OMAP3: PM: Enable SDRAM auto-refresh during sleep

Fix for ES3.0 bug: SDRC not sending auto-refresh when OMAP wakes-up
from OFF mode (warning for HS devices.)

Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 310c189efb5d..3f1f656348fc 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -44,6 +44,13 @@
 
 #include "prm.h"
 #include "pm.h"
+#include "sdrc.h"
+
+#define SDRC_POWER_AUTOCOUNT_SHIFT 8
+#define SDRC_POWER_AUTOCOUNT_MASK (0xffff << SDRC_POWER_AUTOCOUNT_SHIFT)
+#define SDRC_POWER_CLKCTRL_SHIFT 4
+#define SDRC_POWER_CLKCTRL_MASK (0x3 << SDRC_POWER_CLKCTRL_SHIFT)
+#define SDRC_SELF_REFRESH_ON_AUTOCOUNT (0x2 << SDRC_POWER_CLKCTRL_SHIFT)
 
 /* Scratchpad offsets */
 #define OMAP343X_TABLE_ADDRESS_OFFSET      0x31
@@ -297,6 +304,7 @@ static void omap_sram_idle(void)
         int per_next_state = PWRDM_POWER_ON;
         int core_next_state = PWRDM_POWER_ON;
         int core_prev_state, per_prev_state;
+        u32 sdrc_pwr = 0;
 
         if (!_omap_sram_idle)
                 return;
@@ -349,6 +357,21 @@ static void omap_sram_idle(void)
         }
 
         /*
+         * Force SDRAM controller to self-refresh mode after timeout on
+         * autocount. This is needed on ES3.0 to avoid SDRAM controller
+         * hang-ups.
+         */
+        if (omap_rev() >= OMAP3430_REV_ES3_0 &&
+            omap_type() != OMAP2_DEVICE_TYPE_GP &&
+            core_next_state == PWRDM_POWER_OFF) {
+                sdrc_pwr = sdrc_read_reg(SDRC_POWER);
+                sdrc_write_reg((sdrc_pwr &
+                        ~(SDRC_POWER_AUTOCOUNT_MASK|SDRC_POWER_CLKCTRL_MASK)) |
+                        (1 << SDRC_POWER_AUTOCOUNT_SHIFT) |
+                        SDRC_SELF_REFRESH_ON_AUTOCOUNT, SDRC_POWER);
+        }
+
+        /*
          * omap3_arm_context is the location where ARM registers
          * get saved. The restore path then reads from this
          * location and restores them back.
@@ -356,6 +379,12 @@ static void omap_sram_idle(void)
         _omap_sram_idle(omap3_arm_context, save_state);
         cpu_init();
 
+        /* Restore normal SDRAM settings */
+        if (omap_rev() >= OMAP3430_REV_ES3_0 &&
+            omap_type() != OMAP2_DEVICE_TYPE_GP &&
+            core_next_state == PWRDM_POWER_OFF)
+                sdrc_write_reg(sdrc_pwr, SDRC_POWER);
+
         /* Restore table entry modified during MMU restoration */
         if (pwrdm_read_prev_pwrst(mpu_pwrdm) == PWRDM_POWER_OFF)
                 restore_table_entry();