Re: [PATCH 3/4] mfd: twl6030-irq: convert to use linear irq_domain

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On 07/24/2013 02:35 PM, Lee Jones wrote:
On Tue, 23 Jul 2013, Grygorii Strashko wrote:

Since the TWL6030 PMIC is used with OMAP4 SoCs only and OMAP4 legacy
boot is dropped there are no needs to allocate the range of IRQ
descriptors during system boot to support TWL6030 IRQs.

Hence, convert it to use linear irq_domain and move IRQ configuration in
.map()/.unmap() callbacks of irq_domain. So, IRQ mapping and descriptors
allocation will be performed dynamically basing on DT configuration.

The error message will be reported in case if unmapped IRQ is received by
TWL6030 (virq==0).

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
  drivers/mfd/twl6030-irq.c |  114 ++++++++++++++++++++++++---------------------
  1 file changed, 61 insertions(+), 53 deletions(-)

diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
index 790cc28..89f130b 100644
--- a/drivers/mfd/twl6030-irq.c
+++ b/drivers/mfd/twl6030-irq.c
@@ -138,6 +138,7 @@ static struct notifier_block twl6030_irq_pm_notifier_block = {
  static irqreturn_t twl6030_irq_thread(int irq, void *data)
  {
  	int i, ret;
+	struct irq_domain *irq_domain = (struct irq_domain *)data;
  	union {
  		u8 bytes[4];
  		u32 int_sts;
@@ -161,9 +162,14 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)

  	for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++)
  		if (sts.int_sts & 0x1) {
-			int module_irq = twl6030_irq_base +
-					twl6030_interrupt_mapping[i];
-			handle_nested_irq(module_irq);
+			int module_irq =
+				irq_find_mapping(irq_domain,
+						 twl6030_interrupt_mapping[i]);
+			if (module_irq)
+				handle_nested_irq(module_irq);
+			else
+				pr_err("%s: Unmapped PIH ISR %u detected\n",
+				       __func__, i);

Same here. Does the user really care which function failed?

Please consider replacing with the device name.

ok.


  			pr_debug("%s: PIH ISR %u, virq%u\n",
  				 __func__, i, module_irq);
  		}
@@ -186,19 +192,6 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)

  /*----------------------------------------------------------------------*/

-static inline void activate_irq(int irq)
-{
-#ifdef CONFIG_ARM
-	/* ARM requires an extra step to clear IRQ_NOREQUEST, which it
-	 * sets on behalf of every irq_chip.  Also sets IRQ_NOPROBE.
-	 */
-	set_irq_flags(irq, IRQF_VALID);
-#else
-	/* same effect on other architectures */
-	irq_set_noprobe(irq);
-#endif
-}
-
  static int twl6030_irq_set_wake(struct irq_data *d, unsigned int on)
  {
  	if (on)
@@ -308,28 +301,54 @@ int twl6030_mmc_card_detect(struct device *dev, int slot)
  }
  EXPORT_SYMBOL(twl6030_mmc_card_detect);

+static struct irq_chip twl6030_irq_chip;
+
+static int twl6030_irq_map(struct irq_domain *d, unsigned int virq,
+			      irq_hw_number_t hwirq)
+{
+	irq_set_chip_data(virq, &twl6030_irq_chip);
+	irq_set_chip_and_handler(virq,  &twl6030_irq_chip, handle_simple_irq);
+	irq_set_nested_thread(virq, true);
+
+#ifdef CONFIG_ARM
+	/*
+	 * ARM requires an extra step to clear IRQ_NOREQUEST, which it
+	 * sets on behalf of every irq_chip.  Also sets IRQ_NOPROBE.
+	 */
+	set_irq_flags(virq, IRQF_VALID);
+#else
+	/* same effect on other architectures */
+	irq_set_noprobe(virq);
+#endif
+
+	return 0;
+}
+
+static void twl6030_irq_unmap(struct irq_domain *d, unsigned int virq)
+{
+#ifdef CONFIG_ARM
+	set_irq_flags(virq, 0);
+#endif
+	irq_set_chip_and_handler(virq, NULL, NULL);
+	irq_set_chip_data(virq, NULL);
+}
+
+static struct irq_domain_ops twl6030_irq_domain_ops = {
+	.map	= twl6030_irq_map,
+	.unmap	= twl6030_irq_unmap,
+	.xlate	= irq_domain_xlate_onetwocell,
+};
+
  int twl6030_init_irq(struct device *dev, int irq_num)
  {
  	struct			device_node *node = dev->of_node;
-	int			nr_irqs, irq_base, irq_end;
-	static struct irq_chip  twl6030_irq_chip;
+	int			nr_irqs;
  	int			status;
-	int			i;
  	u8			mask[3];
+	struct irq_domain	*irq_domain;

  	nr_irqs = TWL6030_NR_IRQS;

-	irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
-	if (IS_ERR_VALUE(irq_base)) {
-		dev_err(dev, "Fail to allocate IRQ descs\n");
-		return irq_base;
-	}
-
-	irq_domain_add_legacy(node, nr_irqs, irq_base, 0,
-			      &irq_domain_simple_ops, NULL);
-
-	irq_end = irq_base + nr_irqs;
-
  	mask[0] = 0xFF;
  	mask[1] = 0xFF;
  	mask[2] = 0xFF;
@@ -346,8 +365,6 @@ int twl6030_init_irq(struct device *dev, int irq_num)
  		return status;
  	}

-	twl6030_irq_base = irq_base;
-
  	/*
  	 * install an irq handler for each of the modules;
  	 * clone dummy irq_chip since PIH can't *do* anything
@@ -357,20 +374,18 @@ int twl6030_init_irq(struct device *dev, int irq_num)
  	twl6030_irq_chip.irq_set_type = NULL;
  	twl6030_irq_chip.irq_set_wake = twl6030_irq_set_wake;

-	for (i = irq_base; i < irq_end; i++) {
-		irq_set_chip_and_handler(i, &twl6030_irq_chip,
-					 handle_simple_irq);
-		irq_set_chip_data(i, (void *)irq_num);
-		irq_set_nested_thread(i, true);
-		activate_irq(i);
+	irq_domain = irq_domain_add_linear(node, nr_irqs,
+					   &twl6030_irq_domain_ops, NULL);
+	if (!irq_domain) {
+		dev_err(dev, "Can't add irq_domain\n");
+		return -ENOMEM;
  	}

-	dev_info(dev, "PIH (irq %d) nested IRQs %d..%d\n",
-		 irq_num, irq_base, irq_end);
+	dev_info(dev, "PIH (irq %d) nested IRQs\n", irq_num);

  	/* install an irq handler to demultiplex the TWL6030 interrupt */
  	status = request_threaded_irq(irq_num, NULL, twl6030_irq_thread,
-				      IRQF_ONESHOT, "TWL6030-PIH", NULL);
+				      IRQF_ONESHOT, "TWL6030-PIH", irq_domain);
  	if (status < 0) {
  		dev_err(dev, "could not claim irq %d: %d\n", irq_num, status);
  		goto fail_irq;
@@ -378,26 +393,19 @@ int twl6030_init_irq(struct device *dev, int irq_num)

  	twl_irq = irq_num;
  	register_pm_notifier(&twl6030_irq_pm_notifier_block);
-	return irq_base;
+	return irq_num;

I think you need to change twl-core to now expect the total number of
IRQs rather than the base one now.

Would it be ok if twl6030_init_irq() will return 0 on success or error code on failure?

The change of twl6030_init_irq() will not affect twl-core in case of TWL6030/32 DT-boot --- not DT boot (legacy mode) seems need to be dropped form twl-core for TWL6030/32.


  fail_irq:
-	for (i = irq_base; i < irq_end; i++)
-		irq_set_chip_and_handler(i, NULL, NULL);
-
+	irq_domain_remove(irq_domain);

Why do you kill the irqdomain here, but not in exit()?

this is a failure path and twl_irq == 0, so exit will do nothing,
and it safe to delete irq_domain here, because no child devices will be
created.


  	return status;
  }

  int twl6030_exit_irq(void)
  {
-	unregister_pm_notifier(&twl6030_irq_pm_notifier_block);
-
-	if (!twl6030_irq_base) {
-		pr_err("twl6030: can't yet clean up IRQs?\n");
-		return -ENOSYS;
+	if (twl_irq) {
+		unregister_pm_notifier(&twl6030_irq_pm_notifier_block);
+		free_irq(twl_irq, NULL);

In general, I need to add irq_domain_remove(irq_domain) here too
But, there is a big BUT!

  	}

Ah yes, that's better.

-
-	free_irq(twl_irq, NULL);
-
  	return 0;
  }



Unfortunately, I'm not fully understand how to dispose IRQ mapping and free IRQ domain/descriptors correctly. - IRQ mapping is done when devices are being created from DT (including IRQ desc allocation) - there is API irq_dispose_mapping(), but It's not been called from irq_domain_remove() and OF and Driver cores.
- there is no of_platform_unpopulate() yet

So, I can call irq_dispose_mapping() manually from twl6030_exit_irq, but child devices will still keep mapped IRQ numbers as their Resources.
:((

More over, in this case I can't use devm_*() API to request IRQ, because free_irq() will be called after irq_domian de-initialization.

That's why I've not added irq_domian de-initialization in twl6030_exit_irq() and not used devm_*() to request IRQ.


Regards,
- grygorii

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