Add an ISR for EMIF that:
1. reports details of access errors
2. takes action on thermal events
On thermal events SDRAM timing parameters are
adjusted to ensure safe operation
Also clear all interrupts on shut-down. Pending IRQs
may casue problems during warm-reset.
Signed-off-by: Aneesh V <aneesh@xxxxxx>
---
drivers/misc/emif.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 207 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/emif.c b/drivers/misc/emif.c
index 36ba6f4..5c2b0ae 100644
--- a/drivers/misc/emif.c
+++ b/drivers/misc/emif.c
@@ -500,6 +500,45 @@ 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;
+ unsigned long irqs;
+ 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);
+ }
+
+ spin_lock_irqsave(&emif->lock, irqs);
+ /* 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;
+ spin_unlock_irqrestore(&emif->lock, irqs);
+}
+
+/*
* Program EMIF shadow registers that are not dependent on temperature
* or voltage
*/
@@ -553,7 +592,8 @@ static void setup_volt_sensitive_regs(struct emif_data *emif,
static void setup_temperature_sensitive_regs(struct emif_data *emif,
struct emif_regs *regs)
{
- u32 tim1, tim3, ref_ctrl, type, irqs;
+ u32 tim1, tim3, ref_ctrl, type;
+ unsigned long irqs;
void __iomem *base = emif->base;
u32 temperature;
@@ -568,7 +608,7 @@ static void setup_temperature_sensitive_regs(struct emif_data *emif,
if (type != DDR_TYPE_LPDDR2_S2 && type != DDR_TYPE_LPDDR2_S4)
goto out;
- temperature_level = emif->temperature_level;
+ temperature = emif->temperature_level;
if (temperature == SDRAM_TEMP_HIGH_DERATE_REFRESH) {
ref_ctrl = regs->ref_ctrl_shdw_derated;
} else if (temperature == SDRAM_TEMP_HIGH_DERATE_REFRESH_AND_TIMINGS) {
@@ -584,6 +624,153 @@ out:
spin_unlock_irqrestore(&emif->lock, irqs);
}
+static irqreturn_t handle_temp_alert(void __iomem *base, struct emif_data *emif)
+{
+ u32 old_temp_level;
+
+ old_temp_level = emif->temperature_level;
+ get_temperature_level(emif);
+
+ if (unlikely(emif->temperature_level == old_temp_level))
+ goto handled;
+
+ 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
+ */
+ goto thread;
+ } else {
+ /* Temperature is going up - handle immediately */
+ if (!emif->curr_regs) {
+ dev_err(emif->dev, "temperature alert before registers are calculated, not de-rating timings\n");
+ goto handled;
+ }
+ setup_temperature_sensitive_regs(emif, emif->curr_regs);
+ do_freq_update();
+ }
+
+handled:
+ return IRQ_HANDLED;
+thread:
+ return IRQ_WAKE_THREAD;
+}
+
+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;
+ }
+
+ 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");
+ }
+
+ 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 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 request_threaded_irq(emif->irq,
+ emif_interrupt_handler,
+ emif_threaded_isr,
+ 0, dev_name(emif->dev),
+ emif);
+
+}
+
static void __exit cleanup_emif(struct emif_data *emif)
{
if (emif) {
@@ -779,6 +966,8 @@ static int __init emif_probe(struct platform_device *pdev)
goto error;
emif->irq = res->start;
+ disable_and_clear_all_interrupts(emif);
+
dev_info(&pdev->dev, "Device configured with addr = %p and IRQ%d\n",
emif->base, emif->irq);
return 0;
@@ -798,6 +987,13 @@ static int __exit emif_remove(struct platform_device *pdev)
return 0;
}
+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)
{
@@ -1002,6 +1198,14 @@ static void __attribute__((unused)) do_freq_pre_notify_handling(void *emif_data,
if (!regs)
return;
+ /*
+ * As soon as registers are calculated for the first time
+ * setup interrupts. We are ready to handle the thermal events
+ * now.
+ */
+ if (!emif->curr_regs)
+ setup_interrupts(emif);
+
emif->curr_regs = regs;
/*
@@ -1018,6 +1222,7 @@ static void __attribute__((unused)) do_freq_pre_notify_handling(void *emif_data,
static struct platform_driver emif_driver = {
.remove = __exit_p(emif_remove),
+ .shutdown = emif_shutdown,
.driver = {
.name = "emif",
},
--
1.7.1
--
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