On Thu, Feb 04, 2021 at 08:26:52AM -0500, Tom Rini wrote: > On Thu, Feb 04, 2021 at 06:56:47AM -0300, Fabio Estevam wrote: > > Hi Tom, > > > > [Adding Bryan] > > > > On Thu, Feb 4, 2021 at 12:49 AM Tom Rini <tr...@konsulko.com> wrote: > > > > > CONFIG_SERIAL_TAG is only used to configure the ATAG serial record. It > > > does nothing else. On i.MX8* this is already being discarded. On i.MX7 > > > we see things like: > > > warp7 : all -144 rodata +32 text -176 > > > u-boot: add: 0/-2, grow: 0/-2 bytes: 0/-160 (-160) > > > function old new > > > delta > > > params 4 - > > > -4 > > > get_board_serial 20 - > > > -20 > > > board_late_init 96 56 > > > -40 > > > boot_prep_linux 156 60 > > > -96 > > > > But then it will remove the support of reading serial number via fuses > > which was added by: > > > > commit 852cc548b3fdf6d5b46e2a96f876d14608ccdcf4 > > Author: Bryan O'Donoghue <bryan.odonog...@linaro.org> > > Date: Mon Mar 26 15:27:34 2018 +0100 > > > > warp7: Set u-boot serial# based on OTP value > > > > u-boot has a standard "serial#" environment variable that is suitable > > for storing the iSerial number we will supply via the USB device > > descriptor. serial# is automatically picked up by the disk subsystem in > > u-boot - thus providing a handy unique identifier in /dev/disk/by-id as > > detailed below. > > > > Storing the hardware serial identifier in serial# means we can change > > the > > serial# if we want before USB enumeration - thus making iSerial > > automatic > > via OTP but overridable if necessary. > > > > This patch reads the defined OTP fuse and sets environment variable > > "serial#" to the value read. > > > > With this patch in place the USB mass storage device will appear in > > /dev/disk/by-id with a unique name based on the OTP value. For example > > > > /dev/disk/by-id/usb-Linux_UMS_disk_0_WaRP7-0xf42400d3000001d4-0:0 > > > > Signed-off-by: Bryan O'Donoghue <bryan.odonog...@linaro.org> > > Cc: Fabio Estevam <fabio.este...@nxp.com> > > Cc: Rui Miguel Silva <rui.si...@linaro.org> > > Cc: Ryan Harkin <ryan.har...@linaro.org> > > Reviewed-by: Fabio Estevam <fabio.este...@nxp.com> > > I did miss that one. I'm not sure if that's abusing a symbol or clever > use of the symbol. I will have to v2 this one then.
This should end up under CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG someway or another. I'm going to make an attempt at it, but the biggest hurdle is that most often "serial#" is just the fuse(s) value and not prepended by a board-specific string (OR if it is, it's just in the fdt property we read and set from). -- Tom
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