Commit f91a595d authored by Nishanth Menon's avatar Nishanth Menon Committed by Greg Kroah-Hartman
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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: default avatarRichard Woodruff <r-woodruff2@ti.com>
Signed-off-by: default avatarNishanth Menon <nm@ti.com>
Signed-off-by: default avatarLokesh Vutla <lokeshvutla@ti.com>
Acked-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 25aaacd2

drivers/memory/emif.c

+27 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/platform_data/emif_plat.h

+1 −0
Original line number Diff line number Diff line
@@ -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__

/**

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