drm/amdgpu: correct ROM_INDEX/DATA offset for VEGA20

The ROMC_INDEX/DATA offset was changed to e4/e5 since
from smuio_v11 (vega20/arcturus).
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Tested-by: Candice Li <Candice.Li@amd.com>
Reviewed-by: Candice Li <Candice.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/soc15.c

@@ -89,6 +89,13 @@
 #define HDP_MEM_POWER_CTRL__RC_MEM_POWER_CTRL_EN_MASK	0x00010000L
 #define HDP_MEM_POWER_CTRL__RC_MEM_POWER_LS_EN_MASK		0x00020000L
 #define mmHDP_MEM_POWER_CTRL_BASE_IDX	0
+
+/* for Vega20/arcturus regiter offset change */
+#define	mmROM_INDEX_VG20				0x00e4
+#define	mmROM_INDEX_VG20_BASE_IDX			0
+#define	mmROM_DATA_VG20					0x00e5
+#define	mmROM_DATA_VG20_BASE_IDX			0
+
 /*
  * Indirect registers accessor
  */
@@ -309,6 +316,8 @@ static bool soc15_read_bios_from_rom(struct amdgpu_device *adev,
 {
 	u32 *dw_ptr;
 	u32 i, length_dw;
+	uint32_t rom_index_offset;
+	uint32_t rom_data_offset;
 
 	if (bios == NULL)
 		return false;
@@ -321,11 +330,23 @@ static bool soc15_read_bios_from_rom(struct amdgpu_device *adev,
 	dw_ptr = (u32 *)bios;
 	length_dw = ALIGN(length_bytes, 4) / 4;
 
+	switch (adev->asic_type) {
+	case CHIP_VEGA20:
+	case CHIP_ARCTURUS:
+		rom_index_offset = SOC15_REG_OFFSET(SMUIO, 0, mmROM_INDEX_VG20);
+		rom_data_offset = SOC15_REG_OFFSET(SMUIO, 0, mmROM_DATA_VG20);
+		break;
+	default:
+		rom_index_offset = SOC15_REG_OFFSET(SMUIO, 0, mmROM_INDEX);
+		rom_data_offset = SOC15_REG_OFFSET(SMUIO, 0, mmROM_DATA);
+		break;
+	}
+
 	/* set rom index to 0 */
-	WREG32(SOC15_REG_OFFSET(SMUIO, 0, mmROM_INDEX), 0);
+	WREG32(rom_index_offset, 0);
 	/* read out the rom data */
 	for (i = 0; i < length_dw; i++)
-		dw_ptr[i] = RREG32(SOC15_REG_OFFSET(SMUIO, 0, mmROM_DATA));
+		dw_ptr[i] = RREG32(rom_data_offset);
 
 	return true;
 }