target/linux/brcm2708/patches-4.4/0467-drm-vc4-Use-runtime-PM-to-power-cycle-the-device-whe.patch

   1 From a933cf6cc414d067087f311598e4acd42bc4f6d2 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 8 Feb 2016 12:59:02 -0800
   4 Subject: [PATCH] drm/vc4: Use runtime PM to power cycle the device when the
   5  GPU hangs.
   6
   7 This gets us functional GPU reset again, like we had until a refactor
   8 at merge time.  Tested with a little patch to stuff in a broken binner
   9 job every 100 frames.
  10
  11 Signed-off-by: Eric Anholt <eric@anholt.net>
  12 (cherry picked from commit 36cb6253f9383fd9a59ee7b8458c6232ef48577c)
  13 ---
  14  drivers/gpu/drm/vc4/vc4_drv.h |  6 +++++-
  15  drivers/gpu/drm/vc4/vc4_gem.c | 26 +++++++++++++++++++++-----
  16  2 files changed, 26 insertions(+), 6 deletions(-)
  17
  18 --- a/drivers/gpu/drm/vc4/vc4_drv.h
  19 +++ b/drivers/gpu/drm/vc4/vc4_drv.h
  20 @@ -104,6 +104,11 @@ struct vc4_dev {
  21         struct vc4_bo *overflow_mem;
  22         struct work_struct overflow_mem_work;
  23
  24 +       int power_refcount;
  25 +
  26 +       /* Mutex controlling the power refcount. */
  27 +       struct mutex power_lock;
  28 +
  29         struct {
  30                 struct timer_list timer;
  31                 struct work_struct reset_work;
  32 @@ -495,7 +500,6 @@ void vc4_plane_async_set_fb(struct drm_p
  33  extern struct platform_driver vc4_v3d_driver;
  34  int vc4_v3d_debugfs_ident(struct seq_file *m, void *unused);
  35  int vc4_v3d_debugfs_regs(struct seq_file *m, void *unused);
  36 -int vc4_v3d_set_power(struct vc4_dev *vc4, bool on);
  37
  38  /* vc4_validate.c */
  39  int
  40 --- a/drivers/gpu/drm/vc4/vc4_gem.c
  41 +++ b/drivers/gpu/drm/vc4/vc4_gem.c
  42 @@ -261,8 +261,16 @@ vc4_reset(struct drm_device *dev)
  43         struct vc4_dev *vc4 = to_vc4_dev(dev);
  44
  45         DRM_INFO("Resetting GPU.\n");
  46 -       vc4_v3d_set_power(vc4, false);
  47 -       vc4_v3d_set_power(vc4, true);
  48 +
  49 +       mutex_lock(&vc4->power_lock);
  50 +       if (vc4->power_refcount) {
  51 +               /* Power the device off and back on the by dropping the
  52 +                * reference on runtime PM.
  53 +                */
  54 +               pm_runtime_put_sync_suspend(&vc4->v3d->pdev->dev);
  55 +               pm_runtime_get_sync(&vc4->v3d->pdev->dev);
  56 +       }
  57 +       mutex_unlock(&vc4->power_lock);
  58
  59         vc4_irq_reset(dev);
  60
  61 @@ -709,7 +717,10 @@ vc4_complete_exec(struct drm_device *dev
  62         }
  63         mutex_unlock(&dev->struct_mutex);
  64
  65 -       pm_runtime_put(&vc4->v3d->pdev->dev);
  66 +       mutex_lock(&vc4->power_lock);
  67 +       if (--vc4->power_refcount == 0)
  68 +               pm_runtime_put(&vc4->v3d->pdev->dev);
  69 +       mutex_unlock(&vc4->power_lock);
  70
  71         kfree(exec);
  72  }
  73 @@ -851,7 +862,7 @@ vc4_submit_cl_ioctl(struct drm_device *d
  74         struct vc4_dev *vc4 = to_vc4_dev(dev);
  75         struct drm_vc4_submit_cl *args = data;
  76         struct vc4_exec_info *exec;
  77 -       int ret;
  78 +       int ret = 0;
  79
  80         if ((args->flags & ~VC4_SUBMIT_CL_USE_CLEAR_COLOR) != 0) {
  81                 DRM_ERROR("Unknown flags: 0x%02x\n", args->flags);
  82 @@ -864,7 +875,10 @@ vc4_submit_cl_ioctl(struct drm_device *d
  83                 return -ENOMEM;
  84         }
  85
  86 -       ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
  87 +       mutex_lock(&vc4->power_lock);
  88 +       if (vc4->power_refcount++ == 0)
  89 +               ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
  90 +       mutex_unlock(&vc4->power_lock);
  91         if (ret < 0) {
  92                 kfree(exec);
  93                 return ret;
  94 @@ -925,6 +939,8 @@ vc4_gem_init(struct drm_device *dev)
  95                     (unsigned long)dev);
  96
  97         INIT_WORK(&vc4->job_done_work, vc4_job_done_work);
  98 +
  99 +       mutex_init(&vc4->power_lock);
 100  }
 101
 102  void