 pcie_data,
+				  u32 reg_addr);
+void amdgpu_device_indirect_wreg(struct amdgpu_device *adev,
+				 u32 pcie_index, u32 pcie_data,
+				 u32 reg_addr, u32 reg_data);
+void amdgpu_device_indirect_wreg64(struct amdgpu_device *adev,
+				   u32 pcie_index, u32 pcie_data,
+				   u32 reg_addr, u64 reg_data);
+
 bool amdgpu_device_asic_has_dc_support(enum amd_asic_type asic_type);
 bool amdgpu_device_has_dc_support(struct amdgpu_device *adev);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 76581c59f196..83aeacaf94d5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -593,6 +593,135 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v)
 }
 
 /**
+ * amdgpu_device_indirect_rreg - read an indirect register
+ *
+ * @adev: amdgpu_device pointer
+ * @pcie_index: mmio register offset
+ * @pcie_data: mmio register offset
+ *
+ * Returns the value of indirect register @reg_addr
+ */
+u32 amdgpu_device_indirect_rreg(struct amdgpu_device *adev,
+				u32 pcie_index, u32 pcie_data,
+				u32 reg_addr)
+{
+	unsigned long flags;
+	u32 r;
+	void __iomem *pcie_index_offset;
+	void __iomem *pcie_data_offset;
+
+	spin_lock_irqsave(&adev->pcie_idx_lock, flags);
+	pcie_index_offset = (void __iomem *)adev->rmmio + pcie_index * 4;
+	pcie_data_offset = (void __iomem *)adev->rmmio + pcie_data * 4;
+
+	writel(reg_addr, pcie_index_offset);
+	readl(pcie_index_offset);
+	r = readl(pcie_data_offset);
+	spin_unlock_irqrestore(&adev->pcie_idx_lock, flags);
+
+	return r;
+}
+
+/**
+ * amdgpu_device_indirect_rreg64 - read a 64bits indirect register
+ *
+ * @adev: amdgpu_device pointer
+ * @pcie_index: mmio register offset
+ * @pcie_data: mmio register offset
+ *
+ * Returns the value of indirect register @reg_addr
+ */
+u64 amdgpu_device_indirect_rreg64(struct amdgpu_device *adev,
+				  u32 pcie_index, u32 pcie_data,
+				  u32 reg_addr)
+{
+	unsigned long flags;
+	u64 r;
+	void __iomem *pcie_index_offset;
+	void __iomem *pcie_data_offset;
+
+	spin_lock_irqsave(&adev->pcie_idx_lock, flags);
+	pcie_index_offset = (void __iomem *)adev->rmmio + pcie_index * 4;
+	pcie_data_offset = (void __iomem *)adev->rmmio + pcie_data * 4;
+
+	/* read low 32 bits */
+	writel(reg_addr, pcie_index_offset);
+	readl(pcie_index_offset);
+	r = readl(pcie_data_offset);
+	/* read high 32 bits */
+	writel(reg_addr + 4, pcie_index_offset);
+	readl(pcie_index_offset);
+	r |= ((u64)readl(pcie_data_offset) << 32);
+	spin_unlock_irqrestore(&adev->pcie_idx_lock, flags);
+
+	return r;
+}
+
+/**
+ * amdgpu_device_indirect_wreg - write an indirect register address
+ *
+ * @adev: amdgpu_device pointer
+ * @pcie_index: mmio register offset
+ * @pcie_data: mmio register offset
+ * @reg_addr: indirect register offset
+ * @reg_data: indirect register data
+ *
+ */
+void amdgpu_device_indirect_wreg(struct amdgpu_device *adev,
+				 u32 pcie_index, u32 pcie_data,
+				 u32 reg_addr, u32 reg_data)
+{
+	unsigned long flags;
+	void __iomem *pcie_index_offset;
+	void __iomem *pcie_data_offset;
+
+	spin_lock_irqsave(&adev->pcie_idx_lock, flags);
+	pcie_index_offset = (void __iomem *)adev->rmmio + pcie_index * 4;
+	pcie_data_offset = (void __iomem *)adev->rmmio + pcie_data * 4;
+
+	writel(reg_addr, pcie_index_offset);
+	readl(pcie_index_offset);
+	writel(reg_data, pcie_data_offset);
+	readl(pcie_data_offset);
+	spin_unlock_irqrestore(&adev->pcie_idx_lock, flags);
+}
+
+/**
+ * amdgpu_device_indirect_wreg64 - write a 64bits indirect register address
+ *
+ * @adev: amdgpu_device pointer
+ * @pcie_index: mmio register offset
+ * @pcie_data: mmio register offset
+ * @reg_addr: indirect register offset
+ * @reg_data: indirect register data
+ *
+ */
+void amdgpu_device_indirect_wreg64(struct amdgpu_device *adev,
+				   u32 pcie_index, u32 pcie_data,
+				   u32 reg_addr, u64 reg_data)
+{
+	unsigned long flags;
+	void __iomem *pcie_index_offset;
+	void __iomem *pcie_data_offset;
+
+	spin_lock_irqsave(&adev->pcie_idx_lock, flags);
+	pcie_index_offset = (void __iomem *)adev->rmmio + pcie_index * 4;
+	pcie_data_offset = (void __iomem *)adev->rmmio + pcie_data * 4;
+
+	/* write low 32 bits */
+	writel(reg_addr, pcie_index_offset);
+	readl(pcie_index_offset);
+	writel((u32)(reg_data & 0xffffffffULL), pcie_data_offset);
+	readl(pcie_data_offset);
+	/* write high 32 bits */
+	writel(reg_addr + 4, pcie_index_offset);
+	readl(pcie_index_offset);
+	writel((u32)(reg_data >> 32), pcie_data_offset);
+	readl(pcie_data_offset);
+	spin_unlock_irqrestore(&adev->pcie_idx_lock, flags);
+}
+
+/**
  * amdgpu_invalid_rreg - dummy reg read function
  *
  * @adev: amdgpu device pointer