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can: gs_usb: use union and FLEX_ARRAY for data in struct gs_host_frame
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Modify struct gs_host_frame to make use of a union and
DECLARE_FLEX_ARRAY to be able to store different data (lengths), which
will be added in later commits.

Store the gs_host_frame length in TX direction (host -> device) in
struct gs_can::hf_size_tx and RX direction (device -> host) in struct
gs_usb::hf_size_rx so it must be calculated only once.

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 0bdcc36 commit ffca688
Showing 1 changed file with 27 additions and 13 deletions.
40 changes: 27 additions & 13 deletions drivers/net/can/usb/gs_usb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,10 @@ struct gs_device_bt_const {

#define GS_CAN_FLAG_OVERFLOW BIT(0)

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

struct gs_host_frame {
u32 echo_id;
__le32 can_id;
Expand All @@ -155,7 +159,9 @@ struct gs_host_frame {
u8 flags;
u8 reserved;

u8 data[8];
union {
DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
};
} __packed;
/* The GS USB devices make use of the same flags and masks as in
* linux/can.h and linux/can/error.h, and no additional mapping is necessary.
Expand Down Expand Up @@ -187,6 +193,8 @@ struct gs_can {
struct can_bittiming_const bt_const;
unsigned int channel; /* channel number */

unsigned int hf_size_tx;

/* This lock prevents a race condition between xmit and receive. */
spinlock_t tx_ctx_lock;
struct gs_tx_context tx_context[GS_MAX_TX_URBS];
Expand All @@ -199,6 +207,7 @@ struct gs_can {
struct gs_usb {
struct gs_can *canch[GS_MAX_INTF];
struct usb_anchor rx_submitted;
unsigned int hf_size_rx;
atomic_t active_channels;
struct usb_device *udev;
};
Expand Down Expand Up @@ -346,7 +355,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
cf->can_id = le32_to_cpu(hf->can_id);

can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);
memcpy(cf->data, hf->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)
Expand Down Expand Up @@ -401,7 +410,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
resubmit_urb:
usb_fill_bulk_urb(urb, usbcan->udev,
usb_rcvbulkpipe(usbcan->udev, GSUSB_ENDPOINT_IN),
hf, sizeof(struct gs_host_frame),
hf, dev->parent->hf_size_rx,
gs_usb_receive_bulk_callback, usbcan);

rc = usb_submit_urb(urb, GFP_ATOMIC);
Expand Down Expand Up @@ -498,7 +507,7 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
if (!urb)
goto nomem_urb;

hf = usb_alloc_coherent(dev->udev, sizeof(*hf), GFP_ATOMIC,
hf = usb_alloc_coherent(dev->udev, dev->hf_size_tx, GFP_ATOMIC,
&urb->transfer_dma);
if (!hf) {
netdev_err(netdev, "No memory left for USB buffer\n");
Expand All @@ -522,11 +531,11 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
hf->can_id = cpu_to_le32(cf->can_id);
hf->can_dlc = can_get_cc_dlc(cf, dev->can.ctrlmode);

memcpy(hf->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),
hf, sizeof(*hf),
hf, dev->hf_size_tx,
gs_usb_xmit_callback, txc);

urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
Expand All @@ -544,8 +553,8 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
gs_free_tx_context(txc);

usb_unanchor_urb(urb);
usb_free_coherent(dev->udev,
sizeof(*hf), hf, urb->transfer_dma);
usb_free_coherent(dev->udev, urb->transfer_buffer_length,
urb->transfer_buffer, urb->transfer_dma);

if (rc == -ENODEV) {
netif_device_detach(netdev);
Expand All @@ -565,7 +574,8 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
return NETDEV_TX_OK;

badidx:
usb_free_coherent(dev->udev, sizeof(*hf), hf, urb->transfer_dma);
usb_free_coherent(dev->udev, urb->transfer_buffer_length,
urb->transfer_buffer, urb->transfer_dma);
nomem_hf:
usb_free_urb(urb);

Expand All @@ -582,13 +592,16 @@ static int gs_can_open(struct net_device *netdev)
struct gs_usb *parent = dev->parent;
int rc, i;
struct gs_device_mode *dm;
struct gs_host_frame *hf;
u32 ctrlmode;
u32 flags = 0;

rc = open_candev(netdev);
if (rc)
return rc;

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++) {
struct urb *urb;
Expand All @@ -601,7 +614,7 @@ static int gs_can_open(struct net_device *netdev)

/* alloc rx buffer */
buf = usb_alloc_coherent(dev->udev,
sizeof(struct gs_host_frame),
dev->parent->hf_size_rx,
GFP_KERNEL,
&urb->transfer_dma);
if (!buf) {
Expand All @@ -617,7 +630,7 @@ static int gs_can_open(struct net_device *netdev)
usb_rcvbulkpipe(dev->udev,
GSUSB_ENDPOINT_IN),
buf,
sizeof(struct gs_host_frame),
dev->parent->hf_size_rx,
gs_usb_receive_bulk_callback, parent);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

Expand All @@ -632,8 +645,7 @@ static int gs_can_open(struct net_device *netdev)
"usb_submit failed (err=%d)\n", rc);

usb_unanchor_urb(urb);
usb_free_coherent(urb->dev,
urb->transfer_buffer_length,
usb_free_coherent(urb->dev, urb->transfer_buffer_length,
urb->transfer_buffer, urb->transfer_dma);
usb_free_urb(urb);
break;
Expand Down Expand Up @@ -903,6 +915,7 @@ static int gs_usb_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
struct usb_device *udev = interface_to_usbdev(intf);
struct gs_host_frame *hf;
struct gs_usb *dev;
int rc = -ENOMEM;
unsigned int icount, i;
Expand Down Expand Up @@ -963,6 +976,7 @@ static int gs_usb_probe(struct usb_interface *intf,
}

init_usb_anchor(&dev->rx_submitted);
dev->hf_size_rx = struct_size(hf, classic_can, 1);

atomic_set(&dev->active_channels, 0);

Expand Down

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