Add USB device support

This patch adds support for USB devices. It uses
the Linux Kernel gadget API. Along with this patch
comes driver support for the Freescale (arc) USB OTG
Core and USB Device Firmware Update (DFU)
The serial gadget support is not working at the moment.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 530 insertions, 0 deletions

diff --git a/drivers/usb/gadget/u_serial.c b/drivers/usb/gadget/u_serial.c
new file mode 100644
index 0000000000..80cbf44f7a
--- /dev/null
+++ b/drivers/usb/gadget/u_serial.c
@@ -0,0 +1,530 @@
+/*
+ * u_serial.c - utilities for USB gadget "serial port"/TTY support
+ *
+ * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
+ * Copyright (C) 2008 David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ *
+ * This code also borrows from usbserial.c, which is
+ * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
+ * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
+ * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
+ *
+ * This software is distributed under the terms of the GNU General
+ * Public License ("GPL") as published by the Free Software Foundation,
+ * either version 2 of that License or (at your option) any later version.
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <common.h>
+#include <usb/cdc.h>
+#include <kfifo.h>
+
+#include "u_serial.h"
+
+
+/*
+ * This component encapsulates the TTY layer glue needed to provide basic
+ * "serial port" functionality through the USB gadget stack.  Each such
+ * port is exposed through a /dev/ttyGS* node.
+ *
+ * After initialization (gserial_setup), these TTY port devices stay
+ * available until they are removed (gserial_cleanup).  Each one may be
+ * connected to a USB function (gserial_connect), or disconnected (with
+ * gserial_disconnect) when the USB host issues a config change event.
+ * Data can only flow when the port is connected to the host.
+ *
+ * A given TTY port can be made available in multiple configurations.
+ * For example, each one might expose a ttyGS0 node which provides a
+ * login application.  In one case that might use CDC ACM interface 0,
+ * while another configuration might use interface 3 for that.  The
+ * work to handle that (including descriptor management) is not part
+ * of this component.
+ *
+ * Configurations may expose more than one TTY port.  For example, if
+ * ttyGS0 provides login service, then ttyGS1 might provide dialer access
+ * for a telephone or fax link.  And ttyGS2 might be something that just
+ * needs a simple byte stream interface for some messaging protocol that
+ * is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
+ */
+
+#define PREFIX	"ttyGS"
+
+/*
+ * gserial is the lifecycle interface, used by USB functions
+ * gs_port is the I/O nexus, used by the tty driver
+ * tty_struct links to the tty/filesystem framework
+ *
+ * gserial <---> gs_port ... links will be null when the USB link is
+ * inactive; managed by gserial_{connect,disconnect}().  each gserial
+ * instance can wrap its own USB control protocol.
+ *	gserial->ioport == usb_ep->driver_data ... gs_port
+ *	gs_port->port_usb ... gserial
+ *
+ * gs_port <---> tty_struct ... links will be null when the TTY file
+ * isn't opened; managed by gs_open()/gs_close()
+ *	gserial->port_tty ... tty_struct
+ *	tty_struct->driver_data ... gserial
+ */
+
+/* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
+ * next layer of buffering.  For TX that's a circular buffer; for RX
+ * consider it a NOP.  A third layer is provided by the TTY code.
+ */
+#define QUEUE_SIZE		16
+#define WRITE_BUF_SIZE		8192		/* TX only */
+
+/*
+ * The port structure holds info for each port, one for each minor number
+ * (and thus for each /dev/ node).
+ */
+struct gs_port {
+
+	struct gserial		*port_usb;
+	struct console_device	cdev;
+	struct kfifo		*recv_fifo;
+
+	unsigned		open_count;
+	int			openclose;	/* open/close in progress */
+	u8			port_num;
+
+	struct list_head	read_pool;
+	unsigned		n_read;
+
+	struct list_head	write_pool;
+
+	/* REVISIT this state ... */
+	struct usb_cdc_line_coding port_line_coding;	/* 8-N-1 etc */
+};
+
+/* increase N_PORTS if you need more */
+#define N_PORTS		4
+static struct portmaster {
+	struct gs_port	*port;
+} ports[N_PORTS];
+static unsigned	n_ports;
+
+#define GS_CLOSE_TIMEOUT		15		/* seconds */
+
+
+
+#ifdef VERBOSE_DEBUG
+#define pr_vdebug(fmt, arg...) \
+	pr_debug(fmt, ##arg)
+#else
+#define pr_vdebug(fmt, arg...) \
+	({ if (0) pr_debug(fmt, ##arg); })
+#endif
+
+static unsigned gs_start_rx(struct gs_port *port)
+{
+	struct list_head	*pool = &port->read_pool;
+	struct usb_ep		*out = port->port_usb->out;
+	unsigned		started = 0;
+
+	while (!list_empty(pool)) {
+		struct usb_request	*req;
+		int			status;
+
+		req = list_entry(pool->next, struct usb_request, list);
+		list_del(&req->list);
+		req->length = out->maxpacket;
+
+		/* drop lock while we call out; the controller driver
+		 * may need to call us back (e.g. for disconnect)
+		 */
+		status = usb_ep_queue(out, req);
+
+		if (status) {
+			pr_debug("%s: %s %s err %d\n",
+					__func__, "queue", out->name, status);
+			list_add(&req->list, pool);
+			break;
+		}
+		started++;
+
+		/* abort immediately after disconnect */
+		if (!port->port_usb)
+			break;
+	}
+	return started;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct gs_port	*port = ep->driver_data;
+
+	if (req->status == -ESHUTDOWN)
+		return;
+
+	kfifo_put(port->recv_fifo, req->buf, req->actual);
+
+	list_add_tail(&req->list, &port->read_pool);
+	gs_start_rx(port);
+}
+
+static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct gs_port	*port = ep->driver_data;
+
+	list_add(&req->list, &port->write_pool);
+
+	switch (req->status) {
+	default:
+		/* presumably a transient fault */
+		pr_warning("%s: unexpected %s status %d\n",
+				__func__, ep->name, req->status);
+		/* FALL THROUGH */
+	case 0:
+		/* normal completion */
+//		gs_start_tx(port);
+		break;
+
+	case -ESHUTDOWN:
+		/* disconnect */
+		pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
+		break;
+	}
+}
+
+/*
+ * gs_alloc_req
+ *
+ * Allocate a usb_request and its buffer.  Returns a pointer to the
+ * usb_request or NULL if there is an error.
+ */
+struct usb_request *
+gs_alloc_req(struct usb_ep *ep, unsigned len)
+{
+	struct usb_request *req;
+
+	req = usb_ep_alloc_request(ep);
+
+	if (req != NULL) {
+		req->length = len;
+		req->buf = memalign(32, len);
+		if (req->buf == NULL) {
+			usb_ep_free_request(ep, req);
+			return NULL;
+		}
+	}
+
+	return req;
+}
+
+static void gs_free_requests(struct usb_ep *ep, struct list_head *head)
+{
+	struct usb_request	*req;
+
+	while (!list_empty(head)) {
+		req = list_entry(head->next, struct usb_request, list);
+		list_del(&req->list);
+		gs_free_req(ep, req);
+	}
+}
+
+static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head,
+		void (*fn)(struct usb_ep *, struct usb_request *))
+{
+	int			i;
+	struct usb_request	*req;
+
+	/* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
+	 * do quite that many this time, don't fail ... we just won't
+	 * be as speedy as we might otherwise be.
+	 */
+	for (i = 0; i < QUEUE_SIZE; i++) {
+		req = gs_alloc_req(ep, ep->maxpacket);
+		if (!req)
+			return list_empty(head) ? -ENOMEM : 0;
+		req->complete = fn;
+		list_add_tail(&req->list, head);
+	}
+	return 0;
+}
+
+/**
+ * gs_start_io - start USB I/O streams
+ * @dev: encapsulates endpoints to use
+ * Context: holding port_lock; port_tty and port_usb are non-null
+ *
+ * We only start I/O when something is connected to both sides of
+ * this port.  If nothing is listening on the host side, we may
+ * be pointlessly filling up our TX buffers and FIFO.
+ */
+static int gs_start_io(struct gs_port *port)
+{
+	struct list_head	*head = &port->read_pool;
+	struct usb_ep		*ep = port->port_usb->out;
+	int			status;
+	unsigned		started;
+
+	/* Allocate RX and TX I/O buffers.  We can't easily do this much
+	 * earlier (with GFP_KERNEL) because the requests are coupled to
+	 * endpoints, as are the packet sizes we'll be using.  Different
+	 * configurations may use different endpoints with a given port;
+	 * and high speed vs full speed changes packet sizes too.
+	 */
+	status = gs_alloc_requests(ep, head, gs_read_complete);
+	if (status)
+		return status;
+
+	status = gs_alloc_requests(port->port_usb->in, &port->write_pool,
+			gs_write_complete);
+	if (status) {
+		gs_free_requests(ep, head);
+		return status;
+	}
+
+	/* queue read requests */
+	port->n_read = 0;
+	started = gs_start_rx(port);
+
+	/* unblock any pending writes into our circular buffer */
+	if (started) {
+//		tty_wakeup(port->port_tty);
+	} else {
+		gs_free_requests(ep, head);
+		gs_free_requests(port->port_usb->in, &port->write_pool);
+		status = -EIO;
+	}
+
+	return status;
+}
+
+/*
+ * gs_free_req
+ *
+ * Free a usb_request and its buffer.
+ */
+void gs_free_req(struct usb_ep *ep, struct usb_request *req)
+{
+	kfree(req->buf);
+	usb_ep_free_request(ep, req);
+}
+
+static int __init
+gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
+{
+	struct gs_port	*port;
+
+	port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
+	if (port == NULL)
+		return -ENOMEM;
+
+	port->port_num = port_num;
+	port->port_line_coding = *coding;
+
+	INIT_LIST_HEAD(&port->read_pool);
+	INIT_LIST_HEAD(&port->write_pool);
+
+	ports[port_num].port = port;
+
+	return 0;
+}
+
+/**
+ * gserial_setup - initialize TTY driver for one or more ports
+ * @g: gadget to associate with these ports
+ * @count: how many ports to support
+ * Context: may sleep
+ *
+ * The TTY stack needs to know in advance how many devices it should
+ * plan to manage.  Use this call to set up the ports you will be
+ * exporting through USB.  Later, connect them to functions based
+ * on what configuration is activated by the USB host; and disconnect
+ * them as appropriate.
+ *
+ * An example would be a two-configuration device in which both
+ * configurations expose port 0, but through different functions.
+ * One configuration could even expose port 1 while the other
+ * one doesn't.
+ *
+ * Returns negative errno or zero.
+ */
+int __init gserial_setup(struct usb_gadget *g, unsigned count)
+{
+	struct usb_cdc_line_coding	coding;
+	int i, status;
+
+	/* make devices be openable */
+	for (i = 0; i < count; i++) {
+		status = gs_port_alloc(i, &coding);
+		if (status) {
+			count = i;
+			goto fail;
+		}
+	}
+	n_ports = count;
+	return 0;
+fail:
+	while (count--)
+		kfree(ports[count].port);
+	return status;
+}
+
+static void serial_putc(struct console_device *cdev, char c)
+{
+	struct gs_port	*port = container_of(cdev,
+					struct gs_port, cdev);
+	struct list_head	*pool = &port->write_pool;
+	struct usb_ep		*in = port->port_usb->in;
+	struct usb_request	*req;
+	int status;
+
+	if (list_empty(pool))
+		return;
+	req = list_entry(pool->next, struct usb_request, list);
+
+	req->length = 1;
+	list_del(&req->list);
+
+	*(unsigned char *)req->buf = c;
+	status = usb_ep_queue(in, req);
+
+	while (list_empty(pool))
+		fsl_udc_irq();
+}
+
+static int serial_tstc(struct console_device *cdev)
+{
+	struct gs_port	*port = container_of(cdev,
+					struct gs_port, cdev);
+
+	return (kfifo_len(port->recv_fifo) == 0) ? 0 : 1;
+}
+
+static int serial_getc(struct console_device *cdev)
+{
+	struct gs_port	*port = container_of(cdev,
+					struct gs_port, cdev);
+	unsigned char ch;
+
+	while (kfifo_getc(port->recv_fifo, &ch));
+
+	return ch;
+}
+
+static void serial_flush(struct console_device *cdev)
+{
+}
+
+static struct console_device *mycdev;
+
+int gserial_connect(struct gserial *gser, u8 port_num)
+{
+	struct gs_port	*port;
+	int		status;
+	struct console_device *cdev;
+
+	printf("%s %p %d\n", __func__, gser, port_num);
+
+	/* we "know" gserial_cleanup() hasn't been called */
+	port = ports[port_num].port;
+
+	/* activate the endpoints */
+	status = usb_ep_enable(gser->in, gser->in_desc);
+	if (status < 0)
+		return status;
+	gser->in->driver_data = port;
+
+	status = usb_ep_enable(gser->out, gser->out_desc);
+	if (status < 0)
+		goto fail_out;
+	gser->out->driver_data = port;
+
+	/* then tell the tty glue that I/O can work */
+	gser->ioport = port;
+	port->port_usb = gser;
+
+	/* REVISIT unclear how best to handle this state...
+	 * we don't really couple it with the Linux TTY.
+	 */
+	gser->port_line_coding = port->port_line_coding;
+
+	port->recv_fifo = kfifo_alloc(1024);
+
+	printf("gserial_connect: start ttyGS%d\n", port->port_num);
+	gs_start_io(port);
+	if (gser->connect)
+		gser->connect(gser);
+
+	cdev = &port->cdev;
+	cdev->f_caps = CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
+	cdev->tstc = serial_tstc;
+	cdev->putc = serial_putc;
+	cdev->getc = serial_getc;
+	cdev->flush = serial_flush;
+	console_register(cdev);
+	mycdev = cdev;
+
+	return status;
+
+fail_out:
+	usb_ep_disable(gser->in);
+	gser->in->driver_data = NULL;
+	return status;
+}
+#include <command.h>
+
+static int do_mycdev (cmd_tbl_t *cmdtp, int argc, char *argv[])
+{
+
+	int i,j;
+	for (i = 'a'; i < 'z'; i++) {
+		mycdev->putc(mycdev, i);
+		printf("%c", i);
+		mdelay(500);
+		for (j = 0; j < 100; j++)
+			fsl_udc_irq();
+	}
+	return 0;
+}
+
+U_BOOT_CMD_START(mycdev)
+	.maxargs	= CONFIG_MAXARGS,
+	.cmd		= do_mycdev,
+U_BOOT_CMD_END
+
+/**
+ * gserial_disconnect - notify TTY I/O glue that USB link is inactive
+ * @gser: the function, on which gserial_connect() was called
+ * Context: any (usually from irq)
+ *
+ * This is called to deactivate endpoints and let the TTY layer know
+ * that the connection went inactive ... not unlike "hangup".
+ *
+ * On return, the state is as if gserial_connect() had never been called;
+ * there is no active USB I/O on these endpoints.
+ */
+void gserial_disconnect(struct gserial *gser)
+{
+	struct gs_port	*port = gser->ioport;
+printf("%s\n", __func__);
+	if (!port)
+		return;
+
+	/* tell the TTY glue not to do I/O here any more */
+
+	/* REVISIT as above: how best to track this? */
+	port->port_line_coding = gser->port_line_coding;
+
+	port->port_usb = NULL;
+	gser->ioport = NULL;
+
+	/* disable endpoints, aborting down any active I/O */
+	usb_ep_disable(gser->out);
+	gser->out->driver_data = NULL;
+
+	usb_ep_disable(gser->in);
+	gser->in->driver_data = NULL;
+
+	/* finally, free any unused/unusable I/O buffers */
+
+	gs_free_requests(gser->out, &port->read_pool);
+	gs_free_requests(gser->in, &port->write_pool);
+}
+