[U-Boot] [PATCH] exynos5: Don't potentially undervoltage the CPU

For snow when chainloading u-boot the CPU seems to be running at full speed. The lower CPU voltage seems to be ok for u-boot, but when booting linux (bringing up all cores) I'm seeing random crashes.
Bump the voltage up to a level that's safe for all cpu frequencies.
Signed-off-by: Sjoerd Simons sjoerd.simons@collabora.co.uk
---
board/samsung/common/exynos5-dt.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/board/samsung/common/exynos5-dt.c b/board/samsung/common/exynos5-dt.c index 2e3b16df45..aec1f396b0 100644 --- a/board/samsung/common/exynos5-dt.c +++ b/board/samsung/common/exynos5-dt.c @@ -123,13 +123,7 @@ int exynos_power_init(void) if (ret) return ret;
- /* - * This would normally be 1.3V, but since we are running slowly 1.1V - * is enough. For spring it helps reduce CPU temperature and avoid - * hangs with the case open. 1.1V is minimum voltage borderline for - * chained bootloaders. - */ - ret = exynos_set_regulator("vdd_arm", 1100000); + ret = exynos_set_regulator("vdd_arm", 1300000); if (ret) return ret; ret = exynos_set_regulator("vdd_int", 1012500);

Hello Sjoerd,
On 01/10/2017 08:28 AM, Sjoerd Simons wrote:
For snow when chainloading u-boot the CPU seems to be running at full speed. The lower CPU voltage seems to be ok for u-boot, but when booting linux (bringing up all cores) I'm seeing random crashes.
Bump the voltage up to a level that's safe for all cpu frequencies.
Signed-off-by: Sjoerd Simons sjoerd.simons@collabora.co.uk
Your patch looks good to me, 1.3V matches the operating point defined in the Exynos5250.dtsi for the maximum CPU frequency (1.7 GHz).
Reviewed-by: Javier Martinez Canillas javier@osg.samsung.com
Best regards,

On Tuesday, 10 January 2017, Javier Martinez Canillas < javier@osg.samsung.com> wrote:
Hello Sjoerd,
On 01/10/2017 08:28 AM, Sjoerd Simons wrote:
For snow when chainloading u-boot the CPU seems to be running at full speed. The lower CPU voltage seems to be ok for u-boot, but when booting linux (bringing up all cores) I'm seeing random crashes.
Bump the voltage up to a level that's safe for all cpu frequencies.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk
Your patch looks good to me, 1.3V matches the operating point defined in the Exynos5250.dtsi for the maximum CPU frequency (1.7 GHz).
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com javascript:;>
Best regards,
Javier Martinez Canillas Open Source Group Samsung Research America _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de javascript:; http://lists.denx.de/mailman/listinfo/u-boot
applied to u-boot-samsung
Thanks
participants (3)
-
Javier Martinez Canillas
-
Minkyu Kang
-
Sjoerd Simons