[PATCH 0/6] env: scsi: support SCSI env without partition UUID

[PATCH 0/6] env: scsi: support SCSI env without partition UUID

[David Lechner]

This is a series adding support for reading U-Boot env directly from
SCSI devices that do not have a partition table, similar to how we can
already do this for MMC devices.

The motivation behind this is that MediaTek's BSP is already using the
same disk images for both MMC and UFS devices, so we need to be able to
read the env from SCSI devices without requiring a partition UUID.

The series starts with cleaning up a few oddities we noticed in the
existing code. Then some refactoring so that the env code manages
calling scsi_scan() so that we don't have to duplicate that for the
new code path. Then finally, the last few patches add and document the
new functionality.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
David Lechner (6):
      env: scsi: rename ENV_SCSI_PART_UUID
      scsi: return ENODEV in scsi_get_blk_by_uuid()
      scsi: document return values of public functions
      scsi: move scsi_scan() call out of scsi_get_blk_by_uuid()
      env: scsi: add CONFIG_ENV_SCSI_HW_PARTITION
      env: scsi: document requirements for ENV_IS_IN_SCSI

 configs/qcom_qcs9100_defconfig |  2 +-
 drivers/scsi/scsi-uclass.c     |  8 +-------
 env/Kconfig                    | 30 +++++++++++++++++++++++++++++-
 env/scsi.c                     | 28 ++++++++++++++++++++++++----
 include/scsi.h                 |  5 +++++
 5 files changed, 60 insertions(+), 13 deletions(-)
---
base-commit: 80a4c49a4ab2ad06fa84a8b7bdf6e33b3b5101bf
change-id: 20260326-env-scsi-hw-part-support-77446f742f27

Best regards,
--  
David Lechner <dlechner@baylibre.com>

[PATCH 1/6] env: scsi: rename ENV_SCSI_PART_UUID

[David Lechner]

Rename SCSI_ENV_PART_UUID to ENV_SCSI_PART_UUID. All other environment-
related config names are of the form ENV_<name>, so this is more
consistent.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 configs/qcom_qcs9100_defconfig | 2 +-
 env/Kconfig                    | 2 +-
 env/scsi.c                     | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/configs/qcom_qcs9100_defconfig b/configs/qcom_qcs9100_defconfig
index 371448b8b1b..082106157bb 100644
--- a/configs/qcom_qcs9100_defconfig
+++ b/configs/qcom_qcs9100_defconfig
@@ -11,6 +11,6 @@ CONFIG_REMAKE_ELF=y
 CONFIG_FASTBOOT_BUF_ADDR=0xdb300000
 CONFIG_DEFAULT_DEVICE_TREE="qcom/qcs9100-ride-r3"
 CONFIG_ENV_IS_IN_SCSI=y
-CONFIG_SCSI_ENV_PART_UUID="71cb9cd0-acf1-b6cb-ad91-be9572fe11a9"
+CONFIG_ENV_SCSI_PART_UUID="71cb9cd0-acf1-b6cb-ad91-be9572fe11a9"
 # CONFIG_ENV_IS_DEFAULT is not set
 # CONFIG_ENV_IS_NOWHERE is not set
diff --git a/env/Kconfig b/env/Kconfig
index 2feff0b382e..5824f762870 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -762,7 +762,7 @@ config ENV_MMC_USE_DT
 	  The 2 defines CONFIG_ENV_OFFSET, CONFIG_ENV_OFFSET_REDUND
 	  are not used as fallback.
 
-config SCSI_ENV_PART_UUID
+config ENV_SCSI_PART_UUID
 	string "SCSI partition UUID for saving environment"
 	depends on ENV_IS_IN_SCSI
 	help
diff --git a/env/scsi.c b/env/scsi.c
index 207717e17b1..f376f731870 100644
--- a/env/scsi.c
+++ b/env/scsi.c
@@ -35,7 +35,7 @@ static inline struct env_scsi_info *env_scsi_get_part(void)
 {
 	struct env_scsi_info *ep = &env_part;
 
-	if (scsi_get_blk_by_uuid(CONFIG_SCSI_ENV_PART_UUID, &ep->blk, &ep->part))
+	if (scsi_get_blk_by_uuid(CONFIG_ENV_SCSI_PART_UUID, &ep->blk, &ep->part))
 		return NULL;
 
 	ep->count = CONFIG_ENV_SIZE / ep->part.blksz;
@@ -83,12 +83,12 @@ static int env_scsi_load(void)
 	int ret;
 
 	if (!ep) {
-		env_set_default(CONFIG_SCSI_ENV_PART_UUID " partition not found", 0);
+		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition not found", 0);
 		return -ENOENT;
 	}
 
 	if (blk_dread(ep->blk, ep->part.start, ep->count, &envbuf) != ep->count) {
-		env_set_default(CONFIG_SCSI_ENV_PART_UUID " partition read failed", 0);
+		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition read failed", 0);
 		return -EIO;
 	}
 

-- 
2.43.0

[PATCH 2/6] scsi: return ENODEV in scsi_get_blk_by_uuid()

[David Lechner]

Change scsi_get_blk_by_uuid() to return -ENODEV instead of -1 on error.
Other scsi_* functions return an error code rather than -1.

1 is EPERM, which doesn't make sense here. So we use ENODEV instead. The
only caller only checks for !success, so changing the value has no
effect on the caller.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 drivers/scsi/scsi-uclass.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi-uclass.c b/drivers/scsi/scsi-uclass.c
index 3eb6069649f..e7870d7f831 100644
--- a/drivers/scsi/scsi-uclass.c
+++ b/drivers/scsi/scsi-uclass.c
@@ -50,7 +50,7 @@ int scsi_get_blk_by_uuid(const char *uuid,
 		}
 	}
 
-	return -1;
+	return -ENODEV;
 }
 
 int scsi_bus_reset(struct udevice *dev)

-- 
2.43.0

[PATCH 3/6] scsi: document return values of public functions

[David Lechner]

Add Return: documentation for some public functions in scsi.h that were
missing it.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 include/scsi.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/scsi.h b/include/scsi.h
index 8d6c5116419..c244120c283 100644
--- a/include/scsi.h
+++ b/include/scsi.h
@@ -340,6 +340,7 @@ int scsi_bus_reset(struct udevice *dev);
  * scsi_scan() - Scan all SCSI controllers for available devices
  *
  * @vebose: true to show information about each device found
+ * Return: 0 if OK, -ve on error
  */
 int scsi_scan(bool verbose);
 
@@ -348,6 +349,7 @@ int scsi_scan(bool verbose);
  *
  * @dev:	SCSI bus
  * @verbose:	true to show information about each device found
+ * Return: 0 if OK, -ve on error
  */
 int scsi_scan_dev(struct udevice *dev, bool verbose);
 
@@ -357,6 +359,7 @@ int scsi_scan_dev(struct udevice *dev, bool verbose);
  * @uuid:		UUID of the partition for fetching its info
  * @blk_desc_ptr:	Provides the blk descriptor
  * @part_info_ptr:	Provides partition info
+ * Return: 0 if OK, -ve on error
  */
 int scsi_get_blk_by_uuid(const char *uuid, struct blk_desc **blk_desc_ptr,
 			 struct disk_partition *part_info_ptr);

-- 
2.43.0

[PATCH 4/6] scsi: move scsi_scan() call out of scsi_get_blk_by_uuid()

[David Lechner]

Move scsi_scan() call out of scsi_get_blk_by_uuid().

The only caller, env_scsi_get_part(), should be managing this call since
it may also want to use different ways to get the partition information
in the future.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 drivers/scsi/scsi-uclass.c | 6 ------
 env/scsi.c                 | 6 ++++++
 include/scsi.h             | 2 ++
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/scsi-uclass.c b/drivers/scsi/scsi-uclass.c
index e7870d7f831..39b4c7476d4 100644
--- a/drivers/scsi/scsi-uclass.c
+++ b/drivers/scsi/scsi-uclass.c
@@ -29,15 +29,9 @@ int scsi_get_blk_by_uuid(const char *uuid,
 			 struct blk_desc **blk_desc_ptr,
 			 struct disk_partition *part_info_ptr)
 {
-	static int is_scsi_scanned;
 	struct blk_desc *blk;
 	int i, ret;
 
-	if (!is_scsi_scanned) {
-		scsi_scan(false /* no verbose */);
-		is_scsi_scanned = 1;
-	}
-
 	for (i = 0; i < blk_find_max_devnum(UCLASS_SCSI) + 1; i++) {
 		ret = blk_get_desc(UCLASS_SCSI, i, &blk);
 		if (ret)
diff --git a/env/scsi.c b/env/scsi.c
index f376f731870..1787dcca92a 100644
--- a/env/scsi.c
+++ b/env/scsi.c
@@ -33,8 +33,14 @@ static struct env_scsi_info env_part;
 
 static inline struct env_scsi_info *env_scsi_get_part(void)
 {
+	static bool is_scsi_scanned;
 	struct env_scsi_info *ep = &env_part;
 
+	if (!is_scsi_scanned) {
+		scsi_scan(false /* no verbose */);
+		is_scsi_scanned = true;
+	}
+
 	if (scsi_get_blk_by_uuid(CONFIG_ENV_SCSI_PART_UUID, &ep->blk, &ep->part))
 		return NULL;
 
diff --git a/include/scsi.h b/include/scsi.h
index c244120c283..2520a8b8fe6 100644
--- a/include/scsi.h
+++ b/include/scsi.h
@@ -356,6 +356,8 @@ int scsi_scan_dev(struct udevice *dev, bool verbose);
 /**
  * scsi_get_blk_by_uuid() - Provides SCSI partition information.
  *
+ * scsi_scan() must have been called before calling this function.
+ *
  * @uuid:		UUID of the partition for fetching its info
  * @blk_desc_ptr:	Provides the blk descriptor
  * @part_info_ptr:	Provides partition info

-- 
2.43.0

[PATCH 5/6] env: scsi: add CONFIG_ENV_SCSI_HW_PARTITION

[David Lechner]

Add CONFIG_ENV_SCSI_HW_PARTITION and supporting code to allow loading
the environment directly from a SCSI device without a partition table.
Some platforms store the environment directly on the SCSI device without
a way to look it up by partition UUID.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 env/Kconfig | 11 +++++++++++
 env/scsi.c  | 22 ++++++++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/env/Kconfig b/env/Kconfig
index 5824f762870..ffaf16c581c 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -762,6 +762,17 @@ config ENV_MMC_USE_DT
 	  The 2 defines CONFIG_ENV_OFFSET, CONFIG_ENV_OFFSET_REDUND
 	  are not used as fallback.
 
+config ENV_SCSI_HW_PARTITION
+	string "SCSI hardware partition number"
+	depends on ENV_IS_IN_SCSI
+	default 0
+	help
+	  SCSI hardware partition device number on the platform where the
+	  environment is stored.  Note that this is not related to any software
+	  defined partition table but instead if we are in the user area, which is
+	  partition 0 or the first boot partition, which is 1 or some other defined
+	  partition.
+
 config ENV_SCSI_PART_UUID
 	string "SCSI partition UUID for saving environment"
 	depends on ENV_IS_IN_SCSI
diff --git a/env/scsi.c b/env/scsi.c
index 1787dcca92a..f4986353da5 100644
--- a/env/scsi.c
+++ b/env/scsi.c
@@ -41,8 +41,14 @@ static inline struct env_scsi_info *env_scsi_get_part(void)
 		is_scsi_scanned = true;
 	}
 
-	if (scsi_get_blk_by_uuid(CONFIG_ENV_SCSI_PART_UUID, &ep->blk, &ep->part))
-		return NULL;
+	if (CONFIG_ENV_SCSI_PART_UUID[0] == '\0') {
+		if (blk_get_device_part_str("scsi", CONFIG_ENV_SCSI_HW_PARTITION,
+					    &ep->blk, &ep->part, true))
+			return NULL;
+	} else {
+		if (scsi_get_blk_by_uuid(CONFIG_ENV_SCSI_PART_UUID, &ep->blk, &ep->part))
+			return NULL;
+	}
 
 	ep->count = CONFIG_ENV_SIZE / ep->part.blksz;
 
@@ -89,12 +95,20 @@ static int env_scsi_load(void)
 	int ret;
 
 	if (!ep) {
-		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition not found", 0);
+		if (CONFIG_ENV_SCSI_PART_UUID[0] == '\0')
+			env_set_default("SCSI partition " CONFIG_ENV_SCSI_HW_PARTITION " not found", 0);
+		else
+			env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition not found", 0);
+
 		return -ENOENT;
 	}
 
 	if (blk_dread(ep->blk, ep->part.start, ep->count, &envbuf) != ep->count) {
-		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition read failed", 0);
+		if (CONFIG_ENV_SCSI_PART_UUID[0] == '\0')
+			env_set_default("SCSI partition " CONFIG_ENV_SCSI_HW_PARTITION " read failed", 0);
+		else
+			env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition read failed", 0);
+
 		return -EIO;
 	}
 

-- 
2.43.0

[PATCH 6/6] env: scsi: document requirements for ENV_IS_IN_SCSI

[David Lechner]

Expand the Kconfig help for ENV_IS_IN_SCSI to explain the other
required config options when this option is enabled.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 env/Kconfig | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/env/Kconfig b/env/Kconfig
index ffaf16c581c..9eb941b74a4 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -293,6 +293,23 @@ config ENV_IS_IN_SCSI
 	  Define this if you have an SCSI device which you want to use for the
 	  environment.
 
+	  - CONFIG_ENV_SIZE:
+
+	  The size of the partition where the environment is stored in bytes. Must
+	  be a multiple of the partition block size.
+
+	  - CONFIG_ENV_SCSI_HW_PARTITION:
+
+	  Specifies which SCSI partition the environment is stored in. If not
+	  set, defaults to partition 0, the user area. Common values might be
+	  1 (first SCSI boot partition), 2 (second SCSI boot partition). Ignored
+	  if CONFIG_ENV_SCSI_PART_UUID is set to non-empty string.
+
+	  - CONFIG_ENV_SCSI_PART_UUID:
+
+	  UUID of the SCSI partition where the environment is stored.
+
+
 config ENV_RANGE
 	hex "Length of the region in which the environment can be written"
 	depends on ENV_IS_IN_NAND

-- 
2.43.0

Re: [PATCH 1/6] env: scsi: rename ENV_SCSI_PART_UUID

[Sumit Garg]

On Thu, Mar 26, 2026 at 05:59:23PM -0500, David Lechner wrote:
> Rename SCSI_ENV_PART_UUID to ENV_SCSI_PART_UUID. All other environment-
> related config names are of the form ENV_<name>, so this is more
> consistent.
> 
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---
>  configs/qcom_qcs9100_defconfig | 2 +-
>  env/Kconfig                    | 2 +-
>  env/scsi.c                     | 6 +++---
>  3 files changed, 5 insertions(+), 5 deletions(-)

Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>

-Sumit

> 
> diff --git a/configs/qcom_qcs9100_defconfig b/configs/qcom_qcs9100_defconfig
> index 371448b8b1b..082106157bb 100644
> --- a/configs/qcom_qcs9100_defconfig
> +++ b/configs/qcom_qcs9100_defconfig
> @@ -11,6 +11,6 @@ CONFIG_REMAKE_ELF=y
>  CONFIG_FASTBOOT_BUF_ADDR=0xdb300000
>  CONFIG_DEFAULT_DEVICE_TREE="qcom/qcs9100-ride-r3"
>  CONFIG_ENV_IS_IN_SCSI=y
> -CONFIG_SCSI_ENV_PART_UUID="71cb9cd0-acf1-b6cb-ad91-be9572fe11a9"
> +CONFIG_ENV_SCSI_PART_UUID="71cb9cd0-acf1-b6cb-ad91-be9572fe11a9"
>  # CONFIG_ENV_IS_DEFAULT is not set
>  # CONFIG_ENV_IS_NOWHERE is not set
> diff --git a/env/Kconfig b/env/Kconfig
> index 2feff0b382e..5824f762870 100644
> --- a/env/Kconfig
> +++ b/env/Kconfig
> @@ -762,7 +762,7 @@ config ENV_MMC_USE_DT
>  	  The 2 defines CONFIG_ENV_OFFSET, CONFIG_ENV_OFFSET_REDUND
>  	  are not used as fallback.
>  
> -config SCSI_ENV_PART_UUID
> +config ENV_SCSI_PART_UUID
>  	string "SCSI partition UUID for saving environment"
>  	depends on ENV_IS_IN_SCSI
>  	help
> diff --git a/env/scsi.c b/env/scsi.c
> index 207717e17b1..f376f731870 100644
> --- a/env/scsi.c
> +++ b/env/scsi.c
> @@ -35,7 +35,7 @@ static inline struct env_scsi_info *env_scsi_get_part(void)
>  {
>  	struct env_scsi_info *ep = &env_part;
>  
> -	if (scsi_get_blk_by_uuid(CONFIG_SCSI_ENV_PART_UUID, &ep->blk, &ep->part))
> +	if (scsi_get_blk_by_uuid(CONFIG_ENV_SCSI_PART_UUID, &ep->blk, &ep->part))
>  		return NULL;
>  
>  	ep->count = CONFIG_ENV_SIZE / ep->part.blksz;
> @@ -83,12 +83,12 @@ static int env_scsi_load(void)
>  	int ret;
>  
>  	if (!ep) {
> -		env_set_default(CONFIG_SCSI_ENV_PART_UUID " partition not found", 0);
> +		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition not found", 0);
>  		return -ENOENT;
>  	}
>  
>  	if (blk_dread(ep->blk, ep->part.start, ep->count, &envbuf) != ep->count) {
> -		env_set_default(CONFIG_SCSI_ENV_PART_UUID " partition read failed", 0);
> +		env_set_default(CONFIG_ENV_SCSI_PART_UUID " partition read failed", 0);
>  		return -EIO;
>  	}
>  
> 
> -- 
> 2.43.0
> 

Re: [PATCH 0/6] env: scsi: support SCSI env without partition UUID

[Tom Rini]

On Thu, 26 Mar 2026 17:59:22 -0500, David Lechner wrote:

> This is a series adding support for reading U-Boot env directly from
> SCSI devices that do not have a partition table, similar to how we can
> already do this for MMC devices.
> 
> The motivation behind this is that MediaTek's BSP is already using the
> same disk images for both MMC and UFS devices, so we need to be able to
> read the env from SCSI devices without requiring a partition UUID.
> 
> [...]

Applied to u-boot/master, thanks!

[1/6] env: scsi: rename ENV_SCSI_PART_UUID
      commit: ad4831d7a51d53bdb5ed0493fdc7bb510ce3f9a5
[2/6] scsi: return ENODEV in scsi_get_blk_by_uuid()
      commit: e5d8ad260bb7de1729a6454e8b95a83e629dff7a
[3/6] scsi: document return values of public functions
      commit: 7b824e75056a45d7c40eea9014edffa1b5289750
[4/6] scsi: move scsi_scan() call out of scsi_get_blk_by_uuid()
      commit: b382cd0973521a5197a097d4e190f47aadb79757
[5/6] env: scsi: add CONFIG_ENV_SCSI_HW_PARTITION
      commit: 83223d4f86980f09fdf341b64f69e03313cac14b
[6/6] env: scsi: document requirements for ENV_IS_IN_SCSI
      commit: d72c2b63da5c004bb41855577d4fd783598b004a
-- 
Tom