diff options
| author | Peter Rosin <peda@axentia.se> | 2015-02-05 09:02:09 +0300 |
|---|---|---|
| committer | Nicolas Ferre <nicolas.ferre@atmel.com> | 2015-03-03 21:43:59 +0300 |
| commit | 02f513a0970d97e4fc5f262f5a6c814014af524e (patch) | |
| tree | 1608f7b1eaf9cd1e42df3f021031742bdbf68fcc /arch/arm/mach-at91 | |
| parent | ad4a38d2187720a3d1442d693c99675ccd955f32 (diff) | |
| download | linux-02f513a0970d97e4fc5f262f5a6c814014af524e.tar.xz | |
pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories.
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 <peda@axentia.se>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Diffstat (limited to 'arch/arm/mach-at91')
| -rw-r--r-- | arch/arm/mach-at91/pm_slowclock.S | 43 |
1 files changed, 38 insertions, 5 deletions
diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S index 50744e7d5577..a2cc49f96f61 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 @@ -255,12 +277,17 @@ 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] @@ -294,5 +321,11 @@ 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 |