On 09/05/14 10:50, Johannes Berg wrote:
From: Johannes Berg<johannes.berg@xxxxxxxxx>
Many devices run firmware and/or complex hardware, and most of that
can have bugs. When it misbehaves, however, it is often much harder
to debug than software running on the host.
Introduce a "device coredump" mechanism to allow dumping internal
device/firmware state through a generalized mechanism. As devices
are different and information needed can vary accordingly, this
doesn't prescribe a file format - it just provides mechanism to
get data to be able to capture it in a generalized way (e.g. in
distributions.)
Although it can be found in the patch it would not hurt to point out
where the coredump can be found in sysfs in this patch description.
[...]
+static struct class devcd_class = {
+ .name = "devcoredump",
+ .owner = THIS_MODULE,
+ .dev_release = devcd_dev_release,
+ .dev_groups = devcd_dev_groups,
+};
[...]
+/**
+ * dev_coredumpm - create firmware coredump with read/free methods
+ * @dev: the struct device for the crashed device
+ * @data: data cookie for the @read/@free functions
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ * @read: function to read from the given buffer
+ * @free: function to free the given buffer
+ */
+void dev_coredumpm(struct device *dev, struct module *owner,
+ const void *data, size_t datalen, gfp_t gfp,
+ ssize_t (*read)(char *buffer, loff_t offset, size_t count,
+ const void *data, size_t datalen),
+ void (*free)(const void *data))
+{
+ static atomic_t devcd_count = ATOMIC_INIT(0);
+ struct devcd_entry *devcd;
+ struct device *existing;
+
+ existing = class_find_device(&devcd_class, NULL, dev,
+ devcd_match_failing);
+ if (existing) {
+ put_device(existing);
+ return;
+ }
+
+ if (!try_module_get(owner))
+ return;
+
+ devcd = kzalloc(sizeof(*devcd), gfp);
+ if (!devcd)
+ goto put_module;
+
+ devcd->owner = owner;
+ devcd->data = data;
+ devcd->datalen = datalen;
+ devcd->read = read;
+ devcd->free = free;
+ devcd->failing_dev = get_device(dev);
+
+ device_initialize(&devcd->devcd_dev);
+
+ dev_set_name(&devcd->devcd_dev, "devcd%d",
+ atomic_inc_return(&devcd_count));
+ devcd->devcd_dev.class =&devcd_class;
+
+ if (device_add(&devcd->devcd_dev))
+ goto put_device;
+
+ if (sysfs_create_link(&devcd->devcd_dev.kobj,&dev->kobj,
+ "failing_device"))
+ /* nothing - symlink will be missing */;
+
+ if (sysfs_create_link(&dev->kobj,&devcd->devcd_dev.kobj,
+ "dev_coredump"))
+ /* nothing - symlink will be missing */;
The class is called "devcoredump" so you may want to be consistent here
and get rid of the underscore.
Regards,
Arend
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