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Commit 4c13ac1c authored by Aaro Koskinen's avatar Aaro Koskinen Committed by Herbert Xu
Browse files

hwrng: omap3-rom - convert timer to delayed work 



We cannot put the HW RNG to idle using a timer because we cannot disable
clocks from atomic context. Use a delayed work instead.

Fixes a warning with CONFIG_DEBUG_MUTEXES on Nokia N900 during boot.

Reported-by: default avatarSebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 56b85c9d

drivers/char/hw_random/omap3-rom-rng.c

+7 −6
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 
#include <linux/init.h>

#include <linux/random.h>

#include <linux/hw_random.h>

#include <linux/timer.h>

#include <linux/workqueue.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/platform_device.h>
@@ -29,11 +29,11 @@ 
/* param1: ptr, param2: count, param3: flag */

static u32 (*omap3_rom_rng_call)(u32, u32, u32);



static struct timer_list idle_timer;

static struct delayed_work idle_work;

static int rng_idle;

static struct clk *rng_clk;



static void omap3_rom_rng_idle(unsigned long data)

static void omap3_rom_rng_idle(struct work_struct *work)

{

	int r;
@@ -51,7 +51,7 @@ static int omap3_rom_rng_get_random(void *buf, unsigned int count) 
	u32 r;

	u32 ptr;



	del_timer_sync(&idle_timer);

	cancel_delayed_work_sync(&idle_work);

	if (rng_idle) {

		clk_prepare_enable(rng_clk);

		r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
@@ -65,7 +65,7 @@ static int omap3_rom_rng_get_random(void *buf, unsigned int count) 


	ptr = virt_to_phys(buf);

	r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);

	mod_timer(&idle_timer, jiffies + msecs_to_jiffies(500));

	schedule_delayed_work(&idle_work, msecs_to_jiffies(500));

	if (r != 0)

		return -EINVAL;

	return 0;
@@ -102,7 +102,7 @@ static int omap3_rom_rng_probe(struct platform_device *pdev) 
		return -EINVAL;

	}



	setup_timer(&idle_timer, omap3_rom_rng_idle, 0);

	INIT_DELAYED_WORK(&idle_work, omap3_rom_rng_idle);

	rng_clk = devm_clk_get(&pdev->dev, "ick");

	if (IS_ERR(rng_clk)) {

		pr_err("unable to get RNG clock\n");
@@ -118,6 +118,7 @@ static int omap3_rom_rng_probe(struct platform_device *pdev) 


static int omap3_rom_rng_remove(struct platform_device *pdev)

{

	cancel_delayed_work_sync(&idle_work);

	hwrng_unregister(&omap3_rom_rng_ops);

	clk_disable_unprepare(rng_clk);

	return 0;