1 files changed, 571 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
new file mode 100644
index 000000000000..4557cd03f0b1
--- /dev/null
+++ b/drivers/usb/gadget/function/f_loopback.c
@@ -0,0 +1,571 @@
+/*
+ * f_loopback.c - USB peripheral loopback configuration driver
+ *
+ * Copyright (C) 2003-2008 David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/usb/composite.h>
+
+#include "g_zero.h"
+#include "u_f.h"
+
+/*
+ * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
+ *
+ * This takes messages of various sizes written OUT to a device, and loops
+ * them back so they can be read IN from it.  It has been used by certain
+ * test applications.  It supports limited testing of data queueing logic.
+ *
+ *
+ * This is currently packaged as a configuration driver, which can't be
+ * combined with other functions to make composite devices.  However, it
+ * can be combined with other independent configurations.
+ */
+struct f_loopback {
+        struct usb_function     function;
+
+        struct usb_ep           *in_ep;
+        struct usb_ep           *out_ep;
+};
+
+static inline struct f_loopback *func_to_loop(struct usb_function *f)
+{
+        return container_of(f, struct f_loopback, function);
+}
+
+static unsigned qlen;
+static unsigned buflen;
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_interface_descriptor loopback_intf = {
+        .bLength =              sizeof loopback_intf,
+        .bDescriptorType =      USB_DT_INTERFACE,
+
+        .bNumEndpoints =        2,
+        .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
+        /* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor fs_loop_source_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bEndpointAddress =     USB_DIR_IN,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor fs_loop_sink_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bEndpointAddress =     USB_DIR_OUT,
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_loopback_descs[] = {
+        (struct usb_descriptor_header *) &loopback_intf,
+        (struct usb_descriptor_header *) &fs_loop_sink_desc,
+        (struct usb_descriptor_header *) &fs_loop_source_desc,
+        NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor hs_loop_source_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor hs_loop_sink_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *hs_loopback_descs[] = {
+        (struct usb_descriptor_header *) &loopback_intf,
+        (struct usb_descriptor_header *) &hs_loop_source_desc,
+        (struct usb_descriptor_header *) &hs_loop_sink_desc,
+        NULL,
+};
+
+/* super speed support: */
+
+static struct usb_endpoint_descriptor ss_loop_source_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
+        .bLength =              USB_DT_SS_EP_COMP_SIZE,
+        .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
+        .bMaxBurst =            0,
+        .bmAttributes =         0,
+        .wBytesPerInterval =    0,
+};
+
+static struct usb_endpoint_descriptor ss_loop_sink_desc = {
+        .bLength =              USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType =      USB_DT_ENDPOINT,
+
+        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize =       cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
+        .bLength =              USB_DT_SS_EP_COMP_SIZE,
+        .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
+        .bMaxBurst =            0,
+        .bmAttributes =         0,
+        .wBytesPerInterval =    0,
+};
+
+static struct usb_descriptor_header *ss_loopback_descs[] = {
+        (struct usb_descriptor_header *) &loopback_intf,
+        (struct usb_descriptor_header *) &ss_loop_source_desc,
+        (struct usb_descriptor_header *) &ss_loop_source_comp_desc,
+        (struct usb_descriptor_header *) &ss_loop_sink_desc,
+        (struct usb_descriptor_header *) &ss_loop_sink_comp_desc,
+        NULL,
+};
+
+/* function-specific strings: */
+
+static struct usb_string strings_loopback[] = {
+        [0].s = "loop input to output",
+        {  }                    /* end of list */
+};
+
+static struct usb_gadget_strings stringtab_loop = {
+        .language       = 0x0409,       /* en-us */
+        .strings        = strings_loopback,
+};
+
+static struct usb_gadget_strings *loopback_strings[] = {
+        &stringtab_loop,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        struct f_loopback       *loop = func_to_loop(f);
+        int                     id;
+        int ret;
+
+        /* allocate interface ID(s) */
+        id = usb_interface_id(c, f);
+        if (id < 0)
+                return id;
+        loopback_intf.bInterfaceNumber = id;
+
+        id = usb_string_id(cdev);
+        if (id < 0)
+                return id;
+        strings_loopback[0].id = id;
+        loopback_intf.iInterface = id;
+
+        /* allocate endpoints */
+
+        loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
+        if (!loop->in_ep) {
+autoconf_fail:
+                ERROR(cdev, "%s: can't autoconfigure on %s\n",
+                        f->name, cdev->gadget->name);
+                return -ENODEV;
+        }
+        loop->in_ep->driver_data = cdev;        /* claim */
+
+        loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
+        if (!loop->out_ep)
+                goto autoconf_fail;
+        loop->out_ep->driver_data = cdev;       /* claim */
+
+        /* support high speed hardware */
+        hs_loop_source_desc.bEndpointAddress =
+                fs_loop_source_desc.bEndpointAddress;
+        hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
+
+        /* support super speed hardware */
+        ss_loop_source_desc.bEndpointAddress =
+                fs_loop_source_desc.bEndpointAddress;
+        ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
+
+        ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
+                        ss_loopback_descs);
+        if (ret)
+                return ret;
+
+        DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
+            (gadget_is_superspeed(c->cdev->gadget) ? "super" :
+             (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
+                        f->name, loop->in_ep->name, loop->out_ep->name);
+        return 0;
+}
+
+static void lb_free_func(struct usb_function *f)
+{
+        struct f_lb_opts *opts;
+
+        opts = container_of(f->fi, struct f_lb_opts, func_inst);
+
+        mutex_lock(&opts->lock);
+        opts->refcnt--;
+        mutex_unlock(&opts->lock);
+
+        usb_free_all_descriptors(f);
+        kfree(func_to_loop(f));
+}
+
+static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
+{
+        struct f_loopback       *loop = ep->driver_data;
+        struct usb_composite_dev *cdev = loop->function.config->cdev;
+        int                     status = req->status;
+
+        switch (status) {
+
+        case 0:                         /* normal completion? */
+                if (ep == loop->out_ep) {
+                        /* loop this OUT packet back IN to the host */
+                        req->zero = (req->actual < req->length);
+                        req->length = req->actual;
+                        status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
+                        if (status == 0)
+                                return;
+
+                        /* "should never get here" */
+                        ERROR(cdev, "can't loop %s to %s: %d\n",
+                                ep->name, loop->in_ep->name,
+                                status);
+                }
+
+                /* queue the buffer for some later OUT packet */
+                req->length = buflen;
+                status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
+                if (status == 0)
+                        return;
+
+                /* "should never get here" */
+                /* FALLTHROUGH */
+
+        default:
+                ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
+                                status, req->actual, req->length);
+                /* FALLTHROUGH */
+
+        /* NOTE:  since this driver doesn't maintain an explicit record
+         * of requests it submitted (just maintains qlen count), we
+         * rely on the hardware driver to clean up on disconnect or
+         * endpoint disable.
+         */
+        case -ECONNABORTED:             /* hardware forced ep reset */
+        case -ECONNRESET:               /* request dequeued */
+        case -ESHUTDOWN:                /* disconnect from host */
+                free_ep_req(ep, req);
+                return;
+        }
+}
+
+static void disable_loopback(struct f_loopback *loop)
+{
+        struct usb_composite_dev        *cdev;
+
+        cdev = loop->function.config->cdev;
+        disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
+        VDBG(cdev, "%s disabled\n", loop->function.name);
+}
+
+static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
+{
+        return alloc_ep_req(ep, len, buflen);
+}
+
+static int
+enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
+{
+        int                                     result = 0;
+        struct usb_ep                           *ep;
+        struct usb_request                      *req;
+        unsigned                                i;
+
+        /* one endpoint writes data back IN to the host */
+        ep = loop->in_ep;
+        result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+        if (result)
+                return result;
+        result = usb_ep_enable(ep);
+        if (result < 0)
+                return result;
+        ep->driver_data = loop;
+
+        /* one endpoint just reads OUT packets */
+        ep = loop->out_ep;
+        result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+        if (result)
+                goto fail0;
+
+        result = usb_ep_enable(ep);
+        if (result < 0) {
+fail0:
+                ep = loop->in_ep;
+                usb_ep_disable(ep);
+                ep->driver_data = NULL;
+                return result;
+        }
+        ep->driver_data = loop;
+
+        /* allocate a bunch of read buffers and queue them all at once.
+         * we buffer at most 'qlen' transfers; fewer if any need more
+         * than 'buflen' bytes each.
+         */
+        for (i = 0; i < qlen && result == 0; i++) {
+                req = lb_alloc_ep_req(ep, 0);
+                if (req) {
+                        req->complete = loopback_complete;
+                        result = usb_ep_queue(ep, req, GFP_ATOMIC);
+                        if (result)
+                                ERROR(cdev, "%s queue req --> %d\n",
+                                                ep->name, result);
+                } else {
+                        usb_ep_disable(ep);
+                        ep->driver_data = NULL;
+                        result = -ENOMEM;
+                        goto fail0;
+                }
+        }
+
+        DBG(cdev, "%s enabled\n", loop->function.name);
+        return result;
+}
+
+static int loopback_set_alt(struct usb_function *f,
+                unsigned intf, unsigned alt)
+{
+        struct f_loopback       *loop = func_to_loop(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+
+        /* we know alt is zero */
+        if (loop->in_ep->driver_data)
+                disable_loopback(loop);
+        return enable_loopback(cdev, loop);
+}
+
+static void loopback_disable(struct usb_function *f)
+{
+        struct f_loopback       *loop = func_to_loop(f);
+
+        disable_loopback(loop);
+}
+
+static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
+{
+        struct f_loopback       *loop;
+        struct f_lb_opts        *lb_opts;
+
+        loop = kzalloc(sizeof *loop, GFP_KERNEL);
+        if (!loop)
+                return ERR_PTR(-ENOMEM);
+
+        lb_opts = container_of(fi, struct f_lb_opts, func_inst);
+
+        mutex_lock(&lb_opts->lock);
+        lb_opts->refcnt++;
+        mutex_unlock(&lb_opts->lock);
+
+        buflen = lb_opts->bulk_buflen;
+        qlen = lb_opts->qlen;
+        if (!qlen)
+                qlen = 32;
+
+        loop->function.name = "loopback";
+        loop->function.bind = loopback_bind;
+        loop->function.set_alt = loopback_set_alt;
+        loop->function.disable = loopback_disable;
+        loop->function.strings = loopback_strings;
+
+        loop->function.free_func = lb_free_func;
+
+        return &loop->function;
+}
+
+static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
+{
+        return container_of(to_config_group(item), struct f_lb_opts,
+                            func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_lb_opts);
+CONFIGFS_ATTR_OPS(f_lb_opts);
+
+static void lb_attr_release(struct config_item *item)
+{
+        struct f_lb_opts *lb_opts = to_f_lb_opts(item);
+
+        usb_put_function_instance(&lb_opts->func_inst);
+}
+
+static struct configfs_item_operations lb_item_ops = {
+        .release                = lb_attr_release,
+        .show_attribute         = f_lb_opts_attr_show,
+        .store_attribute        = f_lb_opts_attr_store,
+};
+
+static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page)
+{
+        int result;
+
+        mutex_lock(&opts->lock);
+        result = sprintf(page, "%d", opts->qlen);
+        mutex_unlock(&opts->lock);
+
+        return result;
+}
+
+static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts,
+                                    const char *page, size_t len)
+{
+        int ret;
+        u32 num;
+
+        mutex_lock(&opts->lock);
+        if (opts->refcnt) {
+                ret = -EBUSY;
+                goto end;
+        }
+
+        ret = kstrtou32(page, 0, &num);
+        if (ret)
+                goto end;
+
+        opts->qlen = num;
+        ret = len;
+end:
+        mutex_unlock(&opts->lock);
+        return ret;
+}
+
+static struct f_lb_opts_attribute f_lb_opts_qlen =
+        __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR,
+                        f_lb_opts_qlen_show,
+                        f_lb_opts_qlen_store);
+
+static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page)
+{
+        int result;
+
+        mutex_lock(&opts->lock);
+        result = sprintf(page, "%d", opts->bulk_buflen);
+        mutex_unlock(&opts->lock);
+
+        return result;
+}
+
+static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts,
+                                    const char *page, size_t len)
+{
+        int ret;
+        u32 num;
+
+        mutex_lock(&opts->lock);
+        if (opts->refcnt) {
+                ret = -EBUSY;
+                goto end;
+        }
+
+        ret = kstrtou32(page, 0, &num);
+        if (ret)
+                goto end;
+
+        opts->bulk_buflen = num;
+        ret = len;
+end:
+        mutex_unlock(&opts->lock);
+        return ret;
+}
+
+static struct f_lb_opts_attribute f_lb_opts_bulk_buflen =
+        __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR,
+                        f_lb_opts_bulk_buflen_show,
+                        f_lb_opts_bulk_buflen_store);
+
+static struct configfs_attribute *lb_attrs[] = {
+        &f_lb_opts_qlen.attr,
+        &f_lb_opts_bulk_buflen.attr,
+        NULL,
+};
+
+static struct config_item_type lb_func_type = {
+        .ct_item_ops    = &lb_item_ops,
+        .ct_attrs       = lb_attrs,
+        .ct_owner       = THIS_MODULE,
+};
+
+static void lb_free_instance(struct usb_function_instance *fi)
+{
+        struct f_lb_opts *lb_opts;
+
+        lb_opts = container_of(fi, struct f_lb_opts, func_inst);
+        kfree(lb_opts);
+}
+
+static struct usb_function_instance *loopback_alloc_instance(void)
+{
+        struct f_lb_opts *lb_opts;
+
+        lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
+        if (!lb_opts)
+                return ERR_PTR(-ENOMEM);
+        mutex_init(&lb_opts->lock);
+        lb_opts->func_inst.free_func_inst = lb_free_instance;
+        lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
+        lb_opts->qlen = GZERO_QLEN;
+
+        config_group_init_type_name(&lb_opts->func_inst.group, "",
+                                    &lb_func_type);
+
+        return  &lb_opts->func_inst;
+}
+DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
+
+int __init lb_modinit(void)
+{
+        int ret;
+
+        ret = usb_function_register(&Loopbackusb_func);
+        if (ret)
+                return ret;
+        return ret;
+}
+void __exit lb_modexit(void)
+{
+        usb_function_unregister(&Loopbackusb_func);
+}
+
+MODULE_LICENSE("GPL");