[PATCH] ARM: mx6: Add function to read UNIQUE_ID

[Sean Anderson]

On 2/4/21 3:52 PM, Heinrich Schuchardt wrote:
 > On 2/4/21 9:29 PM, Sean Anderson wrote:
 >> This is almost identical to the imx7 version, except that the register
 >> names are different.
 >>
 >> Signed-off-by: Sean Anderson <sean.anderson at seco.com>
 >
 > Hello Sean,
 >
 > I tried to understand where this serial number is ending up.
 >
 > It seems to be used by the bootm command. But shouldn't we use it to
 > define environment variable #serial instead?

Yes. Typically boards will use get_board_serial to set serial#. For
example, the warp7 board does

int board_late_init(void)
{
	/* ... snip ... */

#ifdef CONFIG_SERIAL_TAG
	/* Set serial# standard environment variable based on OTP settings */
	get_board_serial(&serialnr);
	snprintf(serial_string, sizeof(serial_string), "WaRP7-0x%08x%08x",
		 serialnr.low, serialnr.high);
	env_set("serial#", serial_string);
#endif

	return 0;
}

I would like to do the same on an i.MX6-based board.

--Sean

 >
 > Best regards
 >
 > Heinrich
 >
 >> ---
 >>
 >>   arch/arm/mach-imx/mx6/soc.c | 33 +++++++++++++++++++++++++++++++++
 >>   1 file changed, 33 insertions(+)
 >>
 >> diff --git a/arch/arm/mach-imx/mx6/soc.c b/arch/arm/mach-imx/mx6/soc.c
 >> index bf6dddfdc9..cb729be46f 100644
 >> --- a/arch/arm/mach-imx/mx6/soc.c
 >> +++ b/arch/arm/mach-imx/mx6/soc.c
 >> @@ -11,6 +11,7 @@
 >>   #include <linux/delay.h>
 >>   #include <linux/errno.h>
 >>   #include <asm/io.h>
 >> +#include <asm/setup.h>
 >>   #include <asm/arch/imx-regs.h>
 >>   #include <asm/arch/clock.h>
 >>   #include <asm/arch/sys_proto.h>
 >> @@ -705,6 +706,38 @@ int arch_misc_init(void)
 >>   }
 >>   #endif
 >>
 >> +#ifdef CONFIG_SERIAL_TAG
 >> +/*
 >> + * UNIQUE_ID describes a unique ID based on silicon wafer
 >> + * and die X/Y position
 >> + *
 >> + * UNIQUE_ID offset 0x410
 >> + * 31:0 fuse 0
 >> + * FSL-wide unique, encoded LOT ID STD II/SJC CHALLENGE/ Unique ID
 >> + *
 >> + * UNIQUE_ID offset 0x420
 >> + * 31:24 fuse 1
 >> + * The X-coordinate of the die location on the wafer/SJC CHALLENGE/
 >> Unique ID
 >> + * 23:16 fuse 1
 >> + * The Y-coordinate of the die location on the wafer/SJC CHALLENGE/
 >> Unique ID
 >> + * 15:11 fuse 1
 >> + * The wafer number of the wafer on which the device was fabricated/SJC
 >> + * CHALLENGE/ Unique ID
 >> + * 10:0 fuse 1
 >> + * FSL-wide unique, encoded LOT ID STD II/SJC CHALLENGE/ Unique ID
 >> + */
 >> +void get_board_serial(struct tag_serialnr *serialnr)
 >> +{
 >> +    struct ocotp_regs *ocotp = (struct ocotp_regs *)OCOTP_BASE_ADDR;
 >> +    struct fuse_bank *bank = &ocotp->bank[0];
 >> +    struct fuse_bank0_regs *fuse =
 >> +        (struct fuse_bank0_regs *)bank->fuse_regs;
 >> +
 >> +    serialnr->low = fuse->uid_low;
 >> +    serialnr->high = fuse->uid_high;
 >> +}
 >> +#endif
 >> +
 >>   /*
 >>    * gpr_init() function is common for boards using MX6S, MX6DL, MX6D,
 >>    * MX6Q and MX6QP processors
 >>
 >