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arm: am33xx: Initialize EMIF REG_PR_OLD_COUNT 

This patch is based on a patch from the U-Boot and fixes two errors with
the LCDC. Original commit message from Jyri Sarha [1]:
"Initialize EMIF OCP_CONFIG registers REG_COS_COUNT_1, REG_COS_COUNT_2,
and REG_PR_OLD_COUNT field for Beaglebone-Black and am335x-evm. With
the default values LCDC suffers from DMA FIFO underflows and frame
synchronization lost errors. The initialization values are the highest
that work flawlessly when heavy memory load is generated by CPU. 32bpp
colors were used in the test. On BBB the video mode used 110MHz pixel
clock. The mode supported by the panel of am335x-evm uses 30MHz pixel
clock."

The register values are generated by testing, because there is no formula
to calculate them. Also from Jyri Sarha [1]:
"In practice the only rule to find an optimal value is to find as high as
possible REG_PR_OLD_COUNT value that does not produce LCDC FIFO
underflows under worst case scenario. The worst case happens when the
highest pixel clock videomode with maximum bpp is used while memory
subsystem is stressed by endless stream of writes hitting the same
memory memory bank (can be the same address)."

It only contains the BeagleBone Black and the Phytec SoM, because I
don't have other boards.

[1] https://patchwork.ozlabs.org/patch/704013/

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Daniel Schultz 2017-01-26 09:25:44 +01:00 committed by Sascha Hauer
parent aa01ab27ff
commit 80807102b9
4 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/boards/beaglebone/lowlevel.c
View File

@ -41,6 +41,7 @@ static const struct am33xx_emif_regs ddr2_regs = {
.emif_tim1 = 0x0666B3C9,
.emif_tim2 = 0x243631CA,
.emif_tim3 = 0x0000033F,
.ocp_config = 0x00141414,
.sdram_config = 0x41805332,
.sdram_config2 = 0x41805332,
.sdram_ref_ctrl = 0x0000081A,
@ -97,6 +98,7 @@ static const struct am33xx_emif_regs ddr3_regs = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x266B7FDA,
.emif_tim3 = 0x501F867F,
.ocp_config = 0x00141414,
.zq_config = 0x50074BE4,
.sdram_config = 0x61C05332,
.sdram_config2 = 0x0,

11
arch/arm/boards/phytec-som-am335x/ram-timings.h
View File

@ -45,6 +45,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x26437FDA,
.emif_tim3 = 0x501F83FF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C052B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -66,6 +67,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAE4DB,
.emif_tim2 = 0x266B7FDA,
.emif_tim3 = 0x501F867F,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C05332,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -87,6 +89,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x26437FDA,
.emif_tim3 = 0x501F83FF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C052B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -106,6 +109,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAE4DB,
.emif_tim2 = 0x262F7FDA,
.emif_tim3 = 0x501F82BF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C05232,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -125,6 +129,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAE4DB,
.emif_tim2 = 0x266B7FDA,
.emif_tim3 = 0x501F867F,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C05332,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30
@ -144,6 +149,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAE4DB,
.emif_tim2 = 0x266B7FDA,
.emif_tim3 = 0x501F867F,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C053B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30
@ -163,6 +169,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAE4DB,
.emif_tim2 = 0x268F7FDA,
.emif_tim3 = 0x501F88BF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C053B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30
@ -182,6 +189,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x26437FDA,
.emif_tim3 = 0x501F83FF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C052B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -203,6 +211,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x266B7FDA,
.emif_tim3 = 0x501F867F,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C05332,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -222,6 +231,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x26437FDA,
.emif_tim3 = 0x501F83FF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C052B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,
@ -241,6 +251,7 @@ struct am335x_sdram_timings physom_timings[] = {
.emif_tim1 = 0x0AAAD4DB,
.emif_tim2 = 0x268F7FDA,
.emif_tim3 = 0x501F88BF,
.ocp_config = 0x003d3d3d,
.sdram_config = 0x61C053B2,
.zq_config = 0x50074BE4,
.sdram_ref_ctrl = 0x00000C30,

3
arch/arm/mach-omap/am33xx_generic.c
View File

@ -341,6 +341,9 @@ void am33xx_config_sdram(const struct am33xx_emif_regs *regs)
writel(regs->emif_tim3, AM33XX_EMIF4_0_REG(SDRAM_TIM_3));
writel(regs->emif_tim3, AM33XX_EMIF4_0_REG(SDRAM_TIM_3_SHADOW));
if (regs->ocp_config)
writel(regs->ocp_config, AM33XX_EMIF4_0_REG(OCP_CONFIG));
if (regs->zq_config) {
/*
* A value of 0x2800 for the REF CTRL will give us

2
arch/arm/mach-omap/include/mach/am33xx-silicon.h
View File

@ -114,6 +114,7 @@
#define EMIF4_SDRAM_TIM_3_SHADOW 0x2C
#define EMIF0_SDRAM_MGMT_CTRL 0x38
#define EMIF0_SDRAM_MGMT_CTRL_SHD 0x3C
#define EMIF4_OCP_CONFIG 0x54
#define EMIF4_ZQ_CONFIG 0xC8
#define EMIF4_DDR_PHY_CTRL_1 0xE4
#define EMIF4_DDR_PHY_CTRL_1_SHADOW 0xE8
@ -217,6 +218,7 @@ struct am33xx_emif_regs {
u32 emif_tim1;
u32 emif_tim2;
u32 emif_tim3;
u32 ocp_config;
u32 sdram_config;
u32 sdram_config2;
u32 zq_config;