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cmd: rng: Add support for selecting RNG device

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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>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Sughosh Ganu 2022-07-22 21:32:06 +05:30 committed by Ilias Apalodimas
parent aedd45138e
commit 87ab234c1c
1 changed files with 23 additions and 8 deletions
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31
cmd/rng.c
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@ -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_by_seq(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
);