[{"id":3683637,"web_url":"http://patchwork.ozlabs.org/comment/3683637/","msgid":"","list_archive_url":null,"date":"2026-04-28T18:18:42","subject":"Re: [PATCH v2 1/4] fastboot: block: Add device selection syntax","submitter":{"id":6170,"url":"http://patchwork.ozlabs.org/api/people/6170/","name":"Simon Glass","email":"sjg@chromium.org"},"content":"Hi Balaji,\n\nOn 2026-04-27T12:06:41, Balaji Selvanathan\n wrote:\n> fastboot: block: Add device selection syntax\n>\n> Implement device selection syntax allowing users to specify the\n> target block device using 'N:partition' format, where N is the\n> device number. When no device is specified, the default from\n> CONFIG_FASTBOOT_FLASH_BLOCK_DEVICE_ID is used.\n>\n> Modify fastboot_block_get_part_info() to use the new parsing\n> function, enabling operations like \"fastboot flash 0:boot boot.img\"\n> to write to specific devices while maintaining backward compatibility\n> with the existing \"fastboot flash boot boot.img\" syntax.\n>\n> Example usage:\n> fastboot flash 0:boot boot.img # Flash to device 0\n> fastboot flash 1:system system.img # Flash to device 1\n> fastboot flash boot boot.img # Use default device\n>\n> Signed-off-by: Balaji Selvanathan \n>\n> drivers/fastboot/fb_block.c | 53 +++++++++++++++++++++++++++++++++++++++++----\n> 1 file changed, 49 insertions(+), 4 deletions(-)\n\n> diff --git a/drivers/fastboot/fb_block.c b/drivers/fastboot/fb_block.c\n> @@ -133,25 +172,31 @@ int fastboot_block_get_part_info(const char *part_name,\n> *dev_desc = blk_get_dev(interface, device);\n> - if (!dev_desc) {\n> + if (!*dev_desc) {\n> fastboot_fail(\"no such device\", response);\n> return -ENODEV;\n> }\n\nThis is a real bug fix - the old test could never fail since dev_desc\nis the address of a local pointer - but it is unrelated to the\ndevice-selection syntax. Please split it into its own patch at the\nstart of the series so it is easy to backport.\n\n> diff --git a/drivers/fastboot/fb_block.c b/drivers/fastboot/fb_block.c\n> @@ -124,6 +125,44 @@ static lbaint_t fb_block_sparse_reserve(struct sparse_storage *info,\n> + /* Override if device:partition format detected */\n> + if (colon_pos && colon_pos > part_name) {\n> + *device = simple_strtoul(part_name, NULL, 10);\n\nsimple_strtoul() with a NULL endp silently accepts anything -\n'foo:boot' parses as device 0 and quietly writes to the default\ndevice, which is exactly the surprise the new syntax is meant to\navoid. Please pass an endp and reject input where the consumed length\ndoesn't reach colon_pos, so a malformed prefix becomes -EINVAL.\ndectoul() is preferred over simple_strtoul(..., 10) in new code.\n\n> diff --git a/drivers/fastboot/fb_block.c b/drivers/fastboot/fb_block.c\n> @@ -124,6 +125,44 @@ static lbaint_t fb_block_sparse_reserve(struct sparse_storage *info,\n> +static int parse_device_partition(const char *part_name, int *device,\n> + const char **partition_name)\n\nU-Boot already uses dev:partnum for partition numbers\n(part_get_info_by_dev_and_name_or_num() - '0:1' means device 0,\npartition 1) and dev#partname for names. Reusing ':' for a name lookup\nmeans '0:1' becomes ambiguous on boards that label partitions\nnumerically. How about '#' instead, to match the rest of the disk\nlayer?\n\n> diff --git a/drivers/fastboot/fb_block.c b/drivers/fastboot/fb_block.c\n> @@ -124,6 +125,44 @@ static lbaint_t fb_block_sparse_reserve(struct sparse_storage *info,\n> + * @partition_name: Output partition name pointer (can be NULL)\n\nJust to clarify, the kernel-doc says partition_name can be NULL but\nevery caller in this patch passes non-NULL - the NULL handling only\nbecomes useful in patch 3, so please move it to the patch that needs\nit, so each patch is self-contained.\n\nRegards,\nSimon","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256\n header.s=google header.b=k6cnUu4Q;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.denx.de\n (client-ip=2a01:238:438b:c500:173d:9f52:ddab:ee01; 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Tue, 28 Apr 2026\n 11:18:54 -0700 (PDT)","MIME-Version":"1.0","References":"<20260427-fb_gpt-v2-0-9e7fe3c1649a@oss.qualcomm.com>\n <20260427-fb_gpt-v2-1-9e7fe3c1649a@oss.qualcomm.com>","In-Reply-To":"<20260427-fb_gpt-v2-1-9e7fe3c1649a@oss.qualcomm.com>","From":"Simon Glass ","Date":"Tue, 28 Apr 2026 12:18:42 -0600","X-Gm-Features":"AVHnY4If9Cs7KEYoc175YfIk6wqZmbNHZBSvc_kxvbPcbLgraIquDcClKH89xbo","Message-ID":"\n ","Subject":"Re: [PATCH v2 1/4] fastboot: block: Add device selection syntax","To":"balaji.selvanathan@oss.qualcomm.com","Cc":"u-boot@lists.denx.de, Mattijs Korpershoek ,\n Tom Rini , Heiko Schocher ,\n Neil Armstrong ,\n Dmitrii Merkurev ,\n Adrian Freihofer , Peng Fan ,\n Jaehoon Chung ,\n \"Ariel D'Alessandro\" ","Content-Type":"text/plain; charset=\"UTF-8\"","X-BeenThere":"u-boot@lists.denx.de","X-Mailman-Version":"2.1.39","Precedence":"list","List-Id":"U-Boot discussion ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"u-boot-bounces@lists.denx.de","Sender":"\"U-Boot\" ","X-Virus-Scanned":"clamav-milter 0.103.8 at phobos.denx.de","X-Virus-Status":"Clean"}}]