drm/exynos: fimd: clear channel before enabling iommu
If any fimd channel was already active, initializing iommu will result
in a PAGE FAULT (e.e. u-boot could have turned on the display and
not disabled it before the kernel starts). This patch checks if any
channel is active before initializing iommu and disables it.
Signed-off-by: Akshu Agrawal <akshu.a@samsung.com>
Signed-off-by: Prathyush K <prathyush.k@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 40fd6cc..99ae79e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -143,6 +143,48 @@
return (struct fimd_driver_data *)of_id->data;
}
+static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
+{
+ struct fimd_context *ctx = mgr->ctx;
+
+ if (ctx->suspended)
+ return;
+
+ atomic_set(&ctx->wait_vsync_event, 1);
+
+ /*
+ * wait for FIMD to signal VSYNC interrupt or return after
+ * timeout which is set to 50ms (refresh rate of 20).
+ */
+ if (!wait_event_timeout(ctx->wait_vsync_queue,
+ !atomic_read(&ctx->wait_vsync_event),
+ HZ/20))
+ DRM_DEBUG_KMS("vblank wait timed out.\n");
+}
+
+
+static void fimd_clear_channel(struct exynos_drm_manager *mgr)
+{
+ struct fimd_context *ctx = mgr->ctx;
+ int win, ch_enabled = 0;
+
+ DRM_DEBUG_KMS("%s\n", __FILE__);
+
+ /* Check if any channel is enabled. */
+ for (win = 0; win < WINDOWS_NR; win++) {
+ u32 val = readl(ctx->regs + SHADOWCON);
+ if (val & SHADOWCON_CHx_ENABLE(win)) {
+ val &= ~SHADOWCON_CHx_ENABLE(win);
+ writel(val, ctx->regs + SHADOWCON);
+ ch_enabled = 1;
+ }
+ }
+
+ /* Wait for vsync, as disable channel takes effect at next vsync */
+ if (ch_enabled)
+ fimd_wait_for_vblank(mgr);
+}
+
static int fimd_mgr_initialize(struct exynos_drm_manager *mgr,
struct drm_device *drm_dev, int pipe)
{
@@ -169,8 +211,14 @@
drm_dev->vblank_disable_allowed = true;
/* attach this sub driver to iommu mapping if supported. */
- if (is_drm_iommu_supported(ctx->drm_dev))
+ if (is_drm_iommu_supported(ctx->drm_dev)) {
+ /*
+ * If any channel is already active, iommu will throw
+ * a PAGE FAULT when enabled. So clear any channel if enabled.
+ */
+ fimd_clear_channel(mgr);
drm_iommu_attach_device(ctx->drm_dev, ctx->dev);
+ }
return 0;
}
@@ -324,25 +372,6 @@
}
}
-static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
-{
- struct fimd_context *ctx = mgr->ctx;
-
- if (ctx->suspended)
- return;
-
- atomic_set(&ctx->wait_vsync_event, 1);
-
- /*
- * wait for FIMD to signal VSYNC interrupt or return after
- * timeout which is set to 50ms (refresh rate of 20).
- */
- if (!wait_event_timeout(ctx->wait_vsync_queue,
- !atomic_read(&ctx->wait_vsync_event),
- HZ/20))
- DRM_DEBUG_KMS("vblank wait timed out.\n");
-}
-
static void fimd_win_mode_set(struct exynos_drm_manager *mgr,
struct exynos_drm_overlay *overlay)
{