[v6,07/13] HID: playstation: add DualSense Bluetooth support.

Commit Message

Roderick Colenbrander Feb. 7, 2021, 9:49 p.m. UTC

From: Roderick Colenbrander <[e-mail]>

This patch adds support for the DualSense when operating in Bluetooth mode.
The device has the same behavior as the DualShock 4 in that by default it
sends a limited input report (0x1), but after requesting calibration data,
it switches to an extended input report (report 49), which adds data for
touchpad, motion sensors, battery and more.

Signed-off-by: Roderick Colenbrander <[e-mail]>
---
 drivers/hid/Kconfig           |  1 +
 drivers/hid/hid-playstation.c | 41 +++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

Patch

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 0c141f2312f7..b3ec01c7a0b7 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -856,6 +856,7 @@  config HID_PLANTRONICS
 config HID_PLAYSTATION
 	tristate "PlayStation HID Driver"
 	depends on HID
+	select CRC32
 	select POWER_SUPPLY
 	help
 	  Provides support for Sony PS5 controllers including support for
diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
index 20fe29fc61c0..a4ef9fae7a36 100644
--- a/drivers/hid/hid-playstation.c
+++ b/drivers/hid/hid-playstation.c
@@ -6,6 +6,7 @@ 
  */
 
 #include <linux/bits.h>
+#include <linux/crc32.h>
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/input/mt.h>
@@ -45,8 +46,14 @@  struct ps_calibration_data {
 	int sens_denom;
 };
 
+/* Seed values for DualShock4 / DualSense CRC32 for different report types. */
+#define PS_INPUT_CRC32_SEED	0xA1
+#define PS_FEATURE_CRC32_SEED	0xA3
+
 #define DS_INPUT_REPORT_USB			0x01
 #define DS_INPUT_REPORT_USB_SIZE		64
+#define DS_INPUT_REPORT_BT			0x31
+#define DS_INPUT_REPORT_BT_SIZE			78
 
 #define DS_FEATURE_REPORT_CALIBRATION		0x05
 #define DS_FEATURE_REPORT_CALIBRATION_SIZE	41
@@ -300,6 +307,17 @@  static int ps_device_register_battery(struct ps_device *dev)
 	return 0;
 }
 
+/* Compute crc32 of HID data and compare against expected CRC. */
+static bool ps_check_crc32(uint8_t seed, uint8_t *data, size_t len, uint32_t report_crc)
+{
+	uint32_t crc;
+
+	crc = crc32_le(0xFFFFFFFF, &seed, 1);
+	crc = ~crc32_le(crc, data, len);
+
+	return crc == report_crc;
+}
+
 static struct input_dev *ps_gamepad_create(struct hid_device *hdev)
 {
 	struct input_dev *gamepad;
@@ -351,6 +369,17 @@  static int ps_get_report(struct hid_device *hdev, uint8_t report_id, uint8_t *bu
 		return -EINVAL;
 	}
 
+	if (hdev->bus == BUS_BLUETOOTH) {
+		/* Last 4 bytes contains crc32. */
+		uint8_t crc_offset = size - 4;
+		uint32_t report_crc = get_unaligned_le32(&buf[crc_offset]);
+
+		if (!ps_check_crc32(PS_FEATURE_CRC32_SEED, buf, crc_offset, report_crc)) {
+			hid_err(hdev, "CRC check failed for reportID=%d\n", report_id);
+			return -EILSEQ;
+		}
+	}
+
 	return 0;
 }
 
@@ -552,6 +581,17 @@  static int dualsense_parse_report(struct ps_device *ps_dev, struct hid_report *r
 	if (hdev->bus == BUS_USB && report->id == DS_INPUT_REPORT_USB &&
 			size == DS_INPUT_REPORT_USB_SIZE) {
 		ds_report = (struct dualsense_input_report *)&data[1];
+	} else if (hdev->bus == BUS_BLUETOOTH && report->id == DS_INPUT_REPORT_BT &&
+			size == DS_INPUT_REPORT_BT_SIZE) {
+		/* Last 4 bytes of input report contain crc32 */
+		uint32_t report_crc = get_unaligned_le32(&data[size - 4]);
+
+		if (!ps_check_crc32(PS_INPUT_CRC32_SEED, data, size - 4, report_crc)) {
+			hid_err(hdev, "DualSense input CRC's check failed\n");
+			return -EILSEQ;
+		}
+
+		ds_report = (struct dualsense_input_report *)&data[2];
 	} else {
 		hid_err(hdev, "Unhandled reportID=%d\n", report->id);
 		return -1;
@@ -815,6 +855,7 @@  static void ps_remove(struct hid_device *hdev)
 }
 
 static const struct hid_device_id ps_devices[] = {
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS5_CONTROLLER) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS5_CONTROLLER) },
 	{ }
 };