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: Aneesh V <aneesh@ti.com>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Benoit Cousson <b-cousson@ti.com>
[santosh.shilimkar@ti.com: Moved to drivers/memory from drivers/misc]
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 209 insertions, 2 deletions

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index bd116eb8c738..a8dcf3515573 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -545,6 +545,42 @@ static u32 get_pwr_mgmt_ctrl(u32 freq, struct emif_data *emif, u32 ip_rev)
 }
 
 /*
+ * 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",
         },