From: Akshu Agrawal <akshu.a@xxxxxxxxxxx>
If any fimd channel was already active, initializing iommu will result
in a PAGE FAULT (e.g. 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@xxxxxxxxxxx>
Signed-off-by: Prathyush K <prathyush.k@xxxxxxxxxxx>
---
drivers/gpu/drm/exynos/exynos_drm_fimd.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index f88eaa4..3aeedf5 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -733,6 +733,28 @@ out:
return IRQ_HANDLED;
}
+static void fimd_clear_channel(struct device *dev)
+{
+ struct fimd_context *ctx = get_fimd_context(dev);
+ 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(dev);
+}
+
static int fimd_subdrv_probe(struct drm_device *drm_dev, struct device *dev)
{
DRM_DEBUG_KMS("%s\n", __FILE__);
@@ -755,9 +777,14 @@ static int fimd_subdrv_probe(struct drm_device *drm_dev, struct device *dev)
drm_dev->vblank_disable_allowed = 1;
/* attach this sub driver to iommu mapping if supported. */
- if (is_drm_iommu_supported(drm_dev))
+ if (is_drm_iommu_supported(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(dev);
drm_iommu_attach_device(drm_dev, dev);
-
+ }
return 0;
}
--
1.8.0
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