diff options
| author | Claudiu Beznea <claudiu.beznea@microchip.com> | 2022-02-21 09:59:22 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2022-03-03 10:46:18 +1200 |
| commit | 0934683dd1c7d307cac29902ee5e0ab50aa279f9 (patch) | |
| tree | 76e87371e7ad1436920b71ced11da1a353581eb4 /drivers/char | |
| parent | 0a2a464f863187f97e96ebc6384c052cafd4a54c (diff) | |
| download | linux-0934683dd1c7d307cac29902ee5e0ab50aa279f9.tar.bz2 | |
hwrng: atmel - add wait for ready support on read
Add wait for ready support on read.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/hw_random/atmel-rng.c | 43 |
1 files changed, 30 insertions, 13 deletions
diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c index ecb71c4317a5..1a4874668c04 100644 --- a/drivers/char/hw_random/atmel-rng.c +++ b/drivers/char/hw_random/atmel-rng.c @@ -13,6 +13,7 @@ #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/hw_random.h> #include <linux/of_device.h> #include <linux/platform_device.h> @@ -20,6 +21,7 @@ #define TRNG_CR 0x00 #define TRNG_MR 0x04 #define TRNG_ISR 0x1c +#define TRNG_ISR_DATRDY BIT(0) #define TRNG_ODATA 0x50 #define TRNG_KEY 0x524e4700 /* RNG */ @@ -36,25 +38,40 @@ struct atmel_trng { struct hwrng rng; }; +static bool atmel_trng_wait_ready(struct atmel_trng *trng, bool wait) +{ + int ready; + + ready = readl(trng->base + TRNG_ISR) & TRNG_ISR_DATRDY; + if (!ready && wait) + readl_poll_timeout(trng->base + TRNG_ISR, ready, + ready & TRNG_ISR_DATRDY, 1000, 20000); + + return !!ready; +} + static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng); u32 *data = buf; + int ret; + + ret = atmel_trng_wait_ready(trng, wait); + if (!ret) + goto out; - /* data ready? */ - if (readl(trng->base + TRNG_ISR) & 1) { - *data = readl(trng->base + TRNG_ODATA); - /* - ensure data ready is only set again AFTER the next data - word is ready in case it got set between checking ISR - and reading ODATA, so we don't risk re-reading the - same word - */ - readl(trng->base + TRNG_ISR); - return 4; - } else - return 0; + *data = readl(trng->base + TRNG_ODATA); + /* + * ensure data ready is only set again AFTER the next data word is ready + * in case it got set between checking ISR and reading ODATA, so we + * don't risk re-reading the same word + */ + readl(trng->base + TRNG_ISR); + ret = 4; + +out: + return ret; } static void atmel_trng_enable(struct atmel_trng *trng) |