| Message ID | 20170328111938.21297-7-alexandre.belloni@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> -----Original Message----- > From: Alexandre Belloni [mailto:alexandre.belloni@free-electrons.com] > Sent: 2017年3月28日 19:20 > To: Nicolas Ferre - M43238 <Nicolas.Ferre@microchip.com> > Cc: linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Boris > Brezillon <boris.brezillon@free-electrons.com>; Wenyou Yang - A41535 > <Wenyou.Yang@microchip.com>; Alexandre Belloni <alexandre.belloni@free- > electrons.com> > Subject: [PATCH v2 06/11] 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. > > Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Wenyou Yang <wenyou.yang@atmel.com> > --- > arch/arm/mach-at91/pm.c | 20 +++++++++++++++++++- > 1 file changed, 19 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index > 3d68d93c11c7..488549bc2bed 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) > -- > 2.11.0
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 3d68d93c11c7..488549bc2bed 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)
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. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> --- arch/arm/mach-at91/pm.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)