From: Michael Trimarchi michael@amarulasolutions.com
While the exact problem is not known, based on discussion between Philipp Tomsich and André Przywara it is guessed that exit self-refresh timing is not set with correct value. There may be implicit enter or exit Self-Refresh anywhere as part of some training phase.
In ZynqMP register guide [1], which is close to the various Allwinner DRAM controllers, tXSDLL is bits [14:8], while the non-DLL tXS is bits [6:0]: Self refresh exit delay. So it could be safely increased and it only affects the time after the self-refresh “exit”, which happens only after (re-)initialisation.
There was no document for cpu in question so based on oscilloscope readings [2][3] and observed result by comparing allwinner architecture. So set it same as Allwinner H5 silicon.
Before this patch, failure rate of was 7%.
This was tested on A33 allwinner cpu, dual rank connection connected with two MT41K512M16HA-125:A memory model. Memory is configured as DDR3 1.5V
[1] https://www.xilinx.com/html_docs/registers/ug1087/ddrc___dramtmg8.html [2] https://ibb.co/R70zmyS [3] https://ibb.co/HVVCGQ8
Signed-off-by: Michael Trimarchi michael@amarulasolutions.com Signed-off-by: Shyam Saini shyam.saini@amarulasolutions.com --- Changelogs: V1->V2: adjust commit message V2->V3: Adjust commit message based on V2 Discussion --- arch/arm/mach-sunxi/dram_sun8i_a33.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/mach-sunxi/dram_sun8i_a33.c b/arch/arm/mach-sunxi/dram_sun8i_a33.c index 1da2727f9874..5da01922bfaf 100644 --- a/arch/arm/mach-sunxi/dram_sun8i_a33.c +++ b/arch/arm/mach-sunxi/dram_sun8i_a33.c @@ -152,7 +152,7 @@ static void auto_set_timing_para(struct dram_para *para) reg_val &= ~(0xff << 8); reg_val &= ~(0xff << 0); reg_val |= (0x33 << 8); - reg_val |= (0x8 << 0); + reg_val |= (0x10 << 0); writel(reg_val, &mctl_ctl->dramtmg8); /* Set phy interface time */ reg_val = (0x2 << 24) | (t_rdata_en << 16) | (0x1 << 8)