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

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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>
This commit is contained in:
Nishanth Menon 2013-03-16 11:46:44 +05:30 committed by Greg Kroah-Hartman
parent 25aaacd283
commit f91a595d0b
2 changed files with 28 additions and 0 deletions
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27
drivers/memory/emif.c
View file

@ -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;

1
include/linux/platform_data/emif_plat.h
View file

@ -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__
/**