can: gs_usb: add extended bt_const feature

For example CANext FD needs to distinguish between bittiming constants
valid for arbitration phase and data phase to reach maximum
performance at higher speeds.

Link: https://lore.kernel.org/all/20220309124132.291861-20-mkl@pengutronix.de
Signed-off-by: Peter Fink <pfink@christ-es.de>
Signed-off-by: Christoph Möhring <cmoehring@christ-es.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index 915c5dd8199b7332f4daae3833dcc1849ee983ef..8bc219823ccfe48b0e0b6a7600b2088cddebe123 100644 (file)
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -45,6 +45,7 @@ enum gs_usb_breq {
        GS_USB_BREQ_QUIRK_CANTACT_PRO_DATA_BITTIMING = GS_USB_BREQ_GET_USER_ID,
        GS_USB_BREQ_SET_USER_ID,
        GS_USB_BREQ_DATA_BITTIMING,
+       GS_USB_BREQ_BT_CONST_EXT,
 };
 
 enum gs_can_mode {
@@ -103,6 +104,7 @@ struct gs_device_config {
 #define GS_CAN_MODE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
 #define GS_CAN_MODE_FD BIT(8)
 /* GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9) */
+/* GS_CAN_FEATURE_BT_CONST_EXT BIT(10) */
 
 struct gs_device_mode {
        __le32 mode;
@@ -137,7 +139,8 @@ struct gs_identify_mode {
 #define GS_CAN_FEATURE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
 #define GS_CAN_FEATURE_FD BIT(8)
 #define GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9)
-#define GS_CAN_FEATURE_MASK GENMASK(9, 0)
+#define GS_CAN_FEATURE_BT_CONST_EXT BIT(10)
+#define GS_CAN_FEATURE_MASK GENMASK(10, 0)
 
 /* internal quirks - keep in GS_CAN_FEATURE space for now */
 
@@ -159,6 +162,28 @@ struct gs_device_bt_const {
        __le32 brp_inc;
 } __packed;
 
+struct gs_device_bt_const_extended {
+       __le32 feature;
+       __le32 fclk_can;
+       __le32 tseg1_min;
+       __le32 tseg1_max;
+       __le32 tseg2_min;
+       __le32 tseg2_max;
+       __le32 sjw_max;
+       __le32 brp_min;
+       __le32 brp_max;
+       __le32 brp_inc;
+
+       __le32 dtseg1_min;
+       __le32 dtseg1_max;
+       __le32 dtseg2_min;
+       __le32 dtseg2_max;
+       __le32 dsjw_max;
+       __le32 dbrp_min;
+       __le32 dbrp_max;
+       __le32 dbrp_inc;
+} __packed;
+
 #define GS_CAN_FLAG_OVERFLOW BIT(0)
 #define GS_CAN_FLAG_FD BIT(1)
 #define GS_CAN_FLAG_BRS BIT(2)
@@ -225,7 +250,7 @@ struct gs_can {
        struct usb_device *udev;
        struct usb_interface *iface;
 
-       struct can_bittiming_const bt_const;
+       struct can_bittiming_const bt_const, data_bt_const;
        unsigned int channel;   /* channel number */
 
        u32 feature;
@@ -906,6 +931,7 @@ static struct gs_can *gs_make_candev(unsigned int channel,
        struct net_device *netdev;
        int rc;
        struct gs_device_bt_const *bt_const;
+       struct gs_device_bt_const_extended *bt_const_extended;
        u32 feature;
 
        bt_const = kmalloc(sizeof(*bt_const), GFP_KERNEL);
@@ -989,6 +1015,9 @@ static struct gs_can *gs_make_candev(unsigned int channel,
 
        if (feature & GS_CAN_FEATURE_FD) {
                dev->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
+               /* The data bit timing will be overwritten, if
+                * GS_CAN_FEATURE_BT_CONST_EXT is set.
+                */
                dev->can.data_bittiming_const = &dev->bt_const;
                dev->can.do_set_data_bittiming = gs_usb_set_data_bittiming;
        }
@@ -1022,6 +1051,43 @@ static struct gs_can *gs_make_candev(unsigned int channel,
 
        kfree(bt_const);
 
+       /* fetch extended bit timing constants if device has feature
+        * GS_CAN_FEATURE_FD and GS_CAN_FEATURE_BT_CONST_EXT
+        */
+       if (feature & GS_CAN_FEATURE_FD &&
+           feature & GS_CAN_FEATURE_BT_CONST_EXT) {
+               bt_const_extended = kmalloc(sizeof(*bt_const_extended), GFP_KERNEL);
+               if (!bt_const_extended)
+                       return ERR_PTR(-ENOMEM);
+
+               rc = usb_control_msg(interface_to_usbdev(intf),
+                                    usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
+                                    GS_USB_BREQ_BT_CONST_EXT,
+                                    USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
+                                    channel, 0, bt_const_extended,
+                                    sizeof(*bt_const_extended),
+                                    1000);
+               if (rc < 0) {
+                       dev_err(&intf->dev,
+                               "Couldn't get extended bit timing const for channel (err=%d)\n",
+                               rc);
+                       kfree(bt_const_extended);
+                       return ERR_PTR(rc);
+               }
+
+               strcpy(dev->data_bt_const.name, "gs_usb");
+               dev->data_bt_const.tseg1_min = le32_to_cpu(bt_const_extended->dtseg1_min);
+               dev->data_bt_const.tseg1_max = le32_to_cpu(bt_const_extended->dtseg1_max);
+               dev->data_bt_const.tseg2_min = le32_to_cpu(bt_const_extended->dtseg2_min);
+               dev->data_bt_const.tseg2_max = le32_to_cpu(bt_const_extended->dtseg2_max);
+               dev->data_bt_const.sjw_max = le32_to_cpu(bt_const_extended->dsjw_max);
+               dev->data_bt_const.brp_min = le32_to_cpu(bt_const_extended->dbrp_min);
+               dev->data_bt_const.brp_max = le32_to_cpu(bt_const_extended->dbrp_max);
+               dev->data_bt_const.brp_inc = le32_to_cpu(bt_const_extended->dbrp_inc);
+
+               dev->can.data_bittiming_const = &dev->data_bt_const;
+       }
+
        SET_NETDEV_DEV(netdev, &intf->dev);
 
        rc = register_candev(dev->netdev);