[PATCH 4/4 V3] irqchip: gicv2m: Add support for multiple MSI for ARM64 GICv2m

[<suravee.suthikulpanit@amd.com>]

From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

This patch extend GICv2m MSI to support multiple MSI in ARM64.

This requires the common arch_setup_msi_irqs() to be overwriten
with ARM64 version which does not return 1 for PCI_CAP_ID_MSI and
nvec > 1.

Cc: Mark Rutland <Mark.Rutland@arm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>
Cc: Will Deacon <Will.Deacon@arm.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
---
 arch/arm64/include/asm/msi.h  | 15 ++++++++
 arch/arm64/kernel/Makefile    |  1 +
 arch/arm64/kernel/msi.c       | 57 ++++++++++++++++++++++++++++++
 drivers/irqchip/irq-gic-v2m.c | 80 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 153 insertions(+)
 create mode 100644 arch/arm64/include/asm/msi.h
 create mode 100644 arch/arm64/kernel/msi.c

diff --git a/arch/arm64/include/asm/msi.h b/arch/arm64/include/asm/msi.h
new file mode 100644
index 0000000..2a0944a
--- /dev/null
+++ b/arch/arm64/include/asm/msi.h
@@ -0,0 +1,15 @@
+#ifndef _ASM_ARM64_MSI_H_
+#define _ASM_ARM64_MSI_H_
+
+struct pci_dev;
+struct msi_desc;
+
+struct arm64_msi_ops {
+	int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
+	void (*teardown_msi_irqs)(struct pci_dev *dev);
+};
+
+extern struct arm64_msi_ops arm64_msi;
+extern int arm64_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
+
+#endif /* _ASM_ARM64_MSI_H_ */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index cdaedad..0636e27 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -29,6 +29,7 @@ arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)	+= sleep.o suspend.o
 arm64-obj-$(CONFIG_JUMP_LABEL)		+= jump_label.o
 arm64-obj-$(CONFIG_KGDB)		+= kgdb.o
 arm64-obj-$(CONFIG_EFI)			+= efi.o efi-stub.o efi-entry.o
+arm64-obj-$(CONFIG_PCI_MSI)		+= msi.o
 
 obj-y					+= $(arm64-obj-y) vdso/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/msi.c b/arch/arm64/kernel/msi.c
new file mode 100644
index 0000000..ed62397
--- /dev/null
+++ b/arch/arm64/kernel/msi.c
@@ -0,0 +1,57 @@
+/*
+ * ARM64 architectural MSI implemention
+ *
+ * Support for Message Signalelled Interrupts for systems that
+ * implement ARM Generic Interrupt Controller: GICv2m.
+ *
+ * Copyright (C) 2014 Advanced Micro Devices, Inc.
+ * Authors: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/irq.h>
+#include <linux/msi.h>
+#include <linux/pci.h>
+
+#include <asm/msi.h>
+
+/*
+ * ARM64 function for seting up MSI irqs.
+ * Copied from driver/pci/msi.c: arch_setup_msi_irqs().
+ */
+int arm64_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	struct msi_desc *entry;
+	int ret;
+
+	if (type == PCI_CAP_ID_MSI && nvec > 1)
+		return 1;
+
+	list_for_each_entry(entry, &dev->msi_list, list) {
+		ret = arch_setup_msi_irq(dev, entry);
+		if (ret < 0)
+			return ret;
+		if (ret > 0)
+			return -ENOSPC;
+	}
+
+	return 0;
+}
+
+struct arm64_msi_ops arm64_msi = {
+	.setup_msi_irqs         = arm64_setup_msi_irqs,
+	.teardown_msi_irqs      = default_teardown_msi_irqs,
+};
+
+int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	return arm64_msi.setup_msi_irqs(dev, nvec, type);
+}
+
+void arch_teardown_msi_irqs(struct pci_dev *dev)
+{
+	arm64_msi.teardown_msi_irqs(dev);
+}
diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index e54ca1d..9d88ad9 100644
--- a/drivers/irqchip/irq-gic-v2m.c
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -24,6 +24,10 @@
 #include <linux/of_pci.h>
 #include <linux/bitmap.h>
 
+#ifdef CONFIG_ARM64
+#include <asm/msi.h>
+#endif
+
 #include "irqchip.h"
 #include "irq-gic.h"
 
@@ -216,6 +220,80 @@ static struct irq_chip gicv2m_chip = {
 #endif
 };
 
+
+/*
+ * _gicv2m_setup_msi_irqs - Setup MSI interrupts for the given PCI device.
+ * This overrides the weak definition in ./drivers/pci/msi.c.
+ * If nvec interrupts are irqable, then assign it to PCI device.
+ * Otherwise return error.
+ *
+ * @pdev: PCI device which is requesting to enable MSI
+ * @nvec: number of MSI vectors
+ */
+static int _gicv2m_setup_msi_irqs(struct pci_dev *pdev, int nvec)
+{
+	int irq = 0, nvec_pow2 = 0, avail;
+	int i = 0;
+	struct msi_msg msg;
+	phys_addr_t addr;
+	struct msi_desc *entry;
+	struct msi_chip *chip = pdev->bus->msi;
+	struct v2m_data *data = to_v2m_data(chip);
+
+	BUG_ON(list_empty(&pdev->msi_list));
+	WARN_ON(!list_is_singular(&pdev->msi_list));
+
+	entry = list_first_entry(&pdev->msi_list, struct msi_desc, list);
+	WARN_ON(entry->irq);
+	WARN_ON(entry->msi_attrib.multiple);
+	WARN_ON(entry->nvec_used);
+	WARN_ON(!entry->dev);
+
+	avail = alloc_msi_irq(data, nvec, &irq);
+	if (avail != 0) {
+		dev_err(&pdev->dev,
+			"GICv2m: Failed to allocate %d irqs.\n", nvec);
+		return avail;
+	}
+
+	/* Set lowest of the new interrupts assigned to the PCI device */
+	nvec_pow2 = __roundup_pow_of_two(nvec);
+	entry->nvec_used = nvec;
+	entry->msi_attrib.multiple = ilog2(nvec_pow2);
+
+	for (i = 0; i < nvec; i++) {
+		irq_set_chip_data(irq+i, chip);
+		if (irq_set_msi_desc_off(irq, i, entry)) {
+			dev_err(&pdev->dev,
+				"GICv2m: Failed to set up MSI irq %d\n",
+				(irq+i));
+			return -EINVAL;
+		}
+
+		irq_set_irq_type((irq+i), IRQ_TYPE_EDGE_RISING);
+	}
+
+	addr = data->res.start + V2M_MSI_SETSPI_NS;
+	msg.address_hi = (u32)(addr >> 32);
+	msg.address_lo = (u32)(addr);
+	msg.data = irq;
+	write_msi_msg(irq, &msg);
+
+	return 0;
+}
+
+static int
+gicv2m_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
+{
+	int ret;
+
+	if (type == PCI_CAP_ID_MSI)
+		ret = _gicv2m_setup_msi_irqs(pdev, nvec);
+	else
+		ret = arm64_setup_msi_irqs(pdev, nvec, type);
+	return ret;
+}
+
 #ifdef CONFIG_OF
 static int __init
 gicv2m_of_init(struct device_node *node, struct device_node *parent)
@@ -229,6 +307,8 @@ gicv2m_of_init(struct device_node *node, struct device_node *parent)
 		return ret;
 	}
 
+	arm64_msi.setup_msi_irqs = &gicv2m_setup_msi_irqs;
+
 	gic->msi_chip.owner = THIS_MODULE;
 	gic->msi_chip.of_node = node;
 	gic->msi_chip.setup_irq = gicv2m_setup_msi_irq;
-- 
1.9.0