| /* |
| * Greybus "AP" USB driver |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * Released under the GPLv2 only. |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/errno.h> |
| #include <linux/sizes.h> |
| #include <linux/usb.h> |
| |
| #include "greybus.h" |
| #include "svc_msg.h" |
| #include "kernel_ver.h" |
| |
| /* |
| * Macros for making pointers explicitly opaque, such that the result |
| * isn't valid but also can't be mistaken for an ERR_PTR() value. |
| */ |
| #define conceal_urb(urb) ((void *)((uintptr_t)(urb) ^ 0xbad)) |
| #define reveal_urb(cookie) ((void *)((uintptr_t)(cookie) ^ 0xbad)) |
| |
| /* Memory sizes for the buffers sent to/from the ES1 controller */ |
| #define ES1_SVC_MSG_SIZE (sizeof(struct svc_msg) + SZ_64K) |
| #define ES1_GBUF_MSG_SIZE_MAX PAGE_SIZE |
| |
| static const struct usb_device_id id_table[] = { |
| /* Made up numbers for the SVC USB Bridge in ES1 */ |
| { USB_DEVICE(0xffff, 0x0001) }, |
| { }, |
| }; |
| MODULE_DEVICE_TABLE(usb, id_table); |
| |
| /* |
| * Number of CPort IN urbs in flight at any point in time. |
| * Adjust if we are having stalls in the USB buffer due to not enough urbs in |
| * flight. |
| */ |
| #define NUM_CPORT_IN_URB 4 |
| |
| /* Number of CPort OUT urbs in flight at any point in time. |
| * Adjust if we get messages saying we are out of urbs in the system log. |
| */ |
| #define NUM_CPORT_OUT_URB 8 |
| |
| /** |
| * es1_ap_dev - ES1 USB Bridge to AP structure |
| * @usb_dev: pointer to the USB device we are. |
| * @usb_intf: pointer to the USB interface we are bound to. |
| * @hd: pointer to our greybus_host_device structure |
| * @control_endpoint: endpoint to send data to SVC |
| * @svc_endpoint: endpoint for SVC data in |
| * @cport_in_endpoint: bulk in endpoint for CPort data |
| * @cport-out_endpoint: bulk out endpoint for CPort data |
| * @svc_buffer: buffer for SVC messages coming in on @svc_endpoint |
| * @svc_urb: urb for SVC messages coming in on @svc_endpoint |
| * @cport_in_urb: array of urbs for the CPort in messages |
| * @cport_in_buffer: array of buffers for the @cport_in_urb urbs |
| * @cport_out_urb: array of urbs for the CPort out messages |
| * @cport_out_urb_busy: array of flags to see if the @cport_out_urb is busy or |
| * not. |
| * @cport_out_urb_lock: locks the @cport_out_urb_busy "list" |
| */ |
| struct es1_ap_dev { |
| struct usb_device *usb_dev; |
| struct usb_interface *usb_intf; |
| struct greybus_host_device *hd; |
| |
| __u8 control_endpoint; |
| __u8 svc_endpoint; |
| __u8 cport_in_endpoint; |
| __u8 cport_out_endpoint; |
| |
| u8 *svc_buffer; |
| struct urb *svc_urb; |
| |
| struct urb *cport_in_urb[NUM_CPORT_IN_URB]; |
| u8 *cport_in_buffer[NUM_CPORT_IN_URB]; |
| struct urb *cport_out_urb[NUM_CPORT_OUT_URB]; |
| bool cport_out_urb_busy[NUM_CPORT_OUT_URB]; |
| spinlock_t cport_out_urb_lock; |
| }; |
| |
| static inline struct es1_ap_dev *hd_to_es1(struct greybus_host_device *hd) |
| { |
| return (struct es1_ap_dev *)&hd->hd_priv; |
| } |
| |
| static void cport_out_callback(struct urb *urb); |
| |
| /* |
| * Buffer constraints for the host driver. |
| * |
| * A "buffer" is used to hold data to be transferred for Greybus by |
| * the host driver. A buffer is represented by a "buffer pointer", |
| * which defines a region of memory used by the host driver for |
| * transferring the data. When Greybus allocates a buffer, it must |
| * do so subject to the constraints associated with the host driver. |
| * These constraints are specified by two parameters: the |
| * headroom; and the maximum buffer size. |
| * |
| * +------------------+ |
| * | Host driver | \ |
| * | reserved area | }- headroom |
| * | . . . | / |
| * buffer pointer ---> +------------------+ |
| * | Buffer space for | \ |
| * | transferred data | }- buffer size |
| * | . . . | / (limited to size_max) |
| * +------------------+ |
| * |
| * headroom: Every buffer must have at least this much space |
| * *before* the buffer pointer, reserved for use by the |
| * host driver. I.e., ((char *)buffer - headroom) must |
| * point to valid memory, usable only by the host driver. |
| * size_max: The maximum size of a buffer (not including the |
| * headroom) must not exceed this. |
| */ |
| static void hd_buffer_constraints(struct greybus_host_device *hd) |
| { |
| /* |
| * Only one byte is required, but this produces a result |
| * that's better aligned for the user. |
| */ |
| hd->buffer_headroom = sizeof(u32); /* For cport id */ |
| hd->buffer_size_max = ES1_GBUF_MSG_SIZE_MAX; |
| } |
| |
| #define ES1_TIMEOUT 500 /* 500 ms for the SVC to do something */ |
| static int submit_svc(struct svc_msg *svc_msg, struct greybus_host_device *hd) |
| { |
| struct es1_ap_dev *es1 = hd_to_es1(hd); |
| int retval; |
| |
| /* SVC messages go down our control pipe */ |
| retval = usb_control_msg(es1->usb_dev, |
| usb_sndctrlpipe(es1->usb_dev, |
| es1->control_endpoint), |
| 0x01, /* vendor request AP message */ |
| USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE, |
| 0x00, 0x00, |
| (char *)svc_msg, |
| sizeof(*svc_msg), |
| ES1_TIMEOUT); |
| if (retval != sizeof(*svc_msg)) |
| return retval; |
| |
| return 0; |
| } |
| |
| static struct urb *next_free_urb(struct es1_ap_dev *es1, gfp_t gfp_mask) |
| { |
| struct urb *urb = NULL; |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&es1->cport_out_urb_lock, flags); |
| |
| /* Look in our pool of allocated urbs first, as that's the "fastest" */ |
| for (i = 0; i < NUM_CPORT_OUT_URB; ++i) { |
| if (es1->cport_out_urb_busy[i] == false) { |
| es1->cport_out_urb_busy[i] = true; |
| urb = es1->cport_out_urb[i]; |
| break; |
| } |
| } |
| spin_unlock_irqrestore(&es1->cport_out_urb_lock, flags); |
| if (urb) |
| return urb; |
| |
| /* |
| * Crap, pool is empty, complain to the syslog and go allocate one |
| * dynamically as we have to succeed. |
| */ |
| dev_err(&es1->usb_dev->dev, |
| "No free CPort OUT urbs, having to dynamically allocate one!\n"); |
| urb = usb_alloc_urb(0, gfp_mask); |
| if (!urb) |
| return NULL; |
| |
| return urb; |
| } |
| |
| /* |
| * Returns an opaque cookie value if successful, or a pointer coded |
| * error otherwise. If the caller wishes to cancel the in-flight |
| * buffer, it must supply the returned cookie to the cancel routine. |
| */ |
| static void *buffer_send(struct greybus_host_device *hd, u16 dest_cport_id, |
| void *buffer, size_t buffer_size, gfp_t gfp_mask) |
| { |
| struct es1_ap_dev *es1 = hd_to_es1(hd); |
| struct usb_device *udev = es1->usb_dev; |
| u8 *transfer_buffer = buffer; |
| int transfer_buffer_size; |
| int retval; |
| struct urb *urb; |
| |
| if (!buffer) { |
| pr_err("null buffer supplied to send\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| if (buffer_size > (size_t)INT_MAX) { |
| pr_err("bad buffer size (%zu) supplied to send\n", buffer_size); |
| return ERR_PTR(-EINVAL); |
| } |
| transfer_buffer--; |
| transfer_buffer_size = buffer_size + 1; |
| |
| /* |
| * The data actually transferred will include an indication |
| * of where the data should be sent. Do one last check of |
| * the target CPort id before filling it in. |
| */ |
| if (dest_cport_id == CPORT_ID_BAD) { |
| pr_err("request to send inbound data buffer\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| if (dest_cport_id > (u16)U8_MAX) { |
| pr_err("dest_cport_id (%hd) is out of range for ES1\n", |
| dest_cport_id); |
| return ERR_PTR(-EINVAL); |
| } |
| /* OK, the destination is fine; record it in the transfer buffer */ |
| *transfer_buffer = dest_cport_id; |
| |
| /* Find a free urb */ |
| urb = next_free_urb(es1, gfp_mask); |
| if (!urb) |
| return ERR_PTR(-ENOMEM); |
| |
| usb_fill_bulk_urb(urb, udev, |
| usb_sndbulkpipe(udev, es1->cport_out_endpoint), |
| transfer_buffer, transfer_buffer_size, |
| cport_out_callback, hd); |
| retval = usb_submit_urb(urb, gfp_mask); |
| if (retval) { |
| pr_err("error %d submitting URB\n", retval); |
| return ERR_PTR(retval); |
| } |
| |
| return conceal_urb(urb); |
| } |
| |
| static void buffer_cancel(void *cookie) |
| { |
| struct urb *urb = reveal_urb(cookie); |
| |
| /* |
| * We really should be defensive and track all outstanding |
| * (sent) buffers rather than trusting the cookie provided |
| * is valid. For the time being, this will do. |
| */ |
| usb_kill_urb(urb); |
| } |
| |
| static struct greybus_host_driver es1_driver = { |
| .hd_priv_size = sizeof(struct es1_ap_dev), |
| .buffer_send = buffer_send, |
| .buffer_cancel = buffer_cancel, |
| .submit_svc = submit_svc, |
| }; |
| |
| /* Common function to report consistent warnings based on URB status */ |
| static int check_urb_status(struct urb *urb) |
| { |
| struct device *dev = &urb->dev->dev; |
| int status = urb->status; |
| |
| switch (status) { |
| case 0: |
| return 0; |
| |
| case -EOVERFLOW: |
| dev_err(dev, "%s: overflow actual length is %d\n", |
| __func__, urb->actual_length); |
| case -ECONNRESET: |
| case -ENOENT: |
| case -ESHUTDOWN: |
| case -EILSEQ: |
| case -EPROTO: |
| /* device is gone, stop sending */ |
| return status; |
| } |
| dev_err(dev, "%s: unknown status %d\n", __func__, status); |
| |
| return -EAGAIN; |
| } |
| |
| static void ap_disconnect(struct usb_interface *interface) |
| { |
| struct es1_ap_dev *es1; |
| int i; |
| |
| es1 = usb_get_intfdata(interface); |
| if (!es1) |
| return; |
| |
| /* Tear down everything! */ |
| for (i = 0; i < NUM_CPORT_OUT_URB; ++i) { |
| struct urb *urb = es1->cport_out_urb[i]; |
| |
| if (!urb) |
| break; |
| usb_kill_urb(urb); |
| usb_free_urb(urb); |
| es1->cport_out_urb[i] = NULL; |
| es1->cport_out_urb_busy[i] = false; /* just to be anal */ |
| } |
| |
| for (i = 0; i < NUM_CPORT_IN_URB; ++i) { |
| struct urb *urb = es1->cport_in_urb[i]; |
| |
| if (!urb) |
| break; |
| usb_kill_urb(urb); |
| usb_free_urb(urb); |
| kfree(es1->cport_in_buffer[i]); |
| es1->cport_in_buffer[i] = NULL; |
| } |
| |
| usb_kill_urb(es1->svc_urb); |
| usb_free_urb(es1->svc_urb); |
| es1->svc_urb = NULL; |
| kfree(es1->svc_buffer); |
| es1->svc_buffer = NULL; |
| |
| usb_set_intfdata(interface, NULL); |
| greybus_remove_hd(es1->hd); |
| |
| usb_put_dev(es1->usb_dev); |
| } |
| |
| /* Callback for when we get a SVC message */ |
| static void svc_in_callback(struct urb *urb) |
| { |
| struct greybus_host_device *hd = urb->context; |
| struct device *dev = &urb->dev->dev; |
| int status = check_urb_status(urb); |
| int retval; |
| |
| if (status) { |
| if (status == -EAGAIN) |
| goto exit; |
| dev_err(dev, "urb svc in error %d (dropped)\n", status); |
| return; |
| } |
| |
| /* We have a message, create a new message structure, add it to the |
| * list, and wake up our thread that will process the messages. |
| */ |
| greybus_svc_in(hd, urb->transfer_buffer, urb->actual_length); |
| |
| exit: |
| /* resubmit the urb to get more messages */ |
| retval = usb_submit_urb(urb, GFP_ATOMIC); |
| if (retval) |
| dev_err(dev, "Can not submit urb for AP data: %d\n", retval); |
| } |
| |
| static void cport_in_callback(struct urb *urb) |
| { |
| struct greybus_host_device *hd = urb->context; |
| struct device *dev = &urb->dev->dev; |
| int status = check_urb_status(urb); |
| int retval; |
| u16 cport_id; |
| u8 *data; |
| |
| if (status) { |
| if (status == -EAGAIN) |
| goto exit; |
| dev_err(dev, "urb cport in error %d (dropped)\n", status); |
| return; |
| } |
| |
| /* The size has to be at least one, for the cport id */ |
| if (!urb->actual_length) { |
| dev_err(dev, "%s: no cport id in input buffer?\n", __func__); |
| goto exit; |
| } |
| |
| /* |
| * The CPort number is the first byte of the data stream, the rest of |
| * the stream is "real" data |
| */ |
| data = urb->transfer_buffer; |
| cport_id = (u16)data[0]; |
| data = &data[1]; |
| |
| /* Pass this data to the greybus core */ |
| greybus_data_rcvd(hd, cport_id, data, urb->actual_length - 1); |
| |
| exit: |
| /* put our urb back in the request pool */ |
| retval = usb_submit_urb(urb, GFP_ATOMIC); |
| if (retval) |
| dev_err(dev, "%s: error %d in submitting urb.\n", |
| __func__, retval); |
| } |
| |
| static void cport_out_callback(struct urb *urb) |
| { |
| struct greybus_host_device *hd = urb->context; |
| struct es1_ap_dev *es1 = hd_to_es1(hd); |
| unsigned long flags; |
| int status = check_urb_status(urb); |
| u8 *data = urb->transfer_buffer + 1; |
| int i; |
| |
| /* |
| * Tell the submitter that the buffer send (attempt) is |
| * complete, and report the status. The submitter's buffer |
| * starts after the one-byte CPort id we inserted. |
| */ |
| data = urb->transfer_buffer + 1; |
| greybus_data_sent(hd, data, status); |
| |
| /* |
| * See if this was an urb in our pool, if so mark it "free", otherwise |
| * we need to free it ourselves. |
| */ |
| spin_lock_irqsave(&es1->cport_out_urb_lock, flags); |
| for (i = 0; i < NUM_CPORT_OUT_URB; ++i) { |
| if (urb == es1->cport_out_urb[i]) { |
| es1->cport_out_urb_busy[i] = false; |
| urb = NULL; |
| break; |
| } |
| } |
| spin_unlock_irqrestore(&es1->cport_out_urb_lock, flags); |
| |
| /* If urb is not NULL, then we need to free this urb */ |
| usb_free_urb(urb); |
| |
| /* |
| * Rest assured Greg, this craziness is getting fixed. |
| * |
| * Yes, you are right, we aren't telling anyone that the urb finished. |
| * "That's crazy! How does this all even work?" you might be saying. |
| * The "magic" is the idea that greybus works on the "operation" level, |
| * not the "send a buffer" level. All operations are "round-trip" with |
| * a response from the device that the operation finished, or it will |
| * time out. Because of that, we don't care that this urb finished, or |
| * failed, or did anything else, as higher levels of the protocol stack |
| * will handle completions and timeouts and the rest. |
| * |
| * This protocol is "needed" due to some hardware restrictions on the |
| * current generation of Unipro controllers. Think about it for a |
| * minute, this is a USB driver, talking to a Unipro bridge, impedance |
| * mismatch is huge, yet the Unipro controller are even more |
| * underpowered than this little USB controller. We rely on the round |
| * trip to keep stalls in the Unipro controllers from happening so that |
| * we can keep data flowing properly, no matter how slow it might be. |
| * |
| * Once again, a wonderful bus protocol cut down in its prime by a naive |
| * controller chip. We dream of the day we have a "real" HCD for |
| * Unipro. Until then, we suck it up and make the hardware work, as |
| * that's the job of the firmware and kernel. |
| * </rant> |
| */ |
| } |
| |
| /* |
| * The ES1 USB Bridge device contains 4 endpoints |
| * 1 Control - usual USB stuff + AP -> SVC messages |
| * 1 Interrupt IN - SVC -> AP messages |
| * 1 Bulk IN - CPort data in |
| * 1 Bulk OUT - CPort data out |
| */ |
| static int ap_probe(struct usb_interface *interface, |
| const struct usb_device_id *id) |
| { |
| struct es1_ap_dev *es1; |
| struct greybus_host_device *hd; |
| struct usb_device *udev; |
| struct usb_host_interface *iface_desc; |
| struct usb_endpoint_descriptor *endpoint; |
| bool int_in_found = false; |
| bool bulk_in_found = false; |
| bool bulk_out_found = false; |
| int retval = -ENOMEM; |
| int i; |
| u8 svc_interval = 0; |
| |
| udev = usb_get_dev(interface_to_usbdev(interface)); |
| |
| hd = greybus_create_hd(&es1_driver, &udev->dev); |
| if (!hd) { |
| usb_put_dev(udev); |
| return -ENOMEM; |
| } |
| |
| /* Fill in the buffer allocation constraints */ |
| hd_buffer_constraints(hd); |
| |
| es1 = hd_to_es1(hd); |
| es1->hd = hd; |
| es1->usb_intf = interface; |
| es1->usb_dev = udev; |
| spin_lock_init(&es1->cport_out_urb_lock); |
| usb_set_intfdata(interface, es1); |
| |
| /* Control endpoint is the pipe to talk to this AP, so save it off */ |
| endpoint = &udev->ep0.desc; |
| es1->control_endpoint = endpoint->bEndpointAddress; |
| |
| /* find all 3 of our endpoints */ |
| iface_desc = interface->cur_altsetting; |
| for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) { |
| endpoint = &iface_desc->endpoint[i].desc; |
| |
| if (usb_endpoint_is_int_in(endpoint)) { |
| es1->svc_endpoint = endpoint->bEndpointAddress; |
| svc_interval = endpoint->bInterval; |
| int_in_found = true; |
| } else if (usb_endpoint_is_bulk_in(endpoint)) { |
| es1->cport_in_endpoint = endpoint->bEndpointAddress; |
| bulk_in_found = true; |
| } else if (usb_endpoint_is_bulk_out(endpoint)) { |
| es1->cport_out_endpoint = endpoint->bEndpointAddress; |
| bulk_out_found = true; |
| } else { |
| dev_err(&udev->dev, |
| "Unknown endpoint type found, address %x\n", |
| endpoint->bEndpointAddress); |
| } |
| } |
| if ((int_in_found == false) || |
| (bulk_in_found == false) || |
| (bulk_out_found == false)) { |
| dev_err(&udev->dev, "Not enough endpoints found in device, aborting!\n"); |
| goto error; |
| } |
| |
| /* Create our buffer and URB to get SVC messages, and start it up */ |
| es1->svc_buffer = kmalloc(ES1_SVC_MSG_SIZE, GFP_KERNEL); |
| if (!es1->svc_buffer) |
| goto error; |
| |
| es1->svc_urb = usb_alloc_urb(0, GFP_KERNEL); |
| if (!es1->svc_urb) |
| goto error; |
| |
| usb_fill_int_urb(es1->svc_urb, udev, |
| usb_rcvintpipe(udev, es1->svc_endpoint), |
| es1->svc_buffer, ES1_SVC_MSG_SIZE, svc_in_callback, |
| hd, svc_interval); |
| retval = usb_submit_urb(es1->svc_urb, GFP_KERNEL); |
| if (retval) |
| goto error; |
| |
| /* Allocate buffers for our cport in messages and start them up */ |
| for (i = 0; i < NUM_CPORT_IN_URB; ++i) { |
| struct urb *urb; |
| u8 *buffer; |
| |
| urb = usb_alloc_urb(0, GFP_KERNEL); |
| if (!urb) |
| goto error; |
| buffer = kmalloc(ES1_GBUF_MSG_SIZE_MAX, GFP_KERNEL); |
| if (!buffer) |
| goto error; |
| |
| usb_fill_bulk_urb(urb, udev, |
| usb_rcvbulkpipe(udev, es1->cport_in_endpoint), |
| buffer, ES1_GBUF_MSG_SIZE_MAX, |
| cport_in_callback, hd); |
| es1->cport_in_urb[i] = urb; |
| es1->cport_in_buffer[i] = buffer; |
| retval = usb_submit_urb(urb, GFP_KERNEL); |
| if (retval) |
| goto error; |
| } |
| |
| /* Allocate urbs for our CPort OUT messages */ |
| for (i = 0; i < NUM_CPORT_OUT_URB; ++i) { |
| struct urb *urb; |
| |
| urb = usb_alloc_urb(0, GFP_KERNEL); |
| if (!urb) |
| goto error; |
| |
| es1->cport_out_urb[i] = urb; |
| es1->cport_out_urb_busy[i] = false; /* just to be anal */ |
| } |
| |
| return 0; |
| error: |
| ap_disconnect(interface); |
| |
| return retval; |
| } |
| |
| static struct usb_driver es1_ap_driver = { |
| .name = "es1_ap_driver", |
| .probe = ap_probe, |
| .disconnect = ap_disconnect, |
| .id_table = id_table, |
| }; |
| |
| module_usb_driver(es1_ap_driver); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>"); |