[PATCH v2 7/7] spmi: apple: interrupt controller functionality

[Sasha Finkelstein]

From: Alba Mendez <me@xxxxxxx>

Add support for interrupts sent by slave devices.

Signed-off-by: Alba Mendez <me@xxxxxxx>
Signed-off-by: Sasha Finkelstein <k@xxxxxxxxxxxxxx>
---
 drivers/spmi/Kconfig                 |   3 ++-
 drivers/spmi/spmi-apple-controller.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 150 insertions(+), 2 deletions(-)

diff --git a/drivers/spmi/Kconfig b/drivers/spmi/Kconfig
index a80cf4047b86..7243863a09b4 100644
--- a/drivers/spmi/Kconfig
+++ b/drivers/spmi/Kconfig
@@ -13,7 +13,8 @@ if SPMI
 
 config SPMI_APPLE
 	tristate "Apple SoC SPMI Controller platform driver"
-	depends on ARCH_APPLE || COMPILE_TEST
+	select IRQ_DOMAIN_HIERARCHY
+	depends on ARCH_APPLE || (COMPILE_TEST && 64BIT)
 	help
 	  If you say yes to this option, support will be included for the
 	  SPMI controller present on many Apple SoCs, including the
diff --git a/drivers/spmi/spmi-apple-controller.c b/drivers/spmi/spmi-apple-controller.c
index 109c5d2c735d..8f6a0d560da8 100644
--- a/drivers/spmi/spmi-apple-controller.c
+++ b/drivers/spmi/spmi-apple-controller.c
@@ -15,9 +15,12 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
+#include <linux/spinlock.h>
 #include <linux/spmi.h>
 
 /* SPMI Controller Registers */
@@ -47,6 +50,9 @@ struct apple_spmi {
 	struct mutex fifo_lock;
 	bool fifo_rx_irq;
 	struct completion fifo_rx;
+	struct irq_domain *irqd;
+	raw_spinlock_t irq_mask_lock;
+	u64 irq_mask_cache[SPMI_IRQ_USER_SIZE / sizeof(u64)];
 };
 
 #define poll_reg(spmi, reg, val, cond) \
@@ -226,11 +232,123 @@ static void apple_spmi_irq_unmask_raw(struct apple_spmi *spmi, u32 irq)
 	writel(readl(reg) | BIT(irq % 32), reg);
 }
 
+static void apple_spmi_irq_ack(struct irq_data *d)
+{
+	struct apple_spmi *spmi = irq_data_get_irq_chip_data(d);
+
+	apple_spmi_irq_ack_raw(spmi, d->hwirq);
+}
+
+static void apple_spmi_irq_mask(struct irq_data *d)
+{
+	struct apple_spmi *spmi = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&spmi->irq_mask_lock, flags);
+	apple_spmi_irq_mask_raw(spmi, d->hwirq);
+	spmi->irq_mask_cache[d->hwirq / 64] &= ~BIT_ULL(d->hwirq % 64);
+	raw_spin_unlock_irqrestore(&spmi->irq_mask_lock, flags);
+}
+
+static void apple_spmi_irq_unmask(struct irq_data *d)
+{
+	struct apple_spmi *spmi = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&spmi->irq_mask_lock, flags);
+	apple_spmi_irq_unmask_raw(spmi, d->hwirq);
+	spmi->irq_mask_cache[d->hwirq / 64] |= BIT_ULL(d->hwirq % 64);
+	raw_spin_unlock_irqrestore(&spmi->irq_mask_lock, flags);
+}
+
+static int apple_spmi_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	/* all interrupts have MSI semantics */
+	return type == IRQ_TYPE_EDGE_RISING ? 0 : -EINVAL;
+}
+
+static struct irq_chip apple_spmi_irq_chip = {
+	.name = "apple_spmi",
+	.irq_mask = apple_spmi_irq_mask,
+	.irq_unmask = apple_spmi_irq_unmask,
+	.irq_ack = apple_spmi_irq_ack,
+	.irq_set_type = apple_spmi_irq_set_type,
+	.flags = IRQCHIP_ONESHOT_SAFE,
+};
+
+static int apple_spmi_irq_domain_map(struct irq_domain *irqd,
+					unsigned int irq, irq_hw_number_t hw)
+{
+	irq_domain_set_info(irqd, irq, hw, &apple_spmi_irq_chip, irqd->host_data,
+				handle_edge_irq, NULL, NULL);
+	return 0;
+}
+
+static int apple_spmi_irq_domain_translate(struct irq_domain *irqd,
+					struct irq_fwspec *fwspec,
+					unsigned long *hwirq,
+					unsigned int *type)
+{
+	u32 *args = fwspec->param;
+
+	if (fwspec->param_count != 2)
+		return -EINVAL;
+
+	if (args[0] >= SPMI_IRQ_USER_SIZE * 8)
+		return -EINVAL;
+	*hwirq = args[0];
+	*type = args[1] & IRQ_TYPE_SENSE_MASK;
+	return 0;
+}
+
+static int apple_spmi_irq_domain_alloc(struct irq_domain *irqd, unsigned int virq,
+				unsigned int nr_irqs, void *arg)
+{
+	unsigned int type = IRQ_TYPE_NONE;
+	struct irq_fwspec *fwspec = arg;
+	irq_hw_number_t hwirq;
+	int i, ret;
+
+	ret = apple_spmi_irq_domain_translate(irqd, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	if (hwirq + nr_irqs > SPMI_IRQ_USER_SIZE * 8)
+		return -EINVAL;
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = apple_spmi_irq_domain_map(irqd, virq + i, hwirq + i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void apple_spmi_irq_domain_free(struct irq_domain *irqd, unsigned int virq,
+				unsigned int nr_irqs)
+{
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		struct irq_data *d = irq_domain_get_irq_data(irqd, virq + i);
+
+		irq_set_handler(virq + i, NULL);
+		irq_domain_reset_irq_data(d);
+	}
+}
+
+static const struct irq_domain_ops apple_spmi_irq_domain_ops = {
+	.translate	= apple_spmi_irq_domain_translate,
+	.alloc		= apple_spmi_irq_domain_alloc,
+	.free		= apple_spmi_irq_domain_free,
+};
+
 static irqreturn_t apple_spmi_irq_handler(int irq, void *dev_id)
 {
 	struct apple_spmi *spmi = dev_id;
 	bool handled = false;
-	u32 val;
+	u64 val, offset, bit;
 
 	val = readl(spmi->regs + SPMI_IRQ_ACK_BASE + SPMI_IRQ_USER_SIZE);
 	if (val & BIT(SPMI_IRQ_FIFO_RX)) {
@@ -239,6 +357,23 @@ static irqreturn_t apple_spmi_irq_handler(int irq, void *dev_id)
 		handled = true;
 	}
 
+	for (offset = 0; offset < SPMI_IRQ_USER_SIZE; offset += sizeof(val)) {
+		val = readq(spmi->regs + SPMI_IRQ_ACK_BASE + offset);
+		/**
+		 * because of other masters in the bus, we're going to get a multitude of
+		 * interrupts we're not interested in. irq_resolve_mapping isn't very
+		 * optimized for the nonexistent path, so instead we mask with (a locally
+		 * cached version of) the IRQ mask
+		 */
+		val &= spmi->irq_mask_cache[offset / sizeof(val)];
+		while (val) {
+			bit = __builtin_ctzll(val);
+			generic_handle_domain_irq(spmi->irqd, offset * 8 + bit);
+			handled = true;
+			val &= ~BIT(bit);
+		}
+	}
+
 	return handled ? IRQ_HANDLED : IRQ_NONE;
 }
 
@@ -246,12 +381,24 @@ static int apple_spmi_init_irq(struct platform_device *pdev,
 			  struct apple_spmi *spmi, int irq)
 {
 	int ret;
+	struct irq_domain_info info = {
+		.fwnode		= pdev->dev.fwnode,
+		.hwirq_max	= ~0U,
+		.ops		= &apple_spmi_irq_domain_ops,
+		.host_data	= spmi,
+	};
+
+	raw_spin_lock_init(&spmi->irq_mask_lock);
 
 	for (size_t offset = 0; offset < SPMI_IRQ_USER_SIZE + 4; offset += 4) {
 		writel(0, spmi->regs + SPMI_IRQ_MASK_BASE + offset);
 		writel(U32_MAX, spmi->regs + SPMI_IRQ_ACK_BASE + offset);
 	}
 
+	spmi->irqd = devm_irq_domain_instantiate(&pdev->dev, &info);
+	if (IS_ERR(spmi->irqd))
+		return PTR_ERR(spmi->irqd);
+
 	spmi->fifo_rx_irq = true;
 	apple_spmi_irq_unmask_raw(spmi, SPMI_IRQ_USER_SIZE * 8 + SPMI_IRQ_FIFO_RX);
 

-- 
2.55.0