[coreboot-gerrit] New patch to review for coreboot: 1c97210 google/pit: disable SYSMMU for graphics

Stefan Reinauer (stefan.reinauer@coreboot.org) gerrit at coreboot.org
Tue Dec 3 23:55:36 CET 2013


Stefan Reinauer (stefan.reinauer at coreboot.org) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/4410

-gerrit

commit 1c97210037b63e4df4369a875270a2c3805cef99
Author: Ronald G. Minnich <rminnich at google.com>
Date:   Tue Jul 16 17:30:16 2013 -0700

    google/pit: disable SYSMMU for graphics
    
    It's not needed and it's a potential problem source.
    
    Change-Id: Ic4cafe74e7fc3a9031d852895ad7fd5e5cd64d11
    Signed-off-by: Ronald G. Minnich <rminnich at google.com>
    Reviewed-on: https://gerrit.chromium.org/gerrit/62279
    Commit-Queue: David Hendricks <dhendrix at chromium.org>
    Reviewed-by: David Hendricks <dhendrix at chromium.org>
    Tested-by: David Hendricks <dhendrix at chromium.org>
---
 src/mainboard/google/pit/mainboard.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/mainboard/google/pit/mainboard.c b/src/mainboard/google/pit/mainboard.c
index 042ced0..04010ac 100644
--- a/src/mainboard/google/pit/mainboard.c
+++ b/src/mainboard/google/pit/mainboard.c
@@ -325,6 +325,15 @@ static void mainboard_init(device_t dev)
 
 	set_vbe_mode_info_valid(&edid, (uintptr_t)fb_addr);
 
+	/*
+	 * The reset value for FIMD SYSMMU register MMU_CTRL:0x14640000
+	 * should be 0 according to the datasheet, but has experimentally
+	 * been found to come up as 3. This means FIMD SYSMMU is on by
+	 * default on Exynos5420. For now we are disabling FIMD SYSMMU.
+	 */
+	writel(0x0, (void *)0x14640000);
+	writel(0x0, (void *)0x14680000);
+
 	lcd_vdd();
 
 	parade_dp_bridge_setup();



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