[PATCH] irqchip: irq-mvebu-odmi: new driver

[Thomas Petazzoni]

This commits adds a new irqchip driver that handles the ODMI
controller found on Marvell 7K/8K processors. The ODMI controller
provide MSI interrupt functionality to on-board peripherals, much like
the GIC-v2m.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
---
 .../marvell,odmi-controller.txt                    |  36 +++
 drivers/irqchip/Kconfig                            |   4 +
 drivers/irqchip/Makefile                           |   1 +
 drivers/irqchip/irq-mvebu-odmi.c                   | 270 +++++++++++++++++++++
 4 files changed, 311 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/marvell,odmi-controller.txt
 create mode 100644 drivers/irqchip/irq-mvebu-odmi.c

diff --git a/Documentation/devicetree/bindings/interrupt-controller/marvell,odmi-controller.txt b/Documentation/devicetree/bindings/interrupt-controller/marvell,odmi-controller.txt
new file mode 100644
index 0000000..a2470af
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/marvell,odmi-controller.txt
@@ -0,0 +1,36 @@
+
+* Marvell ODMI for MSI support
+
+Some Marvell SoCs have an On-Die Message Interrupt (ODMI) controller
+which can be used by on-board peripheral for MSI interrupts.
+
+Required properties:
+
+- compatible	       : The value here should contain "marvell,odmi-controller".
+
+- interrupt,controller : Identifies the node as an interrupt controller.
+
+- msi-controller       : Identifies the node as an MSI controller.
+
+- marvell,odmi-frames  : Number of ODMI frames available. Each frame
+                         provides a number of events.
+
+- reg		       : List of register definitions, one for each
+                         ODMI frame.
+
+- marvell,spi-base     : List of GIC base SPI interrupts, one for each
+                         ODMI frame.
+
+Example:
+
+	odmi: odmi@300000 {
+		compatible = "marvell,odmi-controller";
+		interrupt-controller;
+		msi-controller;
+		marvell,odmi-frames = <4>;
+		reg = <0x300000 0x4000>,
+		      <0x304000 0x4000>,
+		      <0x308000 0x4000>,
+		      <0x30C000 0x4000>;
+		marvell,spi-base = <128>, <136>, <144>, <152>;
+	};
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 715923d..18bed3c 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -217,3 +217,7 @@ config IRQ_MXS
 	def_bool y if MACH_ASM9260 || ARCH_MXS
 	select IRQ_DOMAIN
 	select STMP_DEVICE
+
+config MVEBU_ODMI
+	bool
+	select GENERIC_MSI_IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 18caacb..29c388f 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -59,3 +59,4 @@ 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_ODMI)		+= irq-mvebu-odmi.o
diff --git a/drivers/irqchip/irq-mvebu-odmi.c b/drivers/irqchip/irq-mvebu-odmi.c
new file mode 100644
index 0000000..c3e00b9
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-odmi.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2016 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "GIC-ODMI: " fmt
+
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+#define GICP_ODMIN_SET			0x40
+#define   GICP_ODMI_INT_NUM_SHIFT	12
+#define GICP_ODMIN_GM_EP_R0		0x110
+#define GICP_ODMIN_GM_EP_R1		0x114
+#define GICP_ODMIN_GM_EA_R0		0x108
+#define GICP_ODMIN_GM_EA_R1		0x118
+
+/*
+ * We don't support the group events, so we simply have 8 interrupts
+ * per frame.
+ */
+#define NODMIS_PER_FRAME 8
+
+struct odmi_data {
+	struct resource res;
+	void __iomem *base;
+	unsigned int spi_base;
+	unsigned long bm;
+};
+
+static struct odmi_data *odmis;
+static unsigned int odmis_count;
+
+/*
+ * Lock protecting the allocation bitmap embedded in the odmi_data
+ * structure. Only one spinlock is used, since allocation/freeing of
+ * MSI interrupts is infrequent.
+ */
+static DEFINE_SPINLOCK(odmis_lock);
+
+static int odmi_set_affinity(struct irq_data *irq_data,
+			       const struct cpumask *mask, bool force)
+{
+	int ret;
+
+	ret = irq_chip_set_affinity_parent(irq_data, mask, force);
+	if (ret == IRQ_SET_MASK_OK)
+		ret = IRQ_SET_MASK_OK_DONE;
+
+	return ret;
+}
+
+static void odmi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct odmi_data *odmi = NULL;
+	phys_addr_t addr;
+	unsigned int odmi_offset, i;
+
+	/* Search the ODMI frame handling this interrupt */
+	for (i = 0; i < odmis_count; i++) {
+		if (data->hwirq >= odmis[i].spi_base &&
+		    data->hwirq < (odmis[i].spi_base + NODMIS_PER_FRAME)) {
+			odmi = &odmis[i];
+			break;
+		}
+	}
+
+	if (WARN_ON(!odmi))
+		return;
+
+	odmi_offset = (data->hwirq - odmi->spi_base);
+
+	addr = odmi->res.start + GICP_ODMIN_SET;
+
+	msg->address_hi = upper_32_bits(addr);
+	msg->address_lo = lower_32_bits(addr);
+	msg->data = odmi_offset << GICP_ODMI_INT_NUM_SHIFT;
+}
+
+static struct irq_chip odmi_irq_chip = {
+	.name			= "ODMI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= odmi_set_affinity,
+	.irq_compose_msi_msg	= odmi_compose_msi_msg,
+};
+
+static int odmi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs, void *args)
+{
+	struct odmi_data *odmi = NULL;
+	struct irq_fwspec fwspec;
+	struct irq_data *d;
+	unsigned int offset, hwirq;
+	int i, ret;
+
+	spin_lock(&odmis_lock);
+	for (i = 0; i < odmis_count; i++) {
+		offset = find_first_zero_bit(&odmis[i].bm, NODMIS_PER_FRAME);
+		if (offset < NODMIS_PER_FRAME) {
+			__set_bit(offset, &odmis[i].bm);
+			odmi = &odmis[i];
+			break;
+		}
+	}
+	spin_unlock(&odmis_lock);
+
+	if (!odmi)
+		return -ENOSPC;
+
+	hwirq = odmi->spi_base + offset;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = GIC_SPI;
+	fwspec.param[1] = hwirq - 32;
+	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (ret) {
+		pr_err("Cannot allocate parent IRQ\n");
+		spin_lock(&odmis_lock);
+		__clear_bit(offset, &odmi->bm);
+		spin_unlock(&odmis_lock);
+		return ret;
+	}
+
+	/* Configure the interrupt line to be edge */
+	d = irq_domain_get_irq_data(domain->parent, virq);
+	d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+				      &odmi_irq_chip, NULL);
+
+	return 0;
+}
+
+static void odmi_irq_domain_free(struct irq_domain *domain,
+				 unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct odmi_data *odmi = NULL;
+	unsigned int offset;
+	int i;
+
+	/*
+	 * Check if the hwirq number is valid, and if so, to which
+	 * ODMI frame it belongs
+	 */
+	spin_lock(&odmis_lock);
+	for (i = 0; i < odmis_count; i++) {
+		if (d->hwirq >= odmis[i].spi_base &&
+		    d->hwirq < (odmis[i].spi_base + NODMIS_PER_FRAME)) {
+			odmi = &odmis[i];
+			offset = d->hwirq - odmis[i].spi_base;
+			break;
+		}
+	}
+	spin_unlock(&odmis_lock);
+
+	if (!odmi) {
+		pr_err("Failed to teardown msi. Invalid hwirq %lu\n", d->hwirq);
+		return;
+	}
+
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+
+	/* Actually free the MSI */
+	spin_lock(&odmis_lock);
+	__clear_bit(offset, &odmi->bm);
+	spin_unlock(&odmis_lock);
+}
+
+static const struct irq_domain_ops odmi_domain_ops = {
+	.alloc	= odmi_irq_domain_alloc,
+	.free	= odmi_irq_domain_free,
+};
+
+static struct irq_chip odmi_msi_irq_chip = {
+	.name	= "ODMI",
+};
+
+static struct msi_domain_ops odmi_msi_ops = {
+};
+
+static struct msi_domain_info odmi_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.ops	= &odmi_msi_ops,
+	.chip	= &odmi_msi_irq_chip,
+};
+
+static int __init mvebu_odmi_init(struct device_node *node,
+				  struct device_node *parent)
+{
+	struct irq_domain *inner_domain, *plat_domain;
+	int ret, i;
+
+	if (of_property_read_u32(node, "marvell,odmi-frames", &odmis_count))
+		return -EINVAL;
+
+	odmis = kcalloc(odmis_count, sizeof(struct odmi_data), GFP_KERNEL);
+	if (!odmis)
+		return -ENOMEM;
+
+	for (i = 0; i < odmis_count; i++) {
+		struct odmi_data *odmi = &odmis[i];
+
+		ret = of_address_to_resource(node, i, &odmi->res);
+		if (ret)
+			goto err_unmap;
+
+		odmi->base = of_io_request_and_map(node, i, "odmi");
+		if (IS_ERR(odmi->base)) {
+			ret = PTR_ERR(odmi->base);
+			goto err_unmap;
+		}
+
+		if (of_property_read_u32_index(node, "marvell,spi-base",
+					       i, &odmi->spi_base)) {
+			ret = -EINVAL;
+			goto err_unmap;
+		}
+	}
+
+	inner_domain = irq_domain_create_linear(of_node_to_fwnode(node),
+						odmis_count * NODMIS_PER_FRAME,
+						&odmi_domain_ops, NULL);
+	if (!inner_domain) {
+		ret = -ENOMEM;
+		goto err_unmap;
+	}
+
+	inner_domain->parent = irq_find_host(parent);
+
+	plat_domain = platform_msi_create_irq_domain(of_node_to_fwnode(node),
+						     &odmi_msi_domain_info,
+						     inner_domain);
+	if (!plat_domain) {
+		ret = -ENOMEM;
+		goto err_remove_inner;
+	}
+
+	return 0;
+
+err_remove_inner:
+	irq_domain_remove(inner_domain);
+err_unmap:
+	for (i = 0; i < odmis_count; i++) {
+		struct odmi_data *odmi = &odmis[i];
+
+		if (odmi->base && !IS_ERR(odmi->base))
+			iounmap(odmis[i].base);
+	}
+	kfree(odmis);
+	return ret;
+}
+
+IRQCHIP_DECLARE(mvebu_odmi, "marvell,odmi-controller", mvebu_odmi_init);
-- 
2.6.4