USB: gadget: add HID gadget driver

g_hid is a USB gadget driver implementing the Human Interface Device class
specification. The driver handles basic HID protocol handling in the
kernel, and allows userspace to read/write HID reports trough /dev/hidgX
character devices.

Signed-off-by: Fabien Chouteau <fabien.chouteau@barco.com>
Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 673 insertions, 0 deletions

diff --git a/drivers/usb/gadget/f_hid.c b/drivers/usb/gadget/f_hid.c
new file mode 100644
index 000000000000..1e00ff9866af
--- /dev/null
+++ b/drivers/usb/gadget/f_hid.c
@@ -0,0 +1,673 @@
+/*
+ * f_hid.c -- USB HID function driver
+ *
+ * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/utsname.h>
+#include <linux/module.h>
+#include <linux/hid.h>
+#include <linux/cdev.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/smp_lock.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/usb/g_hid.h>
+
+static int major, minors;
+static struct class *hidg_class;
+
+/*-------------------------------------------------------------------------*/
+/*                            HID gadget struct                            */
+
+struct f_hidg {
+        /* configuration */
+        unsigned char                   bInterfaceSubClass;
+        unsigned char                   bInterfaceProtocol;
+        unsigned short                  report_desc_length;
+        char                            *report_desc;
+        unsigned short                  report_length;
+
+        /* recv report */
+        char                            *set_report_buff;
+        unsigned short                  set_report_length;
+        spinlock_t                      spinlock;
+        wait_queue_head_t               read_queue;
+
+        /* send report */
+        struct mutex                    lock;
+        bool                            write_pending;
+        wait_queue_head_t               write_queue;
+        struct usb_request              *req;
+
+        int                             minor;
+        struct cdev                     cdev;
+        struct usb_function             func;
+        struct usb_ep                   *in_ep;
+        struct usb_endpoint_descriptor  *fs_in_ep_desc;
+        struct usb_endpoint_descriptor  *hs_in_ep_desc;
+};
+
+static inline struct f_hidg *func_to_hidg(struct usb_function *f)
+{
+        return container_of(f, struct f_hidg, func);
+}
+
+/*-------------------------------------------------------------------------*/
+/*                           Static descriptors                            */
+
+static struct usb_interface_descriptor hidg_interface_desc = {
+        .bLength                = sizeof hidg_interface_desc,
+        .bDescriptorType        = USB_DT_INTERFACE,
+        /* .bInterfaceNumber    = DYNAMIC */
+        .bAlternateSetting      = 0,
+        .bNumEndpoints          = 1,
+        .bInterfaceClass        = USB_CLASS_HID,
+        /* .bInterfaceSubClass  = DYNAMIC */
+        /* .bInterfaceProtocol  = DYNAMIC */
+        /* .iInterface          = DYNAMIC */
+};
+
+static struct hid_descriptor hidg_desc = {
+        .bLength                        = sizeof hidg_desc,
+        .bDescriptorType                = HID_DT_HID,
+        .bcdHID                         = 0x0101,
+        .bCountryCode                   = 0x00,
+        .bNumDescriptors                = 0x1,
+        /*.desc[0].bDescriptorType      = DYNAMIC */
+        /*.desc[0].wDescriptorLenght    = DYNAMIC */
+};
+
+/* High-Speed Support */
+
+static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+        .bEndpointAddress       = USB_DIR_IN,
+        .bmAttributes           = USB_ENDPOINT_XFER_INT,
+        /*.wMaxPacketSize       = DYNAMIC */
+        .bInterval              = 4, /* FIXME: Add this field in the
+                                      * HID gadget configuration?
+                                      * (struct hidg_func_descriptor)
+                                      */
+};
+
+static struct usb_descriptor_header *hidg_hs_descriptors[] = {
+        (struct usb_descriptor_header *)&hidg_interface_desc,
+        (struct usb_descriptor_header *)&hidg_desc,
+        (struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
+        NULL,
+};
+
+/* Full-Speed Support */
+
+static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+        .bEndpointAddress       = USB_DIR_IN,
+        .bmAttributes           = USB_ENDPOINT_XFER_INT,
+        /*.wMaxPacketSize       = DYNAMIC */
+        .bInterval              = 10, /* FIXME: Add this field in the
+                                       * HID gadget configuration?
+                                       * (struct hidg_func_descriptor)
+                                       */
+};
+
+static struct usb_descriptor_header *hidg_fs_descriptors[] = {
+        (struct usb_descriptor_header *)&hidg_interface_desc,
+        (struct usb_descriptor_header *)&hidg_desc,
+        (struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+/*                              Char Device                                */
+
+static ssize_t f_hidg_read(struct file *file, char __user *buffer,
+                        size_t count, loff_t *ptr)
+{
+        struct f_hidg   *hidg     = (struct f_hidg *)file->private_data;
+        char            *tmp_buff = NULL;
+        unsigned long   flags;
+
+        if (!count)
+                return 0;
+
+        if (!access_ok(VERIFY_WRITE, buffer, count))
+                return -EFAULT;
+
+        spin_lock_irqsave(&hidg->spinlock, flags);
+
+#define READ_COND (hidg->set_report_buff != NULL)
+
+        while (!READ_COND) {
+                spin_unlock_irqrestore(&hidg->spinlock, flags);
+                if (file->f_flags & O_NONBLOCK)
+                        return -EAGAIN;
+
+                if (wait_event_interruptible(hidg->read_queue, READ_COND))
+                        return -ERESTARTSYS;
+
+                spin_lock_irqsave(&hidg->spinlock, flags);
+        }
+
+
+        count = min_t(unsigned, count, hidg->set_report_length);
+        tmp_buff = hidg->set_report_buff;
+        hidg->set_report_buff = NULL;
+
+        spin_unlock_irqrestore(&hidg->spinlock, flags);
+
+        if (tmp_buff != NULL) {
+                /* copy to user outside spinlock */
+                count -= copy_to_user(buffer, tmp_buff, count);
+                kfree(tmp_buff);
+        } else
+                count = -ENOMEM;
+
+        return count;
+}
+
+static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
+{
+        struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
+
+        if (req->status != 0) {
+                ERROR(hidg->func.config->cdev,
+                        "End Point Request ERROR: %d\n", req->status);
+        }
+
+        hidg->write_pending = 0;
+        wake_up(&hidg->write_queue);
+}
+
+static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
+                            size_t count, loff_t *offp)
+{
+        struct f_hidg *hidg  = (struct f_hidg *)file->private_data;
+        ssize_t status = -ENOMEM;
+
+        if (!access_ok(VERIFY_READ, buffer, count))
+                return -EFAULT;
+
+        mutex_lock(&hidg->lock);
+
+#define WRITE_COND (!hidg->write_pending)
+
+        /* write queue */
+        while (!WRITE_COND) {
+                mutex_unlock(&hidg->lock);
+                if (file->f_flags & O_NONBLOCK)
+                        return -EAGAIN;
+
+                if (wait_event_interruptible_exclusive(
+                                hidg->write_queue, WRITE_COND))
+                        return -ERESTARTSYS;
+
+                mutex_lock(&hidg->lock);
+        }
+
+        count  = min_t(unsigned, count, hidg->report_length);
+        status = copy_from_user(hidg->req->buf, buffer, count);
+
+        if (status != 0) {
+                ERROR(hidg->func.config->cdev,
+                        "copy_from_user error\n");
+                mutex_unlock(&hidg->lock);
+                return -EINVAL;
+        }
+
+        hidg->req->status   = 0;
+        hidg->req->zero     = 0;
+        hidg->req->length   = count;
+        hidg->req->complete = f_hidg_req_complete;
+        hidg->req->context  = hidg;
+        hidg->write_pending = 1;
+
+        status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
+        if (status < 0) {
+                ERROR(hidg->func.config->cdev,
+                        "usb_ep_queue error on int endpoint %zd\n", status);
+                hidg->write_pending = 0;
+                wake_up(&hidg->write_queue);
+        } else {
+                status = count;
+        }
+
+        mutex_unlock(&hidg->lock);
+
+        return status;
+}
+
+static unsigned int f_hidg_poll(struct file *file, poll_table *wait)
+{
+        struct f_hidg   *hidg  = (struct f_hidg *)file->private_data;
+        unsigned int    ret = 0;
+
+        poll_wait(file, &hidg->read_queue, wait);
+        poll_wait(file, &hidg->write_queue, wait);
+
+        if (WRITE_COND)
+                ret |= POLLOUT | POLLWRNORM;
+
+        if (READ_COND)
+                ret |= POLLIN | POLLRDNORM;
+
+        return ret;
+}
+
+#undef WRITE_COND
+#undef READ_COND
+
+static int f_hidg_release(struct inode *inode, struct file *fd)
+{
+        fd->private_data = NULL;
+        return 0;
+}
+
+static int f_hidg_open(struct inode *inode, struct file *fd)
+{
+        struct f_hidg *hidg =
+                container_of(inode->i_cdev, struct f_hidg, cdev);
+
+        fd->private_data = hidg;
+
+        return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+/*                                usb_function                             */
+
+static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
+{
+        struct f_hidg *hidg = (struct f_hidg *)req->context;
+
+        if (req->status != 0 || req->buf == NULL || req->actual == 0) {
+                ERROR(hidg->func.config->cdev, "%s FAILED\n", __func__);
+                return;
+        }
+
+        spin_lock(&hidg->spinlock);
+
+        hidg->set_report_buff = krealloc(hidg->set_report_buff,
+                                         req->actual, GFP_ATOMIC);
+
+        if (hidg->set_report_buff == NULL) {
+                spin_unlock(&hidg->spinlock);
+                return;
+        }
+        hidg->set_report_length = req->actual;
+        memcpy(hidg->set_report_buff, req->buf, req->actual);
+
+        spin_unlock(&hidg->spinlock);
+
+        wake_up(&hidg->read_queue);
+
+        return;
+}
+
+static int hidg_setup(struct usb_function *f,
+                const struct usb_ctrlrequest *ctrl)
+{
+        struct f_hidg                   *hidg = func_to_hidg(f);
+        struct usb_composite_dev        *cdev = f->config->cdev;
+        struct usb_request              *req  = cdev->req;
+        int status = 0;
+        __u16 value, length;
+
+        value   = __le16_to_cpu(ctrl->wValue);
+        length  = __le16_to_cpu(ctrl->wLength);
+
+        VDBG(cdev, "hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x "
+                "Value:0x%x\n", ctrl->bRequestType, ctrl->bRequest, value);
+
+        switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
+        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+                  | HID_REQ_GET_REPORT):
+                VDBG(cdev, "get_report\n");
+
+                /* send an empty report */
+                length = min_t(unsigned, length, hidg->report_length);
+                memset(req->buf, 0x0, length);
+
+                goto respond;
+                break;
+
+        case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+                  | HID_REQ_GET_PROTOCOL):
+                VDBG(cdev, "get_protocol\n");
+                goto stall;
+                break;
+
+        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+                  | HID_REQ_SET_REPORT):
+                VDBG(cdev, "set_report | wLenght=%d\n", ctrl->wLength);
+                req->context  = hidg;
+                req->complete = hidg_set_report_complete;
+                goto respond;
+                break;
+
+        case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
+                  | HID_REQ_SET_PROTOCOL):
+                VDBG(cdev, "set_protocol\n");
+                goto stall;
+                break;
+
+        case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
+                  | USB_REQ_GET_DESCRIPTOR):
+                switch (value >> 8) {
+                case HID_DT_REPORT:
+                        VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
+                        length = min_t(unsigned short, length,
+                                                   hidg->report_desc_length);
+                        memcpy(req->buf, hidg->report_desc, length);
+                        goto respond;
+                        break;
+
+                default:
+                        VDBG(cdev, "Unknown decriptor request 0x%x\n",
+                                 value >> 8);
+                        goto stall;
+                        break;
+                }
+                break;
+
+        default:
+                VDBG(cdev, "Unknown request 0x%x\n",
+                         ctrl->bRequest);
+                goto stall;
+                break;
+        }
+
+stall:
+        return -EOPNOTSUPP;
+
+respond:
+        req->zero = 0;
+        req->length = length;
+        status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+        if (status < 0)
+                ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
+        return status;
+}
+
+static void hidg_disable(struct usb_function *f)
+{
+        struct f_hidg *hidg = func_to_hidg(f);
+
+        usb_ep_disable(hidg->in_ep);
+        hidg->in_ep->driver_data = NULL;
+
+        return;
+}
+
+static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+        struct usb_composite_dev                *cdev = f->config->cdev;
+        struct f_hidg                           *hidg = func_to_hidg(f);
+        const struct usb_endpoint_descriptor    *ep_desc;
+        int status = 0;
+
+        VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
+
+        if (hidg->in_ep != NULL) {
+                /* restart endpoint */
+                if (hidg->in_ep->driver_data != NULL)
+                        usb_ep_disable(hidg->in_ep);
+
+                ep_desc = ep_choose(f->config->cdev->gadget,
+                                hidg->hs_in_ep_desc, hidg->fs_in_ep_desc);
+                status = usb_ep_enable(hidg->in_ep, ep_desc);
+                if (status < 0) {
+                        ERROR(cdev, "Enable endpoint FAILED!\n");
+                        goto fail;
+                }
+                hidg->in_ep->driver_data = hidg;
+        }
+fail:
+        return status;
+}
+
+const struct file_operations f_hidg_fops = {
+        .owner          = THIS_MODULE,
+        .open           = f_hidg_open,
+        .release        = f_hidg_release,
+        .write          = f_hidg_write,
+        .read           = f_hidg_read,
+        .poll           = f_hidg_poll,
+};
+
+static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct usb_ep           *ep;
+        struct f_hidg           *hidg = func_to_hidg(f);
+        int                     status;
+        dev_t                   dev;
+
+        /* allocate instance-specific interface IDs, and patch descriptors */
+        status = usb_interface_id(c, f);
+        if (status < 0)
+                goto fail;
+        hidg_interface_desc.bInterfaceNumber = status;
+
+
+        /* allocate instance-specific endpoints */
+        status = -ENODEV;
+        ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
+        if (!ep)
+                goto fail;
+        ep->driver_data = c->cdev;      /* claim */
+        hidg->in_ep = ep;
+
+        /* preallocate request and buffer */
+        status = -ENOMEM;
+        hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
+        if (!hidg->req)
+                goto fail;
+
+
+        hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
+        if (!hidg->req->buf)
+                goto fail;
+
+        /* set descriptor dynamic values */
+        hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
+        hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
+        hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
+        hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
+        hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
+        hidg_desc.desc[0].wDescriptorLength =
+                cpu_to_le16(hidg->report_desc_length);
+
+        hidg->set_report_buff = NULL;
+
+        /* copy descriptors */
+        f->descriptors = usb_copy_descriptors(hidg_fs_descriptors);
+        if (!f->descriptors)
+                goto fail;
+
+        hidg->fs_in_ep_desc = usb_find_endpoint(hidg_fs_descriptors,
+                                                f->descriptors,
+                                                &hidg_fs_in_ep_desc);
+
+        if (gadget_is_dualspeed(c->cdev->gadget)) {
+                hidg_hs_in_ep_desc.bEndpointAddress =
+                        hidg_fs_in_ep_desc.bEndpointAddress;
+                f->hs_descriptors = usb_copy_descriptors(hidg_hs_descriptors);
+                if (!f->hs_descriptors)
+                        goto fail;
+                hidg->hs_in_ep_desc = usb_find_endpoint(hidg_hs_descriptors,
+                                                        f->hs_descriptors,
+                                                        &hidg_hs_in_ep_desc);
+        } else {
+                hidg->hs_in_ep_desc = NULL;
+        }
+
+        mutex_init(&hidg->lock);
+        spin_lock_init(&hidg->spinlock);
+        init_waitqueue_head(&hidg->write_queue);
+        init_waitqueue_head(&hidg->read_queue);
+
+        /* create char device */
+        cdev_init(&hidg->cdev, &f_hidg_fops);
+        dev = MKDEV(major, hidg->minor);
+        status = cdev_add(&hidg->cdev, dev, 1);
+        if (status)
+                goto fail;
+
+        device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);
+
+        return 0;
+
+fail:
+        ERROR(f->config->cdev, "hidg_bind FAILED\n");
+        if (hidg->req != NULL) {
+                kfree(hidg->req->buf);
+                if (hidg->in_ep != NULL)
+                        usb_ep_free_request(hidg->in_ep, hidg->req);
+        }
+
+        usb_free_descriptors(f->hs_descriptors);
+        usb_free_descriptors(f->descriptors);
+
+        return status;
+}
+
+static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct f_hidg *hidg = func_to_hidg(f);
+
+        device_destroy(hidg_class, MKDEV(major, hidg->minor));
+        cdev_del(&hidg->cdev);
+
+        /* disable/free request and end point */
+        usb_ep_disable(hidg->in_ep);
+        usb_ep_dequeue(hidg->in_ep, hidg->req);
+        kfree(hidg->req->buf);
+        usb_ep_free_request(hidg->in_ep, hidg->req);
+
+        /* free descriptors copies */
+        usb_free_descriptors(f->hs_descriptors);
+        usb_free_descriptors(f->descriptors);
+
+        kfree(hidg->report_desc);
+        kfree(hidg->set_report_buff);
+        kfree(hidg);
+}
+
+/*-------------------------------------------------------------------------*/
+/*                                 Strings                                 */
+
+#define CT_FUNC_HID_IDX 0
+
+static struct usb_string ct_func_string_defs[] = {
+        [CT_FUNC_HID_IDX].s     = "HID Interface",
+        {},                     /* end of list */
+};
+
+static struct usb_gadget_strings ct_func_string_table = {
+        .language       = 0x0409,       /* en-US */
+        .strings        = ct_func_string_defs,
+};
+
+static struct usb_gadget_strings *ct_func_strings[] = {
+        &ct_func_string_table,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+/*                             usb_configuration                           */
+
+int __init hidg_bind_config(struct usb_configuration *c,
+                            struct hidg_func_descriptor *fdesc, int index)
+{
+        struct f_hidg *hidg;
+        int status;
+
+        if (index >= minors)
+                return -ENOENT;
+
+        /* maybe allocate device-global string IDs, and patch descriptors */
+        if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
+                status = usb_string_id(c->cdev);
+                if (status < 0)
+                        return status;
+                ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
+                hidg_interface_desc.iInterface = status;
+        }
+
+        /* allocate and initialize one new instance */
+        hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
+        if (!hidg)
+                return -ENOMEM;
+
+        hidg->minor = index;
+        hidg->bInterfaceSubClass = fdesc->subclass;
+        hidg->bInterfaceProtocol = fdesc->protocol;
+        hidg->report_length = fdesc->report_length;
+        hidg->report_desc_length = fdesc->report_desc_length;
+        hidg->report_desc = kmemdup(fdesc->report_desc,
+                                    fdesc->report_desc_length,
+                                    GFP_KERNEL);
+        if (!hidg->report_desc) {
+                kfree(hidg);
+                return -ENOMEM;
+        }
+
+        hidg->func.name    = "hid";
+        hidg->func.strings = ct_func_strings;
+        hidg->func.bind    = hidg_bind;
+        hidg->func.unbind  = hidg_unbind;
+        hidg->func.set_alt = hidg_set_alt;
+        hidg->func.disable = hidg_disable;
+        hidg->func.setup   = hidg_setup;
+
+        status = usb_add_function(c, &hidg->func);
+        if (status)
+                kfree(hidg);
+
+        return status;
+}
+
+int __init ghid_setup(struct usb_gadget *g, int count)
+{
+        int status;
+        dev_t dev;
+
+        hidg_class = class_create(THIS_MODULE, "hidg");
+
+        status = alloc_chrdev_region(&dev, 0, count, "hidg");
+        if (!status) {
+                major = MAJOR(dev);
+                minors = count;
+        }
+
+        return status;
+}
+
+void ghid_cleanup(void)
+{
+        if (major) {
+                unregister_chrdev_region(MKDEV(major, 0), minors);
+                major = minors = 0;
+        }
+
+        class_destroy(hidg_class);
+        hidg_class = NULL;
+}