Commit 68b4aee3 authored by Aneesh V's avatar Aneesh V Committed by Greg Kroah-Hartman
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memory: emif: add interrupt and temperature handling 



Add an ISR for EMIF that:
	1. reports details of access errors
	2. takes action on thermal events

Also clear all interrupts on shut-down. Pending IRQs
may casue problems during warm-reset.

Temperature handling:
EMIF can be configured to poll the temperature level
of an LPDDR2 device from the MR4 mode register in the
device. EMIF generates an interrupt whenever it identifies
a temperature level change between two consecutive pollings.

Some of the timing parameters need to be de-rated at high
temperatures. The interrupt handler takes care of doing
this and also takes care of going back to nominal settings
when temperature falls back to nominal levels.

Signed-off-by: default avatarAneesh V <aneesh@ti.com>
Reviewed-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: default avatarBenoit Cousson <b-cousson@ti.com>
[santosh.shilimkar@ti.com: Moved to drivers/memory from drivers/misc]
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a93de288

drivers/memory/emif.c

+209 −2
Original line number Diff line number Diff line
@@ -544,6 +544,42 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev) 
	return pwr_mgmt_ctrl;

}



/*

 * Get the temperature level of the EMIF instance:

 * Reads the MR4 register of attached SDRAM parts to find out the temperature

 * level. If there are two parts attached(one on each CS), then the temperature

 * level for the EMIF instance is the higher of the two temperatures.

 */

static void get_temperature_level(struct emif_data *emif)

{

	u32		temp, temperature_level;

	void __iomem	*base;



	base = emif->base;



	/* Read mode register 4 */

	writel(DDR_MR4, base + EMIF_LPDDR2_MODE_REG_CONFIG);

	temperature_level = readl(base + EMIF_LPDDR2_MODE_REG_DATA);

	temperature_level = (temperature_level & MR4_SDRAM_REF_RATE_MASK) >>

				MR4_SDRAM_REF_RATE_SHIFT;



	if (emif->plat_data->device_info->cs1_used) {

		writel(DDR_MR4 | CS_MASK, base + EMIF_LPDDR2_MODE_REG_CONFIG);

		temp = readl(base + EMIF_LPDDR2_MODE_REG_DATA);

		temp = (temp & MR4_SDRAM_REF_RATE_MASK)

				>> MR4_SDRAM_REF_RATE_SHIFT;

		temperature_level = max(temp, temperature_level);

	}



	/* treat everything less than nominal(3) in MR4 as nominal */

	if (unlikely(temperature_level < SDRAM_TEMP_NOMINAL))

		temperature_level = SDRAM_TEMP_NOMINAL;



	/* if we get reserved value in MR4 persist with the existing value */

	if (likely(temperature_level != SDRAM_TEMP_RESERVED_4))

		emif->temperature_level = temperature_level;

}



/*

 * Program EMIF shadow registers that are not dependent on temperature

 * or voltage
@@ -627,6 +663,158 @@ out: 
	writel(ref_ctrl, base + EMIF_SDRAM_REFRESH_CTRL_SHDW);

}



static irqreturn_t handle_temp_alert(void __iomem *base, struct emif_data *emif)

{

	u32		old_temp_level;

	irqreturn_t	ret = IRQ_HANDLED;



	spin_lock_irqsave(&emif_lock, irq_state);

	old_temp_level = emif->temperature_level;

	get_temperature_level(emif);



	if (unlikely(emif->temperature_level == old_temp_level)) {

		goto out;

	} else if (!emif->curr_regs) {

		dev_err(emif->dev, "temperature alert before registers are calculated, not de-rating timings\n");

		goto out;

	}



	if (emif->temperature_level < old_temp_level ||

		emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN) {

		/*

		 * Temperature coming down - defer handling to thread OR

		 * Temperature far too high - do kernel_power_off() from

		 * thread context

		 */

		ret = IRQ_WAKE_THREAD;

	} else {

		/* Temperature is going up - handle immediately */

		setup_temperature_sensitive_regs(emif, emif->curr_regs);

		do_freq_update();

	}



out:

	spin_unlock_irqrestore(&emif_lock, irq_state);

	return ret;

}



static irqreturn_t emif_interrupt_handler(int irq, void *dev_id)

{

	u32			interrupts;

	struct emif_data	*emif = dev_id;

	void __iomem		*base = emif->base;

	struct device		*dev = emif->dev;

	irqreturn_t		ret = IRQ_HANDLED;



	/* Save the status and clear it */

	interrupts = readl(base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);

	writel(interrupts, base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);



	/*

	 * Handle temperature alert

	 * Temperature alert should be same for all ports

	 * So, it's enough to process it only for one of the ports

	 */

	if (interrupts & TA_SYS_MASK)

		ret = handle_temp_alert(base, emif);



	if (interrupts & ERR_SYS_MASK)

		dev_err(dev, "Access error from SYS port - %x\n", interrupts);



	if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE) {

		/* Save the status and clear it */

		interrupts = readl(base + EMIF_LL_OCP_INTERRUPT_STATUS);

		writel(interrupts, base + EMIF_LL_OCP_INTERRUPT_STATUS);



		if (interrupts & ERR_LL_MASK)

			dev_err(dev, "Access error from LL port - %x\n",

				interrupts);

	}



	return ret;

}



static irqreturn_t emif_threaded_isr(int irq, void *dev_id)

{

	struct emif_data	*emif = dev_id;



	if (emif->temperature_level == SDRAM_TEMP_VERY_HIGH_SHUTDOWN) {

		dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");

		kernel_power_off();

		return IRQ_HANDLED;

	}



	spin_lock_irqsave(&emif_lock, irq_state);



	if (emif->curr_regs) {

		setup_temperature_sensitive_regs(emif, emif->curr_regs);

		do_freq_update();

	} else {

		dev_err(emif->dev, "temperature alert before registers are calculated, not de-rating timings\n");

	}



	spin_unlock_irqrestore(&emif_lock, irq_state);



	return IRQ_HANDLED;

}



static void clear_all_interrupts(struct emif_data *emif)

{

	void __iomem	*base = emif->base;



	writel(readl(base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS),

		base + EMIF_SYSTEM_OCP_INTERRUPT_STATUS);

	if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE)

		writel(readl(base + EMIF_LL_OCP_INTERRUPT_STATUS),

			base + EMIF_LL_OCP_INTERRUPT_STATUS);

}



static void disable_and_clear_all_interrupts(struct emif_data *emif)

{

	void __iomem		*base = emif->base;



	/* Disable all interrupts */

	writel(readl(base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_SET),

		base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_CLEAR);

	if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE)

		writel(readl(base + EMIF_LL_OCP_INTERRUPT_ENABLE_SET),

			base + EMIF_LL_OCP_INTERRUPT_ENABLE_CLEAR);



	/* Clear all interrupts */

	clear_all_interrupts(emif);

}



static int __init_or_module setup_interrupts(struct emif_data *emif, u32 irq)

{

	u32		interrupts, type;

	void __iomem	*base = emif->base;



	type = emif->plat_data->device_info->type;



	clear_all_interrupts(emif);



	/* Enable interrupts for SYS interface */

	interrupts = EN_ERR_SYS_MASK;

	if (type == DDR_TYPE_LPDDR2_S2 || type == DDR_TYPE_LPDDR2_S4)

		interrupts |= EN_TA_SYS_MASK;

	writel(interrupts, base + EMIF_SYSTEM_OCP_INTERRUPT_ENABLE_SET);



	/* Enable interrupts for LL interface */

	if (emif->plat_data->hw_caps & EMIF_HW_CAPS_LL_INTERFACE) {

		/* TA need not be enabled for LL */

		interrupts = EN_ERR_LL_MASK;

		writel(interrupts, base + EMIF_LL_OCP_INTERRUPT_ENABLE_SET);

	}



	/* setup IRQ handlers */

	return devm_request_threaded_irq(emif->dev, irq,

				    emif_interrupt_handler,

				    emif_threaded_isr,

				    0, dev_name(emif->dev),

				    emif);



}



static void get_default_timings(struct emif_data *emif)

{

	struct emif_platform_data *pd = emif->plat_data;
@@ -803,6 +991,7 @@ static int __init_or_module emif_probe(struct platform_device *pdev) 
{

	struct emif_data	*emif;

	struct resource		*res;

	int			irq;



	emif = get_device_details(pdev);

	if (!emif) {
@@ -831,6 +1020,16 @@ static int __init_or_module emif_probe(struct platform_device *pdev) 
		goto error;

	}



	irq = platform_get_irq(pdev, 0);

	if (irq < 0) {

		dev_err(emif->dev, "%s: error getting IRQ resource - %d\n",

			__func__, irq);

		goto error;

	}



	disable_and_clear_all_interrupts(emif);

	setup_interrupts(emif, irq);



	/* One-time actions taken on probing the first device */

	if (!emif1) {

		emif1 = emif;
@@ -843,14 +1042,21 @@ static int __init_or_module emif_probe(struct platform_device *pdev) 
		 */

	}



	dev_info(&pdev->dev, "%s: device configured with addr = %p\n",

		__func__, emif->base);

	dev_info(&pdev->dev, "%s: device configured with addr = %p and IRQ%d\n",

		__func__, emif->base, irq);



	return 0;

error:

	return -ENODEV;

}



static void emif_shutdown(struct platform_device *pdev)

{

	struct emif_data	*emif = platform_get_drvdata(pdev);



	disable_and_clear_all_interrupts(emif);

}



static int get_emif_reg_values(struct emif_data *emif, u32 freq,

		struct emif_regs *regs)

{
@@ -1154,6 +1360,7 @@ static void __attribute__((unused)) freq_post_notify_handling(void) 
}



static struct platform_driver emif_driver = {

	.shutdown	= emif_shutdown,

	.driver = {

		.name = "emif",

	},

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