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| author | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2017-02-01 22:10:34 +0100 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2017-03-31 20:36:07 +0200 |
| commit | 56387634b7604c141b8645d2377980164e18da0d (patch) | |
| tree | 054a5bdf2303b8714b130081e6b7a3d14cb38034 /arch/arm/mach-at91 | |
| parent | 5a2d4f053f67d03d212c2d036166934f4958173d (diff) | |
| download | linux-0-day-56387634b7604c141b8645d2377980164e18da0d.tar.gz linux-0-day-56387634b7604c141b8645d2377980164e18da0d.tar.xz | |
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>
Diffstat (limited to 'arch/arm/mach-at91')
| -rw-r--r-- | arch/arm/mach-at91/pm.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 3d68d93c11c71..488549bc2bed3 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -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) |