drm/pl111: Support variants with broken VBLANK

The early Integrator CLCD synthesized in the Integrator CP and
IM-PD1 FPGAs are broken: their vertical and next base interrupts
are not functional. Support these variants by simply disabling
the use of the vblank interrupt on these variants.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180206093540.8147-4-linus.walleij@linaro.org

4 files changed, 18 insertions, 10 deletions

diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c
index 4d4e38b4c9d5..d75923896609 100644
--- a/drivers/gpu/drm/pl111/pl111_display.c
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -256,7 +256,8 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe,
         cntl |= CNTL_LCDPWR;
         writel(cntl, priv->regs + priv->ctrl);
 
-        drm_crtc_vblank_on(crtc);
+        if (!priv->variant->broken_vblank)
+                drm_crtc_vblank_on(crtc);
 }
 
 void pl111_display_disable(struct drm_simple_display_pipe *pipe)
@@ -266,7 +267,8 @@ void pl111_display_disable(struct drm_simple_display_pipe *pipe)
         struct pl111_drm_dev_private *priv = drm->dev_private;
         u32 cntl;
 
-        drm_crtc_vblank_off(crtc);
+        if (!priv->variant->broken_vblank)
+                drm_crtc_vblank_off(crtc);
 
         /* Power Down */
         cntl = readl(priv->regs + priv->ctrl);
diff --git a/drivers/gpu/drm/pl111/pl111_drm.h b/drivers/gpu/drm/pl111/pl111_drm.h
index a9b18195d11d..6d0e450e51b1 100644
--- a/drivers/gpu/drm/pl111/pl111_drm.h
+++ b/drivers/gpu/drm/pl111/pl111_drm.h
@@ -40,6 +40,7 @@ struct drm_minor;
  *      BGR/RGB routing
  * @broken_clockdivider: the clock divider is broken and we need to
  *      use the supplied clock directly
+ * @broken_vblank: the vblank IRQ is broken on this variant
  * @formats: array of supported pixel formats on this variant
  * @nformats: the length of the array of supported pixel formats
  */
@@ -48,6 +49,7 @@ struct pl111_variant_data {
         bool is_pl110;
         bool external_bgr;
         bool broken_clockdivider;
+        bool broken_vblank;
         const u32 *formats;
         unsigned int nformats;
 };
diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
index ad8dfead2d00..94fbc7cc5e19 100644
--- a/drivers/gpu/drm/pl111/pl111_drv.c
+++ b/drivers/gpu/drm/pl111/pl111_drv.c
@@ -132,10 +132,12 @@ static int pl111_modeset_init(struct drm_device *dev)
         if (ret)
                 return ret;
 
-        ret = drm_vblank_init(dev, 1);
-        if (ret != 0) {
-                dev_err(dev->dev, "Failed to init vblank\n");
-                goto out_bridge;
+        if (!priv->variant->broken_vblank) {
+                ret = drm_vblank_init(dev, 1);
+                if (ret != 0) {
+                        dev_err(dev->dev, "Failed to init vblank\n");
+                        goto out_bridge;
+                }
         }
 
         drm_mode_config_reset(dev);
@@ -172,10 +174,6 @@ static struct drm_driver pl111_drm_driver = {
         .dumb_create = drm_gem_cma_dumb_create,
         .gem_free_object_unlocked = drm_gem_cma_free_object,
         .gem_vm_ops = &drm_gem_cma_vm_ops,
-
-        .enable_vblank = pl111_enable_vblank,
-        .disable_vblank = pl111_disable_vblank,
-
         .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
         .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
         .gem_prime_import = drm_gem_prime_import,
@@ -201,6 +199,11 @@ static int pl111_amba_probe(struct amba_device *amba_dev,
         if (!priv)
                 return -ENOMEM;
 
+        if (!variant->broken_vblank) {
+                pl111_drm_driver.enable_vblank = pl111_enable_vblank;
+                pl111_drm_driver.disable_vblank = pl111_disable_vblank;
+        }
+
         drm = drm_dev_alloc(&pl111_drm_driver, dev);
         if (IS_ERR(drm))
                 return PTR_ERR(drm);
diff --git a/drivers/gpu/drm/pl111/pl111_versatile.c b/drivers/gpu/drm/pl111/pl111_versatile.c
index 4b0a54825424..05a4b89e0934 100644
--- a/drivers/gpu/drm/pl111/pl111_versatile.c
+++ b/drivers/gpu/drm/pl111/pl111_versatile.c
@@ -238,6 +238,7 @@ static const struct pl111_variant_data pl110_integrator = {
         .name = "PL110 Integrator",
         .is_pl110 = true,
         .broken_clockdivider = true,
+        .broken_vblank = true,
         .formats = pl110_integrator_pixel_formats,
         .nformats = ARRAY_SIZE(pl110_integrator_pixel_formats),
 };