Add wait for ready support on read.
Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
drivers/char/hw_random/atmel-rng.c | 43 +++++++++++++++++++++---------
1 file 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)
--
2.32.0
