clk: at91: remove IRQ handling and use polling

The AT91 clock drivers make use of IRQs to avoid polling when waiting for
some clocks to be enabled. Unfortunately, this leads to a crash when those
IRQs are threaded (which happens when using preempt-rt) because they are
registered before thread creation is possible.

Use polling on those clocks instead to avoid the problem.

Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

1 files changed, 3 insertions, 141 deletions

diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 295b17b9c689..f17a2a1f1e85 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -13,12 +13,6 @@
 #include <linux/clk/at91_pmc.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
-#include <linux/io.h>
-#include <linux/interrupt.h>
-#include <linux/irq.h>
-#include <linux/irqchip/chained_irq.h>
-#include <linux/irqdomain.h>
-#include <linux/of_irq.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
 
@@ -67,118 +61,6 @@ int of_at91_get_clk_range(struct device_node *np, const char *propname,
 }
 EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
 
-static void pmc_irq_mask(struct irq_data *d)
-{
-	struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
-
-	regmap_write(pmc->regmap, AT91_PMC_IDR, 1 << d->hwirq);
-}
-
-static void pmc_irq_unmask(struct irq_data *d)
-{
-	struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
-
-	regmap_write(pmc->regmap, AT91_PMC_IER, 1 << d->hwirq);
-}
-
-static int pmc_irq_set_type(struct irq_data *d, unsigned type)
-{
-	if (type != IRQ_TYPE_LEVEL_HIGH) {
-		pr_warn("PMC: type not supported (support only IRQ_TYPE_LEVEL_HIGH type)\n");
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
-static void pmc_irq_suspend(struct irq_data *d)
-{
-	struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
-
-	regmap_read(pmc->regmap, AT91_PMC_IMR, &pmc->imr);
-	regmap_write(pmc->regmap, AT91_PMC_IDR, pmc->imr);
-}
-
-static void pmc_irq_resume(struct irq_data *d)
-{
-	struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
-
-	regmap_write(pmc->regmap, AT91_PMC_IER, pmc->imr);
-}
-
-static struct irq_chip pmc_irq = {
-	.name = "PMC",
-	.irq_disable = pmc_irq_mask,
-	.irq_mask = pmc_irq_mask,
-	.irq_unmask = pmc_irq_unmask,
-	.irq_set_type = pmc_irq_set_type,
-	.irq_suspend = pmc_irq_suspend,
-	.irq_resume = pmc_irq_resume,
-};
-
-static struct lock_class_key pmc_lock_class;
-
-static int pmc_irq_map(struct irq_domain *h, unsigned int virq,
-		       irq_hw_number_t hw)
-{
-	struct at91_pmc	*pmc = h->host_data;
-
-	irq_set_lockdep_class(virq, &pmc_lock_class);
-
-	irq_set_chip_and_handler(virq, &pmc_irq,
-				 handle_level_irq);
-	irq_set_chip_data(virq, pmc);
-
-	return 0;
-}
-
-static int pmc_irq_domain_xlate(struct irq_domain *d,
-				struct device_node *ctrlr,
-				const u32 *intspec, unsigned int intsize,
-				irq_hw_number_t *out_hwirq,
-				unsigned int *out_type)
-{
-	struct at91_pmc *pmc = d->host_data;
-	const struct at91_pmc_caps *caps = pmc->caps;
-
-	if (WARN_ON(intsize < 1))
-		return -EINVAL;
-
-	*out_hwirq = intspec[0];
-
-	if (!(caps->available_irqs & (1 << *out_hwirq)))
-		return -EINVAL;
-
-	*out_type = IRQ_TYPE_LEVEL_HIGH;
-
-	return 0;
-}
-
-static const struct irq_domain_ops pmc_irq_ops = {
-	.map	= pmc_irq_map,
-	.xlate	= pmc_irq_domain_xlate,
-};
-
-static irqreturn_t pmc_irq_handler(int irq, void *data)
-{
-	struct at91_pmc *pmc = (struct at91_pmc *)data;
-	unsigned int tmpsr, imr;
-	unsigned long sr;
-	int n;
-
-	regmap_read(pmc->regmap, AT91_PMC_SR, &tmpsr);
-	regmap_read(pmc->regmap, AT91_PMC_IMR, &imr);
-
-	sr = tmpsr & imr;
-	if (!sr)
-		return IRQ_NONE;
-
-	for_each_set_bit(n, &sr, BITS_PER_LONG)
-		generic_handle_irq(irq_find_mapping(pmc->irqdomain, n));
-
-	return IRQ_HANDLED;
-}
-
 static const struct at91_pmc_caps at91rm9200_caps = {
 	.available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_LOCKB |
 			  AT91_PMC_MCKRDY | AT91_PMC_PCK0RDY |
@@ -230,12 +112,12 @@ static const struct at91_pmc_caps sama5d3_caps = {
 
 static struct at91_pmc *__init at91_pmc_init(struct device_node *np,
 					     struct regmap *regmap,
-					     void __iomem *regbase, int virq,
+					     void __iomem *regbase,
 					     const struct at91_pmc_caps *caps)
 {
 	struct at91_pmc *pmc;
 
-	if (!regbase || !virq ||  !caps)
+	if (!regbase || !caps)
 		return NULL;
 
 	at91_pmc_base = regbase;
@@ -245,26 +127,11 @@ static struct at91_pmc *__init at91_pmc_init(struct device_node *np,
 		return NULL;
 
 	pmc->regmap = regmap;
-	pmc->virq = virq;
 	pmc->caps = caps;
 
-	pmc->irqdomain = irq_domain_add_linear(np, 32, &pmc_irq_ops, pmc);
-	if (!pmc->irqdomain)
-		goto out_free_pmc;
-
 	regmap_write(pmc->regmap, AT91_PMC_IDR, 0xffffffff);
-	if (request_irq(pmc->virq, pmc_irq_handler,
-			IRQF_SHARED | IRQF_COND_SUSPEND, "pmc", pmc))
-		goto out_remove_irqdomain;
 
 	return pmc;
-
-out_remove_irqdomain:
-	irq_domain_remove(pmc->irqdomain);
-out_free_pmc:
-	kfree(pmc);
-
-	return NULL;
 }
 
 static void __init of_at91_pmc_setup(struct device_node *np,
@@ -273,17 +140,12 @@ static void __init of_at91_pmc_setup(struct device_node *np,
 	struct at91_pmc *pmc;
 	void __iomem *regbase = of_iomap(np, 0);
 	struct regmap *regmap;
-	int virq;
 
 	regmap = syscon_node_to_regmap(np);
 	if (IS_ERR(regmap))
 		panic("Could not retrieve syscon regmap");
 
-	virq = irq_of_parse_and_map(np, 0);
-	if (!virq)
-		return;
-
-	pmc = at91_pmc_init(np, regmap, regbase, virq, caps);
+	pmc = at91_pmc_init(np, regmap, regbase, caps);
 	if (!pmc)
 		return;
 }