[PATCH 0/4] Fix reading IPMI data on newer boards

[PATCH 0/4] Fix reading IPMI data on newer boards

[Luben Tuikov]

Bug fix reading the product name, product number, and serial number
on newer boards, especially new Aldebaran boards.

This edition fixes reading the actual serial number rather than the
product version, in patch 3. Also rebase to latest
amd-staging-drm-next.

Clarify changes in commits 1-3.

Add tags we've received so far.

Luben Tuikov (4):
  drm/amdgpu: Allow non-standard EEPROM I2C address
  drm/amdgpu: Bug-fix: Reading I2C FRU data on newer ASICs
  drm/amdgpu: Interpret IPMI data for product information (v2)
  drm/amdgpu: Add support for RAS table at 0x40000

 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c    |   2 +-
 .../gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c    | 215 +++++++++---------
 .../gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c    |   7 +-
 3 files changed, 115 insertions(+), 109 deletions(-)


base-commit: f9cb9d9b7cfde813d3b2d19dc0016645f985b543
-- 
2.38.1

[PATCH 1/4] drm/amdgpu: Allow non-standard EEPROM I2C address

[Luben Tuikov]

Allow non-standard EEPROM I2C address of 0x58, where the Device Type
Identifier is 1011b, where we form 1011000b = 0x58 I2C address, as on some
ASICs the FRU data lives there.

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Tested-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
index d6c4293829aab1..7d2a908438e924 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
@@ -87,7 +87,7 @@
  * "eeprom_addr", and set A10 to 0 to write into it, and A10 and A1 to
  * 1 to lock it permanently.
  */
-#define MAKE_I2C_ADDR(_aa) ((0xA << 3) | (((_aa) >> 16) & 7))
+#define MAKE_I2C_ADDR(_aa) ((0xA << 3) | (((_aa) >> 16) & 0xF))
 
 static int __amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap, u32 eeprom_addr,
 				u8 *eeprom_buf, u16 buf_size, bool read)
-- 
2.38.1

[PATCH 2/4] drm/amdgpu: Bug-fix: Reading I2C FRU data on newer ASICs

[Luben Tuikov]

Set the new correct default FRU MCU I2C address for newer ASICs, so that we
can correctly read the Product Name, Product Part/Model Number and Serial
Number.

On newer ASICs, the FRU MCU was moved to I2C address 0x58.

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Tested-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c    | 36 +++++++++++++------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
index e325150879df7e..9b2ff386b7c4f8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
@@ -29,9 +29,10 @@
 #include "amdgpu_fru_eeprom.h"
 #include "amdgpu_eeprom.h"
 
-#define FRU_EEPROM_MADDR        0x60000
+#define FRU_EEPROM_MADDR_6      0x60000
+#define FRU_EEPROM_MADDR_8      0x80000
 
-static bool is_fru_eeprom_supported(struct amdgpu_device *adev)
+static bool is_fru_eeprom_supported(struct amdgpu_device *adev, u32 *fru_addr)
 {
 	/* Only server cards have the FRU EEPROM
 	 * TODO: See if we can figure this out dynamically instead of
@@ -45,6 +46,11 @@ static bool is_fru_eeprom_supported(struct amdgpu_device *adev)
 	if (amdgpu_sriov_vf(adev))
 		return false;
 
+	/* The default I2C EEPROM address of the FRU.
+	 */
+	if (fru_addr)
+		*fru_addr = FRU_EEPROM_MADDR_8;
+
 	/* VBIOS is of the format ###-DXXXYYYY-##. For SKU identification,
 	 * we can use just the "DXXX" portion. If there were more models, we
 	 * could convert the 3 characters to a hex integer and use a switch
@@ -57,21 +63,29 @@ static bool is_fru_eeprom_supported(struct amdgpu_device *adev)
 		if (strnstr(atom_ctx->vbios_version, "D161",
 			    sizeof(atom_ctx->vbios_version)) ||
 		    strnstr(atom_ctx->vbios_version, "D163",
-			    sizeof(atom_ctx->vbios_version)))
+			    sizeof(atom_ctx->vbios_version))) {
+			*fru_addr = FRU_EEPROM_MADDR_6;
 			return true;
-		else
+		} else {
 			return false;
+		}
 	case CHIP_ALDEBARAN:
-		/* All Aldebaran SKUs have the FRU */
+		/* All Aldebaran SKUs have an FRU */
+		if (!strnstr(atom_ctx->vbios_version, "D673",
+			     sizeof(atom_ctx->vbios_version)))
+			if (fru_addr)
+				*fru_addr = FRU_EEPROM_MADDR_6;
 		return true;
 	case CHIP_SIENNA_CICHLID:
 		if (strnstr(atom_ctx->vbios_version, "D603",
-		    sizeof(atom_ctx->vbios_version))) {
+			    sizeof(atom_ctx->vbios_version))) {
 			if (strnstr(atom_ctx->vbios_version, "D603GLXE",
-			    sizeof(atom_ctx->vbios_version)))
+				    sizeof(atom_ctx->vbios_version))) {
 				return false;
-			else
+			} else {
+				*fru_addr = FRU_EEPROM_MADDR_6;
 				return true;
+			}
 		} else {
 			return false;
 		}
@@ -111,10 +125,10 @@ static int amdgpu_fru_read_eeprom(struct amdgpu_device *adev, uint32_t addrptr,
 int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
 {
 	unsigned char buf[AMDGPU_PRODUCT_NAME_LEN];
-	u32 addrptr;
+	u32 addrptr, fru_addr;
 	int size, len;
 
-	if (!is_fru_eeprom_supported(adev))
+	if (!is_fru_eeprom_supported(adev, &fru_addr))
 		return 0;
 
 	/* If algo exists, it means that the i2c_adapter's initialized */
@@ -135,7 +149,7 @@ int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
 	 * Bytes 8-a are all 1-byte and refer to the size of the entire struct,
 	 * and the language field, so just start from 0xb, manufacturer size
 	 */
-	addrptr = FRU_EEPROM_MADDR + 0xb;
+	addrptr = fru_addr + 0xb;
 	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
 	if (size < 1) {
 		DRM_ERROR("Failed to read FRU Manufacturer, ret:%d", size);
-- 
2.38.1

[PATCH 3/4] drm/amdgpu: Interpret IPMI data for product information (v2)

[Luben Tuikov]

Don't assume FRU MCU memory locations for the FRU data fields, or their sizes,
instead reading and interpret the IPMI data, as stipulated in the IPMI spec
version 1.0 rev 1.2.

Extract the Product Name, Product Part/Model Number, and the Product Serial
Number by interpreting the IPMI data.

Check the checksums of the stored IPMI data to make sure we don't read and
give corrupted data back the the user.

Eliminate small I2C reads, and instead read the whole Product Info Area in one
go, and then extract the information we're seeking from it.

Eliminates a whole function, making this file smaller.

v2: Clarify changes in the commit message.

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Tested-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c    | 183 ++++++++----------
 1 file changed, 85 insertions(+), 98 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
index 9b2ff386b7c4f8..2c38ac7bc643d5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
@@ -94,39 +94,12 @@ static bool is_fru_eeprom_supported(struct amdgpu_device *adev, u32 *fru_addr)
 	}
 }
 
-static int amdgpu_fru_read_eeprom(struct amdgpu_device *adev, uint32_t addrptr,
-				  unsigned char *buf, size_t buf_size)
-{
-	int ret;
-	u8 size;
-
-	ret = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addrptr, buf, 1);
-	if (ret < 1) {
-		DRM_WARN("FRU: Failed to get size field");
-		return ret;
-	}
-
-	/* The size returned by the i2c requires subtraction of 0xC0 since the
-	 * size apparently always reports as 0xC0+actual size.
-	 */
-	size = buf[0] & 0x3F;
-	size = min_t(size_t, size, buf_size);
-
-	ret = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addrptr + 1,
-				 buf, size);
-	if (ret < 1) {
-		DRM_WARN("FRU: Failed to get data field");
-		return ret;
-	}
-
-	return size;
-}
-
 int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
 {
-	unsigned char buf[AMDGPU_PRODUCT_NAME_LEN];
-	u32 addrptr, fru_addr;
+	unsigned char buf[8], *pia;
+	u32 addr, fru_addr;
 	int size, len;
+	u8 csum;
 
 	if (!is_fru_eeprom_supported(adev, &fru_addr))
 		return 0;
@@ -137,88 +110,102 @@ int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
 		return -ENODEV;
 	}
 
-	/* There's a lot of repetition here. This is due to the FRU having
-	 * variable-length fields. To get the information, we have to find the
-	 * size of each field, and then keep reading along and reading along
-	 * until we get all of the data that we want. We use addrptr to track
-	 * the address as we go
-	 */
-
-	/* The first fields are all of size 1-byte, from 0-7 are offsets that
-	 * contain information that isn't useful to us.
-	 * Bytes 8-a are all 1-byte and refer to the size of the entire struct,
-	 * and the language field, so just start from 0xb, manufacturer size
-	 */
-	addrptr = fru_addr + 0xb;
-	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
-	if (size < 1) {
-		DRM_ERROR("Failed to read FRU Manufacturer, ret:%d", size);
-		return -EINVAL;
+	/* Read the IPMI Common header */
+	len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, fru_addr, buf,
+				 sizeof(buf));
+	if (len != 8) {
+		DRM_ERROR("Couldn't read the IPMI Common Header: %d", len);
+		return len < 0 ? len : -EIO;
 	}
 
-	/* Increment the addrptr by the size of the field, and 1 due to the
-	 * size field being 1 byte. This pattern continues below.
-	 */
-	addrptr += size + 1;
-	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
-	if (size < 1) {
-		DRM_ERROR("Failed to read FRU product name, ret:%d", size);
-		return -EINVAL;
+	if (buf[0] != 1) {
+		DRM_ERROR("Bad IPMI Common Header version: 0x%02x", buf[0]);
+		return -EIO;
 	}
 
-	len = size;
-	if (len >= AMDGPU_PRODUCT_NAME_LEN) {
-		DRM_WARN("FRU Product Name is larger than %d characters. This is likely a mistake",
-				AMDGPU_PRODUCT_NAME_LEN);
-		len = AMDGPU_PRODUCT_NAME_LEN - 1;
-	}
-	memcpy(adev->product_name, buf, len);
-	adev->product_name[len] = '\0';
-
-	addrptr += size + 1;
-	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
-	if (size < 1) {
-		DRM_ERROR("Failed to read FRU product number, ret:%d", size);
-		return -EINVAL;
+	for (csum = 0; len > 0; len--)
+		csum += buf[len - 1];
+	if (csum) {
+		DRM_ERROR("Bad IPMI Common Header checksum: 0x%02x", csum);
+		return -EIO;
 	}
 
-	len = size;
-	/* Product number should only be 16 characters. Any more,
-	 * and something could be wrong. Cap it at 16 to be safe
-	 */
-	if (len >= sizeof(adev->product_number)) {
-		DRM_WARN("FRU Product Number is larger than 16 characters. This is likely a mistake");
-		len = sizeof(adev->product_number) - 1;
-	}
-	memcpy(adev->product_number, buf, len);
-	adev->product_number[len] = '\0';
+	/* Get the offset to the Product Info Area (PIA). */
+	addr = buf[4] * 8;
+	if (!addr)
+		return 0;
 
-	addrptr += size + 1;
-	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
+	/* Get the absolute address to the PIA. */
+	addr += fru_addr;
 
-	if (size < 1) {
-		DRM_ERROR("Failed to read FRU product version, ret:%d", size);
-		return -EINVAL;
+	/* Read the header of the PIA. */
+	len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addr, buf, 3);
+	if (len != 3) {
+		DRM_ERROR("Couldn't read the Product Info Area header: %d", len);
+		return len < 0 ? len : -EIO;
 	}
 
-	addrptr += size + 1;
-	size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
+	if (buf[0] != 1) {
+		DRM_ERROR("Bad IPMI Product Info Area version: 0x%02x", buf[0]);
+		return -EIO;
+	}
 
-	if (size < 1) {
-		DRM_ERROR("Failed to read FRU serial number, ret:%d", size);
-		return -EINVAL;
+	size = buf[1] * 8;
+	pia = kzalloc(size, GFP_KERNEL);
+	if (!pia)
+		return -ENOMEM;
+
+	/* Read the whole PIA. */
+	len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addr, pia, size);
+	if (len != size) {
+		kfree(pia);
+		DRM_ERROR("Couldn't read the Product Info Area: %d", len);
+		return len < 0 ? len : -EIO;
 	}
 
-	len = size;
-	/* Serial number should only be 16 characters. Any more,
-	 * and something could be wrong. Cap it at 16 to be safe
-	 */
-	if (len >= sizeof(adev->serial)) {
-		DRM_WARN("FRU Serial Number is larger than 16 characters. This is likely a mistake");
-		len = sizeof(adev->serial) - 1;
+	for (csum = 0; size > 0; size--)
+		csum += pia[size - 1];
+	if (csum) {
+		DRM_ERROR("Bad Product Info Area checksum: 0x%02x", csum);
+		return -EIO;
 	}
-	memcpy(adev->serial, buf, len);
-	adev->serial[len] = '\0';
 
+	/* Now extract useful information from the PIA.
+	 *
+	 * Skip the Manufacturer Name at [3] and go directly to
+	 * the Product Name field.
+	 */
+	addr = 3 + 1 + (pia[3] & 0x3F);
+	if (addr + 1 >= len)
+		goto Out;
+	memcpy(adev->product_name, pia + addr + 1,
+	       min_t(size_t,
+		     sizeof(adev->product_name),
+		     pia[addr] & 0x3F));
+	adev->product_name[sizeof(adev->product_name) - 1] = '\0';
+
+	/* Go to the Product Part/Model Number field. */
+	addr += 1 + (pia[addr] & 0x3F);
+	if (addr + 1 >= len)
+		goto Out;
+	memcpy(adev->product_number, pia + addr + 1,
+	       min_t(size_t,
+		     sizeof(adev->product_number),
+		     pia[addr] & 0x3F));
+	adev->product_number[sizeof(adev->product_number) - 1] = '\0';
+
+	/* Go to the Product Version field. */
+	addr += 1 + (pia[addr] & 0x3F);
+
+	/* Go to the Product Serial Number field. */
+	addr += 1 + (pia[addr] & 0x3F);
+	if (addr + 1 >= len)
+		goto Out;
+	memcpy(adev->serial, pia + addr + 1, min_t(size_t,
+						   sizeof(adev->serial),
+						   pia[addr] & 0x3F));
+	adev->serial[sizeof(adev->serial) - 1] = '\0';
+Out:
+	kfree(pia);
 	return 0;
 }
-- 
2.38.1

[PATCH 4/4] drm/amdgpu: Add support for RAS table at 0x40000

[Luben Tuikov]

Add support for RAS table at I2C EEPROM address of 0x40000, since on some
ASICs it is not at 0, but at 0x40000.

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Tested-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c
index f63bd31e199c8e..2d9f3f4cd79e92 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c
@@ -157,6 +157,7 @@ static bool __get_eeprom_i2c_addr_ip_discovery(struct amdgpu_device *adev,
 static bool __get_eeprom_i2c_addr(struct amdgpu_device *adev,
 				  struct amdgpu_ras_eeprom_control *control)
 {
+	struct atom_context *atom_ctx = adev->mode_info.atom_context;
 	u8 i2c_addr;
 
 	if (!control)
@@ -190,7 +191,11 @@ static bool __get_eeprom_i2c_addr(struct amdgpu_device *adev,
 		break;
 
 	case CHIP_ALDEBARAN:
-		control->i2c_address = EEPROM_I2C_MADDR_0;
+		if (strnstr(atom_ctx->vbios_version, "D673",
+			    sizeof(atom_ctx->vbios_version)))
+			control->i2c_address = EEPROM_I2C_MADDR_4;
+		else
+			control->i2c_address = EEPROM_I2C_MADDR_0;
 		break;
 
 	case CHIP_IP_DISCOVERY:
-- 
2.38.1

Re: [PATCH 3/4] drm/amdgpu: Interpret IPMI data for product information (v2)

[Alex Deucher]

On Wed, Nov 16, 2022 at 8:25 PM Luben Tuikov <luben.tuikov@amd.com> wrote:
>
> Don't assume FRU MCU memory locations for the FRU data fields, or their sizes,
> instead reading and interpret the IPMI data, as stipulated in the IPMI spec
> version 1.0 rev 1.2.
>
> Extract the Product Name, Product Part/Model Number, and the Product Serial
> Number by interpreting the IPMI data.
>
> Check the checksums of the stored IPMI data to make sure we don't read and
> give corrupted data back the the user.
>
> Eliminate small I2C reads, and instead read the whole Product Info Area in one
> go, and then extract the information we're seeking from it.
>
> Eliminates a whole function, making this file smaller.
>
> v2: Clarify changes in the commit message.

Thanks for clarifying, Series is:
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

>
> Cc: Alex Deucher <Alexander.Deucher@amd.com>
> Cc: Kent Russell <kent.russell@amd.com>
> Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
> Tested-by: Kent Russell <kent.russell@amd.com>
> Reviewed-by: Kent Russell <kent.russell@amd.com>
> ---
>  .../gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c    | 183 ++++++++----------
>  1 file changed, 85 insertions(+), 98 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
> index 9b2ff386b7c4f8..2c38ac7bc643d5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
> @@ -94,39 +94,12 @@ static bool is_fru_eeprom_supported(struct amdgpu_device *adev, u32 *fru_addr)
>         }
>  }
>
> -static int amdgpu_fru_read_eeprom(struct amdgpu_device *adev, uint32_t addrptr,
> -                                 unsigned char *buf, size_t buf_size)
> -{
> -       int ret;
> -       u8 size;
> -
> -       ret = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addrptr, buf, 1);
> -       if (ret < 1) {
> -               DRM_WARN("FRU: Failed to get size field");
> -               return ret;
> -       }
> -
> -       /* The size returned by the i2c requires subtraction of 0xC0 since the
> -        * size apparently always reports as 0xC0+actual size.
> -        */
> -       size = buf[0] & 0x3F;
> -       size = min_t(size_t, size, buf_size);
> -
> -       ret = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addrptr + 1,
> -                                buf, size);
> -       if (ret < 1) {
> -               DRM_WARN("FRU: Failed to get data field");
> -               return ret;
> -       }
> -
> -       return size;
> -}
> -
>  int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
>  {
> -       unsigned char buf[AMDGPU_PRODUCT_NAME_LEN];
> -       u32 addrptr, fru_addr;
> +       unsigned char buf[8], *pia;
> +       u32 addr, fru_addr;
>         int size, len;
> +       u8 csum;
>
>         if (!is_fru_eeprom_supported(adev, &fru_addr))
>                 return 0;
> @@ -137,88 +110,102 @@ int amdgpu_fru_get_product_info(struct amdgpu_device *adev)
>                 return -ENODEV;
>         }
>
> -       /* There's a lot of repetition here. This is due to the FRU having
> -        * variable-length fields. To get the information, we have to find the
> -        * size of each field, and then keep reading along and reading along
> -        * until we get all of the data that we want. We use addrptr to track
> -        * the address as we go
> -        */
> -
> -       /* The first fields are all of size 1-byte, from 0-7 are offsets that
> -        * contain information that isn't useful to us.
> -        * Bytes 8-a are all 1-byte and refer to the size of the entire struct,
> -        * and the language field, so just start from 0xb, manufacturer size
> -        */
> -       addrptr = fru_addr + 0xb;
> -       size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
> -       if (size < 1) {
> -               DRM_ERROR("Failed to read FRU Manufacturer, ret:%d", size);
> -               return -EINVAL;
> +       /* Read the IPMI Common header */
> +       len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, fru_addr, buf,
> +                                sizeof(buf));
> +       if (len != 8) {
> +               DRM_ERROR("Couldn't read the IPMI Common Header: %d", len);
> +               return len < 0 ? len : -EIO;
>         }
>
> -       /* Increment the addrptr by the size of the field, and 1 due to the
> -        * size field being 1 byte. This pattern continues below.
> -        */
> -       addrptr += size + 1;
> -       size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
> -       if (size < 1) {
> -               DRM_ERROR("Failed to read FRU product name, ret:%d", size);
> -               return -EINVAL;
> +       if (buf[0] != 1) {
> +               DRM_ERROR("Bad IPMI Common Header version: 0x%02x", buf[0]);
> +               return -EIO;
>         }
>
> -       len = size;
> -       if (len >= AMDGPU_PRODUCT_NAME_LEN) {
> -               DRM_WARN("FRU Product Name is larger than %d characters. This is likely a mistake",
> -                               AMDGPU_PRODUCT_NAME_LEN);
> -               len = AMDGPU_PRODUCT_NAME_LEN - 1;
> -       }
> -       memcpy(adev->product_name, buf, len);
> -       adev->product_name[len] = '\0';
> -
> -       addrptr += size + 1;
> -       size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
> -       if (size < 1) {
> -               DRM_ERROR("Failed to read FRU product number, ret:%d", size);
> -               return -EINVAL;
> +       for (csum = 0; len > 0; len--)
> +               csum += buf[len - 1];
> +       if (csum) {
> +               DRM_ERROR("Bad IPMI Common Header checksum: 0x%02x", csum);
> +               return -EIO;
>         }
>
> -       len = size;
> -       /* Product number should only be 16 characters. Any more,
> -        * and something could be wrong. Cap it at 16 to be safe
> -        */
> -       if (len >= sizeof(adev->product_number)) {
> -               DRM_WARN("FRU Product Number is larger than 16 characters. This is likely a mistake");
> -               len = sizeof(adev->product_number) - 1;
> -       }
> -       memcpy(adev->product_number, buf, len);
> -       adev->product_number[len] = '\0';
> +       /* Get the offset to the Product Info Area (PIA). */
> +       addr = buf[4] * 8;
> +       if (!addr)
> +               return 0;
>
> -       addrptr += size + 1;
> -       size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
> +       /* Get the absolute address to the PIA. */
> +       addr += fru_addr;
>
> -       if (size < 1) {
> -               DRM_ERROR("Failed to read FRU product version, ret:%d", size);
> -               return -EINVAL;
> +       /* Read the header of the PIA. */
> +       len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addr, buf, 3);
> +       if (len != 3) {
> +               DRM_ERROR("Couldn't read the Product Info Area header: %d", len);
> +               return len < 0 ? len : -EIO;
>         }
>
> -       addrptr += size + 1;
> -       size = amdgpu_fru_read_eeprom(adev, addrptr, buf, sizeof(buf));
> +       if (buf[0] != 1) {
> +               DRM_ERROR("Bad IPMI Product Info Area version: 0x%02x", buf[0]);
> +               return -EIO;
> +       }
>
> -       if (size < 1) {
> -               DRM_ERROR("Failed to read FRU serial number, ret:%d", size);
> -               return -EINVAL;
> +       size = buf[1] * 8;
> +       pia = kzalloc(size, GFP_KERNEL);
> +       if (!pia)
> +               return -ENOMEM;
> +
> +       /* Read the whole PIA. */
> +       len = amdgpu_eeprom_read(adev->pm.fru_eeprom_i2c_bus, addr, pia, size);
> +       if (len != size) {
> +               kfree(pia);
> +               DRM_ERROR("Couldn't read the Product Info Area: %d", len);
> +               return len < 0 ? len : -EIO;
>         }
>
> -       len = size;
> -       /* Serial number should only be 16 characters. Any more,
> -        * and something could be wrong. Cap it at 16 to be safe
> -        */
> -       if (len >= sizeof(adev->serial)) {
> -               DRM_WARN("FRU Serial Number is larger than 16 characters. This is likely a mistake");
> -               len = sizeof(adev->serial) - 1;
> +       for (csum = 0; size > 0; size--)
> +               csum += pia[size - 1];
> +       if (csum) {
> +               DRM_ERROR("Bad Product Info Area checksum: 0x%02x", csum);
> +               return -EIO;
>         }
> -       memcpy(adev->serial, buf, len);
> -       adev->serial[len] = '\0';
>
> +       /* Now extract useful information from the PIA.
> +        *
> +        * Skip the Manufacturer Name at [3] and go directly to
> +        * the Product Name field.
> +        */
> +       addr = 3 + 1 + (pia[3] & 0x3F);
> +       if (addr + 1 >= len)
> +               goto Out;
> +       memcpy(adev->product_name, pia + addr + 1,
> +              min_t(size_t,
> +                    sizeof(adev->product_name),
> +                    pia[addr] & 0x3F));
> +       adev->product_name[sizeof(adev->product_name) - 1] = '\0';
> +
> +       /* Go to the Product Part/Model Number field. */
> +       addr += 1 + (pia[addr] & 0x3F);
> +       if (addr + 1 >= len)
> +               goto Out;
> +       memcpy(adev->product_number, pia + addr + 1,
> +              min_t(size_t,
> +                    sizeof(adev->product_number),
> +                    pia[addr] & 0x3F));
> +       adev->product_number[sizeof(adev->product_number) - 1] = '\0';
> +
> +       /* Go to the Product Version field. */
> +       addr += 1 + (pia[addr] & 0x3F);
> +
> +       /* Go to the Product Serial Number field. */
> +       addr += 1 + (pia[addr] & 0x3F);
> +       if (addr + 1 >= len)
> +               goto Out;
> +       memcpy(adev->serial, pia + addr + 1, min_t(size_t,
> +                                                  sizeof(adev->serial),
> +                                                  pia[addr] & 0x3F));
> +       adev->serial[sizeof(adev->serial) - 1] = '\0';
> +Out:
> +       kfree(pia);
>         return 0;
>  }
> --
> 2.38.1
>