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can: gs_usb: add CAN-FD support
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CANtact Pro from Linklayer is the first gs_usb compatible device
supporting CAN-FD with a different HW and re-written candlelight FW.

Support for CAN-FD is indicated by the device setting the
GS_CAN_FEATURE_FD flag. CAN-FD support is requested by the driver with
the GS_CAN_MODE_FD flag. The CAN-FD specific data bit timing
parameters are set with the GS_USB_BREQ_DATA_BITTIMING control
message.

This patch is based on the Eric Evenchick's gs_usb_fd driver (which
itself is a fork of gs_usb). The gs_usb_fd code base was reintegrated
into the gs_usb driver, and reworked to not break the existing
classical-CAN only hardware.

Link: linklayer/gs_usb_fd#2
Co-developed-by: Eric Evenchick <eric@evenchick.com>
Signed-off-by: Eric Evenchick <eric@evenchick.com>
Signed-off-by: Peter Fink <pfink@christ-es.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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@pfink-christ @marckleinebudde
pfink-christ authored and marckleinebudde committed Feb 4, 2022
1 parent ffca688 commit a5500c5
Showing 1 changed file with 108 additions and 16 deletions.
124 changes: 108 additions & 16 deletions drivers/net/can/usb/gs_usb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ enum gs_usb_breq {
GS_USB_BREQ_IDENTIFY,
GS_USB_BREQ_GET_USER_ID,
GS_USB_BREQ_SET_USER_ID,
GS_USB_BREQ_DATA_BITTIMING,
};

enum gs_can_mode {
Expand Down Expand Up @@ -98,6 +99,7 @@ struct gs_device_config {
/* GS_CAN_FEATURE_IDENTIFY BIT(5) */
/* GS_CAN_FEATURE_USER_ID BIT(6) */
#define GS_CAN_MODE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
#define GS_CAN_MODE_FD BIT(8)

struct gs_device_mode {
__le32 mode;
Expand Down Expand Up @@ -130,6 +132,7 @@ struct gs_identify_mode {
#define GS_CAN_FEATURE_IDENTIFY BIT(5)
#define GS_CAN_FEATURE_USER_ID BIT(6)
#define GS_CAN_FEATURE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
#define GS_CAN_FEATURE_FD BIT(8)

struct gs_device_bt_const {
__le32 feature;
Expand All @@ -145,11 +148,18 @@ struct gs_device_bt_const {
} __packed;

#define GS_CAN_FLAG_OVERFLOW BIT(0)
#define GS_CAN_FLAG_FD BIT(1)
#define GS_CAN_FLAG_BRS BIT(2)
#define GS_CAN_FLAG_ESI BIT(3)

struct classic_can {
u8 data[8];
} __packed;

struct canfd {
u8 data[64];
} __packed;

struct gs_host_frame {
u32 echo_id;
__le32 can_id;
Expand All @@ -161,6 +171,7 @@ struct gs_host_frame {

union {
DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
DECLARE_FLEX_ARRAY(struct canfd, canfd);
};
} __packed;
/* The GS USB devices make use of the same flags and masks as in
Expand Down Expand Up @@ -317,6 +328,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
struct gs_host_frame *hf = urb->transfer_buffer;
struct gs_tx_context *txc;
struct can_frame *cf;
struct canfd_frame *cfd;
struct sk_buff *skb;

BUG_ON(!usbcan);
Expand Down Expand Up @@ -348,18 +360,33 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
return;

if (hf->echo_id == -1) { /* normal rx */
skb = alloc_can_skb(dev->netdev, &cf);
if (!skb)
goto resubmit_urb;
if (hf->flags & GS_CAN_FLAG_FD) {
skb = alloc_canfd_skb(dev->netdev, &cfd);
if (!skb)
goto resubmit_urb;

cfd->can_id = le32_to_cpu(hf->can_id);
cfd->len = can_fd_dlc2len(hf->can_dlc);
if (hf->flags & GS_CAN_FLAG_BRS)
cfd->flags |= CANFD_BRS;
if (hf->flags & GS_CAN_FLAG_ESI)
cfd->flags |= CANFD_ESI;

memcpy(cfd->data, hf->canfd->data, cfd->len);
} else {
skb = alloc_can_skb(dev->netdev, &cf);
if (!skb)
goto resubmit_urb;

cf->can_id = le32_to_cpu(hf->can_id);
cf->can_id = le32_to_cpu(hf->can_id);
can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);

can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);
memcpy(cf->data, hf->classic_can->data, 8);
memcpy(cf->data, hf->classic_can->data, 8);

/* ERROR frames tell us information about the controller */
if (le32_to_cpu(hf->can_id) & CAN_ERR_FLAG)
gs_update_state(dev, cf);
/* ERROR frames tell us information about the controller */
if (le32_to_cpu(hf->can_id) & CAN_ERR_FLAG)
gs_update_state(dev, cf);
}

netdev->stats.rx_packets++;
netdev->stats.rx_bytes += hf->can_dlc;
Expand Down Expand Up @@ -468,6 +495,40 @@ static int gs_usb_set_bittiming(struct net_device *netdev)
return (rc > 0) ? 0 : rc;
}

static int gs_usb_set_data_bittiming(struct net_device *netdev)
{
struct gs_can *dev = netdev_priv(netdev);
struct can_bittiming *bt = &dev->can.data_bittiming;
struct usb_interface *intf = dev->iface;
struct gs_device_bittiming *dbt;
int rc;

dbt = kmalloc(sizeof(*dbt), GFP_KERNEL);
if (!dbt)
return -ENOMEM;

dbt->prop_seg = cpu_to_le32(bt->prop_seg);
dbt->phase_seg1 = cpu_to_le32(bt->phase_seg1);
dbt->phase_seg2 = cpu_to_le32(bt->phase_seg2);
dbt->sjw = cpu_to_le32(bt->sjw);
dbt->brp = cpu_to_le32(bt->brp);

/* request bit timings */
rc = usb_control_msg(interface_to_usbdev(intf),
usb_sndctrlpipe(interface_to_usbdev(intf), 0),
GS_USB_BREQ_DATA_BITTIMING,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
dev->channel, 0, dbt, sizeof(*dbt), 1000);

kfree(dbt);

if (rc < 0)
dev_err(netdev->dev.parent,
"Couldn't set data bittimings (err=%d)", rc);

return (rc > 0) ? 0 : rc;
}

static void gs_usb_xmit_callback(struct urb *urb)
{
struct gs_tx_context *txc = urb->context;
Expand All @@ -490,6 +551,7 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
struct urb *urb;
struct gs_host_frame *hf;
struct can_frame *cf;
struct canfd_frame *cfd;
int rc;
unsigned int idx;
struct gs_tx_context *txc;
Expand Down Expand Up @@ -526,12 +588,26 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
hf->flags = 0;
hf->reserved = 0;

cf = (struct can_frame *)skb->data;
if (can_is_canfd_skb(skb)) {
cfd = (struct canfd_frame *)skb->data;

hf->can_id = cpu_to_le32(cfd->can_id);
hf->can_dlc = can_fd_len2dlc(cfd->len);
hf->flags |= GS_CAN_FLAG_FD;
if (cfd->flags & CANFD_BRS)
hf->flags |= GS_CAN_FLAG_BRS;
if (cfd->flags & CANFD_ESI)
hf->flags |= GS_CAN_FLAG_ESI;

hf->can_id = cpu_to_le32(cf->can_id);
hf->can_dlc = can_get_cc_dlc(cf, dev->can.ctrlmode);
memcpy(hf->canfd->data, cfd->data, cfd->len);
} else {
cf = (struct can_frame *)skb->data;

hf->can_id = cpu_to_le32(cf->can_id);
hf->can_dlc = can_get_cc_dlc(cf, dev->can.ctrlmode);

memcpy(hf->classic_can->data, cf->data, cf->len);
memcpy(hf->classic_can->data, cf->data, cf->len);
}

usb_fill_bulk_urb(urb, dev->udev,
usb_sndbulkpipe(dev->udev, GSUSB_ENDPOINT_OUT),
Expand Down Expand Up @@ -600,7 +676,13 @@ static int gs_can_open(struct net_device *netdev)
if (rc)
return rc;

dev->hf_size_tx = struct_size(hf, classic_can, 1);
ctrlmode = dev->can.ctrlmode;
if (ctrlmode & CAN_CTRLMODE_FD) {
flags |= GS_CAN_MODE_FD;
dev->hf_size_tx = struct_size(hf, canfd, 1);
} else {
dev->hf_size_tx = struct_size(hf, classic_can, 1);
}

if (atomic_add_return(1, &parent->active_channels) == 1) {
for (i = 0; i < GS_MAX_RX_URBS; i++) {
Expand Down Expand Up @@ -663,8 +745,6 @@ static int gs_can_open(struct net_device *netdev)
return -ENOMEM;

/* flags */
ctrlmode = dev->can.ctrlmode;

if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
flags |= GS_CAN_MODE_LOOP_BACK;
else if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
Expand Down Expand Up @@ -882,6 +962,12 @@ static struct gs_can *gs_make_candev(unsigned int channel,
if (feature & GS_CAN_FEATURE_ONE_SHOT)
dev->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;

if (feature & GS_CAN_FEATURE_FD) {
dev->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
dev->can.data_bittiming_const = &dev->bt_const;
dev->can.do_set_data_bittiming = gs_usb_set_data_bittiming;
}

if (le32_to_cpu(dconf->sw_version) > 1)
if (feature & GS_CAN_FEATURE_IDENTIFY)
netdev->ethtool_ops = &gs_usb_ethtool_ops;
Expand Down Expand Up @@ -976,6 +1062,9 @@ static int gs_usb_probe(struct usb_interface *intf,
}

init_usb_anchor(&dev->rx_submitted);
/* default to classic CAN, switch to CAN-FD if at least one of
* our channels support CAN-FD.
*/
dev->hf_size_rx = struct_size(hf, classic_can, 1);

atomic_set(&dev->active_channels, 0);
Expand All @@ -999,6 +1088,9 @@ static int gs_usb_probe(struct usb_interface *intf,
goto out_kfree_dconf;
}
dev->canch[i]->parent = dev;

if (dev->canch[i]->can.ctrlmode_supported & CAN_CTRLMODE_FD)
dev->hf_size_rx = struct_size(hf, canfd, 1);
}

rc = 0;
Expand Down

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