Should it be:
#if CONFIG_BOARDCTL_UNIQUEID_SIZE <= RP2040_FLASH_ID_SIZE ?
BR,
Alan
On Mon, Apr 1, 2024 at 5:45 PM Anders <andyl...@proton.me.invalid> wrote:
> Hi,
>
> The unique id solution for the Raspberry Pi by Adam and his team works
> very well. However, I suggest a slight modification of the code. In short,
> if the number of bytes of the NuttX unique id is configured equal to the
> actual number of bytes of the id in the Pico flash hardware system (8
> bytes), the hardware id is just copied and not used as a PRNG seed. If the
> configured size of the NuttX unique id is larger than the flash hardware,
> the PRNG code is used to return a unique id with more (non-zero) bytes. The
> advantage of having the function returning the actual hardware id, is that
> this is easily compared to the id returned by the Pico SDK function.
> Remember that the number of bytes (bits) in the flash hardware id sets a
> limit on how many unique ids there are, even if those are embedded
> (distributed) in a larger number of bytes (bits), as is the result of the
> PRNG function.
>
> The suggested code (from the
> boards/arm/rp2040/common/src/rp2040_uniqueid.c):
>
> void rp2040_uniqueid_initialize(void)
> {
> uint8_t txbuf[RP2040_FLASH_ID_BUFFER_SIZE];
> uint8_t rxbuf[RP2040_FLASH_ID_BUFFER_SIZE];
>
> memset(g_uniqueid, 0xac, CONFIG_BOARDCTL_UNIQUEID_SIZE);
> memset(txbuf, 0, RP2040_FLASH_ID_BUFFER_SIZE);
> memset(rxbuf, 0, RP2040_FLASH_ID_BUFFER_SIZE);
> txbuf[0] = RP2040_FLASH_RUID_CMD;
>
> rp2040_flash_cmd(txbuf, rxbuf, RP2040_FLASH_ID_BUFFER_SIZE);
>
> #if CONFIG_BOARDCTL_UNIQUEID_SIZE == RP2040_FLASH_ID_SIZE
> for (int i = 0; i < CONFIG_BOARDCTL_UNIQUEID_SIZE; i++)
> {
> g_uniqueid[i] = rxbuf[i + RP2040_FLASH_ID_BUFFER_OFFSET];
> }
> #else
> /* xorshift PRNG: */
> uint64_t x;
> x = *(uint64_t *)(rxbuf + RP2040_FLASH_ID_BUFFER_OFFSET);
> for (int i = 0; i < CONFIG_BOARDCTL_UNIQUEID_SIZE; i++)
> {
> x ^= x >> 12;
> x ^= x << 25;
> x ^= x >> 27;
> g_uniqueid[i] = (uint8_t)((x * 0x2545f4914f6cdd1dull) >> 32);
> }
> #endif
> }
>
> Any comments?
>
> Anders
>
>
>
>
> On Monday, 18 March 2024 at 06:51, Anders <andyl...@proton.me.INVALID>
> wrote:
>
> > Hello Adam
> >
> > Excellent! Precisely what I was looking for. I'll check it out.
> >
> > Thanks,
> > Anders
> >
> > On Sunday, 17 March 2024 at 12:54, Adam Comley a...@novators.net wrote:
> >
> > > Hi Anders,
> > >
> > > I recently had a need for this feature as well, and put together a PR
> > > based on the pico-sdk implementation. See:
> > >
> > > https://github.com/apache/nuttx/pull/11927
> > >
> > > Hope this helps.
> > >
> > > -- Adam
>
