target/linux/bcm27xx/patches-5.15/950-0009-drm-vc4-hdmi-Prevent-access-to-crtc-state-outside-of.patch

   1 From d6ecbdcba5174488d403ccddc016721243eb1797 Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Tue, 19 Oct 2021 14:19:29 +0200
   4 Subject: [PATCH] drm/vc4: hdmi: Prevent access to crtc->state outside
   5  of KMS
   6
   7 Accessing the crtc->state pointer from outside the modesetting context
   8 is not allowed. We thus need to copy whatever we need from the KMS state
   9 to our structure in order to access it.
  10
  11 However, in the vc4 HDMI driver we do use that pointer in the ALSA code
  12 path, and potentially in the hotplug interrupt handler path.
  13
  14 These paths both need access to the CRTC adjusted mode in order for the
  15 proper dividers to be set for ALSA, and the scrambler state to be
  16 reinstated properly for hotplug.
  17
  18 Let's copy this mode into our private encoder structure and reference it
  19 from there when needed. Since that part is shared between KMS and other
  20 paths, we need to protect it using our mutex.
  21
  22 Link: https://lore.kernel.org/all/YWgteNaNeaS9uWDe@phenom.ffwll.local/
  23 Fixes: bb7d78568814 ("drm/vc4: Add HDMI audio support")
  24 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  25 ---
  26  drivers/gpu/drm/vc4/vc4_hdmi.c | 38 +++++++++++++++++++++++-----------
  27  drivers/gpu/drm/vc4/vc4_hdmi.h |  6 ++++++
  28  2 files changed, 32 insertions(+), 12 deletions(-)
  29
  30 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
  31 +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
  32 @@ -488,8 +488,7 @@ static void vc4_hdmi_set_avi_infoframe(s
  33         struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
  34         struct drm_connector *connector = &vc4_hdmi->connector;
  35         struct drm_connector_state *cstate = connector->state;
  36 -       struct drm_crtc *crtc = encoder->crtc;
  37 -       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
  38 +       const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
  39         union hdmi_infoframe frame;
  40         int ret;
  41
  42 @@ -601,8 +600,8 @@ static bool vc4_hdmi_supports_scrambling
  43
  44  static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
  45  {
  46 -       struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
  47         struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
  48 +       struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
  49         unsigned long flags;
  50
  51         lockdep_assert_held(&vc4_hdmi->mutex);
  52 @@ -628,18 +627,21 @@ static void vc4_hdmi_enable_scrambling(s
  53  static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
  54  {
  55         struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
  56 +       struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
  57         struct drm_crtc *crtc = encoder->crtc;
  58         unsigned long flags;
  59
  60 +       lockdep_assert_held(&vc4_hdmi->mutex);
  61 +
  62         /*
  63          * At boot, encoder->crtc will be NULL. Since we don't know the
  64          * state of the scrambler and in order to avoid any
  65          * inconsistency, let's disable it all the time.
  66          */
  67 -       if (crtc && !vc4_hdmi_supports_scrambling(encoder, &crtc->mode))
  68 +       if (crtc && !vc4_hdmi_supports_scrambling(encoder, mode))
  69                 return;
  70
  71 -       if (crtc && !vc4_hdmi_mode_needs_scrambling(&crtc->mode))
  72 +       if (crtc && !vc4_hdmi_mode_needs_scrambling(mode))
  73                 return;
  74
  75         if (delayed_work_pending(&vc4_hdmi->scrambling_work))
  76 @@ -1018,8 +1020,8 @@ static void vc4_hdmi_encoder_pre_crtc_co
  77                 vc4_hdmi_encoder_get_connector_state(encoder, state);
  78         struct vc4_hdmi_connector_state *vc4_conn_state =
  79                 conn_state_to_vc4_hdmi_conn_state(conn_state);
  80 -       struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
  81         struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
  82 +       struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
  83         unsigned long pixel_rate = vc4_conn_state->pixel_rate;
  84         unsigned long bvb_rate, hsm_rate;
  85         unsigned long flags;
  86 @@ -1121,9 +1123,9 @@ out:
  87  static void vc4_hdmi_encoder_pre_crtc_enable(struct drm_encoder *encoder,
  88                                              struct drm_atomic_state *state)
  89  {
  90 -       struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
  91 -       struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
  92         struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
  93 +       struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
  94 +       struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
  95         unsigned long flags;
  96
  97         mutex_lock(&vc4_hdmi->mutex);
  98 @@ -1151,8 +1153,8 @@ static void vc4_hdmi_encoder_pre_crtc_en
  99  static void vc4_hdmi_encoder_post_crtc_enable(struct drm_encoder *encoder,
 100                                               struct drm_atomic_state *state)
 101  {
 102 -       struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
 103         struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 104 +       struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
 105         struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
 106         bool hsync_pos = mode->flags & DRM_MODE_FLAG_PHSYNC;
 107         bool vsync_pos = mode->flags & DRM_MODE_FLAG_PVSYNC;
 108 @@ -1228,6 +1230,19 @@ static void vc4_hdmi_encoder_enable(stru
 109  {
 110  }
 111
 112 +static void vc4_hdmi_encoder_atomic_mode_set(struct drm_encoder *encoder,
 113 +                                            struct drm_crtc_state *crtc_state,
 114 +                                            struct drm_connector_state *conn_state)
 115 +{
 116 +       struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
 117 +
 118 +       mutex_lock(&vc4_hdmi->mutex);
 119 +       memcpy(&vc4_hdmi->saved_adjusted_mode,
 120 +              &crtc_state->adjusted_mode,
 121 +              sizeof(vc4_hdmi->saved_adjusted_mode));
 122 +       mutex_unlock(&vc4_hdmi->mutex);
 123 +}
 124 +
 125  #define WIFI_2_4GHz_CH1_MIN_FREQ       2400000000ULL
 126  #define WIFI_2_4GHz_CH1_MAX_FREQ       2422000000ULL
 127
 128 @@ -1306,6 +1321,7 @@ vc4_hdmi_encoder_mode_valid(struct drm_e
 129
 130  static const struct drm_encoder_helper_funcs vc4_hdmi_encoder_helper_funcs = {
 131         .atomic_check = vc4_hdmi_encoder_atomic_check,
 132 +       .atomic_mode_set = vc4_hdmi_encoder_atomic_mode_set,
 133         .mode_valid = vc4_hdmi_encoder_mode_valid,
 134         .disable = vc4_hdmi_encoder_disable,
 135         .enable = vc4_hdmi_encoder_enable,
 136 @@ -1359,9 +1375,7 @@ static void vc4_hdmi_audio_set_mai_clock
 137
 138  static void vc4_hdmi_set_n_cts(struct vc4_hdmi *vc4_hdmi, unsigned int samplerate)
 139  {
 140 -       struct drm_encoder *encoder = &vc4_hdmi->encoder.base.base;
 141 -       struct drm_crtc *crtc = encoder->crtc;
 142 -       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
 143 +       const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
 144         u32 n, cts;
 145         u64 tmp;
 146
 147 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
 148 +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
 149 @@ -198,6 +198,12 @@ struct vc4_hdmi {
 150          * be resilient to that.
 151          */
 152         struct mutex mutex;
 153 +
 154 +       /**
 155 +        * @saved_adjusted_mode: Copy of @drm_crtc_state.adjusted_mode
 156 +        * for use by ALSA hooks and interrupt handlers. Protected by @mutex.
 157 +        */
 158 +       struct drm_display_mode saved_adjusted_mode;
 159  };
 160
 161  static inline struct vc4_hdmi *