[U-Boot] [PATCH v4 5/5] bcm2835 video: Map fb as cached

Alexander Graf agraf at suse.de
Thu Mar 24 01:27:06 CET 2016


The bcm2835 frame buffer is in RAM, so we can easily map it as cached and gain
all the glorious performance boost that brings with it.

Signed-off-by: Alexander Graf <agraf at suse.de>

---

v2 -> v3:

  - Fix align parameters
  - Fix whitespace

v3 -> v4:

  - Align start of fb as well to align with segments
  - Align fb size on segment size, not page size
---
 drivers/video/bcm2835.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/video/bcm2835.c b/drivers/video/bcm2835.c
index bff1fcb..a376537 100644
--- a/drivers/video/bcm2835.c
+++ b/drivers/video/bcm2835.c
@@ -44,6 +44,7 @@ void lcd_ctrl_init(void *lcdbase)
 	ALLOC_CACHE_ALIGN_BUFFER(struct msg_setup, msg_setup, 1);
 	int ret;
 	u32 w, h;
+	u32 fb_start, fb_end;
 
 	debug("bcm2835: Query resolution...\n");
 
@@ -106,6 +107,14 @@ void lcd_ctrl_init(void *lcdbase)
 
 	gd->fb_base = bus_to_phys(
 		msg_setup->allocate_buffer.body.resp.fb_address);
+
+	/* Enable dcache for the frame buffer */
+	fb_start = ALIGN(gd->fb_base, 1 << MMU_SECTION_SHIFT);
+	fb_end = gd->fb_base + msg_setup->allocate_buffer.body.resp.fb_size;
+	fb_end = ALIGN(fb_end, 1 << MMU_SECTION_SHIFT);
+	mmu_set_region_dcache_behaviour(fb_start, fb_end - fb_start,
+		DCACHE_WRITEBACK);
+	lcd_set_flush_dcache(1);
 }
 
 void lcd_enable(void)
-- 
1.8.5.6



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