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ARM: at91: pm: Workaround DDRSDRC self-refresh bug with LPDDR1 memories. 

As already explained for pm_suspend.S, the DDRSDR controller fails to put
LPDDR1 memories in self-refresh. Force the controller to think it has DDR2
memories during the self-refresh period, as the DDR2 self-refresh spec is
equivalent to LPDDR1, and is correctly implemented in the controller.

Acked-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
hifive-unleashed-5.1
Alexandre Belloni 2017-02-01 22:10:34 +01:00
parent 5a2d4f053f
commit 56387634b7
1 changed files with 19 additions and 1 deletions
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20
arch/arm/mach-at91/pm.c
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@ -241,12 +241,27 @@ static void at91_ddr_standby(void)
/* Those two values allow us to delay self-refresh activation
* to the maximum. */
u32 lpr0, lpr1 = 0;
u32 mdr, saved_mdr0, saved_mdr1 = 0;
u32 saved_lpr0, saved_lpr1 = 0;
/* LPDDR1 --> force DDR2 mode during self-refresh */
saved_mdr0 = at91_ramc_read(0, AT91_DDRSDRC_MDR);
if ((saved_mdr0 & AT91_DDRSDRC_MD) == AT91_DDRSDRC_MD_LOW_POWER_DDR) {
mdr = saved_mdr0 & ~AT91_DDRSDRC_MD;
mdr |= AT91_DDRSDRC_MD_DDR2;
at91_ramc_write(0, AT91_DDRSDRC_MDR, mdr);
}
if (pm_data.ramc[1]) {
saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
lpr1 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;
saved_mdr1 = at91_ramc_read(1, AT91_DDRSDRC_MDR);
if ((saved_mdr1 & AT91_DDRSDRC_MD) == AT91_DDRSDRC_MD_LOW_POWER_DDR) {
mdr = saved_mdr1 & ~AT91_DDRSDRC_MD;
mdr |= AT91_DDRSDRC_MD_DDR2;
at91_ramc_write(1, AT91_DDRSDRC_MDR, mdr);
}
}
saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
@ -260,9 +275,12 @@ static void at91_ddr_standby(void)
cpu_do_idle();
at91_ramc_write(0, AT91_DDRSDRC_MDR, saved_mdr0);
at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
if (pm_data.ramc[1])
if (pm_data.ramc[1]) {
at91_ramc_write(0, AT91_DDRSDRC_MDR, saved_mdr1);
at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
}
}
static void sama5d3_ddr_standby(void)