From 97ecafc4f6566f538bbde09d3a8baae4a3419eef Mon Sep 17 00:00:00 2001 From: Martin Kaiser Date: Fri, 19 May 2023 18:04:31 +0200 Subject: hwrng: imx-rngc - simpler check for available random bytes The "level" field in the status register contains the number of random bytes that are available in the FIFO. Use GENMASK to extract this field. We only want to check if level is 0 or if we can read another byte. There's no need for the shift or the level variable. Signed-off-by: Martin Kaiser Signed-off-by: Herbert Xu --- drivers/char/hw_random/imx-rngc.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c index a1c24148ed31..cf29c323453a 100644 --- a/drivers/char/hw_random/imx-rngc.c +++ b/drivers/char/hw_random/imx-rngc.c @@ -17,6 +17,7 @@ #include #include #include +#include #define RNGC_VER_ID 0x0000 #define RNGC_COMMAND 0x0004 @@ -44,8 +45,7 @@ #define RNGC_CTRL_AUTO_SEED 0x00000010 #define RNGC_STATUS_ERROR 0x00010000 -#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00 -#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8 +#define RNGC_STATUS_FIFO_LEVEL_MASK GENMASK(11, 8) #define RNGC_STATUS_SEED_DONE 0x00000020 #define RNGC_STATUS_ST_DONE 0x00000010 @@ -122,7 +122,6 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) { struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); unsigned int status; - unsigned int level; int retval = 0; while (max >= sizeof(u32)) { @@ -132,11 +131,7 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait) if (status & RNGC_STATUS_ERROR) break; - /* how many random numbers are in FIFO? [0-16] */ - level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >> - RNGC_STATUS_FIFO_LEVEL_SHIFT; - - if (level) { + if (status & RNGC_STATUS_FIFO_LEVEL_MASK) { /* retrieve a random number from FIFO */ *(u32 *)data = readl(rngc->base + RNGC_FIFO); -- cgit v1.2.3