// SPDX-License-Identifier: GPL-2.0 /* * Generic USB GNSS receiver driver * * Copyright (C) 2021 Johan Hovold <johan@kernel.org> */ #include <linux/errno.h> #include <linux/gnss.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/usb.h> #define GNSS_USB_READ_BUF_LEN 512 #define GNSS_USB_WRITE_TIMEOUT 1000 static const struct usb_device_id gnss_usb_id_table[] = { { USB_DEVICE(0x1199, 0xb000) }, /* Sierra Wireless XM1210 */ { } }; MODULE_DEVICE_TABLE(usb, gnss_usb_id_table); struct gnss_usb { struct usb_device *udev; struct usb_interface *intf; struct gnss_device *gdev; struct urb *read_urb; unsigned int write_pipe; }; static void gnss_usb_rx_complete(struct urb *urb) { struct gnss_usb *gusb = urb->context; struct gnss_device *gdev = gusb->gdev; int status = urb->status; int len; int ret; switch (status) { case 0: break; case -ENOENT: case -ECONNRESET: case -ESHUTDOWN: dev_dbg(&gdev->dev, "urb stopped: %d\n", status); return; case -EPIPE: dev_err(&gdev->dev, "urb stopped: %d\n", status); return; default: dev_dbg(&gdev->dev, "nonzero urb status: %d\n", status); goto resubmit; } len = urb->actual_length; if (len == 0) goto resubmit; ret = gnss_insert_raw(gdev, urb->transfer_buffer, len); if (ret < len) dev_dbg(&gdev->dev, "dropped %d bytes\n", len - ret); resubmit: ret = usb_submit_urb(urb, GFP_ATOMIC); if (ret && ret != -EPERM && ret != -ENODEV) dev_err(&gdev->dev, "failed to resubmit urb: %d\n", ret); } static int gnss_usb_open(struct gnss_device *gdev) { struct gnss_usb *gusb = gnss_get_drvdata(gdev); int ret; ret = usb_submit_urb(gusb->read_urb, GFP_KERNEL); if (ret) { if (ret != -EPERM && ret != -ENODEV) dev_err(&gdev->dev, "failed to submit urb: %d\n", ret); return ret; } return 0; } static void gnss_usb_close(struct gnss_device *gdev) { struct gnss_usb *gusb = gnss_get_drvdata(gdev); usb_kill_urb(gusb->read_urb); } static int gnss_usb_write_raw(struct gnss_device *gdev, const unsigned char *buf, size_t count) { struct gnss_usb *gusb = gnss_get_drvdata(gdev); void *tbuf; int ret; tbuf = kmemdup(buf, count, GFP_KERNEL); if (!tbuf) return -ENOMEM; ret = usb_bulk_msg(gusb->udev, gusb->write_pipe, tbuf, count, NULL, GNSS_USB_WRITE_TIMEOUT); kfree(tbuf); if (ret) return ret; return count; } static const struct gnss_operations gnss_usb_gnss_ops = { .open = gnss_usb_open, .close = gnss_usb_close, .write_raw = gnss_usb_write_raw, }; static int gnss_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) { struct usb_device *udev = interface_to_usbdev(intf); struct usb_endpoint_descriptor *in, *out; struct gnss_device *gdev; struct gnss_usb *gusb; struct urb *urb; size_t buf_len; void *buf; int ret; ret = usb_find_common_endpoints(intf->cur_altsetting, &in, &out, NULL, NULL); if (ret) return ret; gusb = kzalloc(sizeof(*gusb), GFP_KERNEL); if (!gusb) return -ENOMEM; gdev = gnss_allocate_device(&intf->dev); if (!gdev) { ret = -ENOMEM; goto err_free_gusb; } gdev->ops = &gnss_usb_gnss_ops; gdev->type = GNSS_TYPE_NMEA; gnss_set_drvdata(gdev, gusb); urb = usb_alloc_urb(0, GFP_KERNEL); if (!urb) { ret = -ENOMEM; goto err_put_gdev; } buf_len = max(usb_endpoint_maxp(in), GNSS_USB_READ_BUF_LEN); buf = kzalloc(buf_len, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto err_free_urb; } usb_fill_bulk_urb(urb, udev, usb_rcvbulkpipe(udev, usb_endpoint_num(in)), buf, buf_len, gnss_usb_rx_complete, gusb); gusb->intf = intf; gusb->udev = udev; gusb->gdev = gdev; gusb->read_urb = urb; gusb->write_pipe = usb_sndbulkpipe(udev, usb_endpoint_num(out)); ret = gnss_register_device(gdev); if (ret) goto err_free_buf; usb_set_intfdata(intf, gusb); return 0; err_free_buf: kfree(buf); err_free_urb: usb_free_urb(urb); err_put_gdev: gnss_put_device(gdev); err_free_gusb: kfree(gusb); return ret; } static void gnss_usb_disconnect(struct usb_interface *intf) { struct gnss_usb *gusb = usb_get_intfdata(intf); gnss_deregister_device(gusb->gdev); kfree(gusb->read_urb->transfer_buffer); usb_free_urb(gusb->read_urb); gnss_put_device(gusb->gdev); kfree(gusb); } static struct usb_driver gnss_usb_driver = { .name = "gnss-usb", .probe = gnss_usb_probe, .disconnect = gnss_usb_disconnect, .id_table = gnss_usb_id_table, }; module_usb_driver(gnss_usb_driver); MODULE_AUTHOR("Johan Hovold <johan@kernel.org>"); MODULE_DESCRIPTION("Generic USB GNSS receiver driver"); MODULE_LICENSE("GPL v2");