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Message-ID: <20090213201928.19262.86455.stgit@bob.kio>
Date: Fri, 13 Feb 2009 13:19:28 -0700
From: Alex Chiang <achiang@...com>
To: jbarnes@...tuousgeek.org
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
djwong@...ibm.com, Trent Piepho <xyzzy@...akeasy.org>,
Alex Chiang <achiang@...com>
Subject: [RFC PATCH v2 07/12] PCI: Introduce /sys/bus/pci/devices/.../remove
From: Trent Piepho <xyzzy@...akeasy.org>
This patch adds an attribute named "remove" to a PCI device's sysfs
directory. Writing a non-zero value to this attribute will remove the PCI
device and any children of it.
[achiang@...com: document in Documentation/ABI]
[achiang@...com: add #ifdef CONFIG_HOTPLUG]
[achiang@...com: need final pci_dev_put in remove_callback]
Cc: djwong@...ibm.com
Signed-off-by: Trent Piepho <xyzzy@...akeasy.org>
Signed-off-by: Alex Chiang <achiang@...com>
---
Documentation/ABI/testing/sysfs-bus-pci | 8 ++++++++
Documentation/filesystems/sysfs-pci.txt | 9 +++++++++
drivers/pci/pci-sysfs.c | 32 +++++++++++++++++++++++++++++++
3 files changed, 49 insertions(+), 0 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index ba15e2e..8c0abc7 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -7,6 +7,14 @@ Description:
re-discover previously removed devices.
Depends on CONFIG_HOTPLUG.
+What: /sys/bus/pci/devices/.../remove
+Date: January 2009
+Contact: Linux PCI developers <linux-pci@...r.kernel.org>
+Description:
+ Writing a non-zero value to this attribute will
+ hot-remove the PCI device and any of its children.
+ Depends on CONFIG_HOTPLUG.
+
What: /sys/bus/pci/devices/.../vpd
Date: February 2008
Contact: Ben Hutchings <bhutchings@...arflare.com>
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 68ef488..54e014f 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -11,6 +11,7 @@ that support it. For example, a given bus might look like this:
| |-- device
| |-- irq
| |-- local_cpus
+ | |-- remove
| |-- resource
| |-- resource0
| |-- resource1
@@ -34,6 +35,7 @@ files, each with their own function.
device PCI device (ascii, ro)
irq IRQ number (ascii, ro)
local_cpus nearby CPU mask (cpumask, ro)
+ remove remove device from kernel's list (ascii, wo)
resource PCI resource host addresses (ascii, ro)
resource0..N PCI resource N, if present (binary, mmap)
resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap)
@@ -44,6 +46,7 @@ files, each with their own function.
ro - read only file
rw - file is readable and writable
+ wo - write only file
mmap - file is mmapable
ascii - file contains ascii text
binary - file contains binary data
@@ -62,6 +65,12 @@ ROM file, if available. It's disabled by default, however, so applications
should write the string "1" to the file to enable it before attempting a read
call, and disable it following the access by writing "0" to the file.
+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file. This does not involve any kind of hot-plug functionality,
+e.g. powering off the device. The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it removed, and the device will be removed
+from any drivers attached to it.
+
Accessing legacy resources through sysfs
----------------------------------------
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index a2d85f6..e4d2c0d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -219,6 +219,35 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
return count;
}
+#ifdef CONFIG_HOTPLUG
+static void remove_callback(void *data)
+{
+ struct pci_dev *pdev = (struct pci_dev *)data;
+ pci_remove_bus_device(pdev);
+ pci_dev_put(pdev);
+}
+
+static ssize_t
+remove_store(struct device *dev, struct device_attribute *dummy,
+ const char *buf, size_t count)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ unsigned long val;
+
+ if (strict_strtoul(buf, 0, &val) < 0)
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (val)
+ sysfs_schedule_callback(&dev->kobj, remove_callback, pdev,
+ THIS_MODULE);
+
+ return count;
+}
+#endif
+
struct device_attribute pci_dev_attrs[] = {
__ATTR_RO(resource),
__ATTR_RO(vendor),
@@ -237,6 +266,9 @@ struct device_attribute pci_dev_attrs[] = {
__ATTR(broken_parity_status,(S_IRUGO|S_IWUSR),
broken_parity_status_show,broken_parity_status_store),
__ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
+#ifdef CONFIG_HOTPLUG
+ __ATTR(remove, S_IWUSR, NULL, remove_store),
+#endif
__ATTR_NULL,
};
--
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