[PATCH] sunxi: orangepi_zero: reduce DRAM clock to 408 MHz

[PATCH] sunxi: orangepi_zero: reduce DRAM clock to 408 MHz

[Danil Bezborodov]

The Orange Pi Zero uses a single DDR3 chip on a 16-bit bus, unlike
the Orange Pi PC family (two chips, 32-bit) whose values this
defconfig inherited. The 624 MHz clock was never validated on this
board: commit 8792a64d8770 ("sunxi: reduce Orange Pi Zero DRAM clock
speed") lowered 672 to 624 based on lima-memtester results from an
Orange Pi PC and the PC's value in the vendor U-Boot fork.

The vendor BSP configuration for this exact board
(orangepi-xunlong/external, sys_config_orangepi_zero.fex) sets
dram_clk = 408, and Armbian has shipped a 624->408 patch for this
board - and only this board among H3 Orange Pis - since 2017.

On a 512 MB H3 variant of the board, 624 MHz produces reproducible
memory corruption caught by the kernel's early_memtest; 408 MHz
matches the vendor and Armbian values.

Signed-off-by: Danil Bezborodov <xanmilanto@gmail.com>
---
 configs/orangepi_zero_defconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configs/orangepi_zero_defconfig b/configs/orangepi_zero_defconfig
index 49a1f4d0..09ce3a95 100644
--- a/configs/orangepi_zero_defconfig
+++ b/configs/orangepi_zero_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_SUNXI=y
 CONFIG_DEFAULT_DEVICE_TREE="sun8i-h2-plus-orangepi-zero"
-CONFIG_DRAM_CLK=624
+CONFIG_DRAM_CLK=408
 CONFIG_SPL=y
 CONFIG_MACH_SUN8I_H3=y
 # CONFIG_VIDEO_DE2 is not set
-- 
2.50.1 (Apple Git-155)