greybus: es2: add ES2 Greybus Host driver

This is just a copy of ES1 for now, things will start to diverge soon.
Any common functionality will be factored out over time.
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/Makefile

@@ -22,6 +22,7 @@ obj-m += gb-phy.o
 obj-m += gb-vibrator.o
 obj-m += gb-battery.o
 obj-m += gb-es1.o
+obj-m += gb-es2.o
 
 KERNELVER		?= $(shell uname -r)
 KERNELDIR 		?= /lib/modules/$(KERNELVER)/build

drivers/staging/greybus/gb-es2.c

+/*
+ * 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>");