PCI/MSI: Provide mechanism to alloc/free MSI/MSIX interrupt from irqdomain

Provide mechanism to directly alloc/free MSI/MSIX interrupt from
irqdomain, which will be used to replace arch_setup_msi_irq()/
arch_setup_msi_irqs()/arch_teardown_msi_irq()/arch_teardown_msi_irqs().

To kill weak functions, this patch introduce a new weak function
arch_get_pci_msi_domain(), which is to retrieve the MSI irqdomain
for a PCI device. This weak function could be killed once we get
a common way to associate MSI domain with PCI device.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/1416061447-9472-10-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 36b0c2e..4befe09 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -28,6 +28,40 @@ int pci_msi_ignore_mask;
 
 #define msix_table_size(flags) ((flags & PCI_MSIX_FLAGS_QSIZE) + 1)
 
+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+static struct irq_domain *pci_msi_default_domain;
+static DEFINE_MUTEX(pci_msi_domain_lock);
+
+struct irq_domain * __weak arch_get_pci_msi_domain(struct pci_dev *dev)
+{
+       return pci_msi_default_domain;
+}
+
+static int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+       struct irq_domain *domain;
+
+       domain = arch_get_pci_msi_domain(dev);
+       if (domain)
+               return pci_msi_domain_alloc_irqs(domain, dev, nvec, type);
+
+       return arch_setup_msi_irqs(dev, nvec, type);
+}
+
+static void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
+{
+       struct irq_domain *domain;
+
+       domain = arch_get_pci_msi_domain(dev);
+       if (domain)
+               pci_msi_domain_free_irqs(domain, dev);
+       else
+               arch_teardown_msi_irqs(dev);
+}
+#else
+#define pci_msi_setup_msi_irqs         arch_setup_msi_irqs
+#define pci_msi_teardown_msi_irqs      arch_teardown_msi_irqs
+#endif
 
 /* Arch hooks */
 
@@ -348,7 +382,7 @@ static void free_msi_irqs(struct pci_dev *dev)
                        for (i = 0; i < entry->nvec_used; i++)
                                BUG_ON(irq_has_action(entry->irq + i));
 
-       arch_teardown_msi_irqs(dev);
+       pci_msi_teardown_msi_irqs(dev);
 
        list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
                if (entry->msi_attrib.is_msix) {
@@ -600,7 +634,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
        list_add_tail(&entry->list, &dev->msi_list);
 
        /* Configure MSI capability structure */
-       ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
+       ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
        if (ret) {
                msi_mask_irq(entry, mask, ~mask);
                free_msi_irqs(dev);
@@ -715,7 +749,7 @@ static int msix_capability_init(struct pci_dev *dev,
        if (ret)
                return ret;
 
-       ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
+       ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
        if (ret)
                goto out_avail;
 
@@ -1258,4 +1292,31 @@ void pci_msi_domain_free_irqs(struct irq_domain *domain, struct pci_dev *dev)
 {
        msi_domain_free_irqs(domain, &dev->dev);
 }
+
+/**
+ * pci_msi_create_default_irq_domain - Create a default MSI interrupt domain
+ * @node:      Optional device-tree node of the interrupt controller
+ * @info:      MSI domain info
+ * @parent:    Parent irq domain
+ *
+ * Returns: A domain pointer or NULL in case of failure. If successful
+ * the default PCI/MSI irqdomain pointer is updated.
+ */
+struct irq_domain *pci_msi_create_default_irq_domain(struct device_node *node,
+               struct msi_domain_info *info, struct irq_domain *parent)
+{
+       struct irq_domain *domain;
+
+       mutex_lock(&pci_msi_domain_lock);
+       if (pci_msi_default_domain) {
+               pr_err("PCI: default irq domain for PCI MSI has already been created.\n");
+               domain = NULL;
+       } else {
+               domain = pci_msi_create_irq_domain(node, info, parent);
+               pci_msi_default_domain = domain;
+       }
+       mutex_unlock(&pci_msi_domain_lock);
+
+       return domain;
+}
 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 1628788..692f217 100644 (file)
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -228,6 +228,9 @@ struct irq_domain *pci_msi_create_irq_domain(struct device_node *node,
 int pci_msi_domain_alloc_irqs(struct irq_domain *domain, struct pci_dev *dev,
                              int nvec, int type);
 void pci_msi_domain_free_irqs(struct irq_domain *domain, struct pci_dev *dev);
+struct irq_domain *pci_msi_create_default_irq_domain(struct device_node *node,
+                struct msi_domain_info *info, struct irq_domain *parent);
+
 irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
                                          struct msi_desc *desc);
 int pci_msi_domain_check_cap(struct irq_domain *domain,