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 <[email protected]>
Signed-off-by: Aaro Koskinen <[email protected]>
---
drivers/char/hw_random/omap3-rom-rng.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c
index a405cdc..58191c6 100644
--- a/drivers/char/hw_random/omap3-rom-rng.c
+++ b/drivers/char/hw_random/omap3-rom-rng.c
@@ -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
On 11/06/2015 12:15 AM, Aaro Koskinen wrote:
> 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 <[email protected]>
> Signed-off-by: Aaro Koskinen <[email protected]>
> ---
> drivers/char/hw_random/omap3-rom-rng.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c
> index a405cdc..58191c6 100644
> --- a/drivers/char/hw_random/omap3-rom-rng.c
> +++ b/drivers/char/hw_random/omap3-rom-rng.c
> @@ -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;
>
Sry, It looks like PM runtime autosuspend might work well here.
What do you think?
--
regards,
-grygorii
On Fri, Nov 06, 2015 at 12:15:24AM +0200, Aaro Koskinen wrote:
> 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 <[email protected]>
> Signed-off-by: Aaro Koskinen <[email protected]>
Thanks for the patch. Can you please remove timer.h and include
workqueue.h instead?
Cheers,
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt