irqchip/irq-mvebu-gicp: Add new driver for Marvell GICP

This commit adds a simple driver for the Marvell GICP, a hardware unit
that converts memory writes into GIC SPI interrupts. The driver provides
a number of functions to the ICU driver to allocate GICP interrupts, and
get the physical addresses that the ICUs should write to to set/clear
interrupts.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Kconfig

@@ -268,6 +268,9 @@ config IRQ_MXS
 	select IRQ_DOMAIN
 	select STMP_DEVICE
 
+config MVEBU_GICP
+	bool
+
 config MVEBU_ODMI
 	bool
 	select GENERIC_MSI_IRQ_DOMAIN

drivers/irqchip/Makefile

@@ -69,6 +69,7 @@ obj-$(CONFIG_ARCH_SA1100)		+= irq-sa11x0.o
 obj-$(CONFIG_INGENIC_IRQ)		+= irq-ingenic.o
 obj-$(CONFIG_IMX_GPCV2)			+= irq-imx-gpcv2.o
 obj-$(CONFIG_PIC32_EVIC)		+= irq-pic32-evic.o
+obj-$(CONFIG_MVEBU_GICP)		+= irq-mvebu-gicp.o
 obj-$(CONFIG_MVEBU_ODMI)		+= irq-mvebu-odmi.o
 obj-$(CONFIG_MVEBU_PIC)			+= irq-mvebu-pic.o
 obj-$(CONFIG_LS_SCFG_MSI)		+= irq-ls-scfg-msi.o

drivers/irqchip/irq-mvebu-gicp.c

@@ -0,0 +1,279 @@
+/*
+ * Copyright (C) 2017 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+#include "irq-mvebu-gicp.h"
+
+#define GICP_SETSPI_NSR_OFFSET	0x0
+#define GICP_CLRSPI_NSR_OFFSET	0x8
+
+struct mvebu_gicp_spi_range {
+	unsigned int start;
+	unsigned int count;
+};
+
+struct mvebu_gicp {
+	struct mvebu_gicp_spi_range *spi_ranges;
+	unsigned int spi_ranges_cnt;
+	unsigned int spi_cnt;
+	unsigned long *spi_bitmap;
+	spinlock_t spi_lock;
+	struct resource *res;
+	struct device *dev;
+};
+
+static int gicp_idx_to_spi(struct mvebu_gicp *gicp, int idx)
+{
+	int i;
+
+	for (i = 0; i < gicp->spi_ranges_cnt; i++) {
+		struct mvebu_gicp_spi_range *r = &gicp->spi_ranges[i];
+
+		if (idx < r->count)
+			return r->start + idx;
+
+		idx -= r->count;
+	}
+
+	return -EINVAL;
+}
+
+int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
+			     phys_addr_t *clrspi)
+{
+	struct platform_device *pdev;
+	struct mvebu_gicp *gicp;
+
+	pdev = of_find_device_by_node(dn);
+	if (!pdev)
+		return -ENODEV;
+
+	gicp = platform_get_drvdata(pdev);
+	if (!gicp)
+		return -ENODEV;
+
+	*setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
+	*clrspi = gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
+
+	return 0;
+}
+
+static void gicp_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct mvebu_gicp *gicp = data->chip_data;
+	phys_addr_t setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
+
+	msg->data = data->hwirq;
+	msg->address_lo = lower_32_bits(setspi);
+	msg->address_hi = upper_32_bits(setspi);
+}
+
+static struct irq_chip gicp_irq_chip = {
+	.name			= "GICP",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_compose_msi_msg	= gicp_compose_msi_msg,
+};
+
+static int gicp_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs, void *args)
+{
+	struct mvebu_gicp *gicp = domain->host_data;
+	struct irq_fwspec fwspec;
+	unsigned int hwirq;
+	int ret;
+
+	spin_lock(&gicp->spi_lock);
+	hwirq = find_first_zero_bit(gicp->spi_bitmap, gicp->spi_cnt);
+	if (hwirq == gicp->spi_cnt) {
+		spin_unlock(&gicp->spi_lock);
+		return -ENOSPC;
+	}
+	__set_bit(hwirq, gicp->spi_bitmap);
+	spin_unlock(&gicp->spi_lock);
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = GIC_SPI;
+	fwspec.param[1] = gicp_idx_to_spi(gicp, hwirq) - 32;
+	/*
+	 * 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) {
+		dev_err(gicp->dev, "Cannot allocate parent IRQ\n");
+		goto free_hwirq;
+	}
+
+	ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					    &gicp_irq_chip, gicp);
+	if (ret)
+		goto free_irqs_parent;
+
+	return 0;
+
+free_irqs_parent:
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+free_hwirq:
+	spin_lock(&gicp->spi_lock);
+	__clear_bit(hwirq, gicp->spi_bitmap);
+	spin_unlock(&gicp->spi_lock);
+	return ret;
+}
+
+static void gicp_irq_domain_free(struct irq_domain *domain,
+				 unsigned int virq, unsigned int nr_irqs)
+{
+	struct mvebu_gicp *gicp = domain->host_data;
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+
+	if (d->hwirq >= gicp->spi_cnt) {
+		dev_err(gicp->dev, "Invalid hwirq %lu\n", d->hwirq);
+		return;
+	}
+
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+
+	spin_lock(&gicp->spi_lock);
+	__clear_bit(d->hwirq, gicp->spi_bitmap);
+	spin_unlock(&gicp->spi_lock);
+}
+
+static const struct irq_domain_ops gicp_domain_ops = {
+	.alloc	= gicp_irq_domain_alloc,
+	.free	= gicp_irq_domain_free,
+};
+
+static struct irq_chip gicp_msi_irq_chip = {
+	.name		= "GICP",
+	.irq_set_type	= irq_chip_set_type_parent,
+};
+
+static struct msi_domain_ops gicp_msi_ops = {
+};
+
+static struct msi_domain_info gicp_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.ops	= &gicp_msi_ops,
+	.chip	= &gicp_msi_irq_chip,
+};
+
+static int mvebu_gicp_probe(struct platform_device *pdev)
+{
+	struct mvebu_gicp *gicp;
+	struct irq_domain *inner_domain, *plat_domain, *parent_domain;
+	struct device_node *node = pdev->dev.of_node;
+	struct device_node *irq_parent_dn;
+	int ret, i;
+
+	gicp = devm_kzalloc(&pdev->dev, sizeof(*gicp), GFP_KERNEL);
+	if (!gicp)
+		return -ENOMEM;
+
+	gicp->dev = &pdev->dev;
+
+	gicp->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!gicp->res)
+		return -ENODEV;
+
+	ret = of_property_count_u32_elems(node, "marvell,spi-ranges");
+	if (ret < 0)
+		return ret;
+
+	gicp->spi_ranges_cnt = ret / 2;
+
+	gicp->spi_ranges =
+		devm_kzalloc(&pdev->dev,
+			     gicp->spi_ranges_cnt *
+			     sizeof(struct mvebu_gicp_spi_range),
+			     GFP_KERNEL);
+	if (!gicp->spi_ranges)
+		return -ENOMEM;
+
+	for (i = 0; i < gicp->spi_ranges_cnt; i++) {
+		of_property_read_u32_index(node, "marvell,spi-ranges",
+					   i * 2,
+					   &gicp->spi_ranges[i].start);
+
+		of_property_read_u32_index(node, "marvell,spi-ranges",
+					   i * 2 + 1,
+					   &gicp->spi_ranges[i].count);
+
+		gicp->spi_cnt += gicp->spi_ranges[i].count;
+	}
+
+	gicp->spi_bitmap = devm_kzalloc(&pdev->dev,
+					BITS_TO_LONGS(gicp->spi_cnt),
+					GFP_KERNEL);
+	if (!gicp->spi_bitmap)
+		return -ENOMEM;
+
+	irq_parent_dn = of_irq_find_parent(node);
+	if (!irq_parent_dn) {
+		dev_err(&pdev->dev, "failed to find parent IRQ node\n");
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(irq_parent_dn);
+	if (!parent_domain) {
+		dev_err(&pdev->dev, "failed to find parent IRQ domain\n");
+		return -ENODEV;
+	}
+
+	inner_domain = irq_domain_create_hierarchy(parent_domain, 0,
+						   gicp->spi_cnt,
+						   of_node_to_fwnode(node),
+						   &gicp_domain_ops, gicp);
+	if (!inner_domain)
+		return -ENOMEM;
+
+
+	plat_domain = platform_msi_create_irq_domain(of_node_to_fwnode(node),
+						     &gicp_msi_domain_info,
+						     inner_domain);
+	if (!plat_domain) {
+		irq_domain_remove(inner_domain);
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, gicp);
+
+	return 0;
+}
+
+static const struct of_device_id mvebu_gicp_of_match[] = {
+	{ .compatible = "marvell,ap806-gicp", },
+	{},
+};
+
+static struct platform_driver mvebu_gicp_driver = {
+	.probe  = mvebu_gicp_probe,
+	.driver = {
+		.name = "mvebu-gicp",
+		.of_match_table = mvebu_gicp_of_match,
+	},
+};
+builtin_platform_driver(mvebu_gicp_driver);

drivers/irqchip/irq-mvebu-gicp.h

@@ -0,0 +1,11 @@
+#ifndef __MVEBU_GICP_H__
+#define __MVEBU_GICP_H__
+
+#include <linux/types.h>
+
+struct device_node;
+
+int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
+			     phys_addr_t *clrspi);
+
+#endif /* __MVEBU_GICP_H__ */