HID: Handle driver-specific device descriptor in core
The low-level driver can read the report descriptor, but it cannot
determine driver-specific changes to it. The hid core can fixup
and parse the report descriptor during driver attach, but does
not have direct access to the descriptor when doing so.
To be able to handle attach/detach of hid drivers properly,
a semantic change to hid_parse_report() is needed. This function has
been used in two ways, both as descriptor reader in the ll drivers and
as a parsor in the probe of the drivers. This patch splits the usage
by introducing hid_open_report(), and modifies the hid_parse() macro
to call hid_open_report() instead. The only usage of hid_parse_report()
is then to read and store the device descriptor. As a consequence, we
can handle the report fixups automatically inside the hid core.
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Tested-by: Nikolai Kondrashov <spbnick@gmail.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 4da66b4..9ed4ff3 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -546,12 +546,11 @@
}
/*
- * Free a device structure, all reports, and all fields.
+ * Close report. This function returns the device
+ * state to the point prior to hid_open_report().
*/
-
-static void hid_device_release(struct device *dev)
+static void hid_close_report(struct hid_device *device)
{
- struct hid_device *device = container_of(dev, struct hid_device, dev);
unsigned i, j;
for (i = 0; i < HID_REPORT_TYPES; i++) {
@@ -562,11 +561,34 @@
if (report)
hid_free_report(report);
}
+ memset(report_enum, 0, sizeof(*report_enum));
+ INIT_LIST_HEAD(&report_enum->report_list);
}
kfree(device->rdesc);
+ device->rdesc = NULL;
+ device->rsize = 0;
+
kfree(device->collection);
- kfree(device);
+ device->collection = NULL;
+ device->collection_size = 0;
+ device->maxcollection = 0;
+ device->maxapplication = 0;
+
+ device->status &= ~HID_STAT_PARSED;
+}
+
+/*
+ * Free a device structure, all reports, and all fields.
+ */
+
+static void hid_device_release(struct device *dev)
+{
+ struct hid_device *hid = container_of(dev, struct hid_device, dev);
+
+ hid_close_report(hid);
+ kfree(hid->dev_rdesc);
+ kfree(hid);
}
/*
@@ -643,15 +665,37 @@
* @start: report start
* @size: report size
*
+ * Allocate the device report as read by the bus driver. This function should
+ * only be called from parse() in ll drivers.
+ */
+int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
+{
+ hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
+ if (!hid->dev_rdesc)
+ return -ENOMEM;
+ hid->dev_rsize = size;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hid_parse_report);
+
+/**
+ * hid_open_report - open a driver-specific device report
+ *
+ * @device: hid device
+ *
* Parse a report description into a hid_device structure. Reports are
* enumerated, fields are attached to these reports.
* 0 returned on success, otherwise nonzero error value.
+ *
+ * This function (or the equivalent hid_parse() macro) should only be
+ * called from probe() in drivers, before starting the device.
*/
-int hid_parse_report(struct hid_device *device, __u8 *start,
- unsigned size)
+int hid_open_report(struct hid_device *device)
{
struct hid_parser *parser;
struct hid_item item;
+ unsigned int size;
+ __u8 *start;
__u8 *end;
int ret;
static int (*dispatch_type[])(struct hid_parser *parser,
@@ -662,6 +706,14 @@
hid_parser_reserved
};
+ if (WARN_ON(device->status & HID_STAT_PARSED))
+ return -EBUSY;
+
+ start = device->dev_rdesc;
+ if (WARN_ON(!start))
+ return -ENODEV;
+ size = device->dev_rsize;
+
if (device->driver->report_fixup)
start = device->driver->report_fixup(device, start, &size);
@@ -679,6 +731,15 @@
parser->device = device;
end = start + size;
+
+ device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
+ sizeof(struct hid_collection), GFP_KERNEL);
+ if (!device->collection) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
+
ret = -EINVAL;
while ((start = fetch_item(start, end, &item)) != NULL) {
@@ -704,6 +765,7 @@
goto err;
}
vfree(parser);
+ device->status |= HID_STAT_PARSED;
return 0;
}
}
@@ -711,9 +773,10 @@
hid_err(device, "item fetching failed at offset %d\n", (int)(end - start));
err:
vfree(parser);
+ hid_close_report(device);
return ret;
}
-EXPORT_SYMBOL_GPL(hid_parse_report);
+EXPORT_SYMBOL_GPL(hid_open_report);
/*
* Convert a signed n-bit integer to signed 32-bit integer. Common
@@ -1718,12 +1781,14 @@
if (hdrv->probe) {
ret = hdrv->probe(hdev, id);
} else { /* default probe */
- ret = hid_parse(hdev);
+ ret = hid_open_report(hdev);
if (!ret)
ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
}
- if (ret)
+ if (ret) {
+ hid_close_report(hdev);
hdev->driver = NULL;
+ }
}
unlock:
up(&hdev->driver_lock);
@@ -1744,6 +1809,7 @@
hdrv->remove(hdev);
else /* default remove */
hid_hw_stop(hdev);
+ hid_close_report(hdev);
hdev->driver = NULL;
}
@@ -2075,6 +2141,16 @@
&& (hid_ignore(hdev) || (hdev->quirks & HID_QUIRK_IGNORE)))
return -ENODEV;
+ /*
+ * Read the device report descriptor once and use as template
+ * for the driver-specific modifications.
+ */
+ ret = hdev->ll_driver->parse(hdev);
+ if (ret)
+ return ret;
+ if (!hdev->dev_rdesc)
+ return -ENODEV;
+
/* XXX hack, any other cleaner solution after the driver core
* is converted to allow more than 20 bytes as the device name? */
dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
@@ -2103,7 +2179,6 @@
struct hid_device *hid_allocate_device(void)
{
struct hid_device *hdev;
- unsigned int i;
int ret = -ENOMEM;
hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
@@ -2114,23 +2189,13 @@
hdev->dev.release = hid_device_release;
hdev->dev.bus = &hid_bus_type;
- hdev->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
- sizeof(struct hid_collection), GFP_KERNEL);
- if (hdev->collection == NULL)
- goto err;
- hdev->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
-
- for (i = 0; i < HID_REPORT_TYPES; i++)
- INIT_LIST_HEAD(&hdev->report_enum[i].report_list);
+ hid_close_report(hdev);
init_waitqueue_head(&hdev->debug_wait);
INIT_LIST_HEAD(&hdev->debug_list);
sema_init(&hdev->driver_lock, 1);
return hdev;
-err:
- put_device(&hdev->dev);
- return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(hid_allocate_device);
@@ -2141,6 +2206,9 @@
hid_debug_unregister(hdev);
hdev->status &= ~HID_STAT_ADDED;
}
+ kfree(hdev->dev_rdesc);
+ hdev->dev_rdesc = NULL;
+ hdev->dev_rsize = 0;
}
/**