[PATCH v6 04/12] Input: xbox_gip - Add HID relaying

[Vicki Pfau <vi@endrift.com>]

GIP allows tunneling of HID packets, with the HID descriptor embedded in
the GIP metadata exchanged during the initial handshake. This patch creates
a hid_device for this HID descriptor if found, as well as relaying the HID
packets.

Signed-off-by: Vicki Pfau <vi@endrift.com>
---
 drivers/input/joystick/gip/gip-core.c | 115 +++++++++++++++++++++++++-
 drivers/input/joystick/gip/gip.h      |   2 +
 include/uapi/linux/input.h            |   1 +
 3 files changed, 115 insertions(+), 3 deletions(-)

diff --git a/drivers/input/joystick/gip/gip-core.c b/drivers/input/joystick/gip/gip-core.c
index a5ed5f3bf3fe..dc174560ee49 100644
--- a/drivers/input/joystick/gip/gip-core.c
+++ b/drivers/input/joystick/gip/gip-core.c
@@ -560,6 +560,54 @@ int gip_send_vendor_message(struct gip_attachment *attachment,
 		bytes, num_bytes);
 }
 
+static int gip_hid_ll_parse(struct hid_device *hdev)
+{
+	struct gip_attachment *attachment = hdev->driver_data;
+
+	return hid_parse_report(hdev,
+		attachment->metadata.device.hid_descriptor,
+		attachment->metadata.device.hid_descriptor_size);
+}
+
+static int gip_hid_ll_start(struct hid_device *hdev)
+{
+	return 0;
+}
+
+static void gip_hid_ll_stop(struct hid_device *hdev)
+{
+}
+
+static int gip_hid_ll_open(struct hid_device *hdev)
+{
+	return 0;
+}
+
+static void gip_hid_ll_close(struct hid_device *hdev)
+{
+}
+
+static int gip_hid_ll_raw_request(struct hid_device *hdev,
+	unsigned char reportnum, uint8_t *buf, size_t count,
+	unsigned char report_type, int reqtype)
+{
+	/*
+	 * TODO: Based on the metadata, output reports appear to be possible,
+	 * but the chatpad doesn't have the LEDs it claims to support, so
+	 * it's not clear how to test we're sending them properly.
+	 */
+	return 0;
+}
+
+static const struct hid_ll_driver gip_hid_ll_driver = {
+	.parse = gip_hid_ll_parse,
+	.start = gip_hid_ll_start,
+	.stop = gip_hid_ll_stop,
+	.open = gip_hid_ll_open,
+	.close = gip_hid_ll_close,
+	.raw_request = gip_hid_ll_raw_request,
+};
+
 static void gip_metadata_free(struct device *dev, struct gip_metadata *metadata)
 {
 	devm_kfree(dev, metadata->device.audio_formats);
@@ -1310,6 +1358,50 @@ static int gip_init_input_device(struct gip_attachment *attachment)
 	return rc;
 }
 
+static int gip_create_hdev(struct gip_attachment *attachment)
+{
+	struct hid_device *hdev;
+	int rc;
+
+	if (!attachment->metadata.device.hid_descriptor)
+		return 0;
+
+	rcu_read_lock();
+	hdev = rcu_dereference(attachment->hdev);
+	rcu_read_unlock();
+	if (hdev)
+		return 0;
+
+	hdev = hid_allocate_device();
+
+	if (IS_ERR(hdev))
+		return PTR_ERR(hdev);
+
+	hdev->ll_driver = &gip_hid_ll_driver;
+	hdev->bus = BUS_GIP;
+	hdev->vendor = attachment->vendor_id;
+	hdev->product = attachment->product_id;
+	hdev->version = 0x0100;
+	hdev->country = 0;
+	hdev->dev.parent = to_gip_device(attachment);
+	hdev->driver_data = attachment;
+	if (attachment->name)
+		strscpy(hdev->name, attachment->name);
+	else
+		strscpy(hdev->name, "Xbox Chatpad");
+	strscpy(hdev->phys, attachment->phys);
+	rc = hid_add_device(hdev);
+	if (rc) {
+		gip_err(attachment, "HID device add failed: %d\n", rc);
+		hid_destroy_device(hdev);
+	} else {
+		rcu_assign_pointer(attachment->hdev, hdev);
+		synchronize_rcu();
+	}
+
+	return rc;
+}
+
 static int gip_send_init_sequence(struct gip_attachment *attachment)
 {
 	int rc = 0;
@@ -1375,7 +1467,11 @@ static int gip_send_init_sequence(struct gip_attachment *attachment)
 	if (rc)
 		return rc;
 
-	return 0;
+	rc = gip_create_hdev(attachment);
+	if (rc)
+		return rc;
+
+	return rc;
 }
 
 static void gip_fragment_timeout(struct work_struct *work)
@@ -1393,19 +1489,25 @@ static void gip_fragment_timeout(struct work_struct *work)
 static void gip_free_devices(struct gip_attachment *attachment)
 {
 	struct input_dev *input;
+	struct hid_device *hdev;
 
 	if (attachment->driver && attachment->driver->remove)
 		attachment->driver->remove(attachment);
 
 	rcu_read_lock();
 	input = rcu_dereference(attachment->input);
+	hdev = rcu_dereference(attachment->hdev);
 	rcu_read_unlock();
 
 	rcu_assign_pointer(attachment->input, NULL);
+	rcu_assign_pointer(attachment->hdev, NULL);
 	synchronize_rcu();
 
 	if (input)
 		input_unregister_device(input);
+
+	if (hdev)
+		hid_destroy_device(hdev);
 }
 
 static void gip_reset_metadata(struct gip_attachment *attachment)
@@ -1770,9 +1872,16 @@ static int gip_handle_command_firmware(struct gip_attachment *attachment,
 static int gip_handle_command_hid_report(struct gip_attachment *attachment,
 	const struct gip_header *header, uint8_t *bytes, int num_bytes)
 {
-	gip_warn(attachment, "Unimplemented HID report message\n");
+	struct hid_device *hdev;
 
-	return -EOPNOTSUPP;
+	guard(rcu)();
+	hdev = rcu_dereference(attachment->hdev);
+	if (hdev)
+		return hid_input_report(hdev, HID_INPUT_REPORT, bytes, num_bytes, true);
+
+	gip_warn(attachment, "Got HID report with no HID descriptor\n");
+
+	return -EPROTO;
 }
 
 static int gip_handle_command_extended(struct gip_attachment *attachment,
diff --git a/drivers/input/joystick/gip/gip.h b/drivers/input/joystick/gip/gip.h
index 69eef001d91f..e2571fb43aea 100644
--- a/drivers/input/joystick/gip/gip.h
+++ b/drivers/input/joystick/gip/gip.h
@@ -12,6 +12,7 @@
 #ifndef _GIP_H
 #define _GIP_H
 
+#include <linux/hid.h>
 #include <linux/led-class-multicolor.h>
 #include <linux/rcupdate.h>
 #include <linux/usb/input.h>
@@ -250,6 +251,7 @@ struct gip_attachment {
 	int extra_axes;
 
 	bool dpad_as_buttons;
+	struct hid_device __rcu *hdev;
 };
 
 struct gip_urb {
diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h
index 6aa703fcfcfb..d9c630ff8292 100644
--- a/include/uapi/linux/input.h
+++ b/include/uapi/linux/input.h
@@ -276,6 +276,7 @@ struct input_mask {
 #define BUS_INTEL_ISHTP		0x1F
 #define BUS_AMD_SFH		0x20
 #define BUS_SDW			0x21
+#define BUS_GIP			0x22
 
 /*
  * MT_TOOL types
-- 
2.54.0