drm/amdgpu: Refine the way to get atom bios

There are several ways to check out a ATOMBIOS. In previous codes, try
a new way to fetch out vbios/rom, until current vbios/rom is started with
0x55aa, then check if this vbios is ATOMBIOS. Now, try a new way to fetch
out vbios until all flags of ATOMBIOS are verified.

Signed-off-by: Ken Xue <Ken.Xue@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 105 insertions, 74 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index f573a953b4c3..2602ea12971e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -42,6 +42,51 @@
 #define AMD_IS_VALID_VBIOS(p) ((p)[0] == 0x55 && (p)[1] == 0xAA)
 #define AMD_VBIOS_LENGTH(p) ((p)[2] << 9)
 
+/* Check if current bios is an ATOM BIOS.
+ * Return true if it is ATOM BIOS. Otherwise, return false.
+ */
+static bool check_atom_bios(uint8_t *bios, size_t size)
+{
+        uint16_t tmp, bios_header_start;
+
+        if (!bios || size < 0x49) {
+                DRM_INFO("vbios mem is null or mem size is wrong\n");
+                return false;
+        }
+
+        if (!AMD_IS_VALID_VBIOS(bios)) {
+                DRM_INFO("BIOS signature incorrect %x %x\n", bios[0], bios[1]);
+                return false;
+        }
+
+        tmp = bios[0x18] | (bios[0x19] << 8);
+        if (bios[tmp + 0x14] != 0x0) {
+                DRM_INFO("Not an x86 BIOS ROM\n");
+                return false;
+        }
+
+        bios_header_start = bios[0x48] | (bios[0x49] << 8);
+        if (!bios_header_start) {
+                DRM_INFO("Can't locate bios header\n");
+                return false;
+        }
+
+        tmp = bios_header_start + 4;
+        if (size < tmp) {
+                DRM_INFO("BIOS header is broken\n");
+                return false;
+        }
+
+        if (!memcmp(bios + tmp, "ATOM", 4) ||
+            !memcmp(bios + tmp, "MOTA", 4)) {
+                DRM_DEBUG("ATOMBIOS detected\n");
+                return true;
+        }
+
+        return false;
+}
+
+
 /* If you boot an IGP board with a discrete card as the primary,
  * the IGP rom is not accessible via the rom bar as the IGP rom is
  * part of the system bios.  On boot, the system bios puts a
@@ -65,10 +110,6 @@ static bool igp_read_bios_from_vram(struct amdgpu_device *adev)
                 return false;
         }
 
-        if (size == 0 || !AMD_IS_VALID_VBIOS(bios)) {
-                iounmap(bios);
-                return false;
-        }
         adev->bios = kmalloc(size, GFP_KERNEL);
         if (!adev->bios) {
                 iounmap(bios);
@@ -77,12 +118,18 @@ static bool igp_read_bios_from_vram(struct amdgpu_device *adev)
         adev->bios_size = size;
         memcpy_fromio(adev->bios, bios, size);
         iounmap(bios);
+
+        if (!check_atom_bios(adev->bios, size)) {
+                kfree(adev->bios);
+                return false;
+        }
+
         return true;
 }
 
 bool amdgpu_read_bios(struct amdgpu_device *adev)
 {
-        uint8_t __iomem *bios, val[2];
+        uint8_t __iomem *bios;
         size_t size;
 
         adev->bios = NULL;
@@ -92,13 +139,6 @@ bool amdgpu_read_bios(struct amdgpu_device *adev)
                 return false;
         }
 
-        val[0] = readb(&bios[0]);
-        val[1] = readb(&bios[1]);
-
-        if (size == 0 || !AMD_IS_VALID_VBIOS(val)) {
-                pci_unmap_rom(adev->pdev, bios);
-                return false;
-        }
         adev->bios = kzalloc(size, GFP_KERNEL);
         if (adev->bios == NULL) {
                 pci_unmap_rom(adev->pdev, bios);
@@ -107,6 +147,12 @@ bool amdgpu_read_bios(struct amdgpu_device *adev)
         adev->bios_size = size;
         memcpy_fromio(adev->bios, bios, size);
         pci_unmap_rom(adev->pdev, bios);
+
+        if (!check_atom_bios(adev->bios, size)) {
+                kfree(adev->bios);
+                return false;
+        }
+
         return true;
 }
 
@@ -140,7 +186,14 @@ static bool amdgpu_read_bios_from_rom(struct amdgpu_device *adev)
         adev->bios_size = len;
 
         /* read complete BIOS */
-        return amdgpu_asic_read_bios_from_rom(adev, adev->bios, len);
+        amdgpu_asic_read_bios_from_rom(adev, adev->bios, len);
+
+        if (!check_atom_bios(adev->bios, len)) {
+                kfree(adev->bios);
+                return false;
+        }
+
+        return true;
 }
 
 static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
@@ -155,13 +208,17 @@ static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
                 return false;
         }
 
-        if (size == 0 || !AMD_IS_VALID_VBIOS(bios)) {
+        adev->bios = kzalloc(size, GFP_KERNEL);
+        if (adev->bios == NULL)
                 return false;
-        }
-        adev->bios = kmemdup(bios, size, GFP_KERNEL);
-        if (adev->bios == NULL) {
+
+        memcpy_fromio(adev->bios, bios, size);
+
+        if (!check_atom_bios(adev->bios, size)) {
+                kfree(adev->bios);
                 return false;
         }
+
         adev->bios_size = size;
 
         return true;
@@ -273,7 +330,7 @@ static bool amdgpu_atrm_get_bios(struct amdgpu_device *adev)
                         break;
         }
 
-        if (i == 0 || !AMD_IS_VALID_VBIOS(adev->bios)) {
+        if (!check_atom_bios(adev->bios, size)) {
                 kfree(adev->bios);
                 return false;
         }
@@ -298,7 +355,6 @@ static bool amdgpu_read_disabled_bios(struct amdgpu_device *adev)
 #ifdef CONFIG_ACPI
 static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
 {
-        bool ret = false;
         struct acpi_table_header *hdr;
         acpi_size tbl_size;
         UEFI_ACPI_VFCT *vfct;
@@ -310,13 +366,13 @@ static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
         tbl_size = hdr->length;
         if (tbl_size < sizeof(UEFI_ACPI_VFCT)) {
                 DRM_ERROR("ACPI VFCT table present but broken (too short #1)\n");
-                goto out_unmap;
+                return false;
         }
 
         vfct = (UEFI_ACPI_VFCT *)hdr;
         if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) > tbl_size) {
                 DRM_ERROR("ACPI VFCT table present but broken (too short #2)\n");
-                goto out_unmap;
+                return false;
         }
 
         vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + vfct->VBIOSImageOffset);
@@ -331,20 +387,25 @@ static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
             vhdr->VendorID != adev->pdev->vendor ||
             vhdr->DeviceID != adev->pdev->device) {
                 DRM_INFO("ACPI VFCT table is not for this card\n");
-                goto out_unmap;
+                return false;
         }
 
         if (vfct->VBIOSImageOffset + sizeof(VFCT_IMAGE_HEADER) + vhdr->ImageLength > tbl_size) {
                 DRM_ERROR("ACPI VFCT image truncated\n");
-                goto out_unmap;
+                return false;
         }
 
-        adev->bios = kmemdup(&vbios->VbiosContent, vhdr->ImageLength, GFP_KERNEL);
+        adev->bios = kmemdup(&vbios->VbiosContent,
+                                vhdr->ImageLength,
+                                GFP_KERNEL);
+
+        if (!check_atom_bios(adev->bios, vhdr->ImageLength)) {
+                kfree(adev->bios);
+                return false;
+        }
         adev->bios_size = vhdr->ImageLength;
-        ret = !!adev->bios;
 
-out_unmap:
-        return ret;
+        return true;
 }
 #else
 static inline bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
@@ -355,57 +416,27 @@ static inline bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
 
 bool amdgpu_get_bios(struct amdgpu_device *adev)
 {
-        bool r;
-        uint16_t tmp, bios_header_start;
+        if (amdgpu_atrm_get_bios(adev))
+                return true;
 
-        r = amdgpu_atrm_get_bios(adev);
-        if (!r)
-                r = amdgpu_acpi_vfct_bios(adev);
-        if (!r)
-                r = igp_read_bios_from_vram(adev);
-        if (!r)
-                r = amdgpu_read_bios(adev);
-        if (!r) {
-                r = amdgpu_read_bios_from_rom(adev);
-        }
-        if (!r) {
-                r = amdgpu_read_disabled_bios(adev);
-        }
-        if (!r) {
-                r = amdgpu_read_platform_bios(adev);
-        }
-        if (!r || adev->bios == NULL) {
-                DRM_ERROR("Unable to locate a BIOS ROM\n");
-                adev->bios = NULL;
-                return false;
-        }
-        if (!AMD_IS_VALID_VBIOS(adev->bios)) {
-                printk("BIOS signature incorrect %x %x\n", adev->bios[0], adev->bios[1]);
-                goto free_bios;
-        }
+        if (amdgpu_acpi_vfct_bios(adev))
+                return true;
 
-        tmp = RBIOS16(0x18);
-        if (RBIOS8(tmp + 0x14) != 0x0) {
-                DRM_INFO("Not an x86 BIOS ROM, not using.\n");
-                goto free_bios;
-        }
+        if (igp_read_bios_from_vram(adev))
+                return true;
 
-        bios_header_start = RBIOS16(0x48);
-        if (!bios_header_start) {
-                goto free_bios;
-        }
+        if (amdgpu_read_bios(adev))
+                return true;
 
-        /* Must be an ATOMBIOS */
-        tmp = bios_header_start + 4;
-        if (memcmp(adev->bios + tmp, "ATOM", 4) &&
-            memcmp(adev->bios + tmp, "MOTA", 4)) {
-                goto free_bios;
-        }
+        if (amdgpu_read_bios_from_rom(adev))
+                return true;
 
-        DRM_DEBUG("ATOMBIOS detected\n");
-        return true;
-free_bios:
-        kfree(adev->bios);
-        adev->bios = NULL;
+        if (amdgpu_read_disabled_bios(adev))
+                return true;
+
+        if (amdgpu_read_platform_bios(adev))
+                return true;
+
+        DRM_ERROR("Unable to locate a BIOS ROM\n");
         return false;
 }