[PATCH v5 07/14] irqchip/irq-mvebu-sei: add new driver for Marvell SEI

[Miquel Raynal <miquel.raynal@bootlin.com>]

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>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/irqchip/Kconfig         |   3 +
 drivers/irqchip/Makefile        |   1 +
 drivers/irqchip/irq-mvebu-sei.c | 475 ++++++++++++++++++++++++++++++++
 3 files changed, 479 insertions(+)
 create mode 100644 drivers/irqchip/irq-mvebu-sei.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 383e7b70221d..96451b581452 100644
--- a/drivers/irqchip/Kconfig
+++ b/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
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index fbd1ec8070ef..b822199445ff 100644
--- a/drivers/irqchip/Makefile
+++ b/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
diff --git a/drivers/irqchip/irq-mvebu-sei.c b/drivers/irqchip/irq-mvebu-sei.c
new file mode 100644
index 000000000000..7dbc57d017b3
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-sei.c
@@ -0,0 +1,475 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) "mvebu-sei: " fmt
+
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/msi.h>
+#include <linux/platform_device.h>
+#include <linux/irqchip.h>
+#include <asm/smp_plat.h>
+
+#include <dt-bindings/interrupt-controller/arm-gic.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 *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 */
+	struct mutex mask_lock;
+};
+
+static int mvebu_sei_domain_to_sei_irq(struct mvebu_sei *sei,
+				       struct irq_domain *domain,
+				       irq_hw_number_t hwirq)
+{
+	if (domain == sei->ap_domain)
+		return sei->caps->ap_range.first + hwirq;
+	else
+		return sei->caps->cp_range.first + hwirq;
+}
+
+static void mvebu_sei_reset(struct mvebu_sei *sei)
+{
+	u32 reg_idx;
+
+	/* Clear IRQ cause registers */
+	for (reg_idx = 0; reg_idx < SEI_IRQ_REG_COUNT; reg_idx++)
+		writel_relaxed(0xFFFFFFFF, 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 sei_irq = mvebu_sei_domain_to_sei_irq(sei, d->domain, d->hwirq);
+	u32 reg_idx = SEI_IRQ_REG_IDX(sei_irq);
+	u32 reg;
+
+	/* 1 disables the interrupt */
+	mutex_lock(&sei->mask_lock);
+	reg = readl_relaxed(sei->base + GICP_SEMR(reg_idx));
+	reg |= BIT(SEI_IRQ_REG_BIT(sei_irq));
+	writel_relaxed(reg, sei->base + GICP_SEMR(reg_idx));
+	mutex_unlock(&sei->mask_lock);
+}
+
+static void mvebu_sei_unmask_irq(struct irq_data *d)
+{
+	struct mvebu_sei *sei = irq_data_get_irq_chip_data(d);
+	u32 sei_irq = mvebu_sei_domain_to_sei_irq(sei, d->domain, d->hwirq);
+	u32 reg_idx = SEI_IRQ_REG_IDX(sei_irq);
+	u32 reg;
+
+	/* 0 enables the interrupt */
+	mutex_lock(&sei->mask_lock);
+	reg = readl_relaxed(sei->base + GICP_SEMR(reg_idx));
+	reg &= ~BIT(SEI_IRQ_REG_BIT(sei_irq));
+	writel_relaxed(reg, sei->base + GICP_SEMR(reg_idx));
+	mutex_unlock(&sei->mask_lock);
+}
+
+static void mvebu_sei_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 = mvebu_sei_domain_to_sei_irq(sei, data->domain, data->hwirq);
+	msg->address_lo = lower_32_bits(set);
+	msg->address_hi = upper_32_bits(set);
+}
+
+static int mvebu_sei_ap_set_type(struct irq_data *data, unsigned int type)
+{
+	if (!(type & IRQ_TYPE_LEVEL_HIGH))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int mvebu_sei_cp_set_type(struct irq_data *data, unsigned int type)
+{
+	if (!(type & IRQ_TYPE_EDGE_RISING))
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct irq_chip mvebu_sei_ap_irq_chip = {
+	.name			= "AP SEI",
+	.irq_mask		= mvebu_sei_mask_irq,
+	.irq_unmask		= mvebu_sei_unmask_irq,
+	.irq_set_type		= mvebu_sei_ap_set_type,
+};
+
+static struct irq_chip mvebu_sei_cp_irq_chip = {
+	.name			= "CP SEI",
+	.irq_mask		= mvebu_sei_mask_irq,
+	.irq_unmask		= mvebu_sei_unmask_irq,
+	.irq_eoi                = irq_chip_eoi_parent,
+	.irq_set_affinity       = irq_chip_set_affinity_parent,
+	.irq_set_type		= mvebu_sei_cp_set_type,
+	.irq_compose_msi_msg	= mvebu_sei_compose_msi_msg,
+};
+
+static int mvebu_sei_ap_match(struct irq_domain *d, struct device_node *node,
+			      enum irq_domain_bus_token bus_token)
+{
+	struct mvebu_sei *sei = d->host_data;
+
+	if (sei->dev->of_node != node)
+		return 0;
+
+	if (d == sei->ap_domain)
+		return 1;
+
+	return 0;
+}
+
+static int mvebu_sei_ap_irq_map(struct irq_domain *domain, unsigned int virq,
+				irq_hw_number_t hwirq)
+{
+	struct mvebu_sei *sei = domain->host_data;
+
+	irq_set_chip_data(virq, sei);
+	irq_set_chip_and_handler(virq, &mvebu_sei_ap_irq_chip,
+				 handle_level_irq);
+	irq_set_status_flags(virq, IRQ_LEVEL);
+	irq_set_probe(virq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops mvebu_sei_ap_domain_ops = {
+	.match = mvebu_sei_ap_match,
+	.xlate = irq_domain_xlate_onecell,
+	.map = mvebu_sei_ap_irq_map,
+};
+
+static int mvebu_sei_cp_domain_alloc(struct mvebu_sei *sei)
+{
+	int hwirq;
+
+	mutex_lock(&sei->cp_msi_lock);
+	hwirq = find_first_zero_bit(sei->cp_msi_bitmap,
+				    sei->caps->cp_range.size);
+	set_bit(hwirq, sei->cp_msi_bitmap);
+	mutex_unlock(&sei->cp_msi_lock);
+
+	return hwirq;
+}
+
+static void mvebu_sei_cp_domain_free(struct mvebu_sei *sei, int hwirq)
+{
+	mutex_lock(&sei->cp_msi_lock);
+	clear_bit(hwirq, sei->cp_msi_bitmap);
+	mutex_unlock(&sei->cp_msi_lock);
+}
+
+static int mvebu_sei_irq_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 = args;
+	int hwirq;
+	int ret;
+
+	/* The software only supports single allocations for now */
+	if (nr_irqs != 1)
+		return -ENOTSUPP;
+
+	hwirq = mvebu_sei_cp_domain_alloc(sei);
+	if (hwirq < 0)
+		return -ENOSPC;
+
+	fwspec->fwnode = domain->parent->fwnode;
+	fwspec->param_count = 3;
+	fwspec->param[0] = GIC_SPI;
+	fwspec->param[1] = 0;
+	/*
+	 * Assume edge rising for now, it will be properly set when
+	 * ->set_type() is called
+	 */
+	fwspec->param[2] = IRQ_TYPE_EDGE_RISING;
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, fwspec);
+	if (ret)
+		goto free_irq;
+
+	ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					    &mvebu_sei_cp_irq_chip, sei);
+	if (ret)
+		goto free_irq_parents;
+
+	return 0;
+
+free_irq_parents:
+	irq_domain_free_irqs_parent(domain, virq, 1);
+free_irq:
+	mvebu_sei_cp_domain_free(sei, hwirq);
+
+	return ret;
+}
+
+static void mvebu_sei_irq_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);
+	u32 irq_count = sei->caps->ap_range.size + sei->caps->cp_range.size;
+
+	if (nr_irqs != 1 || d->hwirq >= irq_count) {
+		dev_err(sei->dev, "Invalid hwirq %lu\n", d->hwirq);
+		return;
+	}
+
+	mvebu_sei_cp_domain_free(sei, d->hwirq);
+}
+
+static const struct irq_domain_ops mvebu_sei_cp_domain_ops = {
+	.alloc = mvebu_sei_irq_domain_alloc,
+	.free = mvebu_sei_irq_domain_free,
+};
+
+static struct irq_chip mvebu_sei_msi_irq_chip = {
+	.name		= "SEI MSI controller",
+	.irq_set_type	= mvebu_sei_cp_set_type,
+};
+
+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);
+	DECLARE_BITMAP(irqmap, SEI_IRQ_COUNT);
+	u32 *irqreg = (u32 *)&irqmap;
+	u32 idx, irqn;
+
+	chained_irq_enter(chip, desc);
+
+	/* Create the bitmap of the pending interrupts */
+	for (idx = 0; idx < SEI_IRQ_REG_COUNT; idx++)
+		irqreg[idx] = readl_relaxed(sei->base + GICP_SECR(idx));
+
+	/* Call handler for each pending interrupt */
+	for_each_set_bit(irqn, irqmap, SEI_IRQ_COUNT) {
+		struct irq_domain *domain;
+		u32 virq, hwirq;
+
+		/*
+		 * Finding Linux mapping (virq) needs the right domain
+		 * and the relative hwirq (which start at 0 in both
+		 * cases, while irqn is relative to all SEI interrupts).
+		 */
+		if (irqn < sei->caps->ap_range.size) {
+			domain = sei->ap_domain;
+			hwirq = irqn;
+		} else {
+			domain = sei->cp_domain;
+			hwirq = irqn - sei->caps->ap_range.size;
+		}
+
+		virq = irq_find_mapping(domain, hwirq);
+		if (!virq) {
+			dev_warn(sei->dev,
+				 "Spurious IRQ detected (hwirq %d)\n", hwirq);
+			continue;
+		}
+
+		/* Call IRQ handler */
+		generic_handle_irq(virq);
+	}
+
+	/* Clear the pending interrupts by writing 1 to the set bits */
+	for (idx = 0; idx < SEI_IRQ_REG_COUNT; idx++)
+		if (irqreg[idx])
+			writel_relaxed(irqreg[idx], sei->base + GICP_SECR(idx));
+
+	chained_irq_exit(chip, desc);
+}
+
+static int mvebu_sei_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node, *parent;
+	struct irq_domain *parent_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);
+	mutex_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;
+	}
+
+	mvebu_sei_reset(sei);
+
+	/*
+	 * 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;
+	}
+
+	/*
+	 * SEIs can be triggered from the AP through wired interrupts and from
+	 * the CPs through MSIs.
+	 */
+
+	/* Get a reference to the parent domain */
+	parent = of_irq_find_parent(node);
+	if (!parent) {
+		dev_err(sei->dev, "Failed to find parent IRQ node\n");
+		ret = -ENODEV;
+		goto dispose_irq;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		dev_err(sei->dev, "Failed to find parent IRQ domain\n");
+		ret = -ENODEV;
+		goto dispose_irq;
+	}
+
+	/* Create the 'wired' domain */
+	sei->ap_domain = irq_domain_create_hierarchy(parent_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 dispose_irq;
+	}
+
+	/* Create the 'MSI' domain */
+	sei->cp_domain = irq_domain_create_hierarchy(parent_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;
+	}
+
+	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;
+	}
+
+	platform_set_drvdata(pdev, sei);
+
+	irq_set_chained_handler(parent_irq, mvebu_sei_handle_cascade_irq);
+	irq_set_handler_data(parent_irq, sei);
+
+	return 0;
+
+remove_cp_domain:
+	irq_domain_remove(sei->cp_domain);
+remove_ap_domain:
+	irq_domain_remove(sei->ap_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);
-- 
2.17.1