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.ganu@linaro.org --- cmd/rng.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/cmd/rng.c b/cmd/rng.c index 1ad5a096c0..2b197e322e 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 );