--- /dev/null
+/*
+ * Greybus "AP" USB driver for "ES2" controller chips
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * 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;
+ BUILD_BUG_ON(hd->buffer_headroom > GB_BUFFER_HEADROOM_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");
+ return usb_alloc_urb(0, gfp_mask);
+}
+
+static void free_urb(struct es1_ap_dev *es1, struct urb *urb)
+{
+ unsigned long flags;
+ int i;
+ /*
+ * 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);
+}
+
+/*
+ * 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 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 (cport_id == CPORT_ID_BAD) {
+ pr_err("request to send inbound data buffer\n");
+ return ERR_PTR(-EINVAL);
+ }
+ if (cport_id > (u16)U8_MAX) {
+ pr_err("cport_id (%hd) is out of range for ES1\n", cport_id);
+ return ERR_PTR(-EINVAL);
+ }
+ /* OK, the destination is fine; record it in the transfer buffer */
+ *transfer_buffer = 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);
+ free_urb(es1, urb);
+ return ERR_PTR(retval);
+ }
+
+ return conceal_urb(urb);
+}
+
+/*
+ * The cookie value supplied is the value that buffer_send()
+ * returned to its caller. It identifies the buffer that should be
+ * canceled. This function must also handle (which is to say,
+ * ignore) a null cookie value.
+ */
+static void buffer_cancel(void *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.
+ */
+ if (cookie)
+ usb_kill_urb(reveal_urb(cookie));
+}
+
+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;
+ struct usb_device *udev;
+ 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);
+ udev = es1->usb_dev;
+ greybus_remove_hd(es1->hd);
+
+ usb_put_dev(udev);
+}
+
+/* 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) || (status == -EPROTO))
+ 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) || (status == -EPROTO))
+ 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;
+ }
+
+ /*
+ * Our 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);
+ int status = check_urb_status(urb);
+ u8 *data = urb->transfer_buffer + 1;
+
+ /*
+ * 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);
+
+ free_urb(es1, 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>");
projects / platform / kernel / linux-starfive.git / commitdiff