This looks good to me.
On 11/20/2014 12:09 AM, Kevin Hilman wrote:
> From: Viresh Kumar <viresh.ku...@linaro.org>
>
> Currently, the ->set_mode() method of a clockevent device is not
> allowed to fail, so it has no return value. In order to add new
> clockevent modes, and allow the setting of those modes to fail, we
> need the clockevent core to be able to detect when setting a mode
> fails.
>
> To allow detection of mode setting failures, introduce a new method
> ->set_dev_mode() which can return an error if the given mode is not
> supported or fails.
>
> Since all current modes are still not allowed to fail, the core code
> simply WARNs if any modes fail. Future patches that add new mode
> support will add proper error recovery based on failure conditions.
>
> Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
> Reviewed-by: Kevin Hilman <khil...@linaro.org>
> [khilman: rework changelogs, minor formatting/checkpatch cleanups]
> Signed-off-by: Kevin Hilman <khil...@linaro.org>
> ---
> include/linux/clockchips.h | 5 ++++-
> kernel/time/clockevents.c | 21 ++++++++++++++++++---
> kernel/time/timer_list.c | 5 ++++-
> 3 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
> index 2e4cb67f6e56..d969659cf688 100644
> --- a/include/linux/clockchips.h
> +++ b/include/linux/clockchips.h
> @@ -81,7 +81,8 @@ enum clock_event_mode {
> * @mode: operating mode assigned by the management code
> * @features: features
> * @retries: number of forced programming retries
> - * @set_mode: set mode function
> + * @set_dev_mode: set dev mode function
> + * @set_mode: set mode function (deprecated, use set_dev_mode
> instead)
> * @broadcast: function to broadcast events
> * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
> * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
> @@ -109,6 +110,8 @@ struct clock_event_device {
> unsigned long retries;
>
> void (*broadcast)(const struct cpumask *mask);
> + int (*set_dev_mode)(enum clock_event_mode mode,
> + struct clock_event_device *);
> void (*set_mode)(enum clock_event_mode mode,
> struct clock_event_device *);
> void (*suspend)(struct clock_event_device *);
> diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
> index 9c94c19f1305..1d5ce3ce9228 100644
> --- a/kernel/time/clockevents.c
> +++ b/kernel/time/clockevents.c
> @@ -105,7 +105,16 @@ void clockevents_set_mode(struct clock_event_device *dev,
> enum clock_event_mode mode)
> {
> if (dev->mode != mode) {
> - dev->set_mode(mode, dev);
> + if (dev->set_dev_mode) {
> + int ret = dev->set_dev_mode(mode, dev);
> +
> + /* Currently available modes shouldn't fail */
> + WARN_ONCE(ret, "Requested mode: %d, error: %d\n",
> + mode, ret);
> + } else {
> + dev->set_mode(mode, dev);
> + }
> +
> dev->mode = mode;
>
> /*
> @@ -448,8 +457,14 @@ int __clockevents_update_freq(struct clock_event_device
> *dev, u32 freq)
> if (dev->mode == CLOCK_EVT_MODE_ONESHOT)
> return clockevents_program_event(dev, dev->next_event, false);
>
> - if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
> - dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev);
> + if (dev->mode == CLOCK_EVT_MODE_PERIODIC) {
> + /* Shouldn't fail while switching to PERIODIC MODE */
> + if (dev->set_dev_mode)
> + WARN_ON_ONCE(dev->set_dev_mode(CLOCK_EVT_MODE_PERIODIC,
> + dev));
> + else
> + dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev);
> + }
>
> return 0;
> }
> diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
> index 61ed862cdd37..957a04951ef0 100644
> --- a/kernel/time/timer_list.c
> +++ b/kernel/time/timer_list.c
> @@ -229,7 +229,10 @@ print_tickdevice(struct seq_file *m, struct tick_device
> *td, int cpu)
> SEQ_printf(m, "\n");
>
> SEQ_printf(m, " set_mode: ");
> - print_name_offset(m, dev->set_mode);
> + if (dev->set_dev_mode)
> + print_name_offset(m, dev->set_dev_mode);
> + else
> + print_name_offset(m, dev->set_mode);
> SEQ_printf(m, "\n");
>
> SEQ_printf(m, " event_handler: ");
>
Reviewed-by: Preeti U Murthy <pre...@linux.vnet.ibm.com>
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