irqchip/irq-mvebu-icu: Add new driver for Marvell ICU

The Marvell ICU unit is found in the CP110 block of the Marvell Armada
7K and 8K SoCs. It collects the wired interrupts of the devices located
in the CP110 and turns them into SPI interrupts in the GIC located in
the AP806 side of the SoC, by using a memory transaction.

Until now, the ICU was configured in a static fashion by the firmware,
and Linux was relying on this static configuration. By having Linux
configure the ICU, we are more flexible, and we can allocate dynamically
the GIC SPI interrupts only for devices that are actually in use.

The driver was initially written by Hanna Hawa <hannah@marvell.com>.

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

1 files changed, 289 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-mvebu-icu.c b/drivers/irqchip/irq-mvebu-icu.c
new file mode 100644
index 000000000000..e18c48d3a92e
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-icu.c
@@ -0,0 +1,289 @@
+/*
+ * Copyright (C) 2017 Marvell
+ *
+ * Hanna Hawa <hannah@marvell.com>
+ * 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/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include <dt-bindings/interrupt-controller/mvebu-icu.h>
+
+#include "irq-mvebu-gicp.h"
+
+/* ICU registers */
+#define ICU_SETSPI_NSR_AL	0x10
+#define ICU_SETSPI_NSR_AH	0x14
+#define ICU_CLRSPI_NSR_AL	0x18
+#define ICU_CLRSPI_NSR_AH	0x1c
+#define ICU_INT_CFG(x)          (0x100 + 4 * (x))
+#define   ICU_INT_ENABLE	BIT(24)
+#define   ICU_IS_EDGE		BIT(28)
+#define   ICU_GROUP_SHIFT	29
+
+/* ICU definitions */
+#define ICU_MAX_IRQS		207
+#define ICU_SATA0_ICU_ID	109
+#define ICU_SATA1_ICU_ID	107
+
+struct mvebu_icu {
+	struct irq_chip irq_chip;
+	void __iomem *base;
+	struct irq_domain *domain;
+	struct device *dev;
+};
+
+struct mvebu_icu_irq_data {
+	struct mvebu_icu *icu;
+	unsigned int icu_group;
+	unsigned int type;
+};
+
+static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct irq_data *d = irq_get_irq_data(desc->irq);
+	struct mvebu_icu_irq_data *icu_irqd = d->chip_data;
+	struct mvebu_icu *icu = icu_irqd->icu;
+	unsigned int icu_int;
+
+	if (msg->address_lo || msg->address_hi) {
+		/* Configure the ICU with irq number & type */
+		icu_int = msg->data | ICU_INT_ENABLE;
+		if (icu_irqd->type & IRQ_TYPE_EDGE_RISING)
+			icu_int |= ICU_IS_EDGE;
+		icu_int |= icu_irqd->icu_group << ICU_GROUP_SHIFT;
+	} else {
+		/* De-configure the ICU */
+		icu_int = 0;
+	}
+
+	writel_relaxed(icu_int, icu->base + ICU_INT_CFG(d->hwirq));
+
+	/*
+	 * The SATA unit has 2 ports, and a dedicated ICU entry per
+	 * port. The ahci sata driver supports only one irq interrupt
+	 * per SATA unit. To solve this conflict, we configure the 2
+	 * SATA wired interrupts in the south bridge into 1 GIC
+	 * interrupt in the north bridge. Even if only a single port
+	 * is enabled, if sata node is enabled, both interrupts are
+	 * configured (regardless of which port is actually in use).
+	 */
+	if (d->hwirq == ICU_SATA0_ICU_ID || d->hwirq == ICU_SATA1_ICU_ID) {
+		writel_relaxed(icu_int,
+			       icu->base + ICU_INT_CFG(ICU_SATA0_ICU_ID));
+		writel_relaxed(icu_int,
+			       icu->base + ICU_INT_CFG(ICU_SATA1_ICU_ID));
+	}
+}
+
+static int
+mvebu_icu_irq_domain_translate(struct irq_domain *d, struct irq_fwspec *fwspec,
+			       unsigned long *hwirq, unsigned int *type)
+{
+	struct mvebu_icu *icu = d->host_data;
+	unsigned int icu_group;
+
+	/* Check the count of the parameters in dt */
+	if (WARN_ON(fwspec->param_count < 3)) {
+		dev_err(icu->dev, "wrong ICU parameter count %d\n",
+			fwspec->param_count);
+		return -EINVAL;
+	}
+
+	/* Only ICU group type is handled */
+	icu_group = fwspec->param[0];
+	if (icu_group != ICU_GRP_NSR && icu_group != ICU_GRP_SR &&
+	    icu_group != ICU_GRP_SEI && icu_group != ICU_GRP_REI) {
+		dev_err(icu->dev, "wrong ICU group type %x\n", icu_group);
+		return -EINVAL;
+	}
+
+	*hwirq = fwspec->param[1];
+	if (*hwirq >= ICU_MAX_IRQS) {
+		dev_err(icu->dev, "invalid interrupt number %ld\n", *hwirq);
+		return -EINVAL;
+	}
+
+	/* Mask the type to prevent wrong DT configuration */
+	*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
+
+	return 0;
+}
+
+static int
+mvebu_icu_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			   unsigned int nr_irqs, void *args)
+{
+	int err;
+	unsigned long hwirq;
+	struct irq_fwspec *fwspec = args;
+	struct mvebu_icu *icu = platform_msi_get_host_data(domain);
+	struct mvebu_icu_irq_data *icu_irqd;
+
+	icu_irqd = kmalloc(sizeof(*icu_irqd), GFP_KERNEL);
+	if (!icu_irqd)
+		return -ENOMEM;
+
+	err = mvebu_icu_irq_domain_translate(domain, fwspec, &hwirq,
+					     &icu_irqd->type);
+	if (err) {
+		dev_err(icu->dev, "failed to translate ICU parameters\n");
+		goto free_irqd;
+	}
+
+	icu_irqd->icu_group = fwspec->param[0];
+	icu_irqd->icu = icu;
+
+	err = platform_msi_domain_alloc(domain, virq, nr_irqs);
+	if (err) {
+		dev_err(icu->dev, "failed to allocate ICU interrupt in parent domain\n");
+		goto free_irqd;
+	}
+
+	/* Make sure there is no interrupt left pending by the firmware */
+	err = irq_set_irqchip_state(virq, IRQCHIP_STATE_PENDING, false);
+	if (err)
+		goto free_msi;
+
+	err = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+					    &icu->irq_chip, icu_irqd);
+	if (err) {
+		dev_err(icu->dev, "failed to set the data to IRQ domain\n");
+		goto free_msi;
+	}
+
+	return 0;
+
+free_msi:
+	platform_msi_domain_free(domain, virq, nr_irqs);
+free_irqd:
+	kfree(icu_irqd);
+	return err;
+}
+
+static void
+mvebu_icu_irq_domain_free(struct irq_domain *domain, unsigned int virq,
+			  unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_get_irq_data(virq);
+	struct mvebu_icu_irq_data *icu_irqd = d->chip_data;
+
+	kfree(icu_irqd);
+
+	platform_msi_domain_free(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops mvebu_icu_domain_ops = {
+	.translate = mvebu_icu_irq_domain_translate,
+	.alloc     = mvebu_icu_irq_domain_alloc,
+	.free      = mvebu_icu_irq_domain_free,
+};
+
+static int mvebu_icu_probe(struct platform_device *pdev)
+{
+	struct mvebu_icu *icu;
+	struct device_node *node = pdev->dev.of_node;
+	struct device_node *gicp_dn;
+	struct resource *res;
+	phys_addr_t setspi, clrspi;
+	u32 i, icu_int;
+	int ret;
+
+	icu = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_icu),
+			   GFP_KERNEL);
+	if (!icu)
+		return -ENOMEM;
+
+	icu->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	icu->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(icu->base)) {
+		dev_err(&pdev->dev, "Failed to map icu base address.\n");
+		return PTR_ERR(icu->base);
+	}
+
+	icu->irq_chip.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+					    "ICU.%x",
+					    (unsigned int)res->start);
+	if (!icu->irq_chip.name)
+		return -ENOMEM;
+
+	icu->irq_chip.irq_mask = irq_chip_mask_parent;
+	icu->irq_chip.irq_unmask = irq_chip_unmask_parent;
+	icu->irq_chip.irq_eoi = irq_chip_eoi_parent;
+	icu->irq_chip.irq_set_type = irq_chip_set_type_parent;
+#ifdef CONFIG_SMP
+	icu->irq_chip.irq_set_affinity = irq_chip_set_affinity_parent;
+#endif
+
+	/*
+	 * We're probed after MSI domains have been resolved, so force
+	 * resolution here.
+	 */
+	pdev->dev.msi_domain = of_msi_get_domain(&pdev->dev, node,
+						 DOMAIN_BUS_PLATFORM_MSI);
+	if (!pdev->dev.msi_domain)
+		return -EPROBE_DEFER;
+
+	gicp_dn = irq_domain_get_of_node(pdev->dev.msi_domain);
+	if (!gicp_dn)
+		return -ENODEV;
+
+	ret = mvebu_gicp_get_doorbells(gicp_dn, &setspi, &clrspi);
+	if (ret)
+		return ret;
+
+	/* Set Clear/Set ICU SPI message address in AP */
+	writel_relaxed(upper_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AH);
+	writel_relaxed(lower_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AL);
+	writel_relaxed(upper_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AH);
+	writel_relaxed(lower_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AL);
+
+	/*
+	 * Clean all ICU interrupts with type SPI_NSR, required to
+	 * avoid unpredictable SPI assignments done by firmware.
+	 */
+	for (i = 0 ; i < ICU_MAX_IRQS ; i++) {
+		icu_int = readl(icu->base + ICU_INT_CFG(i));
+		if ((icu_int >> ICU_GROUP_SHIFT) == ICU_GRP_NSR)
+			writel_relaxed(0x0, icu->base + ICU_INT_CFG(i));
+	}
+
+	icu->domain =
+		platform_msi_create_device_domain(&pdev->dev, ICU_MAX_IRQS,
+						  mvebu_icu_write_msg,
+						  &mvebu_icu_domain_ops, icu);
+	if (!icu->domain) {
+		dev_err(&pdev->dev, "Failed to create ICU domain\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mvebu_icu_of_match[] = {
+	{ .compatible = "marvell,cp110-icu", },
+	{},
+};
+
+static struct platform_driver mvebu_icu_driver = {
+	.probe  = mvebu_icu_probe,
+	.driver = {
+		.name = "mvebu-icu",
+		.of_match_table = mvebu_icu_of_match,
+	},
+};
+builtin_platform_driver(mvebu_icu_driver);