[PATCH v2] hw_random: omap3-rom-rng: convert timer to delayed work

[Aaro Koskinen]

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: Sebastian Reichel <s...@kernel.org>
Signed-off-by: Aaro Koskinen <aaro.koski...@iki.fi>
---

        v2: Include workqueue.h instead of timer.h.

 drivers/char/hw_random/omap3-rom-rng.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/char/hw_random/omap3-rom-rng.c 
b/drivers/char/hw_random/omap3-rom-rng.c
index a405cdc..8da14f1 100644
--- a/drivers/char/hw_random/omap3-rom-rng.c
+++ b/drivers/char/hw_random/omap3-rom-rng.c
@@ -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;
-- 
2.4.0

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