memory: emif: handle overflow for timing for LP mode

In case the custom timings provide values which overflow
the maximum possible field value, warn and use maximum
permissible value.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 8 deletions

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index bda11ebb25cd..249222905c94 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -715,6 +715,8 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
         u32 timeout_perf        = EMIF_LP_MODE_TIMEOUT_PERFORMANCE;
         u32 timeout_pwr         = EMIF_LP_MODE_TIMEOUT_POWER;
         u32 freq_threshold      = EMIF_LP_MODE_FREQ_THRESHOLD;
+        u32 mask;
+        u8 shift;
 
         struct emif_custom_configs *cust_cfgs = emif->plat_data->custom_configs;
 
@@ -743,27 +745,45 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
 
         switch (lpmode) {
         case EMIF_LP_MODE_CLOCK_STOP:
-                pwr_mgmt_ctrl = (timeout << CS_TIM_SHIFT) |
-                                        SR_TIM_MASK | PD_TIM_MASK;
+                shift = CS_TIM_SHIFT;
+                mask = CS_TIM_MASK;
                 break;
         case EMIF_LP_MODE_SELF_REFRESH:
                 /* Workaround for errata i735 */
                 if (timeout < 6)
                         timeout = 6;
 
-                pwr_mgmt_ctrl = (timeout << SR_TIM_SHIFT) |
-                                        CS_TIM_MASK | PD_TIM_MASK;
+                shift = SR_TIM_SHIFT;
+                mask = SR_TIM_MASK;
                 break;
         case EMIF_LP_MODE_PWR_DN:
-                pwr_mgmt_ctrl = (timeout << PD_TIM_SHIFT) |
-                                        CS_TIM_MASK | SR_TIM_MASK;
+                shift = PD_TIM_SHIFT;
+                mask = PD_TIM_MASK;
                 break;
         case EMIF_LP_MODE_DISABLE:
         default:
-                pwr_mgmt_ctrl = CS_TIM_MASK |
-                                        PD_TIM_MASK | SR_TIM_MASK;
+                mask = 0;
+                shift = 0;
+                break;
+        }
+        /* Round to maximum in case of overflow, BUT warn! */
+        if (lpmode != EMIF_LP_MODE_DISABLE && timeout > mask >> shift) {
+                pr_err("TIMEOUT Overflow - lpmode=%d perf=%d pwr=%d freq=%d\n",
+                       lpmode,
+                       timeout_perf,
+                       timeout_pwr,
+                       freq_threshold);
+                WARN(1, "timeout=0x%02x greater than 0x%02x. Using max\n",
+                     timeout, mask >> shift);
+                timeout = mask >> shift;
         }
 
+        /* Setup required timing */
+        pwr_mgmt_ctrl = (timeout << shift) & mask;
+        /* setup a default mask for rest of the modes */
+        pwr_mgmt_ctrl |= (SR_TIM_MASK | CS_TIM_MASK | PD_TIM_MASK) &
+                          ~mask;
+
         /* No CS_TIM in EMIF_4D5 */
         if (ip_rev == EMIF_4D5)
                 pwr_mgmt_ctrl &= ~CS_TIM_MASK;