Re: [PATCH 1/4] drm: Put platform driver registration/unregistration loops in core.

[Daniel Vetter]

On Wed, Sep 16, 2015 at 11:14 AM, Eric Anholt <eric@xxxxxxxxxx> wrote:
> This is mostly just a move of the code from exynos, with a slight
> reformat.  I wanted to do a similar thing for vc4, and msm looks like
> a good candidate as well.
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/Makefile                |  3 ++-
>  drivers/gpu/drm/drm_platform_helpers.c  | 45 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/exynos/exynos_drm_drv.c | 38 +++++-----------------------
>  include/drm/drmP.h                      |  4 +++
>  4 files changed, 57 insertions(+), 33 deletions(-)
>  create mode 100644 drivers/gpu/drm/drm_platform_helpers.c
>
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 45e7719..266d199 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -7,7 +7,8 @@ drm-y       :=  drm_auth.o drm_bufs.o drm_cache.o \
>                 drm_fops.o drm_gem.o drm_ioctl.o drm_irq.o \
>                 drm_lock.o drm_memory.o drm_drv.o drm_vm.o \
>                 drm_agpsupport.o drm_scatter.o drm_pci.o \
> -               drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
> +               drm_platform.o drm_platform_helpers.o \
> +               drm_sysfs.o drm_hashtab.o drm_mm.o \

Imo it'd would be good to have a separate module for helpers like
these (maybe even put them into the kms helpers). At least that
explicit split on the modeset side seems to help with a clean split
between mandatory core bits and helper code.

>                 drm_crtc.o drm_modes.o drm_edid.o \
>                 drm_info.o drm_debugfs.o drm_encoder_slave.o \
>                 drm_trace_points.o drm_global.o drm_prime.o \
> diff --git a/drivers/gpu/drm/drm_platform_helpers.c b/drivers/gpu/drm/drm_platform_helpers.c
> new file mode 100644
> index 0000000..a54c3e3
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_platform_helpers.c
> @@ -0,0 +1,45 @@
> +/*
> + * Copyright (c) 2011 Samsung Electronics Co., Ltd.
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + */
> +
> +#include <drm/drmP.h>
> +
> +/**
> + * drm_platform_register_drivers - Helper to register an array of
> + * struct platform_drivers.
> + */

Please add a new section to Documentation/DocBook/drm.tmpl so that
these kerneldoc comments are included. Without that 0day won't catch
mismatches in kerneldoc and hopefully including it will also make it a
bit more discoverable. And with the new markdown stuff in
drm-intel-nightly you could even include an example snippet for how to
use it, but that's kinda overkilla ;-) If you do that kerneldoc will
complain about the missing parameter helpers. Also I recommend to
point at other functions which should be used together with this one
(like _unregister), in 4.3 the htmldocs will actually insert
hyperlinks for that.

Thanks, Daniel

> +int drm_platform_register_drivers(struct platform_driver *const *drv,
> +                                 int count)
> +{
> +       int i, ret;
> +
> +       for (i = 0; i < count; ++i) {
> +               ret = platform_driver_register(drv[i]);
> +               if (ret) {
> +                       while (--i >= 0)
> +                               platform_driver_unregister(drv[i]);
> +                       return ret;
> +               }
> +       }
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(drm_platform_register_drivers);
> +
> +/**
> + * drm_platform_unregister_drivers - Helper to unregister an array of
> + * struct platform_drivers (in the opposite order they would have been
> + * registered by drm_platform_register_drivers()).
> + */
> +void drm_platform_unregister_drivers(struct platform_driver *const *drv,
> +                                    int count)
> +{
> +       while (--count >= 0)
> +               platform_driver_unregister(drv[count]);
> +}
> +EXPORT_SYMBOL_GPL(drm_platform_unregister_drivers);
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> index fa5194c..83f829b 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> @@ -520,53 +520,27 @@ static int exynos_drm_register_devices(void)
>         return 0;
>  }
>
> -static void exynos_drm_unregister_drivers(struct platform_driver * const *drv,
> -                                         int count)
> -{
> -       while (--count >= 0)
> -               platform_driver_unregister(drv[count]);
> -}
> -
> -static int exynos_drm_register_drivers(struct platform_driver * const *drv,
> -                                      int count)
> -{
> -       int i, ret;
> -
> -       for (i = 0; i < count; ++i) {
> -               ret = platform_driver_register(drv[i]);
> -               if (!ret)
> -                       continue;
> -
> -               while (--i >= 0)
> -                       platform_driver_unregister(drv[i]);
> -
> -               return ret;
> -       }
> -
> -       return 0;
> -}
> -
>  static inline int exynos_drm_register_kms_drivers(void)
>  {
> -       return exynos_drm_register_drivers(exynos_drm_kms_drivers,
> -                                       ARRAY_SIZE(exynos_drm_kms_drivers));
> +       return drm_platform_register_drivers(exynos_drm_kms_drivers,
> +                                            ARRAY_SIZE(exynos_drm_kms_drivers));
>  }
>
>  static inline int exynos_drm_register_non_kms_drivers(void)
>  {
> -       return exynos_drm_register_drivers(exynos_drm_non_kms_drivers,
> -                                       ARRAY_SIZE(exynos_drm_non_kms_drivers));
> +       return drm_platform_register_drivers(exynos_drm_non_kms_drivers,
> +                                            ARRAY_SIZE(exynos_drm_non_kms_drivers));
>  }
>
>  static inline void exynos_drm_unregister_kms_drivers(void)
>  {
> -       exynos_drm_unregister_drivers(exynos_drm_kms_drivers,
> +       drm_platform_unregister_drivers(exynos_drm_kms_drivers,
>                                         ARRAY_SIZE(exynos_drm_kms_drivers));
>  }
>
>  static inline void exynos_drm_unregister_non_kms_drivers(void)
>  {
> -       exynos_drm_unregister_drivers(exynos_drm_non_kms_drivers,
> +       drm_platform_unregister_drivers(exynos_drm_non_kms_drivers,
>                                         ARRAY_SIZE(exynos_drm_non_kms_drivers));
>  }
>
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index 8b5ce7c..a774574 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -1087,6 +1087,10 @@ extern int drm_pcie_get_speed_cap_mask(struct drm_device *dev, u32 *speed_mask);
>  /* platform section */
>  extern int drm_platform_init(struct drm_driver *driver, struct platform_device *platform_device);
>  extern int drm_platform_set_busid(struct drm_device *d, struct drm_master *m);
> +int drm_platform_register_drivers(struct platform_driver *const *drv,
> +                                 int count);
> +void drm_platform_unregister_drivers(struct platform_driver *const *drv,
> +                                    int count);
>
>  /* returns true if currently okay to sleep */
>  static __inline__ bool drm_can_sleep(void)
> --
> 2.1.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/dri-devel



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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