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authorMichael S. Tsirkin <mst@redhat.com>2009-07-27 23:37:48 +0300
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-09-09 13:29:24 -0700
commit711d57796f5ce2d02d6e62c9034afbb16aedda31 (patch)
tree935861fee775b171cafc96de57fe4fbfa19892eb
parent5228a828ee044834d78abdf25306bf46b19dcc4d (diff)
downloadlinux-711d57796f5ce2d02d6e62c9034afbb16aedda31.tar.bz2
PCI: expose function reset capability in sysfs
Some devices allow an individual function to be reset without affecting other functions in the same device: that's what pci_reset_function does. For devices that have this support, expose reset attribite in sysfs. This is useful e.g. for virtualization, where a qemu userspace process wants to reset the device when the guest is reset, to emulate machine reboot as closely as possible. Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
-rw-r--r--Documentation/ABI/testing/sysfs-bus-pci10
-rw-r--r--drivers/pci/pci-sysfs.c37
-rw-r--r--drivers/pci/pci.c16
-rw-r--r--drivers/pci/pci.h1
-rw-r--r--include/linux/pci.h1
5 files changed, 65 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 6bf68053e4b8..25be3250f7d6 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -84,6 +84,16 @@ Description:
from this part of the device tree.
Depends on CONFIG_HOTPLUG.
+What: /sys/bus/pci/devices/.../reset
+Date: July 2009
+Contact: Michael S. Tsirkin <mst@redhat.com>
+Description:
+ Some devices allow an individual function to be reset
+ without affecting other functions in the same device.
+ For devices that have this support, a file named reset
+ will be present in sysfs. Writing 1 to this file
+ will perform reset.
+
What: /sys/bus/pci/devices/.../vpd
Date: February 2008
Contact: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 85ebd02a64a7..0f6382f090ee 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -916,6 +916,24 @@ int __attribute__ ((weak)) pcibios_add_platform_entries(struct pci_dev *dev)
return 0;
}
+static ssize_t reset_store(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ unsigned long val;
+ ssize_t result = strict_strtoul(buf, 0, &val);
+
+ if (result < 0)
+ return result;
+
+ if (val != 1)
+ return -EINVAL;
+ return pci_reset_function(pdev);
+}
+
+static struct device_attribute reset_attr = __ATTR(reset, 0200, NULL, reset_store);
+
static int pci_create_capabilities_sysfs(struct pci_dev *dev)
{
int retval;
@@ -943,7 +961,22 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
/* Active State Power Management */
pcie_aspm_create_sysfs_dev_files(dev);
+ if (!pci_probe_reset_function(dev)) {
+ retval = device_create_file(&dev->dev, &reset_attr);
+ if (retval)
+ goto error;
+ dev->reset_fn = 1;
+ }
return 0;
+
+error:
+ pcie_aspm_remove_sysfs_dev_files(dev);
+ if (dev->vpd && dev->vpd->attr) {
+ sysfs_remove_bin_file(&dev->dev.kobj, dev->vpd->attr);
+ kfree(dev->vpd->attr);
+ }
+
+ return retval;
}
int __must_check pci_create_sysfs_dev_files (struct pci_dev *pdev)
@@ -1037,6 +1070,10 @@ static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
}
pcie_aspm_remove_sysfs_dev_files(dev);
+ if (dev->reset_fn) {
+ device_remove_file(&dev->dev, &reset_attr);
+ dev->reset_fn = 0;
+ }
}
/**
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7b70312181d7..7d55039ffa05 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2262,6 +2262,22 @@ int __pci_reset_function(struct pci_dev *dev)
EXPORT_SYMBOL_GPL(__pci_reset_function);
/**
+ * pci_probe_reset_function - check whether the device can be safely reset
+ * @dev: PCI device to reset
+ *
+ * Some devices allow an individual function to be reset without affecting
+ * other functions in the same device. The PCI device must be responsive
+ * to PCI config space in order to use this function.
+ *
+ * Returns 0 if the device function can be reset or negative if the
+ * device doesn't support resetting a single function.
+ */
+int pci_probe_reset_function(struct pci_dev *dev)
+{
+ return pci_dev_reset(dev, 1);
+}
+
+/**
* pci_reset_function - quiesce and reset a PCI device function
* @dev: PCI device to reset
*
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 5ff4d25bf0e9..73d9d92715a0 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -16,6 +16,7 @@ extern void pci_cleanup_rom(struct pci_dev *dev);
extern int pci_mmap_fits(struct pci_dev *pdev, int resno,
struct vm_area_struct *vma);
#endif
+int pci_probe_reset_function(struct pci_dev *dev);
/**
* struct pci_platform_pm_ops - Firmware PM callbacks
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 115fb7ba5089..a90f94020798 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -276,6 +276,7 @@ struct pci_dev {
unsigned int state_saved:1;
unsigned int is_physfn:1;
unsigned int is_virtfn:1;
+ unsigned int reset_fn:1;
pci_dev_flags_t dev_flags;
atomic_t enable_cnt; /* pci_enable_device has been called */