memory: emif: Handle devices which are not rated for >85C

As per JESD209-2E specification for LPDDR2,
      http://www.jedec.org/standards-documents/results/jesd209-2E
Table 73, LPDDR2 memories come in two flavors - Standard and
Extended. The Standard types can operate from -25C to +85C
However, beyond that and upto +105C can only be supported by
Extended types.

Unfortunately, it seems there is no info in MR0(device info) or
MR[1,2](device feature) for run time detection of this capability
as far as seen on the spec. Hence, we provide a custom_config
flag to be populated by platforms which have these "extended"
type memories.

For the "Standard" memories, we need to consider MR4 notifications
of temperature triggers >85C as equivalent to thermal shutdown
events (equivalent to Spec specified thermal shutdown events for
"extended" parts).

Reported-by: Richard Woodruff <r-woodruff2@ti.com>
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, 27 insertions, 0 deletions

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 249222905c94..96add5b9ce5d 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -918,6 +918,7 @@ static irqreturn_t handle_temp_alert(void __iomem *base, struct emif_data *emif)
 {
         u32             old_temp_level;
         irqreturn_t     ret = IRQ_HANDLED;
+        struct emif_custom_configs *custom_configs;
 
         spin_lock_irqsave(&emif_lock, irq_state);
         old_temp_level = emif->temperature_level;
@@ -930,6 +931,29 @@ static irqreturn_t handle_temp_alert(void __iomem *base, struct emif_data *emif)
                 goto out;
         }
 
+        custom_configs = emif->plat_data->custom_configs;
+
+        /*
+         * IF we detect higher than "nominal rating" from DDR sensor
+         * on an unsupported DDR part, shutdown system
+         */
+        if (custom_configs && !(custom_configs->mask &
+                                EMIF_CUSTOM_CONFIG_EXTENDED_TEMP_PART)) {
+                if (emif->temperature_level >= SDRAM_TEMP_HIGH_DERATE_REFRESH) {
+                        dev_err(emif->dev,
+                                "%s:NOT Extended temperature capable memory."
+                                "Converting MR4=0x%02x as shutdown event\n",
+                                __func__, emif->temperature_level);
+                        /*
+                         * Temperature far too high - do kernel_power_off()
+                         * from thread context
+                         */
+                        emif->temperature_level = SDRAM_TEMP_VERY_HIGH_SHUTDOWN;
+                        ret = IRQ_WAKE_THREAD;
+                        goto out;
+                }
+        }
+
         if (emif->temperature_level < old_temp_level ||
                 emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN) {
                 /*
@@ -1228,6 +1252,9 @@ static void __init_or_module of_get_custom_configs(struct device_node *np_emif,
                 cust_cfgs->temp_alert_poll_interval_ms = *poll_intvl;
         }
 
+        if (of_find_property(np_emif, "extended-temp-part", &len))
+                cust_cfgs->mask |= EMIF_CUSTOM_CONFIG_EXTENDED_TEMP_PART;
+
         if (!is_custom_config_valid(cust_cfgs, emif->dev)) {
                 devm_kfree(emif->dev, cust_cfgs);
                 return;