Re: [PATCH] Input: Add CLOCK_BOOTTIME support

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Dec 18, 2014 at 04:55:00AM +0530, Aniroop Mathur wrote:
> This patch adds support for CLOCK_BOOTTIME for input event timestamp.
> CLOCK_BOOTTIME includes suspend time, so it would allow aplications
> to get correct time difference between two events even when system
> resumes from suspend state.
> 
> Signed-off-by: Aniroop Mathur <a.mathur@samsung.com>

Applied with minor edits, thank you.

> ---
>  drivers/input/evdev.c | 57 ++++++++++++++++++++++++++++++++++++---------------
>  1 file changed, 41 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index de05545..914b498 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -28,6 +28,13 @@
>  #include <linux/cdev.h>
>  #include "input-compat.h"
>  
> +enum evdev_clock_type {
> +	EV_CLK_REAL = 0,
> +	EV_CLK_MONO,
> +	EV_CLK_BOOT,
> +	EV_CLK_MAX
> +};
> +
>  struct evdev {
>  	int open;
>  	struct input_handle handle;
> @@ -49,12 +56,32 @@ struct evdev_client {
>  	struct fasync_struct *fasync;
>  	struct evdev *evdev;
>  	struct list_head node;
> -	int clkid;
> +	int clk_type;
>  	bool revoked;
>  	unsigned int bufsize;
>  	struct input_event buffer[];
>  };
>  
> +static int evdev_set_clk_type(int id, struct evdev_client *client)
> +{
> +	switch (id) {
> +
> +	case CLOCK_REALTIME:
> +		client->clk_type = EV_CLK_REAL;
> +		break;
> +	case CLOCK_MONOTONIC:
> +		client->clk_type = EV_CLK_MONO;
> +		break;
> +	case CLOCK_BOOTTIME:
> +		client->clk_type = EV_CLK_BOOT;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  /* flush queued events of type @type, caller must hold client->buffer_lock */
>  static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
>  {
> @@ -108,8 +135,9 @@ static void evdev_queue_syn_dropped(struct evdev_client *client)
>  	struct input_event ev;
>  	ktime_t time;
>  
> -	time = (client->clkid == CLOCK_MONOTONIC) ?
> -		ktime_get() : ktime_get_real();
> +	time = (client->clk_type == EV_CLK_REAL) ?
> +		ktime_get_real() : (client->clk_type == EV_CLK_MONO) ?
> +		ktime_get() : ktime_get_boottime();
>  
>  	ev.time = ktime_to_timeval(time);
>  	ev.type = EV_SYN;
> @@ -159,7 +187,7 @@ static void __pass_event(struct evdev_client *client,
>  
>  static void evdev_pass_values(struct evdev_client *client,
>  			const struct input_value *vals, unsigned int count,
> -			ktime_t mono, ktime_t real)
> +			ktime_t *ev_time)
>  {
>  	struct evdev *evdev = client->evdev;
>  	const struct input_value *v;
> @@ -169,8 +197,7 @@ static void evdev_pass_values(struct evdev_client *client,
>  	if (client->revoked)
>  		return;
>  
> -	event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ?
> -				      mono : real);
> +	event.time = ktime_to_timeval(ev_time[client->clk_type]);
>  
>  	/* Interrupts are disabled, just acquire the lock. */
>  	spin_lock(&client->buffer_lock);
> @@ -198,21 +225,22 @@ static void evdev_events(struct input_handle *handle,
>  {
>  	struct evdev *evdev = handle->private;
>  	struct evdev_client *client;
> -	ktime_t time_mono, time_real;
> +	ktime_t ev_time[EV_CLK_MAX];
>  
> -	time_mono = ktime_get();
> -	time_real = ktime_mono_to_real(time_mono);
> +	ev_time[EV_CLK_MONO] = ktime_get();
> +	ev_time[EV_CLK_REAL] = ktime_mono_to_real(ev_time[EV_CLK_MONO]);
> +	ev_time[EV_CLK_BOOT] = ktime_mono_to_any(ev_time[EV_CLK_MONO],
> +						 TK_OFFS_BOOT);
>  
>  	rcu_read_lock();
>  
>  	client = rcu_dereference(evdev->grab);
>  
>  	if (client)
> -		evdev_pass_values(client, vals, count, time_mono, time_real);
> +		evdev_pass_values(client, vals, count, ev_time);
>  	else
>  		list_for_each_entry_rcu(client, &evdev->client_list, node)
> -			evdev_pass_values(client, vals, count,
> -					  time_mono, time_real);
> +			evdev_pass_values(client, vals, count, ev_time);
>  
>  	rcu_read_unlock();
>  }
> @@ -874,10 +902,7 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
>  	case EVIOCSCLOCKID:
>  		if (copy_from_user(&i, p, sizeof(unsigned int)))
>  			return -EFAULT;
> -		if (i != CLOCK_MONOTONIC && i != CLOCK_REALTIME)
> -			return -EINVAL;
> -		client->clkid = i;
> -		return 0;
> +		return evdev_set_clk_type(i, client);
>  
>  	case EVIOCGKEYCODE:
>  		return evdev_handle_get_keycode(dev, p);
> -- 
> 1.9.1
> 

-- 
Dmitry