* [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable
@ 2026-06-13 2:54 Marek Vasut
2026-06-14 10:15 ` Łukasz Majewski
0 siblings, 1 reply; 2+ messages in thread
From: Marek Vasut @ 2026-06-13 2:54 UTC (permalink / raw)
To: u-boot
Cc: Marek Vasut, Lukasz Majewski, Mattijs Korpershoek, Simon Glass,
Tom Rini
The DFU code currently sets the content of "serial#" environment
variable into Device Descriptor iSerial field. This is useful when
there are multiple devices connected to the same host PC and they
have to be told apart. Replicate the same behavior in the UMS code.
Example without serial# set, which is the original behavior:
"
u-boot=> ums 0 mmc 1
UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
$ dmesg -w
...
usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice=7e.a7
usb 5-2.3.7: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 5-2.3.7: Product: USB download gadget
usb 5-2.3.7: Manufacturer: Vendor
<------------------------------- NOT HERE
usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
...
$ lsusb -vd 0525:a4a5
Bus 005 Device 051: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB File-backed Storage Gadget
Negotiated speed: High Speed (480Mbps)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 [unknown]
bDeviceSubClass 0 [unknown]
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0525 Netchip Technology, Inc.
idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
bcdDevice 7e.a7
iManufacturer 1 Vendor
iProduct 2 USB download gadget
iSerial 0 <------------------------------- NOT HERE
...
"
Example with serial# set to 1234abcd, which is the optional new behavior:
"
u-boot=> setenv serial# 1234abcd <------------------------------ HERE
u-boot=> ums 0 mmc 1
UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
$ dmesg -w
...
usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice=7e.a7
usb 5-2.3.7: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 5-2.3.7: Product: USB download gadget
usb 5-2.3.7: Manufacturer: Vendor
usb 5-2.3.7: SerialNumber: 1234abcd <--------------------------- HERE
usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
...
$ lsusb -vd 0525:a4a5
Bus 005 Device 052: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB File-backed Storage Gadget
Negotiated speed: High Speed (480Mbps)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 [unknown]
bDeviceSubClass 0 [unknown]
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0525 Netchip Technology, Inc.
idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
bcdDevice 7e.a7
iManufacturer 1 Vendor
iProduct 2 USB download gadget
iSerial 3 1234abcd <-------------------------- HERE
...
"
Signed-off-by: Marek Vasut <marex@nabladev.com>
---
Cc: Lukasz Majewski <lukma@nabladev.com>
Cc: Mattijs Korpershoek <mkorpershoek@kernel.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: u-boot@lists.denx.de
---
cmd/usb_mass_storage.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/cmd/usb_mass_storage.c b/cmd/usb_mass_storage.c
index e8b87045bdc..335258d7a56 100644
--- a/cmd/usb_mass_storage.c
+++ b/cmd/usb_mass_storage.c
@@ -9,6 +9,7 @@
#include <blk.h>
#include <command.h>
#include <console.h>
+#include <env.h>
#include <errno.h>
#include <g_dnl.h>
#include <malloc.h>
@@ -65,7 +66,7 @@ static void ums_fini(void)
static int ums_init(const char *devtype, const char *devnums_part_str)
{
- char *s, *t, *devnum_part_str, *name;
+ char *s, *t, *devnum_part_str, *name, *sn;
struct blk_desc *block_dev;
struct disk_partition info;
int partnum;
@@ -76,6 +77,12 @@ static int ums_init(const char *devtype, const char *devnums_part_str)
if (!s)
return -1;
+ if (CONFIG_IS_ENABLED(ENV_SUPPORT)) {
+ sn = env_get("serial#");
+ if (sn)
+ g_dnl_set_serialnumber(sn);
+ }
+
t = s;
ums_count = 0;
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable
2026-06-13 2:54 [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable Marek Vasut
@ 2026-06-14 10:15 ` Łukasz Majewski
0 siblings, 0 replies; 2+ messages in thread
From: Łukasz Majewski @ 2026-06-14 10:15 UTC (permalink / raw)
To: Marek Vasut; +Cc: u-boot, Mattijs Korpershoek, Simon Glass, Tom Rini
On Sat, 13 Jun 2026 04:54:23 +0200
Marek Vasut <marex@nabladev.com> wrote:
> The DFU code currently sets the content of "serial#" environment
> variable into Device Descriptor iSerial field. This is useful when
> there are multiple devices connected to the same host PC and they
> have to be told apart. Replicate the same behavior in the UMS code.
>
> Example without serial# set, which is the original behavior:
> "
> u-boot=> ums 0 mmc 1
> UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
>
> $ dmesg -w
> ...
> usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5,
> bcdDevice=7e.a7 usb 5-2.3.7: New USB device strings: Mfr=1,
> Product=2, SerialNumber=0 usb 5-2.3.7: Product: USB download gadget
> usb 5-2.3.7: Manufacturer: Vendor
> <------------------------------- NOT HERE
> usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
> ...
>
> $ lsusb -vd 0525:a4a5
>
> Bus 005 Device 051: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB
> File-backed Storage Gadget Negotiated speed: High Speed (480Mbps)
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.00
> bDeviceClass 0 [unknown]
> bDeviceSubClass 0 [unknown]
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x0525 Netchip Technology, Inc.
> idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
> bcdDevice 7e.a7
> iManufacturer 1 Vendor
> iProduct 2 USB download gadget
> iSerial 0 <------------------------------- NOT HERE
> ...
> "
>
> Example with serial# set to 1234abcd, which is the optional new
> behavior: "
> u-boot=> setenv serial# 1234abcd <------------------------------ HERE
> u-boot=> ums 0 mmc 1
> UMS: LUN 0, dev mmc 1, hwpart 0, sector 0x0, count 0x1d5a000
>
> $ dmesg -w
> ...
> usb 5-2.3.7: New USB device found, idVendor=0525, idProduct=a4a5,
> bcdDevice=7e.a7 usb 5-2.3.7: New USB device strings: Mfr=1,
> Product=2, SerialNumber=3 usb 5-2.3.7: Product: USB download gadget
> usb 5-2.3.7: Manufacturer: Vendor
> usb 5-2.3.7: SerialNumber: 1234abcd <--------------------------- HERE
> usb-storage 5-2.3.7:1.0: USB Mass Storage device detected
> ...
>
> $ lsusb -vd 0525:a4a5
>
> Bus 005 Device 052: ID 0525:a4a5 Netchip Technology, Inc. Linux-USB
> File-backed Storage Gadget Negotiated speed: High Speed (480Mbps)
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.00
> bDeviceClass 0 [unknown]
> bDeviceSubClass 0 [unknown]
> bDeviceProtocol 0
> bMaxPacketSize0 64
> idVendor 0x0525 Netchip Technology, Inc.
> idProduct 0xa4a5 Linux-USB File-backed Storage Gadget
> bcdDevice 7e.a7
> iManufacturer 1 Vendor
> iProduct 2 USB download gadget
> iSerial 3 1234abcd <-------------------------- HERE
> ...
> "
>
> Signed-off-by: Marek Vasut <marex@nabladev.com>
> ---
> Cc: Lukasz Majewski <lukma@nabladev.com>
> Cc: Mattijs Korpershoek <mkorpershoek@kernel.org>
> Cc: Simon Glass <sjg@chromium.org>
> Cc: Tom Rini <trini@konsulko.com>
> Cc: u-boot@lists.denx.de
> ---
> cmd/usb_mass_storage.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/cmd/usb_mass_storage.c b/cmd/usb_mass_storage.c
> index e8b87045bdc..335258d7a56 100644
> --- a/cmd/usb_mass_storage.c
> +++ b/cmd/usb_mass_storage.c
> @@ -9,6 +9,7 @@
> #include <blk.h>
> #include <command.h>
> #include <console.h>
> +#include <env.h>
> #include <errno.h>
> #include <g_dnl.h>
> #include <malloc.h>
> @@ -65,7 +66,7 @@ static void ums_fini(void)
>
> static int ums_init(const char *devtype, const char
> *devnums_part_str) {
> - char *s, *t, *devnum_part_str, *name;
> + char *s, *t, *devnum_part_str, *name, *sn;
> struct blk_desc *block_dev;
> struct disk_partition info;
> int partnum;
> @@ -76,6 +77,12 @@ static int ums_init(const char *devtype, const
> char *devnums_part_str) if (!s)
> return -1;
>
> + if (CONFIG_IS_ENABLED(ENV_SUPPORT)) {
> + sn = env_get("serial#");
> + if (sn)
> + g_dnl_set_serialnumber(sn);
> + }
> +
> t = s;
> ums_count = 0;
>
Reviewed-by: Łukasz Majewski <lukma@nabladev.com>
--
Best regards,
Lukasz Majewski
--
Nabla Software Engineering GmbH
HRB 40522 Augsburg
Phone: +49 821 45592596
E-Mail: office@nabladev.com
Managing Director : Stefano Babic
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-06-13 2:54 [PATCH] cmd: ums: Set Device Descriptor iSerial based on serial# env variable Marek Vasut
2026-06-14 10:15 ` Łukasz Majewski
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