| Message ID | 20190121113218.10708-1-maciej.zagrabski@grinn-global.com |
|---|---|
| State | RFC, archived |
| Delegated to: | Lokesh Vutla |
| Headers | show |
| Series | [U-Boot,RFC] am335x: Changes in DDR init procedure to Support Samsung K4B2G1646EBIH9 memory chip | expand |
On Mon, Jan 21, 2019 at 12:32:18PM +0100, Maciej Zagrabski wrote: > K4B2G1646EBIH9 Samsung memory chip used now on chiliSOM requires > refresh register REF CTRL to be initialized with large enough > value, faster than it is implemented in `config_sdram` in ddr.c > for am33xx, that mean before setting ZQ CTRL. Change should > not interferee with already supported DDR chips cause refresh rate value > is large enough to cover initialization, but it will finish during > `udelay` below anyway. If this is not acceptable I can `ifdef` this > line with config introduced in previous patch. > > Signed-off-by: Maciej Zagrabski <maciej.zagrabski@grinn-global.com> > --- > arch/arm/mach-omap2/am33xx/ddr.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/mach-omap2/am33xx/ddr.c b/arch/arm/mach-omap2/am33xx/ddr.c > index be6f4d72ccd..3684508bb1c 100644 > --- a/arch/arm/mach-omap2/am33xx/ddr.c > +++ b/arch/arm/mach-omap2/am33xx/ddr.c > @@ -171,12 +171,13 @@ void config_sdram(const struct emif_regs *regs, int nr) > writel(regs->ref_ctrl, &emif_reg[nr]->emif_sdram_ref_ctrl); > #else > if (regs->zq_config) { > + /* Trigger initialization */ > + writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl); > + > writel(regs->zq_config, &emif_reg[nr]->emif_zq_config); > writel(regs->sdram_config, &cstat->secure_emif_sdram_config); > writel(regs->sdram_config, &emif_reg[nr]->emif_sdram_config); > > - /* Trigger initialization */ > - writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl); > /* Wait 1ms because of L3 timeout error */ > udelay(1000); > Adding James Doublesin here as I know he knows all the ins and outs of these particular parts. Thanks!
diff --git a/arch/arm/mach-omap2/am33xx/ddr.c b/arch/arm/mach-omap2/am33xx/ddr.c index be6f4d72ccd..3684508bb1c 100644 --- a/arch/arm/mach-omap2/am33xx/ddr.c +++ b/arch/arm/mach-omap2/am33xx/ddr.c @@ -171,12 +171,13 @@ void config_sdram(const struct emif_regs *regs, int nr) writel(regs->ref_ctrl, &emif_reg[nr]->emif_sdram_ref_ctrl); #else if (regs->zq_config) { + /* Trigger initialization */ + writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl); + writel(regs->zq_config, &emif_reg[nr]->emif_zq_config); writel(regs->sdram_config, &cstat->secure_emif_sdram_config); writel(regs->sdram_config, &emif_reg[nr]->emif_sdram_config); - /* Trigger initialization */ - writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl); /* Wait 1ms because of L3 timeout error */ udelay(1000);
K4B2G1646EBIH9 Samsung memory chip used now on chiliSOM requires refresh register REF CTRL to be initialized with large enough value, faster than it is implemented in `config_sdram` in ddr.c for am33xx, that mean before setting ZQ CTRL. Change should not interferee with already supported DDR chips cause refresh rate value is large enough to cover initialization, but it will finish during `udelay` below anyway. If this is not acceptable I can `ifdef` this line with config introduced in previous patch. Signed-off-by: Maciej Zagrabski <maciej.zagrabski@grinn-global.com> --- arch/arm/mach-omap2/am33xx/ddr.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)