Hi Dmitry,
On 02.09.2020 16:18, Dmitry Osipenko wrote:
> Regmap can't sleep if spinlock is used for the locking protection.
> This patch fixes regression caused by a previous commit that switched
> regmap to use fsleep() and this broke Amlogic S922X platform.
>
> This patch adds new configuration option for regmap users, allowing to
> specify whether regmap operations can sleep and assuming that sleep is
> allowed if mutex is used for the regmap locking protection.
>
> Reported-by: Marek Szyprowski <m.szyprow...@samsung.com>
> Fixes: 2b32d2f7ce0a ("regmap: Use flexible sleep")
> Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
This fixes the issue I've reported. Thanks!
Tested-by: Marek Szyprowski <m.szyprow...@samsung.com>
> ---
> drivers/base/regmap/internal.h | 3 +++
> drivers/base/regmap/regmap.c | 19 +++++++++++++++----
> include/linux/regmap.h | 3 +++
> 3 files changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
> index 3d80c4b43f72..8a59359e145f 100644
> --- a/drivers/base/regmap/internal.h
> +++ b/drivers/base/regmap/internal.h
> @@ -161,6 +161,9 @@ struct regmap {
> void *selector_work_buf; /* Scratch buffer used for selector */
>
> struct hwspinlock *hwlock;
> +
> + /* if set, the regmap core can sleep */
> + bool can_sleep;
> };
>
> struct regcache_ops {
> diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
> index a417cb1a11dc..2807e544658e 100644
> --- a/drivers/base/regmap/regmap.c
> +++ b/drivers/base/regmap/regmap.c
> @@ -697,11 +697,13 @@ struct regmap *__regmap_init(struct device *dev,
>
> if (config->disable_locking) {
> map->lock = map->unlock = regmap_lock_unlock_none;
> + map->can_sleep = config->can_sleep;
> regmap_debugfs_disable(map);
> } else if (config->lock && config->unlock) {
> map->lock = config->lock;
> map->unlock = config->unlock;
> map->lock_arg = config->lock_arg;
> + map->can_sleep = config->can_sleep;
> } else if (config->use_hwlock) {
> map->hwlock = hwspin_lock_request_specific(config->hwlock_id);
> if (!map->hwlock) {
> @@ -737,6 +739,7 @@ struct regmap *__regmap_init(struct device *dev,
> mutex_init(&map->mutex);
> map->lock = regmap_lock_mutex;
> map->unlock = regmap_unlock_mutex;
> + map->can_sleep = true;
> lockdep_set_class_and_name(&map->mutex,
> lock_key, lock_name);
> }
> @@ -2230,8 +2233,12 @@ static int _regmap_range_multi_paged_reg_write(struct
> regmap *map,
> if (ret != 0)
> return ret;
>
> - if (regs[i].delay_us)
> - fsleep(regs[i].delay_us);
> + if (regs[i].delay_us) {
> + if (map->can_sleep)
> + fsleep(regs[i].delay_us);
> + else
> + udelay(regs[i].delay_us);
> + }
>
> base += n;
> n = 0;
> @@ -2267,8 +2274,12 @@ static int _regmap_multi_reg_write(struct regmap *map,
> if (ret != 0)
> return ret;
>
> - if (regs[i].delay_us)
> - fsleep(regs[i].delay_us);
> + if (regs[i].delay_us) {
> + if (map->can_sleep)
> + fsleep(regs[i].delay_us);
> + else
> + udelay(regs[i].delay_us);
> + }
> }
> return 0;
> }
> diff --git a/include/linux/regmap.h b/include/linux/regmap.h
> index d865d8fea535..0c49d59168b5 100644
> --- a/include/linux/regmap.h
> +++ b/include/linux/regmap.h
> @@ -342,6 +342,7 @@ typedef void (*regmap_unlock)(void *);
> * @hwlock_id: Specify the hardware spinlock id.
> * @hwlock_mode: The hardware spinlock mode, should be HWLOCK_IRQSTATE,
> * HWLOCK_IRQ or 0.
> + * @can_sleep: Optional, specifies whether regmap operations can sleep.
> */
> struct regmap_config {
> const char *name;
> @@ -398,6 +399,8 @@ struct regmap_config {
> bool use_hwlock;
> unsigned int hwlock_id;
> unsigned int hwlock_mode;
> +
> + bool can_sleep;
> };
>
> /**
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
