From: Nishanth Menon <nm@xxxxxx>
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@xxxxxx>
Signed-off-by: Nishanth Menon <nm@xxxxxx>
Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
---
drivers/memory/emif.c | 27 +++++++++++++++++++++++++++
include/linux/platform_data/emif_plat.h | 1 +
2 files changed, 28 insertions(+)
diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 37e0c77..927fb55 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -914,6 +914,7 @@ 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;
@@ -926,6 +927,29 @@ 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) {
/*
@@ -1224,6 +1248,9 @@ 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;
diff --git a/include/linux/platform_data/emif_plat.h b/include/linux/platform_data/emif_plat.h
index 03378ca..5c19a2a 100644
--- a/include/linux/platform_data/emif_plat.h
+++ b/include/linux/platform_data/emif_plat.h
@@ -40,6 +40,7 @@
/* Custom config requests */
#define EMIF_CUSTOM_CONFIG_LPMODE 0x00000001
#define EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL 0x00000002
+#define EMIF_CUSTOM_CONFIG_EXTENDED_TEMP_PART 0x00000004
#ifndef __ASSEMBLY__
/**
--
1.7.9.5
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