From: Peter Rosin <p...@axentia.se>
The DDRSDR controller fails miserably 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.
Assume that the second controller has the same fault, but that is
untested.
Signed-off-by: Peter Rosin <p...@axentia.se>
Acked-by: Nicolas Ferre <nicolas.fe...@atmel.com>
---
arch/arm/mach-at91/pm_slowclock.S | 43 +++++++++++++++++++++++++++++++-----
include/soc/at91/at91sam9_ddrsdr.h | 2 +-
2 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-at91/pm_slowclock.S
b/arch/arm/mach-at91/pm_slowclock.S
index 75d8b19..487ae1e 100644
--- a/arch/arm/mach-at91/pm_slowclock.S
+++ b/arch/arm/mach-at91/pm_slowclock.S
@@ -109,6 +109,16 @@ ddr_sr_enable:
cmp memctrl, #AT91_MEMCTRL_DDRSDR
bne sdr_sr_enable
+ /* LPDDR1 --> force DDR2 mode during self-refresh */
+ ldr tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+ str tmp1, .saved_sam9_mdr
+ bic tmp1, tmp1, #~AT91_DDRSDRC_MD
+ cmp tmp1, #AT91_DDRSDRC_MD_LOW_POWER_DDR
+ ldreq tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+ biceq tmp1, tmp1, #AT91_DDRSDRC_MD
+ orreq tmp1, tmp1, #AT91_DDRSDRC_MD_DDR2
+ streq tmp1, [sdramc, #AT91_DDRSDRC_MDR]
+
/* prepare for DDRAM self-refresh mode */
ldr tmp1, [sdramc, #AT91_DDRSDRC_LPR]
str tmp1, .saved_sam9_lpr
@@ -117,14 +127,26 @@ ddr_sr_enable:
/* figure out if we use the second ram controller */
cmp ramc1, #0
- ldrne tmp2, [ramc1, #AT91_DDRSDRC_LPR]
- strne tmp2, .saved_sam9_lpr1
- bicne tmp2, #AT91_DDRSDRC_LPCB
- orrne tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
+ beq ddr_no_2nd_ctrl
+
+ ldr tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+ str tmp2, .saved_sam9_mdr1
+ bic tmp2, tmp2, #~AT91_DDRSDRC_MD
+ cmp tmp2, #AT91_DDRSDRC_MD_LOW_POWER_DDR
+ ldreq tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+ biceq tmp2, tmp2, #AT91_DDRSDRC_MD
+ orreq tmp2, tmp2, #AT91_DDRSDRC_MD_DDR2
+ streq tmp2, [ramc1, #AT91_DDRSDRC_MDR]
+
+ ldr tmp2, [ramc1, #AT91_DDRSDRC_LPR]
+ str tmp2, .saved_sam9_lpr1
+ bic tmp2, #AT91_DDRSDRC_LPCB
+ orr tmp2, #AT91_DDRSDRC_LPCB_SELF_REFRESH
/* Enable DDRAM self-refresh mode */
+ str tmp2, [ramc1, #AT91_DDRSDRC_LPR]
+ddr_no_2nd_ctrl:
str tmp1, [sdramc, #AT91_DDRSDRC_LPR]
- strne tmp2, [ramc1, #AT91_DDRSDRC_LPR]
b sdr_sr_done
@@ -236,12 +258,17 @@ sdr_sr_done:
*/
cmp memctrl, #AT91_MEMCTRL_DDRSDR
bne sdr_en_restore
+ /* Restore MDR in case of LPDDR1 */
+ ldr tmp1, .saved_sam9_mdr
+ str tmp1, [sdramc, #AT91_DDRSDRC_MDR]
/* Restore LPR on AT91 with DDRAM */
ldr tmp1, .saved_sam9_lpr
str tmp1, [sdramc, #AT91_DDRSDRC_LPR]
/* if we use the second ram controller */
cmp ramc1, #0
+ ldrne tmp2, .saved_sam9_mdr1
+ strne tmp2, [ramc1, #AT91_DDRSDRC_MDR]
ldrne tmp2, .saved_sam9_lpr1
strne tmp2, [ramc1, #AT91_DDRSDRC_LPR]
@@ -272,5 +299,11 @@ ram_restored:
.saved_sam9_lpr1:
.word 0
+.saved_sam9_mdr:
+ .word 0
+
+.saved_sam9_mdr1:
+ .word 0
+
ENTRY(at91_slow_clock_sz)
.word .-at91_slow_clock
diff --git a/include/soc/at91/at91sam9_ddrsdr.h
b/include/soc/at91/at91sam9_ddrsdr.h
index 0210797..dc10c52 100644
--- a/include/soc/at91/at91sam9_ddrsdr.h
+++ b/include/soc/at91/at91sam9_ddrsdr.h
@@ -92,7 +92,7 @@
#define AT91_DDRSDRC_UPD_MR (3 << 20) /* Update load
mode register and extended mode register */
#define AT91_DDRSDRC_MDR 0x20 /* Memory Device Register */
-#define AT91_DDRSDRC_MD (3 << 0) /*
Memory Device Type */
+#define AT91_DDRSDRC_MD (7 << 0) /* Memory
Device Type */
#define AT91_DDRSDRC_MD_SDR 0
#define AT91_DDRSDRC_MD_LOW_POWER_SDR 1
#define AT91_DDRSDRC_MD_LOW_POWER_DDR 3
--
1.7.9.5
--
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