[Patch Part2 v5 21/31] PCI/MSI: Enhance core to support hierarchy irqdomain

Jiang Liu
2014-11-06T14:25:44Z

Enhance PCI MSI core to support hierarchy irqdomain, so the common
code could be shared among architectures.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
Hi Thomas,
These changes are a temporary solution, I'm working on another
patch set which will refine these interfaces, especially kill
arch_msi_irq_domain_{set|get}_hwirq().
Regards!
Gerry
---
drivers/pci/Kconfig | 4 ++
drivers/pci/msi.c | 134 +++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/msi.h | 14 ++++++
3 files changed, 152 insertions(+)

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index b9db0f2ce11f..022e89745f86 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -16,6 +16,10 @@ config PCI_MSI

If you don't know what to do here, say Y.

+config PCI_MSI_IRQ_DOMAIN
+ bool
+ depends on PCI_MSI && IRQ_DOMAIN_HIERARCHY
+
config PCI_DEBUG
bool "PCI Debugging"
depends on PCI && DEBUG_KERNEL
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index da181c59394b..8de7c8774fd2 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -19,6 +19,7 @@
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/slab.h>
+#include <linux/irqdomain.h>

#include "pci.h"

@@ -1098,3 +1099,136 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
return nvec;
}
EXPORT_SYMBOL(pci_enable_msix_range);
+
+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+/*
+ * Generate a unique ID number for each possible MSI source, the ID number
+ * is only used within the irqdomain.
+ */
+static inline irq_hw_number_t
+msi_get_hwirq(struct pci_dev *dev, struct msi_desc *desc)
+{
+ return (irq_hw_number_t)desc->msi_attrib.entry_nr |
+ PCI_DEVID(dev->bus->number, dev->devfn) << 11 |
+ (pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
+}
+
+static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *arg)
+{
+ int i, ret;
+ irq_hw_number_t hwirq = arch_msi_irq_domain_get_hwirq(arg);
+
+ if (irq_find_mapping(domain, hwirq) > 0)
+ return -EEXIST;
+
+ ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < nr_irqs; i++) {
+ irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+ domain->host_data,
+ (void *)(long)i);
+ __irq_set_handler(virq + i, handle_edge_irq, 0, "edge");
+ }
+
+ return ret;
+}
+
+static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs)
+{
+ int i;
+
+ for (i = 0; i < nr_irqs; i++) {
+ struct msi_desc *desc = irq_get_msi_desc(virq);
+
+ if (desc)
+ desc->irq = 0;
+ }
+ irq_domain_free_irqs_top(domain, virq, nr_irqs);
+}
+
+static void msi_domain_activate(struct irq_domain *domain,
+ struct irq_data *irq_data)
+{
+ struct msi_msg msg;
+
+ /*
+ * irq_data->chip_data is MSI/MSI-X offset.
+ * MSI-X message is written per-IRQ, the offset is always 0.
+ * MSI message denotes a contiguous group of IRQs, written for 0th IRQ.
+ */
+ if (irq_data->chip_data)
+ return;
+
+ BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
+ __write_msi_msg(irq_data->msi_desc, &msg);
+}
+
+static void msi_domain_deactivate(struct irq_domain *domain,
+ struct irq_data *irq_data)
+{
+ struct msi_msg msg;
+
+ if (!irq_data->chip_data) {
+ memset(&msg, 0, sizeof(msg));
+ __write_msi_msg(irq_data->msi_desc, &msg);
+ }
+}
+
+static struct irq_domain_ops msi_domain_ops = {
+ .alloc = msi_domain_alloc,
+ .free = msi_domain_free,
+ .activate = msi_domain_activate,
+ .deactivate = msi_domain_deactivate,
+};
+
+struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
+ struct irq_chip *chip,
+ struct irq_domain *parent)
+{
+ struct irq_domain *domain;
+
+ domain = irq_domain_add_tree(of_node, &msi_domain_ops, chip);
+ if (!domain)
+ return NULL;
+
+ domain->parent = parent;
+
+ return domain;
+}
+
+int msi_irq_domain_alloc_irqs(struct irq_domain *domain, int type,
+ struct pci_dev *dev, void *arg)
+{
+ int i, virq;
+ struct msi_desc *desc;
+ int node = dev_to_node(&dev->dev);
+
+ list_for_each_entry(desc, &dev->msi_list, list) {
+ arch_msi_irq_domain_set_hwirq(arg, msi_get_hwirq(dev, desc));
+ virq = irq_domain_alloc_irqs(domain, desc->nvec_used,
+ node, arg);
+ if (virq < 0) {
+ /* Special handling for pci_enable_msi_range(). */
+ if (type == PCI_CAP_ID_MSI && desc->nvec_used > 1)
+ return 1;
+ else
+ return -ENOSPC;
+ }
+ for (i = 0; i < desc->nvec_used; i++)
+ irq_set_msi_desc_off(virq, i, desc);
+ }
+
+ list_for_each_entry(desc, &dev->msi_list, list)
+ if (desc->nvec_used == 1)
+ dev_dbg(&dev->dev, "irq %d for MSI/MSI-X\n", virq);
+ else
+ dev_dbg(&dev->dev, "irq [%d-%d] for MSI/MSI-X\n",
+ virq, virq + desc->nvec_used - 1);
+
+ return 0;
+}
+#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 44f4746d033b..662c628fc2fa 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -75,4 +75,18 @@ struct msi_chip {
void (*teardown_irq)(struct msi_chip *chip, unsigned int irq);
};

+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+struct irq_domain;
+struct irq_chip;
+
+struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
+ struct irq_chip *chip,
+ struct irq_domain *parent);
+int msi_irq_domain_alloc_irqs(struct irq_domain *domain, int type,
+ struct pci_dev *dev, void *arg);
+
+irq_hw_number_t arch_msi_irq_domain_get_hwirq(void *arg);
+void arch_msi_irq_domain_set_hwirq(void *arg, irq_hw_number_t hwirq);
+#endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
+
#endif /* LINUX_MSI_H */
--
1.7.10.4