There is an approach made to implement gs_usb firmware/driver based on Zephyr RTOS. It was found that USB stack of Zephyr RTOS overwrites USB EP addresses, if they have different last 4 bytes in absence of other endpoints. For example in case of gs_usb candlelight firmware EP-IN is 0x81 and EP-OUT 0x02. If there are no additional USB endpoints, Zephyr RTOS will overwrite EP-OUT to 0x01. More information can be found in the discussion with Zephyr RTOS USB stack maintainer here: https://github.com/zephyrproject-rtos/zephyr/issues/67812 There are already two different gs_usb FW driver implementations based on Zephyr RTOS: 1. https://github.com/CANnectivity/cannectivity (by: https://github.com/henrikbrixandersen) 2. https://github.com/zephyrproject-rtos/zephyr/compare/main...KozhinovAlexander:zephyr:gs_usb (by: https://github.com/KozhinovAlexander) At the moment both Zephyr RTOS implementations use dummy USB endpoint, to overcome described USB stack behavior from Zephyr itself. Since Zephyr RTOS is intended to be used on microcontrollers with very constrained amount of resources (ROM, RAM) and additional endpoint requires memory, it is more convenient to update the gs_usb driver in the Linux kernel. To fix this problem, update the gs_usb driver from using hard coded endpoint numbers to evaluate the endpoint descriptors and use the endpoints provided there. To: linux-can@xxxxxxxxxxxxxxx Cc: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Cc: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Jakub Kicinski <kuba@xxxxxxxxxx> Cc: Paolo Abeni <pabeni@xxxxxxxxxx> Cc: Maximilian Schneider <max@xxxxxxxxxxxxxxxxx> Signed-off-by: Alexander Kozhinov <ak.alexander.kozhinov@xxxxxxxxx> --- Changes in v3: - store pipe instead of endpoint address. This change implements nitpick: Instead of storing the ep_in and ep_out in your priv, you can instead directly store the result of usb_rcvbulkpipe(parent->udev, parent->ep_in) and usb_sndbulkpipe(dev->udev, dev->parent->ep_out). - use reverse xmas tree declaration. This change implements request: Move this declaration up (c.f. the Reverse christmas tree declarations). - use forward usb endpoints search. This change implements request: Any specific reason for doing this in reverse? The previous GS_USB_ENDPOINT_IN and GS_USB_ENDPOINT_OUT macros were respectively 1 and 2, so at the beginning. And in such a case, the normal search would find those quicker. - skip new variable declaration. This change implements nipick: no need to declare a new variable for host_iface which is used only once. Changes in v4: - put in CC most relevant mailing ist linux-can@xxxxxxxxxxxxxxx - use one patch only since only one logical/contextual change were introduced. - add quick changelog over multiple pathc versions. --- drivers/net/can/usb/gs_usb.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index bc86e9b329fd..d93410682d4b 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -43,9 +43,6 @@ #define USB_XYLANTA_SAINT3_VENDOR_ID 0x16d0 #define USB_XYLANTA_SAINT3_PRODUCT_ID 0x0f30 -#define GS_USB_ENDPOINT_IN 1 -#define GS_USB_ENDPOINT_OUT 2 - /* Timestamp 32 bit timer runs at 1 MHz (1 µs tick). Worker accounts * for timer overflow (will be after ~71 minutes) */ @@ -336,6 +333,9 @@ struct gs_usb { unsigned int hf_size_rx; u8 active_channels; + + unsigned int pipe_in; + unsigned int pipe_out; }; /* 'allocate' a tx context. @@ -687,7 +687,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb) resubmit_urb: usb_fill_bulk_urb(urb, parent->udev, - usb_rcvbulkpipe(parent->udev, GS_USB_ENDPOINT_IN), + parent->pipe_in, hf, dev->parent->hf_size_rx, gs_usb_receive_bulk_callback, parent); @@ -819,7 +819,7 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb, } usb_fill_bulk_urb(urb, dev->udev, - usb_sndbulkpipe(dev->udev, GS_USB_ENDPOINT_OUT), + dev->parent->pipe_out, hf, dev->hf_size_tx, gs_usb_xmit_callback, txc); @@ -925,8 +925,7 @@ static int gs_can_open(struct net_device *netdev) /* fill, anchor, and submit rx urb */ usb_fill_bulk_urb(urb, dev->udev, - usb_rcvbulkpipe(dev->udev, - GS_USB_ENDPOINT_IN), + dev->parent->pipe_in, buf, dev->parent->hf_size_rx, gs_usb_receive_bulk_callback, parent); @@ -1413,6 +1412,7 @@ static int gs_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) { struct usb_device *udev = interface_to_usbdev(intf); + struct usb_endpoint_descriptor *ep_in, *ep_out; struct gs_host_frame *hf; struct gs_usb *parent; struct gs_host_config hconf = { @@ -1422,6 +1422,14 @@ static int gs_usb_probe(struct usb_interface *intf, unsigned int icount, i; int rc; + /* Find common bulk endpoints reverse */ + rc = usb_find_common_endpoints(intf->cur_altsetting, + &ep_in, &ep_out, NULL, NULL); + if (rc) { + dev_err(&intf->dev, "Required endpoints not found\n"); + return rc; + } + /* send host config */ rc = usb_control_msg_send(udev, 0, GS_USB_BREQ_HOST_FORMAT, @@ -1466,6 +1474,10 @@ static int gs_usb_probe(struct usb_interface *intf, usb_set_intfdata(intf, parent); parent->udev = udev; + /* store the detected endpoints */ + parent->pipe_in = usb_rcvbulkpipe(parent->udev, ep_in->bEndpointAddress); + parent->pipe_out = usb_sndbulkpipe(parent->udev, ep_out->bEndpointAddress); + for (i = 0; i < icount; i++) { unsigned int hf_size_rx = 0; -- 2.43.0
