@@ -70,6 +70,7 @@ static void set_scanout(struct drm_crtc *crtc, struct drm_framebuffer *fb)
struct drm_gem_cma_object *gem;
unsigned int depth, bpp;
dma_addr_t start, end;
+ u64 dma_base_and_ceiling;
drm_fb_get_bpp_depth(fb->pixel_format, &depth, &bpp);
gem = drm_fb_cma_get_gem_obj(fb, 0);
@@ -80,8 +81,12 @@ static void set_scanout(struct drm_crtc *crtc, struct drm_framebuffer *fb)
end = start + (crtc->mode.vdisplay * fb->pitches[0]);
- tilcdc_write(dev, LCDC_DMA_FB_BASE_ADDR_0_REG, start);
- tilcdc_write(dev, LCDC_DMA_FB_CEILING_ADDR_0_REG, end - 1);
+ /* Write DMA base and ceiling address with a single insruction,
+ * if available. This should make it more unlikely that LCDC would
+ * fetch the DMA addresses in the middle of an update.
+ */
+ dma_base_and_ceiling = (u64)(end - 1) << 32 | start;
+ tilcdc_write64(dev, LCDC_DMA_FB_BASE_ADDR_0_REG, dma_base_and_ceiling);
if (tilcdc_crtc->curr_fb)
drm_flip_work_queue(&tilcdc_crtc->unref_work,
@@ -119,6 +119,19 @@ static inline void tilcdc_write(struct drm_device *dev, u32 reg, u32 data)
iowrite32(data, priv->mmio + reg);
}
+static inline void tilcdc_write64(struct drm_device *dev, u32 reg, u64 data)
+{
+ struct tilcdc_drm_private *priv = dev->dev_private;
+ volatile void __iomem *addr = priv->mmio + reg;
+
+#ifdef iowrite64
+ iowrite64(data, addr);
+#else
+ /* This compiles to strd (=64-bit write) on ARM7 */
+ *(volatile u64 __force *)addr = data;
+#endif
+}
+
static inline u32 tilcdc_read(struct drm_device *dev, u32 reg)
{
struct tilcdc_drm_private *priv = dev->dev_private;
Write DMA base and ceiling address with a single instruction, if available. This should make it more unlikely that LCDC would fetch the DMA addresses in the middle of an update. Having bad combination of addresses in dma base and ceiling (e.g base > ceiling) can cause unpredictaple behavior in LCDC. Signed-off-by: Jyri Sarha <jsarha@ti.com> --- I am not sure what would be the least ugly way of utilizing ARM7 strd instruction. Using inline assebler would be the most straight forward way, but this looks less ugly to me. drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 9 +++++++-- drivers/gpu/drm/tilcdc/tilcdc_regs.h | 13 +++++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-)