From 87ab234c1cf42a38655b4f93d0dc399b9a9561fa Mon Sep 17 00:00:00 2001 From: Sughosh Ganu Date: Fri, 22 Jul 2022 21:32:06 +0530 Subject: cmd: rng: Add support for selecting RNG device 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 Tested-by: Heinrich Schuchardt Reviewed-by: Ilias Apalodimas Signed-off-by: Ilias Apalodimas --- cmd/rng.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) (limited to 'cmd/rng.c') diff --git a/cmd/rng.c b/cmd/rng.c index 1ad5a096c0b..2ddf27545f0 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_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 ); -- cgit v1.2.3 From c79e274c7c6637eeaf631988b18dd68a30596778 Mon Sep 17 00:00:00 2001 From: Sughosh Ganu Date: Fri, 22 Jul 2022 21:32:07 +0530 Subject: cmd: rng: Use a statically allocated array for random bytes Use a statically allocated buffer on stack instead of using malloc for reading the random bytes. Using a local array is faster than allocating heap memory on every initiation of the command. Signed-off-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas Reviewed-by: Simon Glass Signed-off-by: Ilias Apalodimas --- cmd/rng.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) (limited to 'cmd/rng.c') diff --git a/cmd/rng.c b/cmd/rng.c index 2ddf27545f0..81a23964b82 100644 --- a/cmd/rng.c +++ b/cmd/rng.c @@ -14,9 +14,9 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) { size_t n; - struct udevice *dev; - void *buf; + u8 buf[64]; int devnum; + struct udevice *dev; int ret = CMD_RET_SUCCESS; switch (argc) { @@ -41,11 +41,10 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) return CMD_RET_FAILURE; } - buf = malloc(n); - if (!buf) { - printf("Out of memory\n"); - return CMD_RET_FAILURE; - } + if (!n) + return 0; + + n = min(n, sizeof(buf)); if (dm_rng_read(dev, buf, n)) { printf("Reading RNG failed\n"); @@ -54,15 +53,13 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n); } - free(buf); - return ret; } #ifdef CONFIG_SYS_LONGHELP static char rng_help_text[] = "[dev [n]]\n" - " - print n random bytes read from dev\n"; + " - print n random bytes(max 64) read from dev\n"; #endif U_BOOT_CMD( -- cgit v1.2.3