irqchip/gicv3-its: Split PCI/MSI code from the core ITS driver

It is becoming obvious that having the PCI/MSI code in the same
file as the the core ITS code is giving people implementing non-PCI
MSI support the wrong kind of idea.

In order to make things a bit clearer, let's move the PCI/MSI code
out to its own file. Hopefully it will make it clear that whoever
thinks of hooking into the core ITS better have a very strong point.

We use a temporary entry point that will get removed in a subsequent
patch, once the proper infrastructure is added.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Ma Jun <majun258@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Duc Dang <dhdang@apm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1438091186-10244-12-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 105 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
new file mode 100644
index 0000000..7614721
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.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.
+ *
+ * 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/msi.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
+
+static void its_mask_msi_irq(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void its_unmask_msi_irq(struct irq_data *d)
+{
+	pci_msi_unmask_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip its_msi_irq_chip = {
+	.name			= "ITS-MSI",
+	.irq_unmask		= its_unmask_msi_irq,
+	.irq_mask		= its_mask_msi_irq,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_write_msi_msg	= pci_msi_domain_write_msg,
+};
+
+struct its_pci_alias {
+	struct pci_dev	*pdev;
+	u32		dev_id;
+	u32		count;
+};
+
+static int its_pci_msi_vec_count(struct pci_dev *pdev)
+{
+	int msi, msix;
+
+	msi = max(pci_msi_vec_count(pdev), 0);
+	msix = max(pci_msix_vec_count(pdev), 0);
+
+	return max(msi, msix);
+}
+
+static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
+{
+	struct its_pci_alias *dev_alias = data;
+
+	dev_alias->dev_id = alias;
+	if (pdev != dev_alias->pdev)
+		dev_alias->count += its_pci_msi_vec_count(dev_alias->pdev);
+
+	return 0;
+}
+
+static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
+			       int nvec, msi_alloc_info_t *info)
+{
+	struct pci_dev *pdev;
+	struct its_pci_alias dev_alias;
+
+	if (!dev_is_pci(dev))
+		return -EINVAL;
+
+	pdev = to_pci_dev(dev);
+	dev_alias.pdev = pdev;
+	dev_alias.count = nvec;
+
+	pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);
+
+	return its_msi_prepare(domain, dev_alias.dev_id, dev_alias.count, info);
+}
+
+static struct msi_domain_ops its_pci_msi_ops = {
+	.msi_prepare	= its_pci_msi_prepare,
+};
+
+static struct msi_domain_info its_pci_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
+	.ops	= &its_pci_msi_ops,
+	.chip	= &its_msi_irq_chip,
+};
+
+struct irq_domain *its_pci_msi_alloc_domain(struct device_node *np,
+					    struct irq_domain *parent)
+{
+	return pci_msi_create_irq_domain(np, &its_pci_msi_domain_info, parent);
+}