Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7339a0ed authored by Zhen Kong's avatar Zhen Kong
Browse files

msm_rng: optimize qrng driver retry behavior 



optimize retry behaviors to read qrng driver by changing retry
interval and times.

Change-Id: I506512b6bb0f64c94818a09571c85626b0bf56a5
Signed-off-by: default avatarZhen Kong <zkong@codeaurora.org>
parent e7325167

drivers/char/hw_random/msm_rng.c

+24 −18
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ 
#define MAX_HW_FIFO_DEPTH 16                     /* FIFO is 16 words deep */

#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4) /* FIFO is 32 bits wide  */



#define RETRY_MAX_CNT		5	/* max retry times to read register */

#define RETRY_DELAY_INTERVAL	440	/* retry delay interval in us */



struct msm_rng_device {

	struct platform_device *pdev;

	void __iomem *base;
@@ -96,7 +99,7 @@ static int msm_rng_direct_read(struct msm_rng_device *msm_rng_dev, 
	struct platform_device *pdev;

	void __iomem *base;

	size_t currsize = 0;

	u32 val;

	u32 val = 0;

	u32 *retdata = data;

	int ret;

	int failed = 0;
@@ -113,28 +116,29 @@ static int msm_rng_direct_read(struct msm_rng_device *msm_rng_dev, 
	if (msm_rng_dev->qrng_perf_client) {

		ret = msm_bus_scale_client_update_request(

				msm_rng_dev->qrng_perf_client, 1);

		if (ret)

		if (ret) {

			pr_err("bus_scale_client_update_req failed!\n");

			goto bus_err;

		}

	}

	/* enable PRNG clock */

	ret = clk_prepare_enable(msm_rng_dev->prng_clk);

	if (ret) {

		dev_err(&pdev->dev, "failed to enable clock in callback\n");

		pr_err("failed to enable prng clock\n");

		goto err;

	}

	/* read random data from h/w */

	do {

		/* check status bit if data is available */

		while (!(readl_relaxed(base + PRNG_STATUS_OFFSET)

		if (!(readl_relaxed(base + PRNG_STATUS_OFFSET)

				& 0x00000001)) {

			if (failed == 10) {

				pr_err("Data not available after retry\n");

			if (failed++ == RETRY_MAX_CNT) {

				if (currsize == 0)

					pr_err("Data not available\n");

				break;

			}

			pr_err("msm_rng:Data not available!\n");

			msleep_interruptible(10);

			failed++;

		}

			udelay(RETRY_DELAY_INTERVAL);

		} else {



			/* read FIFO */

			val = readl_relaxed(base + PRNG_DATA_OUT_OFFSET);
@@ -145,6 +149,7 @@ static int msm_rng_direct_read(struct msm_rng_device *msm_rng_dev, 
			/* make sure we stay on 32bit boundary */

			if ((max - currsize) < 4)

				break;

		}



	} while (currsize < max);
@@ -157,6 +162,7 @@ static int msm_rng_direct_read(struct msm_rng_device *msm_rng_dev, 
		if (ret)

			pr_err("bus_scale_client_update_req failed!\n");

	}

bus_err:

	mutex_unlock(&msm_rng_dev->rng_lock);



	val = 0L;