PCI/sysfs: add per pci device msi[x] irq listing (v5)

This patch adds a per-pci-device subdirectory in sysfs called:
/sys/bus/pci/devices/<device>/msi_irqs

This sub-directory exports the set of msi vectors allocated by a given
pci device, by creating a numbered sub-directory for each vector beneath
msi_irqs.  For each vector various attributes can be exported.
Currently the only attribute is called mode, which tracks the
operational mode of that vector (msi vs. msix)

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 349ecf26ce108440a5bd0c9fe9414cfa984aed9d..34f51100f0299cb5a96a77984def99dbfdd9367d 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -66,6 +66,24 @@ Description:
                re-discover previously removed devices.
                Depends on CONFIG_HOTPLUG.
 
+What:          /sys/bus/pci/devices/.../msi_irqs/
+Date:          September, 2011
+Contact:       Neil Horman <nhorman@tuxdriver.com>
+Description:
+               The /sys/devices/.../msi_irqs directory contains a variable set
+               of sub-directories, with each sub-directory being named after a
+               corresponding msi irq vector allocated to that device.  Each
+               numbered sub-directory N contains attributes of that irq.
+               Note that this directory is not created for device drivers which
+               do not support msi irqs
+
+What:          /sys/bus/pci/devices/.../msi_irqs/<N>/mode
+Date:          September 2011
+Contact:       Neil Horman <nhorman@tuxdriver.com>
+Description:
+               This attribute indicates the mode that the irq vector named by
+               the parent directory is in (msi vs. msix)
+
 What:          /sys/bus/pci/devices/.../remove
 Date:          January 2009
 Contact:       Linux PCI developers <linux-pci@vger.kernel.org>

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 0e6d04d7ba4f7c0a2f8494f3e99aceaed1eecacb..e6b6b9c67023ecc4a24a5d0baaa60c4ef4e4566e 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -323,6 +323,8 @@ static void free_msi_irqs(struct pci_dev *dev)
                        if (list_is_last(&entry->list, &dev->msi_list))
                                iounmap(entry->mask_base);
                }
+               kobject_del(&entry->kobj);
+               kobject_put(&entry->kobj);
                list_del(&entry->list);
                kfree(entry);
        }
@@ -403,6 +405,98 @@ void pci_restore_msi_state(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_restore_msi_state);
 
+
+#define to_msi_attr(obj) container_of(obj, struct msi_attribute, attr)
+#define to_msi_desc(obj) container_of(obj, struct msi_desc, kobj)
+
+struct msi_attribute {
+       struct attribute        attr;
+       ssize_t (*show)(struct msi_desc *entry, struct msi_attribute *attr,
+                       char *buf);
+       ssize_t (*store)(struct msi_desc *entry, struct msi_attribute *attr,
+                        const char *buf, size_t count);
+};
+
+static ssize_t show_msi_mode(struct msi_desc *entry, struct msi_attribute *atr,
+                            char *buf)
+{
+       return sprintf(buf, "%s\n", entry->msi_attrib.is_msix ? "msix" : "msi");
+}
+
+static ssize_t msi_irq_attr_show(struct kobject *kobj,
+                                struct attribute *attr, char *buf)
+{
+       struct msi_attribute *attribute = to_msi_attr(attr);
+       struct msi_desc *entry = to_msi_desc(kobj);
+
+       if (!attribute->show)
+               return -EIO;
+
+       return attribute->show(entry, attribute, buf);
+}
+
+static const struct sysfs_ops msi_irq_sysfs_ops = {
+       .show = msi_irq_attr_show,
+};
+
+static struct msi_attribute mode_attribute =
+       __ATTR(mode, S_IRUGO, show_msi_mode, NULL);
+
+
+struct attribute *msi_irq_default_attrs[] = {
+       &mode_attribute.attr,
+       NULL
+};
+
+void msi_kobj_release(struct kobject *kobj)
+{
+       struct msi_desc *entry = to_msi_desc(kobj);
+
+       pci_dev_put(entry->dev);
+}
+
+static struct kobj_type msi_irq_ktype = {
+       .release = msi_kobj_release,
+       .sysfs_ops = &msi_irq_sysfs_ops,
+       .default_attrs = msi_irq_default_attrs,
+};
+
+static int populate_msi_sysfs(struct pci_dev *pdev)
+{
+       struct msi_desc *entry;
+       struct kobject *kobj;
+       int ret;
+       int count = 0;
+
+       pdev->msi_kset = kset_create_and_add("msi_irqs", NULL, &pdev->dev.kobj);
+       if (!pdev->msi_kset)
+               return -ENOMEM;
+
+       list_for_each_entry(entry, &pdev->msi_list, list) {
+               kobj = &entry->kobj;
+               kobj->kset = pdev->msi_kset;
+               pci_dev_get(pdev);
+               ret = kobject_init_and_add(kobj, &msi_irq_ktype, NULL,
+                                    "%u", entry->irq);
+               if (ret)
+                       goto out_unroll;
+
+               count++;
+       }
+
+       return 0;
+
+out_unroll:
+       list_for_each_entry(entry, &pdev->msi_list, list) {
+               if (!count)
+                       break;
+               kobject_del(&entry->kobj);
+               kobject_put(&entry->kobj);
+               count--;
+       }
+       return ret;
+}
+
 /**
  * msi_capability_init - configure device's MSI capability structure
  * @dev: pointer to the pci_dev data structure of MSI device function
@@ -454,6 +548,13 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
                return ret;
        }
 
+       ret = populate_msi_sysfs(dev);
+       if (ret) {
+               msi_mask_irq(entry, mask, ~mask);
+               free_msi_irqs(dev);
+               return ret;
+       }
+
        /* Set MSI enabled bits  */
        pci_intx_for_msi(dev, 0);
        msi_set_enable(dev, pos, 1);
@@ -574,6 +675,12 @@ static int msix_capability_init(struct pci_dev *dev,
 
        msix_program_entries(dev, entries);
 
+       ret = populate_msi_sysfs(dev);
+       if (ret) {
+               ret = 0;
+               goto error;
+       }
+
        /* Set MSI-X enabled bits and unmask the function */
        pci_intx_for_msi(dev, 0);
        dev->msix_enabled = 1;
@@ -732,6 +839,8 @@ void pci_disable_msi(struct pci_dev *dev)
 
        pci_msi_shutdown(dev);
        free_msi_irqs(dev);
+       kset_unregister(dev->msi_kset);
+       dev->msi_kset = NULL;
 }
 EXPORT_SYMBOL(pci_disable_msi);
 
@@ -830,6 +939,8 @@ void pci_disable_msix(struct pci_dev *dev)
 
        pci_msix_shutdown(dev);
        free_msi_irqs(dev);
+       kset_unregister(dev->msi_kset);
+       dev->msi_kset = NULL;
 }
 EXPORT_SYMBOL(pci_disable_msix);
 

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 05acced439a38ec1faf822200740d032778e9022..ce93a341337d48a78b5449ea249aac04c3f8284d 100644 (file)
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -1,6 +1,7 @@
 #ifndef LINUX_MSI_H
 #define LINUX_MSI_H
 
+#include <linux/kobject.h>
 #include <linux/list.h>
 
 struct msi_msg {
@@ -44,6 +45,8 @@ struct msi_desc {
 
        /* Last set MSI message */
        struct msi_msg msg;
+
+       struct kobject kobj;
 };
 
 /*

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7cda65b5f79806005af9aada8831f8403a519db7..84225c756bd131ce422e926fa0a43a6ddc3dd459 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -336,6 +336,7 @@ struct pci_dev {
        struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */
 #ifdef CONFIG_PCI_MSI
        struct list_head msi_list;
+       struct kset *msi_kset;
 #endif
        struct pci_vpd *vpd;
 #ifdef CONFIG_PCI_ATS