[PATCH 02/14] arm64: MSI: Add support for stacked MSI domain

[Marc Zyngier]

In the spirit of the new x86 support for stacked domains and MSI,
add the minimum backend to support this feature on arm64.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
 arch/arm64/include/asm/msi.h |  26 ++++++++++
 arch/arm64/kernel/Makefile   |   1 +
 arch/arm64/kernel/msi.c      | 114 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 141 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..d07dab7
--- /dev/null
+++ b/arch/arm64/include/asm/msi.h
@@ -0,0 +1,26 @@
+/*
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM64_MSI_H__
+#define __ARM64_MSI_H__
+
+struct arm64_msi_info {
+	struct pci_dev		*pdev;
+	irq_hw_number_t		msi_hwirq;
+	int			nvec;
+};
+
+void arm64_init_msi_domain(struct irq_domain *parent, irq_flow_handler_t handle);
+
+#endif /* __ARM64_MSI_H__ */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 5bd029b..33283b8 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -31,6 +31,7 @@ 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)			+= pci.o
+arm64-obj-$(CONFIG_PCI_MSI_IRQ_DOMAIN)	+= 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..4e7847b
--- /dev/null
+++ b/arch/arm64/kernel/msi.c
@@ -0,0 +1,114 @@
+/*
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+
+#include <asm/msi.h>
+
+static struct irq_domain *pci_msi_default_domain;
+
+static void arm64_mask_msi_irq(struct irq_data *d)
+{
+	mask_msi_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void arm64_unmask_msi_irq(struct irq_data *d)
+{
+	unmask_msi_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip pci_msi_irq_chip = {
+	.name			= "PCI-MSI",
+	.irq_unmask		= arm64_unmask_msi_irq,
+	.irq_mask		= arm64_mask_msi_irq,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_write_msi_msg	= pci_msi_write_msg,
+};
+
+static void pci_msi_generate_hwirq(struct msi_domain_info *minfo, void *arg,
+				   struct msi_desc *desc)
+{
+	struct arm64_msi_info *info = arg;
+
+	info->msi_hwirq = pci_msi_calc_hwirq(info->pdev, desc);
+}
+
+static irq_hw_number_t pci_msi_get_hwirq(struct msi_domain_info *minfo,
+					 void *arg)
+{
+	struct arm64_msi_info *info = arg;
+
+	return info->msi_hwirq;
+}
+
+static int pci_msi_init(struct irq_domain *domain,
+			struct msi_domain_info *minfo, unsigned int virq,
+			irq_hw_number_t hwirq, void *arg)
+{
+	irq_domain_set_info(domain, virq, hwirq, minfo->chip, NULL,
+			    minfo->data, NULL, NULL);
+
+	return 0;
+}
+
+static void pci_msi_free(struct irq_domain *domain,
+			 struct msi_domain_info *info, unsigned int virq)
+{
+	struct msi_desc *desc = irq_get_msi_desc(virq);
+
+	if (desc)
+		desc->irq = 0;
+}
+
+static struct msi_domain_ops pci_msi_ops = {
+	.calc_hwirq = pci_msi_generate_hwirq,
+	.get_hwirq = pci_msi_get_hwirq,
+	.msi_init = pci_msi_init,
+	.msi_free = pci_msi_free,
+};
+
+static struct msi_domain_info pci_msi_info = {
+	.ops	= &pci_msi_ops,
+	.chip	= &pci_msi_irq_chip,
+	/* .data is used to contain our flow handler */
+};
+
+void arm64_init_msi_domain(struct irq_domain *parent, irq_flow_handler_t handle)
+{
+	WARN_ON(pci_msi_default_domain);
+	WARN_ON(pci_msi_info.data);
+	pci_msi_info.data = handle;
+	pci_msi_default_domain = msi_create_irq_domain(NULL,
+						       &pci_msi_info,
+						       parent);
+	if (!pci_msi_default_domain)
+		pr_warn("failed to initialize irqdomain for MSI/MSI-x.\n");
+}
+
+/* Override the weak version from drivers/pci/msi.c */
+int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
+{
+	struct arm64_msi_info info;
+
+	info.pdev = pdev;
+	info.nvec = nvec;
+
+	return pci_msi_irq_domain_alloc_irqs(pci_msi_default_domain,
+					     type, pdev, &info);
+}
-- 
2.0.4


-- 
Jazz is not dead. It just smells funny...

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