irqchip/irq-mvebu-sei: Add new driver for Marvell SEI

This is a cascaded interrupt controller in the AP806 GIC that collapses
SEIs (System Error Interrupt) coming from the AP and the CPs (through
the ICU).

The SEI handles up to 64 interrupts. The first 21 interrupts are wired
from the AP. The next 43 interrupts are from the CPs and are triggered
through MSI messages. To handle this complexity, the driver has to
declare to the upper layer: one IRQ domain for the wired interrupts,
one IRQ domain for the MSIs; and acts as a MSI controller ('parent')
by declaring an MSI domain.

Suggested-by: Haim Boot <hayim@marvell.com>
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Kconfig

@@ -310,6 +310,9 @@ config MVEBU_ODMI
 config MVEBU_PIC
 	bool
 
+config MVEBU_SEI
+        bool
+
 config LS_SCFG_MSI
 	def_bool y if SOC_LS1021A || ARCH_LAYERSCAPE
 	depends on PCI && PCI_MSI

drivers/irqchip/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_MVEBU_GICP)		+= irq-mvebu-gicp.o
 obj-$(CONFIG_MVEBU_ICU)			+= irq-mvebu-icu.o
 obj-$(CONFIG_MVEBU_ODMI)		+= irq-mvebu-odmi.o
 obj-$(CONFIG_MVEBU_PIC)			+= irq-mvebu-pic.o
+obj-$(CONFIG_MVEBU_SEI)			+= irq-mvebu-sei.o
 obj-$(CONFIG_LS_SCFG_MSI)		+= irq-ls-scfg-msi.o
 obj-$(CONFIG_EZNPS_GIC)			+= irq-eznps.o
 obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o irq-aspeed-i2c-ic.o

drivers/irqchip/irq-mvebu-sei.c

@@ -0,0 +1,507 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) "mvebu-sei: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+/* Cause register */
+#define GICP_SECR(idx)		(0x0  + ((idx) * 0x4))
+/* Mask register */
+#define GICP_SEMR(idx)		(0x20 + ((idx) * 0x4))
+#define GICP_SET_SEI_OFFSET	0x30
+
+#define SEI_IRQ_COUNT_PER_REG	32
+#define SEI_IRQ_REG_COUNT	2
+#define SEI_IRQ_COUNT		(SEI_IRQ_COUNT_PER_REG * SEI_IRQ_REG_COUNT)
+#define SEI_IRQ_REG_IDX(irq_id)	((irq_id) / SEI_IRQ_COUNT_PER_REG)
+#define SEI_IRQ_REG_BIT(irq_id)	((irq_id) % SEI_IRQ_COUNT_PER_REG)
+
+struct mvebu_sei_interrupt_range {
+	u32 first;
+	u32 size;
+};
+
+struct mvebu_sei_caps {
+	struct mvebu_sei_interrupt_range ap_range;
+	struct mvebu_sei_interrupt_range cp_range;
+};
+
+struct mvebu_sei {
+	struct device *dev;
+	void __iomem *base;
+	struct resource *res;
+	struct irq_domain *sei_domain;
+	struct irq_domain *ap_domain;
+	struct irq_domain *cp_domain;
+	const struct mvebu_sei_caps *caps;
+
+	/* Lock on MSI allocations/releases */
+	struct mutex cp_msi_lock;
+	DECLARE_BITMAP(cp_msi_bitmap, SEI_IRQ_COUNT);
+
+	/* Lock on IRQ masking register */
+	raw_spinlock_t mask_lock;
+};
+
+static void mvebu_sei_ack_irq(struct irq_data *d)
+{
+	struct mvebu_sei *sei = irq_data_get_irq_chip_data(d);
+	u32 reg_idx = SEI_IRQ_REG_IDX(d->hwirq);
+
+	writel_relaxed(BIT(SEI_IRQ_REG_BIT(d->hwirq)),
+		       sei->base + GICP_SECR(reg_idx));
+}
+
+static void mvebu_sei_mask_irq(struct irq_data *d)
+{
+	struct mvebu_sei *sei = irq_data_get_irq_chip_data(d);
+	u32 reg, reg_idx = SEI_IRQ_REG_IDX(d->hwirq);
+	unsigned long flags;
+
+	/* 1 disables the interrupt */
+	raw_spin_lock_irqsave(&sei->mask_lock, flags);
+	reg = readl_relaxed(sei->base + GICP_SEMR(reg_idx));
+	reg |= BIT(SEI_IRQ_REG_BIT(d->hwirq));
+	writel_relaxed(reg, sei->base + GICP_SEMR(reg_idx));
+	raw_spin_unlock_irqrestore(&sei->mask_lock, flags);
+}
+
+static void mvebu_sei_unmask_irq(struct irq_data *d)
+{
+	struct mvebu_sei *sei = irq_data_get_irq_chip_data(d);
+	u32 reg, reg_idx = SEI_IRQ_REG_IDX(d->hwirq);
+	unsigned long flags;
+
+	/* 0 enables the interrupt */
+	raw_spin_lock_irqsave(&sei->mask_lock, flags);
+	reg = readl_relaxed(sei->base + GICP_SEMR(reg_idx));
+	reg &= ~BIT(SEI_IRQ_REG_BIT(d->hwirq));
+	writel_relaxed(reg, sei->base + GICP_SEMR(reg_idx));
+	raw_spin_unlock_irqrestore(&sei->mask_lock, flags);
+}
+
+static int mvebu_sei_set_affinity(struct irq_data *d,
+				  const struct cpumask *mask_val,
+				  bool force)
+{
+	return -EINVAL;
+}
+
+static int mvebu_sei_set_irqchip_state(struct irq_data *d,
+				       enum irqchip_irq_state which,
+				       bool state)
+{
+	/* We can only clear the pending state by acking the interrupt */
+	if (which != IRQCHIP_STATE_PENDING || state)
+		return -EINVAL;
+
+	mvebu_sei_ack_irq(d);
+	return 0;
+}
+
+static struct irq_chip mvebu_sei_irq_chip = {
+	.name			= "SEI",
+	.irq_ack		= mvebu_sei_ack_irq,
+	.irq_mask		= mvebu_sei_mask_irq,
+	.irq_unmask		= mvebu_sei_unmask_irq,
+	.irq_set_affinity       = mvebu_sei_set_affinity,
+	.irq_set_irqchip_state	= mvebu_sei_set_irqchip_state,
+};
+
+static int mvebu_sei_ap_set_type(struct irq_data *data, unsigned int type)
+{
+	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH)
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct irq_chip mvebu_sei_ap_irq_chip = {
+	.name			= "AP SEI",
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_set_affinity       = irq_chip_set_affinity_parent,
+	.irq_set_type		= mvebu_sei_ap_set_type,
+};
+
+static void mvebu_sei_cp_compose_msi_msg(struct irq_data *data,
+					 struct msi_msg *msg)
+{
+	struct mvebu_sei *sei = data->chip_data;
+	phys_addr_t set = sei->res->start + GICP_SET_SEI_OFFSET;
+
+	msg->data = data->hwirq + sei->caps->cp_range.first;
+	msg->address_lo = lower_32_bits(set);
+	msg->address_hi = upper_32_bits(set);
+}
+
+static int mvebu_sei_cp_set_type(struct irq_data *data, unsigned int type)
+{
+	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_EDGE_RISING)
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct irq_chip mvebu_sei_cp_irq_chip = {
+	.name			= "CP SEI",
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_set_affinity       = irq_chip_set_affinity_parent,
+	.irq_set_type		= mvebu_sei_cp_set_type,
+	.irq_compose_msi_msg	= mvebu_sei_cp_compose_msi_msg,
+};
+
+static int mvebu_sei_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				  unsigned int nr_irqs, void *arg)
+{
+	struct mvebu_sei *sei = domain->host_data;
+	struct irq_fwspec *fwspec = arg;
+
+	/* Not much to do, just setup the irqdata */
+	irq_domain_set_hwirq_and_chip(domain, virq, fwspec->param[0],
+				      &mvebu_sei_irq_chip, sei);
+
+	return 0;
+}
+
+static void mvebu_sei_domain_free(struct irq_domain *domain, 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(domain, virq + i);
+		irq_set_handler(virq + i, NULL);
+		irq_domain_reset_irq_data(d);
+	}
+}
+
+static const struct irq_domain_ops mvebu_sei_domain_ops = {
+	.alloc	= mvebu_sei_domain_alloc,
+	.free	= mvebu_sei_domain_free,
+};
+
+static int mvebu_sei_ap_translate(struct irq_domain *domain,
+				  struct irq_fwspec *fwspec,
+				  unsigned long *hwirq,
+				  unsigned int *type)
+{
+	*hwirq = fwspec->param[0];
+	*type  = IRQ_TYPE_LEVEL_HIGH;
+
+	return 0;
+}
+
+static int mvebu_sei_ap_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	struct mvebu_sei *sei = domain->host_data;
+	struct irq_fwspec fwspec;
+	unsigned long hwirq;
+	unsigned int type;
+	int err;
+
+	mvebu_sei_ap_translate(domain, arg, &hwirq, &type);
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 1;
+	fwspec.param[0] = hwirq + sei->caps->ap_range.first;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (err)
+		return err;
+
+	irq_domain_set_info(domain, virq, hwirq,
+			    &mvebu_sei_ap_irq_chip, sei,
+			    handle_level_irq, NULL, NULL);
+	irq_set_probe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops mvebu_sei_ap_domain_ops = {
+	.translate	= mvebu_sei_ap_translate,
+	.alloc		= mvebu_sei_ap_alloc,
+	.free		= irq_domain_free_irqs_parent,
+};
+
+static void mvebu_sei_cp_release_irq(struct mvebu_sei *sei, unsigned long hwirq)
+{
+	mutex_lock(&sei->cp_msi_lock);
+	clear_bit(hwirq, sei->cp_msi_bitmap);
+	mutex_unlock(&sei->cp_msi_lock);
+}
+
+static int mvebu_sei_cp_domain_alloc(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs,
+				     void *args)
+{
+	struct mvebu_sei *sei = domain->host_data;
+	struct irq_fwspec fwspec;
+	unsigned long hwirq;
+	int ret;
+
+	/* The software only supports single allocations for now */
+	if (nr_irqs != 1)
+		return -ENOTSUPP;
+
+	mutex_lock(&sei->cp_msi_lock);
+	hwirq = find_first_zero_bit(sei->cp_msi_bitmap,
+				    sei->caps->cp_range.size);
+	if (hwirq < sei->caps->cp_range.size)
+		set_bit(hwirq, sei->cp_msi_bitmap);
+	mutex_unlock(&sei->cp_msi_lock);
+
+	if (hwirq == sei->caps->cp_range.size)
+		return -ENOSPC;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 1;
+	fwspec.param[0] = hwirq + sei->caps->cp_range.first;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (ret)
+		goto free_irq;
+
+	irq_domain_set_info(domain, virq, hwirq,
+			    &mvebu_sei_cp_irq_chip, sei,
+			    handle_edge_irq, NULL, NULL);
+
+	return 0;
+
+free_irq:
+	mvebu_sei_cp_release_irq(sei, hwirq);
+	return ret;
+}
+
+static void mvebu_sei_cp_domain_free(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	struct mvebu_sei *sei = domain->host_data;
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+
+	if (nr_irqs != 1 || d->hwirq >= sei->caps->cp_range.size) {
+		dev_err(sei->dev, "Invalid hwirq %lu\n", d->hwirq);
+		return;
+	}
+
+	mvebu_sei_cp_release_irq(sei, d->hwirq);
+	irq_domain_free_irqs_parent(domain, virq, 1);
+}
+
+static const struct irq_domain_ops mvebu_sei_cp_domain_ops = {
+	.alloc	= mvebu_sei_cp_domain_alloc,
+	.free	= mvebu_sei_cp_domain_free,
+};
+
+static struct irq_chip mvebu_sei_msi_irq_chip = {
+	.name		= "SEI pMSI",
+	.irq_ack	= irq_chip_ack_parent,
+	.irq_set_type	= irq_chip_set_type_parent,
+};
+
+static struct msi_domain_ops mvebu_sei_msi_ops = {
+};
+
+static struct msi_domain_info mvebu_sei_msi_domain_info = {
+	.flags	= MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS,
+	.ops	= &mvebu_sei_msi_ops,
+	.chip	= &mvebu_sei_msi_irq_chip,
+};
+
+static void mvebu_sei_handle_cascade_irq(struct irq_desc *desc)
+{
+	struct mvebu_sei *sei = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u32 idx;
+
+	chained_irq_enter(chip, desc);
+
+	for (idx = 0; idx < SEI_IRQ_REG_COUNT; idx++) {
+		unsigned long irqmap;
+		int bit;
+
+		irqmap = readl_relaxed(sei->base + GICP_SECR(idx));
+		for_each_set_bit(bit, &irqmap, SEI_IRQ_COUNT_PER_REG) {
+			unsigned long hwirq;
+			unsigned int virq;
+
+			hwirq = idx * SEI_IRQ_COUNT_PER_REG + bit;
+			virq = irq_find_mapping(sei->sei_domain, hwirq);
+			if (likely(virq)) {
+				generic_handle_irq(virq);
+				continue;
+			}
+
+			dev_warn(sei->dev,
+				 "Spurious IRQ detected (hwirq %lu)\n", hwirq);
+		}
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void mvebu_sei_reset(struct mvebu_sei *sei)
+{
+	u32 reg_idx;
+
+	/* Clear IRQ cause registers, mask all interrupts */
+	for (reg_idx = 0; reg_idx < SEI_IRQ_REG_COUNT; reg_idx++) {
+		writel_relaxed(0xFFFFFFFF, sei->base + GICP_SECR(reg_idx));
+		writel_relaxed(0xFFFFFFFF, sei->base + GICP_SEMR(reg_idx));
+	}
+}
+
+static int mvebu_sei_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct irq_domain *plat_domain;
+	struct mvebu_sei *sei;
+	u32 parent_irq;
+	int ret;
+
+	sei = devm_kzalloc(&pdev->dev, sizeof(*sei), GFP_KERNEL);
+	if (!sei)
+		return -ENOMEM;
+
+	sei->dev = &pdev->dev;
+
+	mutex_init(&sei->cp_msi_lock);
+	raw_spin_lock_init(&sei->mask_lock);
+
+	sei->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sei->base = devm_ioremap_resource(sei->dev, sei->res);
+	if (!sei->base) {
+		dev_err(sei->dev, "Failed to remap SEI resource\n");
+		return -ENODEV;
+	}
+
+	/* Retrieve the SEI capabilities with the interrupt ranges */
+	sei->caps = of_device_get_match_data(&pdev->dev);
+	if (!sei->caps) {
+		dev_err(sei->dev,
+			"Could not retrieve controller capabilities\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Reserve the single (top-level) parent SPI IRQ from which all the
+	 * interrupts handled by this driver will be signaled.
+	 */
+	parent_irq = irq_of_parse_and_map(node, 0);
+	if (parent_irq <= 0) {
+		dev_err(sei->dev, "Failed to retrieve top-level SPI IRQ\n");
+		return -ENODEV;
+	}
+
+	/* Create the root SEI domain */
+	sei->sei_domain = irq_domain_create_linear(of_node_to_fwnode(node),
+						   (sei->caps->ap_range.size +
+						    sei->caps->cp_range.size),
+						   &mvebu_sei_domain_ops,
+						   sei);
+	if (!sei->sei_domain) {
+		dev_err(sei->dev, "Failed to create SEI IRQ domain\n");
+		ret = -ENOMEM;
+		goto dispose_irq;
+	}
+
+	irq_domain_update_bus_token(sei->sei_domain, DOMAIN_BUS_NEXUS);
+
+	/* Create the 'wired' domain */
+	sei->ap_domain = irq_domain_create_hierarchy(sei->sei_domain, 0,
+						     sei->caps->ap_range.size,
+						     of_node_to_fwnode(node),
+						     &mvebu_sei_ap_domain_ops,
+						     sei);
+	if (!sei->ap_domain) {
+		dev_err(sei->dev, "Failed to create AP IRQ domain\n");
+		ret = -ENOMEM;
+		goto remove_sei_domain;
+	}
+
+	irq_domain_update_bus_token(sei->ap_domain, DOMAIN_BUS_WIRED);
+
+	/* Create the 'MSI' domain */
+	sei->cp_domain = irq_domain_create_hierarchy(sei->sei_domain, 0,
+						     sei->caps->cp_range.size,
+						     of_node_to_fwnode(node),
+						     &mvebu_sei_cp_domain_ops,
+						     sei);
+	if (!sei->cp_domain) {
+		pr_err("Failed to create CPs IRQ domain\n");
+		ret = -ENOMEM;
+		goto remove_ap_domain;
+	}
+
+	irq_domain_update_bus_token(sei->cp_domain, DOMAIN_BUS_GENERIC_MSI);
+
+	plat_domain = platform_msi_create_irq_domain(of_node_to_fwnode(node),
+						     &mvebu_sei_msi_domain_info,
+						     sei->cp_domain);
+	if (!plat_domain) {
+		pr_err("Failed to create CPs MSI domain\n");
+		ret = -ENOMEM;
+		goto remove_cp_domain;
+	}
+
+	mvebu_sei_reset(sei);
+
+	irq_set_chained_handler_and_data(parent_irq,
+					 mvebu_sei_handle_cascade_irq,
+					 sei);
+
+	return 0;
+
+remove_cp_domain:
+	irq_domain_remove(sei->cp_domain);
+remove_ap_domain:
+	irq_domain_remove(sei->ap_domain);
+remove_sei_domain:
+	irq_domain_remove(sei->sei_domain);
+dispose_irq:
+	irq_dispose_mapping(parent_irq);
+
+	return ret;
+}
+
+struct mvebu_sei_caps mvebu_sei_ap806_caps = {
+	.ap_range = {
+		.first = 0,
+		.size = 21,
+	},
+	.cp_range = {
+		.first = 21,
+		.size = 43,
+	},
+};
+
+static const struct of_device_id mvebu_sei_of_match[] = {
+	{
+		.compatible = "marvell,ap806-sei",
+		.data = &mvebu_sei_ap806_caps,
+	},
+	{},
+};
+
+static struct platform_driver mvebu_sei_driver = {
+	.probe  = mvebu_sei_probe,
+	.driver = {
+		.name = "mvebu-sei",
+		.of_match_table = mvebu_sei_of_match,
+	},
+};
+builtin_platform_driver(mvebu_sei_driver);

include/linux/irqdomain.h

@@ -75,6 +75,7 @@ struct irq_fwspec {
 enum irq_domain_bus_token {
 	DOMAIN_BUS_ANY		= 0,
 	DOMAIN_BUS_WIRED,
+	DOMAIN_BUS_GENERIC_MSI,
 	DOMAIN_BUS_PCI_MSI,
 	DOMAIN_BUS_PLATFORM_MSI,
 	DOMAIN_BUS_NEXUS,