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Message-ID: <20231017160505.10640-7-abhijit.gangurde@amd.com>
Date: Tue, 17 Oct 2023 21:35:04 +0530
From: Abhijit Gangurde <abhijit.gangurde@....com>
To: <gregkh@...uxfoundation.org>, <masahiroy@...nel.org>,
<linux-kernel@...r.kernel.org>
CC: <puneet.gupta@....com>, <Nipun.Gupta@....com>,
<nikhil.agarwal@....com>, <michal.simek@....com>, <git@....com>,
Abhijit Gangurde <abhijit.gangurde@....com>
Subject: [PATCH v7 6/7] cdx: add sysfs for bus reset
Add sysfs interface reset to reset all the devices on the CDX bus.
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@....com>
---
Changes in v7:
- None
Changes in v6:
- Remove reset bus attribute
- Use reset attribute of cdx device for bus reset.
Changes in v5:
- None
Changes in v4:
- None
Changes in v3:
- None
Changes in v2:
- Improve documentation
- sysfs entry reset takes bus number as an argument
Documentation/ABI/testing/sysfs-bus-cdx | 8 ++++----
drivers/cdx/cdx.c | 26 +++++++++++++++++++++----
2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-cdx b/Documentation/ABI/testing/sysfs-bus-cdx
index c12bdaa4152a..c2c54abffed5 100644
--- a/Documentation/ABI/testing/sysfs-bus-cdx
+++ b/Documentation/ABI/testing/sysfs-bus-cdx
@@ -45,10 +45,10 @@ What: /sys/bus/cdx/devices/.../reset
Date: March 2023
Contact: nipun.gupta@....com
Description:
- Writing y/1/on to this file resets the CDX device.
- On resetting the device, the corresponding driver is notified
- twice, once before the device is being reset, and again after
- the reset has been complete.
+ Writing y/1/on to this file resets the CDX device or all devices
+ on the bus. On resetting the device, the corresponding driver is
+ notified twice, once before the device is being reset, and again
+ after the reset has been complete.
For example::
diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index 8eb484c37e97..e22a7138292e 100644
--- a/drivers/cdx/cdx.c
+++ b/drivers/cdx/cdx.c
@@ -110,6 +110,20 @@ int cdx_dev_reset(struct device *dev)
}
EXPORT_SYMBOL_GPL(cdx_dev_reset);
+/**
+ * reset_cdx_device - Reset a CDX device
+ * @dev: CDX device
+ * @data: This is always passed as NULL, and is not used in this API,
+ * but is required here as the device_for_each_child() API expects
+ * the passed function to have this as an argument.
+ *
+ * Return: -errno on failure, 0 on success.
+ */
+static int reset_cdx_device(struct device *dev, void *data)
+{
+ return cdx_dev_reset(dev);
+}
+
/**
* cdx_unregister_device - Unregister a CDX device
* @dev: CDX device
@@ -343,6 +357,7 @@ static DEVICE_ATTR_WO(remove);
static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
+ struct cdx_device *cdx_dev = to_cdx_device(dev);
bool val;
int ret;
@@ -352,11 +367,13 @@ static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
if (!val)
return -EINVAL;
- ret = cdx_dev_reset(dev);
- if (ret)
- return ret;
+ if (cdx_dev->is_bus)
+ /* Reset all the devices attached to cdx bus */
+ ret = device_for_each_child(dev, NULL, reset_cdx_device);
+ else
+ ret = cdx_dev_reset(dev);
- return count;
+ return ret < 0 ? ret : count;
}
static DEVICE_ATTR_WO(reset);
@@ -461,6 +478,7 @@ static const struct attribute_group cdx_dev_group = {
static struct attribute *cdx_bus_dev_attrs[] = {
&dev_attr_enable.attr,
+ &dev_attr_reset.attr,
NULL,
};
--
2.34.1
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