Commit 0934683d authored by Claudiu Beznea's avatar Claudiu Beznea Committed by Herbert Xu
Browse files

hwrng: atmel - add wait for ready support on read 



Add wait for ready support on read.

Signed-off-by: default avatarClaudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 0a2a464f

drivers/char/hw_random/atmel-rng.c

+30 −13
Original line number Diff line number Diff line
@@ -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

	 * 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;

	ret = 4;



out:

	return ret;

}



static void atmel_trng_enable(struct atmel_trng *trng)