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cdx: add support for bus enable and disable

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CDX bus needs to be disabled before updating/writing devices
in the FPGA. Once the devices are written, the bus shall be
rescanned. This change provides sysfs entry to enable/disable the
CDX bus.

Co-developed-by: Nipun Gupta <nipun.gupta@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Link: https://lore.kernel.org/r/20231017160505.10640-6-abhijit.gangurde@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Abhijit Gangurde
2023-10-17 21:35:03 +05:30
committed by Greg Kroah-Hartman
parent ce558a391d
commit e3cfd49cb9
7 changed files with 203 additions and 0 deletions
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72
drivers/cdx/cdx.c
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@@ -124,9 +124,12 @@ static int cdx_unregister_device(struct device *dev,
void *data)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
struct cdx_controller *cdx = cdx_dev->cdx;
if (cdx_dev->is_bus) {
device_for_each_child(dev, NULL, cdx_unregister_device);
if (cdx_dev->enabled && cdx->ops->bus_disable)
cdx->ops->bus_disable(cdx, cdx_dev->bus_num);
} else {
kfree(cdx_dev->driver_override);
cdx_dev->driver_override = NULL;
@@ -383,6 +386,41 @@ static ssize_t driver_override_show(struct device *dev,
}
static DEVICE_ATTR_RW(driver_override);
static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
struct cdx_controller *cdx = cdx_dev->cdx;
bool enable;
int ret;
if (kstrtobool(buf, &enable) < 0)
return -EINVAL;
if (enable == cdx_dev->enabled)
return count;
if (enable && cdx->ops->bus_enable)
ret = cdx->ops->bus_enable(cdx, cdx_dev->bus_num);
else if (!enable && cdx->ops->bus_disable)
ret = cdx->ops->bus_disable(cdx, cdx_dev->bus_num);
else
ret = -EOPNOTSUPP;
if (!ret)
cdx_dev->enabled = enable;
return ret < 0 ? ret : count;
}
static ssize_t enable_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct cdx_device *cdx_dev = to_cdx_device(dev);
return sysfs_emit(buf, "%u\n", cdx_dev->enabled);
}
static DEVICE_ATTR_RW(enable);
static umode_t cdx_dev_attrs_are_visible(struct kobject *kobj, struct attribute *a, int n)
{
struct device *dev = kobj_to_dev(kobj);
@@ -395,6 +433,18 @@ static umode_t cdx_dev_attrs_are_visible(struct kobject *kobj, struct attribute
return 0;
}
static umode_t cdx_bus_attrs_are_visible(struct kobject *kobj, struct attribute *a, int n)
{
struct device *dev = kobj_to_dev(kobj);
struct cdx_device *cdx_dev;
cdx_dev = to_cdx_device(dev);
if (cdx_dev->is_bus)
return a->mode;
return 0;
}
static struct attribute *cdx_dev_attrs[] = {
&dev_attr_remove.attr,
&dev_attr_reset.attr,
@@ -409,8 +459,19 @@ static const struct attribute_group cdx_dev_group = {
.is_visible = cdx_dev_attrs_are_visible,
};
static struct attribute *cdx_bus_dev_attrs[] = {
&dev_attr_enable.attr,
NULL,
};
static const struct attribute_group cdx_bus_dev_group = {
.attrs = cdx_bus_dev_attrs,
.is_visible = cdx_bus_attrs_are_visible,
};
static const struct attribute_group *cdx_dev_groups[] = {
&cdx_dev_group,
&cdx_bus_dev_group,
NULL,
};
@@ -588,8 +649,19 @@ struct device *cdx_bus_add(struct cdx_controller *cdx, u8 bus_num)
goto device_add_fail;
}
if (cdx->ops->bus_enable) {
ret = cdx->ops->bus_enable(cdx, bus_num);
if (ret && ret != -EALREADY) {
dev_err(cdx->dev, "cdx bus enable failed: %d\n", ret);
goto bus_enable_fail;
}
}
cdx_dev->enabled = true;
return &cdx_dev->dev;
bus_enable_fail:
device_del(&cdx_dev->dev);
device_add_fail:
put_device(&cdx_dev->dev);