[PATCH 2/6] drm: add helper for printing to log or seq_file

Rob Clark robdclark at gmail.com
Mon Oct 17 12:35:00 UTC 2016 

On Mon, Oct 17, 2016 at 8:30 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Mon, Oct 17, 2016 at 07:59:51AM -0400, Rob Clark wrote:
>> On Mon, Oct 17, 2016 at 2:38 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
>> > On Fri, Oct 14, 2016 at 07:55:49PM -0400, Rob Clark wrote:
>> >> Sometimes it is nice not to duplicate equivalent printk() and
>> >> seq_printf() code.
>> >>
>> >> Signed-off-by: Rob Clark <robdclark at gmail.com>
>> >
>> > Ok, maybe I should wait for coffee to kick in before commenting on patches
>> > ;-)
>> >
>> > Two bits:
>> > - kerneldoc for this pls, plus pulling into drm-internals.rst.
>> > - Would be awesome to de-dupe the existing dumping code in drm_mm.c with
>> >   this.
>>
>> I have a couple things in drm/msm that I want to de-dup.. and I guess
>> most drivers probably do as well..
>>
>> I'm toying with the idea to convert drm_info_list::show over to take a
>> drm_print ptr instead of seq_file, then we could just re-use the
>> debugfs fxns directly without having extra wrappers fxns.. question is
>> best way to do that in a non-flag-day way..
>
> One idea I had in the other reply is to create a seq_file which can dump
> to debugfs. Not sure how feasible that is ...

that was my first approach..  but seq_file carries a lot of baggage..

BR,
-R

> -Daniel
>
>>
>> BR,
>> -R
>>
>> > -Daniel
>> >
>> >> ---
>> >>  drivers/gpu/drm/Makefile    |  3 ++-
>> >>  drivers/gpu/drm/drm_print.c | 54 +++++++++++++++++++++++++++++++++++++++
>> >>  include/drm/drm_print.h     | 62 +++++++++++++++++++++++++++++++++++++++++++++
>> >>  3 files changed, 118 insertions(+), 1 deletion(-)
>> >>  create mode 100644 drivers/gpu/drm/drm_print.c
>> >>  create mode 100644 include/drm/drm_print.h
>> >>
>> >> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>> >> index e3dba6f..4894ebb 100644
>> >> --- a/drivers/gpu/drm/Makefile
>> >> +++ b/drivers/gpu/drm/Makefile
>> >> @@ -12,7 +12,8 @@ drm-y       :=      drm_auth.o drm_bufs.o drm_cache.o \
>> >>               drm_info.o drm_debugfs.o drm_encoder_slave.o \
>> >>               drm_trace_points.o drm_global.o drm_prime.o \
>> >>               drm_rect.o drm_vma_manager.o drm_flip_work.o \
>> >> -             drm_modeset_lock.o drm_atomic.o drm_bridge.o
>> >> +             drm_modeset_lock.o drm_atomic.o drm_bridge.o \
>> >> +             drm_print.o
>> >>
>> >>  drm-$(CONFIG_COMPAT) += drm_ioc32.o
>> >>  drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
>> >> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
>> >> new file mode 100644
>> >> index 0000000..ddcb437
>> >> --- /dev/null
>> >> +++ b/drivers/gpu/drm/drm_print.c
>> >> @@ -0,0 +1,54 @@
>> >> +/*
>> >> + * Copyright (C) 2016 Red Hat
>> >> + *
>> >> + * Permission is hereby granted, free of charge, to any person obtaining a
>> >> + * copy of this software and associated documentation files (the "Software"),
>> >> + * to deal in the Software without restriction, including without limitation
>> >> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> >> + * and/or sell copies of the Software, and to permit persons to whom the
>> >> + * Software is furnished to do so, subject to the following conditions:
>> >> + *
>> >> + * The above copyright notice and this permission notice shall be included in
>> >> + * all copies or substantial portions of the Software.
>> >> + *
>> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> >> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> >> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> >> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> >> + * OTHER DEALINGS IN THE SOFTWARE.
>> >> + *
>> >> + * Authors:
>> >> + * Rob Clark <robdclark at gmail.com>
>> >> + */
>> >> +
>> >> +#include <linux/seq_file.h>
>> >> +#include <drm/drmP.h>
>> >> +#include <drm/drm_print.h>
>> >> +
>> >> +void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args)
>> >> +{
>> >> +     seq_vprintf(p->arg, f, args);
>> >> +}
>> >> +
>> >> +void __drm_printfn_info(struct drm_print *p, const char *f, va_list args)
>> >> +{
>> >> +     const char *hdr = KERN_INFO "[" DRM_NAME "] ";
>> >> +     char fmt[strlen(hdr) + strlen(f) + 1];
>> >> +
>> >> +     memcpy(fmt, hdr, strlen(hdr));
>> >> +     memcpy(fmt + strlen(hdr), f, strlen(f));
>> >> +     fmt[strlen(hdr) + strlen(f)] = 0;
>> >> +
>> >> +     vprintk(fmt, args);
>> >> +}
>> >> +
>> >> +void drm_printf(struct drm_print *p, const char *f, ...)
>> >> +{
>> >> +     va_list args;
>> >> +
>> >> +     va_start(args, f);
>> >> +     p->printfn(p, f, args);
>> >> +     va_end(args);
>> >> +}
>> >> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
>> >> new file mode 100644
>> >> index 0000000..f294a9a
>> >> --- /dev/null
>> >> +++ b/include/drm/drm_print.h
>> >> @@ -0,0 +1,62 @@
>> >> +/*
>> >> + * Copyright (C) 2016 Red Hat
>> >> + *
>> >> + * Permission is hereby granted, free of charge, to any person obtaining a
>> >> + * copy of this software and associated documentation files (the "Software"),
>> >> + * to deal in the Software without restriction, including without limitation
>> >> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> >> + * and/or sell copies of the Software, and to permit persons to whom the
>> >> + * Software is furnished to do so, subject to the following conditions:
>> >> + *
>> >> + * The above copyright notice and this permission notice shall be included in
>> >> + * all copies or substantial portions of the Software.
>> >> + *
>> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> >> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> >> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> >> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> >> + * OTHER DEALINGS IN THE SOFTWARE.
>> >> + *
>> >> + * Authors:
>> >> + * Rob Clark <robdclark at gmail.com>
>> >> + */
>> >> +
>> >> +#ifndef DRM_PRINT_H_
>> >> +#define DRM_PRINT_H_
>> >> +
>> >> +#include <stdarg.h>
>> >> +#include <linux/seq_file.h>
>> >> +
>> >> +/* A simple wrapper to abstract seq_file vs printk, so same logging code
>> >> + * does not have to be duplicated.
>> >> + */
>> >> +struct drm_print {
>> >> +     void (*printfn)(struct drm_print *p, const char *f, va_list args);
>> >> +     void *arg;
>> >> +};
>> >> +
>> >> +void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args);
>> >> +void __drm_printfn_info(struct drm_print *p, const char *f, va_list args);
>> >> +
>> >> +void drm_printf(struct drm_print *p, const char *f, ...);
>> >> +
>> >> +static inline struct drm_print drm_print_seq_file(struct seq_file *f)
>> >> +{
>> >> +     struct drm_print p = {
>> >> +             .printfn = __drm_printfn_seq_file,
>> >> +             .arg = f,
>> >> +     };
>> >> +     return p;
>> >> +}
>> >> +
>> >> +static inline struct drm_print drm_print_info(void)
>> >> +{
>> >> +     struct drm_print p = {
>> >> +             .printfn = __drm_printfn_info,
>> >> +     };
>> >> +     return p;
>> >> +}
>> >> +
>> >> +#endif /* DRM_PRINT_H_ */
>> >> --
>> >> 2.7.4
>> >>
>> >
>> > --
>> > Daniel Vetter
>> > Software Engineer, Intel Corporation
>> > http://blog.ffwll.ch
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

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