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Date:   Mon, 7 May 2018 16:19:06 +0300
From:   Sakari Ailus <sakari.ailus@iki.fi>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [RESEND] [media] omap3isp: support 64-bit version of
 omap3isp_stat_data
Message-ID: <20180507131906.rdvcmvim5gvi5odk@valkosipuli.retiisi.org.uk>
References: <20180425213044.1535393-1-arnd@arndb.de>
 <2922276.lKgGZtlCEW@avalon>
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On Mon, May 07, 2018 at 04:17:32PM +0300, Laurent Pinchart wrote:
> Hi Arnd,
> 
> Thank you for the patch.
> 
> On Thursday, 26 April 2018 00:30:10 EEST Arnd Bergmann wrote:
> > C libraries with 64-bit time_t use an incompatible format for
> > struct omap3isp_stat_data. This changes the kernel code to
> > support either version, by moving over the normal handling
> > to the 64-bit variant, and adding compatiblity code to handle
> > the old binary format with the existing ioctl command code.
> > 
> > Fortunately, the command code includes the size of the structure,
> > so the difference gets handled automatically. In the process of
> > eliminating the references to 'struct timeval' from the kernel,
> > I also change the way the timestamp is generated internally,
> > basically by open-coding the v4l2_get_timestamp() call.
> > 
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Sakari Ailus <sakari.ailus@iki.fi>
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > I submitted this one in November and asked again in January,
> > still waiting for a review so it can be applied.
> > ---
> >  drivers/media/platform/omap3isp/isph3a_aewb.c |  2 ++
> >  drivers/media/platform/omap3isp/isph3a_af.c   |  2 ++
> >  drivers/media/platform/omap3isp/isphist.c     |  2 ++
> >  drivers/media/platform/omap3isp/ispstat.c     | 21 +++++++++++++++++++--
> >  drivers/media/platform/omap3isp/ispstat.h     |  4 +++-
> >  include/uapi/linux/omap3isp.h                 | 22 ++++++++++++++++++++++
> >  6 files changed, 50 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/media/platform/omap3isp/isph3a_aewb.c
> > b/drivers/media/platform/omap3isp/isph3a_aewb.c index
> > d44626f20ac6..3c82dea4d375 100644
> > --- a/drivers/media/platform/omap3isp/isph3a_aewb.c
> > +++ b/drivers/media/platform/omap3isp/isph3a_aewb.c
> > @@ -250,6 +250,8 @@ static long h3a_aewb_ioctl(struct v4l2_subdev *sd,
> > unsigned int cmd, void *arg) return omap3isp_stat_config(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_REQ:
> >  		return omap3isp_stat_request_statistics(stat, arg);
> > +	case VIDIOC_OMAP3ISP_STAT_REQ_TIME32:
> > +		return omap3isp_stat_request_statistics_time32(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_EN: {
> >  		unsigned long *en = arg;
> >  		return omap3isp_stat_enable(stat, !!*en);
> > diff --git a/drivers/media/platform/omap3isp/isph3a_af.c
> > b/drivers/media/platform/omap3isp/isph3a_af.c index
> > 99bd6cc21d86..4da25c84f0c6 100644
> > --- a/drivers/media/platform/omap3isp/isph3a_af.c
> > +++ b/drivers/media/platform/omap3isp/isph3a_af.c
> > @@ -314,6 +314,8 @@ static long h3a_af_ioctl(struct v4l2_subdev *sd,
> > unsigned int cmd, void *arg) return omap3isp_stat_config(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_REQ:
> >  		return omap3isp_stat_request_statistics(stat, arg);
> > +	case VIDIOC_OMAP3ISP_STAT_REQ_TIME32:
> > +		return omap3isp_stat_request_statistics_time32(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_EN: {
> >  		int *en = arg;
> >  		return omap3isp_stat_enable(stat, !!*en);
> > diff --git a/drivers/media/platform/omap3isp/isphist.c
> > b/drivers/media/platform/omap3isp/isphist.c index
> > a4ed5d140d48..d4be3d0e06f9 100644
> > --- a/drivers/media/platform/omap3isp/isphist.c
> > +++ b/drivers/media/platform/omap3isp/isphist.c
> > @@ -435,6 +435,8 @@ static long hist_ioctl(struct v4l2_subdev *sd, unsigned
> > int cmd, void *arg) return omap3isp_stat_config(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_REQ:
> >  		return omap3isp_stat_request_statistics(stat, arg);
> > +	case VIDIOC_OMAP3ISP_STAT_REQ_TIME32:
> > +		return omap3isp_stat_request_statistics_time32(stat, arg);
> >  	case VIDIOC_OMAP3ISP_STAT_EN: {
> >  		int *en = arg;
> >  		return omap3isp_stat_enable(stat, !!*en);
> > diff --git a/drivers/media/platform/omap3isp/ispstat.c
> > b/drivers/media/platform/omap3isp/ispstat.c index
> > 47cbc7e3d825..5967dfd0a9f7 100644
> > --- a/drivers/media/platform/omap3isp/ispstat.c
> > +++ b/drivers/media/platform/omap3isp/ispstat.c
> > @@ -18,6 +18,7 @@
> >  #include <linux/dma-mapping.h>
> >  #include <linux/slab.h>
> >  #include <linux/uaccess.h>
> > +#include <linux/timekeeping.h>
> 
> Could you please keep the headers alphabetically sorted ?
> 
> > 
> >  #include "isp.h"
> > 
> > @@ -237,7 +238,7 @@ static int isp_stat_buf_queue(struct ispstat *stat)
> >  	if (!stat->active_buf)
> >  		return STAT_NO_BUF;
> > 
> > -	v4l2_get_timestamp(&stat->active_buf->ts);
> > +	ktime_get_ts64(&stat->active_buf->ts);
> > 
> >  	stat->active_buf->buf_size = stat->buf_size;
> >  	if (isp_stat_buf_check_magic(stat, stat->active_buf)) {
> > @@ -500,7 +501,8 @@ int omap3isp_stat_request_statistics(struct ispstat
> > *stat, return PTR_ERR(buf);
> >  	}
> > 
> > -	data->ts = buf->ts;
> > +	data->ts.tv_sec = buf->ts.tv_sec;
> > +	data->ts.tv_usec = buf->ts.tv_nsec / NSEC_PER_USEC;
> >  	data->config_counter = buf->config_counter;
> >  	data->frame_number = buf->frame_number;
> >  	data->buf_size = buf->buf_size;
> > @@ -512,6 +514,21 @@ int omap3isp_stat_request_statistics(struct ispstat
> > *stat, return 0;
> >  }
> > 
> > +int omap3isp_stat_request_statistics_time32(struct ispstat *stat,
> > +					struct omap3isp_stat_data_time32 *data)
> > +{
> > +	struct omap3isp_stat_data data64;
> > +	int ret;
> > +
> > +	ret = omap3isp_stat_request_statistics(stat, &data64);
> > +
> > +	data->ts.tv_sec = data64.ts.tv_sec;
> > +	data->ts.tv_usec = data64.ts.tv_usec;
> > +	memcpy(&data->buf, &data64.buf, sizeof(*data) - sizeof(data->ts));
> > +
> > +	return ret;
> 
> We could return immediately after omap3isp_stat_request_statistics() if the 
> function fails, but that's no big deal, the error path is clearly a cold path.
> 
> > +}
> > +
> >  /*
> >   * omap3isp_stat_config - Receives new statistic engine configuration.
> >   * @new_conf: Pointer to config structure.
> > diff --git a/drivers/media/platform/omap3isp/ispstat.h
> > b/drivers/media/platform/omap3isp/ispstat.h index
> > 6d9b0244f320..923b38cfc682 100644
> > --- a/drivers/media/platform/omap3isp/ispstat.h
> > +++ b/drivers/media/platform/omap3isp/ispstat.h
> > @@ -39,7 +39,7 @@ struct ispstat_buffer {
> >  	struct sg_table sgt;
> >  	void *virt_addr;
> >  	dma_addr_t dma_addr;
> > -	struct timeval ts;
> > +	struct timespec64 ts;
> >  	u32 buf_size;
> >  	u32 frame_number;
> >  	u16 config_counter;
> > @@ -130,6 +130,8 @@ struct ispstat_generic_config {
> >  int omap3isp_stat_config(struct ispstat *stat, void *new_conf);
> >  int omap3isp_stat_request_statistics(struct ispstat *stat,
> >  				     struct omap3isp_stat_data *data);
> > +int omap3isp_stat_request_statistics_time32(struct ispstat *stat,
> > +				     struct omap3isp_stat_data_time32 *data);
> >  int omap3isp_stat_init(struct ispstat *stat, const char *name,
> >  		       const struct v4l2_subdev_ops *sd_ops);
> >  void omap3isp_stat_cleanup(struct ispstat *stat);
> > diff --git a/include/uapi/linux/omap3isp.h b/include/uapi/linux/omap3isp.h
> > index 1a920145db04..87b55755f4ff 100644
> > --- a/include/uapi/linux/omap3isp.h
> > +++ b/include/uapi/linux/omap3isp.h
> > @@ -55,6 +55,8 @@
> >  	_IOWR('V', BASE_VIDIOC_PRIVATE + 5, struct omap3isp_h3a_af_config)
> >  #define VIDIOC_OMAP3ISP_STAT_REQ \
> >  	_IOWR('V', BASE_VIDIOC_PRIVATE + 6, struct omap3isp_stat_data)
> > +#define VIDIOC_OMAP3ISP_STAT_REQ_TIME32 \
> > +	_IOWR('V', BASE_VIDIOC_PRIVATE + 6, struct omap3isp_stat_data_time32)
> >  #define VIDIOC_OMAP3ISP_STAT_EN \
> >  	_IOWR('V', BASE_VIDIOC_PRIVATE + 7, unsigned long)
> > 
> > @@ -165,7 +167,14 @@ struct omap3isp_h3a_aewb_config {
> >   * @config_counter: Number of the configuration associated with the data.
> >   */
> >  struct omap3isp_stat_data {
> > +#ifdef __KERNEL__
> > +	struct {
> > +		__s64	tv_sec;
> > +		__s64	tv_usec;
> > +	} ts;
> 
> I share Sakari's comment about this method implying a little-endian system, 
> but as the SoCs that integrate this device are all little-endian, that's not a 
> problem in practice.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> If you agree with the small comment about header ordering, let's get this 
> patch finally merged.

I can make the change locally in my tree, no need to resend.

Thanks.

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi