[PATCH V2 3/8] memory: emif: handle overflow for timing for LP mode

[Lokesh Vutla]

From: Nishanth Menon <n...@ti.com>

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 <n...@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvu...@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilim...@ti.com>
---
Changes since V1: No changes

 drivers/memory/emif.c |   36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 5f3b7ed..e513889 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;
-- 
1.7.9.5

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