On Fri, Mar 04, 2022 at 07:04:27PM +0530, Sughosh Ganu wrote:
> The 'rng' u-boot command is used for printing a select number of
> random bytes on the console. Currently, the RNG device from which the
> random bytes are read is fixed. However, a platform can have multiple
> RNG devices, one example being qemu, which has a virtio RNG device and
> the RNG pseudo device through the TPM chip.
>
> Extend the 'rng' command so that the user can provide the RNG device
> number from which the random bytes are to be read. This will be the
> device index under the RNG uclass.
>
> Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
> Tested-by: Heinrich Schuchardt <xypron.g...@gmx.de>
> ---
>
> Changes since V2: None
>
> cmd/rng.c | 31 +++++++++++++++++++++++--------
> 1 file changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/cmd/rng.c b/cmd/rng.c
> index 1ad5a096c0..bb89cfa784 100644
> --- a/cmd/rng.c
> +++ b/cmd/rng.c
> @@ -13,19 +13,34 @@
>
> static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const
> argv[])
> {
> - size_t n = 0x40;
> + size_t n;
> struct udevice *dev;
> void *buf;
> + int devnum;
> int ret = CMD_RET_SUCCESS;
>
> - if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
> + switch (argc) {
> + case 1:
> + devnum = 0;
> + n = 0x40;
> + break;
> + case 2:
> + devnum = hextoul(argv[1], NULL);
> + n = 0x40;
> + break;
> + case 3:
> + devnum = hextoul(argv[1], NULL);
> + n = hextoul(argv[2], NULL);
> + break;
> + default:
> + return CMD_RET_USAGE;
> + }
> +
> + if (uclass_get_device(UCLASS_RNG, devnum, &dev) || !dev) {
> printf("No RNG device\n");
> return CMD_RET_FAILURE;
> }
>
> - if (argc >= 2)
> - n = hextoul(argv[1], NULL);
> -
> buf = malloc(n);
> if (!buf) {
> printf("Out of memory\n");
> @@ -46,12 +61,12 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int
> argc, char *const argv[])
>
> #ifdef CONFIG_SYS_LONGHELP
> static char rng_help_text[] =
> - "[n]\n"
> - " - print n random bytes\n";
> + "[dev [n]]\n"
> + " - print n random bytes read from dev\n";
> #endif
>
> U_BOOT_CMD(
> - rng, 2, 0, do_rng,
> + rng, 3, 0, do_rng,
> "print bytes from the hardware random number generator",
> rng_help_text
> );
> --
> 2.25.1
>
Reviewed-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
