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Message-Id: <1331222065-3579-7-git-send-email-aneesh@ti.com>
Date: Thu, 8 Mar 2012 21:24:23 +0530
From: Aneesh V <aneesh@...com>
To: linux-kernel@...r.kernel.org
Cc: linux-omap@...r.kernel.org, Aneesh V <aneesh@...com>,
Greg KH <greg@...ah.com>
Subject: [PATCH 6/8] misc: 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.
Cc: Greg KH <greg@...ah.com>
Signed-off-by: Aneesh V <aneesh@...com>
---
Changes since RFC:
- Improved commit log
- Improved synchronization with thread context
---
drivers/misc/emif.c | 211 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 209 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/emif.c b/drivers/misc/emif.c
index 5ab130b..09d0e68 100644
--- a/drivers/misc/emif.c
+++ b/drivers/misc/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 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 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 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 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",
},
--
1.7.1
--
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