drm/amdgpu: fetch the A+A VF VBIOS from the SRAT HBM range

On A+A the VF has no usable FB BAR, so the VBIOS copy cannot be read
through BAR 0. It lives in HBM, which the SRAT describes as
specific-purpose memory reachable at a system physical address.

Add a dedicated amdgpu_read_bios_from_spm() path that resolves the HBM
range from SRAT and maps it as write-back system memory. Keep the
existing SR-IOV dynamic critical region path when it is enabled,
matching the VRAM reader.

v2:
- Use a separate amdgpu_read_bios_from_spm() helper and leave
  amdgpu_read_bios_from_vram() unchanged.
- Keep the SR-IOV dynamic critical region path for SPM-backed VBIOS.
- Fetch VBIOS after the COMMON block and make it optional for
  SPM-backed SR-IOV VF and passthrough configurations.

v3:
- Keep the SRAT range local to the VBIOS path; GMC owns aper_base and
  aper_size.
- Map SPM with memremap(), memcpy(), and memunmap().
- Rely on amdgpu_virt_vram_is_spm() without redundant VF/passthrough
  checks.

Signed-off-by: Zhigang Luo <zhigang.luo@amd.com>
Signed-off-by: Fangsheng Huang <Fangsheng.Huang@amd.com>
Signed-off-by: YuBiao Wang <YuBiao.Wang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 58 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index 08ed1eb69558..f9315e0472fe 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -152,6 +152,56 @@ static bool amdgpu_read_bios_from_vram(struct amdgpu_device *adev)
 	return true;
 }
 
+static bool amdgpu_read_bios_from_spm(struct amdgpu_device *adev)
+{
+	u64 spm_base, spm_size;
+	void *bios = NULL;
+	u32 size = 256U * 1024U; /* ??? */
+	int r;
+
+	if (!amdgpu_virt_vram_is_spm(adev))
+		return false;
+
+	r = amdgpu_acpi_find_gpu_memory_in_srat(adev, &spm_base, &spm_size);
+	if (r)
+		return false;
+
+	adev->bios = kmalloc(size, GFP_KERNEL);
+	if (!adev->bios)
+		return false;
+
+	/* For SRIOV with dynamic critical region is enabled,
+	 * the vbios image is put at a dynamic offset of VRAM in the VF.
+	 * If dynamic critical region is disabled, read it from SPM.
+	 */
+	if (amdgpu_sriov_vf(adev) && adev->virt.is_dynamic_crit_regn_enabled) {
+		if (amdgpu_virt_get_dynamic_data_info(adev,
+						      AMD_SRIOV_MSG_VBIOS_IMG_TABLE_ID,
+						      adev->bios, &size)) {
+			amdgpu_bios_release(adev);
+			return false;
+		}
+	} else {
+		bios = memremap(spm_base, size, MEMREMAP_WB);
+		if (!bios) {
+			amdgpu_bios_release(adev);
+			return false;
+		}
+
+		memcpy(adev->bios, bios, size);
+		memunmap(bios);
+	}
+
+	adev->bios_size = size;
+
+	if (!check_atom_bios(adev, size)) {
+		amdgpu_bios_release(adev);
+		return false;
+	}
+
+	return true;
+}
+
 bool amdgpu_read_bios(struct amdgpu_device *adev)
 {
 	uint8_t __iomem *bios;
@@ -530,6 +580,11 @@ static bool amdgpu_get_bios_dgpu(struct amdgpu_device *adev)
 		goto success;
 	}
 
+	if (amdgpu_read_bios_from_spm(adev)) {
+		dev_info(adev->dev, "Fetched VBIOS from SPM\n");
+		goto success;
+	}
+
 	/* this is required for SR-IOV */
 	if (amdgpu_read_bios_from_vram(adev)) {
 		dev_info(adev->dev, "Fetched VBIOS from VRAM BAR\n");
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index e7b0b2e1cd73..2daea1980c28 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -949,6 +949,9 @@ u32 amdgpu_device_get_rev_id(struct amdgpu_device *adev)
 
 static uint32_t amdgpu_device_get_vbios_flags(struct amdgpu_device *adev)
 {
+	if (amdgpu_virt_vram_is_spm(adev))
+		return AMDGPU_VBIOS_OPTIONAL;
+
 	if (hweight32(adev->aid_mask) && (adev->flags & AMD_IS_APU))
 		return AMDGPU_VBIOS_SKIP;