diff options
Diffstat (limited to 'drivers/usb/gadget/config.c')
| -rw-r--r-- | drivers/usb/gadget/config.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c new file mode 100644 index 000000000..34e12fc52 --- /dev/null +++ b/drivers/usb/gadget/config.c @@ -0,0 +1,197 @@ +/* + * usb/gadget/config.c -- simplify building config descriptors + * + * Copyright (C) 2003 David Brownell + * + * 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. + */ + +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/list.h> +#include <linux/string.h> +#include <linux/device.h> + +#include <linux/usb/ch9.h> +#include <linux/usb/gadget.h> +#include <linux/usb/composite.h> + +/** + * usb_descriptor_fillbuf - fill buffer with descriptors + * @buf: Buffer to be filled + * @buflen: Size of buf + * @src: Array of descriptor pointers, terminated by null pointer. + * + * Copies descriptors into the buffer, returning the length or a + * negative error code if they can't all be copied. Useful when + * assembling descriptors for an associated set of interfaces used + * as part of configuring a composite device; or in other cases where + * sets of descriptors need to be marshaled. + */ +int +usb_descriptor_fillbuf(void *buf, unsigned buflen, + const struct usb_descriptor_header **src) +{ + u8 *dest = buf; + + if (!src) + return -EINVAL; + + /* fill buffer from src[] until null descriptor ptr */ + for (; NULL != *src; src++) { + unsigned len = (*src)->bLength; + + if (len > buflen) + return -EINVAL; + memcpy(dest, *src, len); + buflen -= len; + dest += len; + } + return dest - (u8 *)buf; +} +EXPORT_SYMBOL_GPL(usb_descriptor_fillbuf); + +/** + * usb_gadget_config_buf - builts a complete configuration descriptor + * @config: Header for the descriptor, including characteristics such + * as power requirements and number of interfaces. + * @desc: Null-terminated vector of pointers to the descriptors (interface, + * endpoint, etc) defining all functions in this device configuration. + * @buf: Buffer for the resulting configuration descriptor. + * @length: Length of buffer. If this is not big enough to hold the + * entire configuration descriptor, an error code will be returned. + * + * This copies descriptors into the response buffer, building a descriptor + * for that configuration. It returns the buffer length or a negative + * status code. The config.wTotalLength field is set to match the length + * of the result, but other descriptor fields (including power usage and + * interface count) must be set by the caller. + * + * Gadget drivers could use this when constructing a config descriptor + * in response to USB_REQ_GET_DESCRIPTOR. They will need to patch the + * resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed. + */ +int usb_gadget_config_buf( + const struct usb_config_descriptor *config, + void *buf, + unsigned length, + const struct usb_descriptor_header **desc +) +{ + struct usb_config_descriptor *cp = buf; + int len; + + /* config descriptor first */ + if (length < USB_DT_CONFIG_SIZE || !desc) + return -EINVAL; + *cp = *config; + + /* then interface/endpoint/class/vendor/... */ + len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8*)buf, + length - USB_DT_CONFIG_SIZE, desc); + if (len < 0) + return len; + len += USB_DT_CONFIG_SIZE; + if (len > 0xffff) + return -EINVAL; + + /* patch up the config descriptor */ + cp->bLength = USB_DT_CONFIG_SIZE; + cp->bDescriptorType = USB_DT_CONFIG; + cp->wTotalLength = cpu_to_le16(len); + cp->bmAttributes |= USB_CONFIG_ATT_ONE; + return len; +} +EXPORT_SYMBOL_GPL(usb_gadget_config_buf); + +/** + * usb_copy_descriptors - copy a vector of USB descriptors + * @src: null-terminated vector to copy + * Context: initialization code, which may sleep + * + * This makes a copy of a vector of USB descriptors. Its primary use + * is to support usb_function objects which can have multiple copies, + * each needing different descriptors. Functions may have static + * tables of descriptors, which are used as templates and customized + * with identifiers (for interfaces, strings, endpoints, and more) + * as needed by a given function instance. + */ +struct usb_descriptor_header ** +usb_copy_descriptors(struct usb_descriptor_header **src) +{ + struct usb_descriptor_header **tmp; + unsigned bytes; + unsigned n_desc; + void *mem; + struct usb_descriptor_header **ret; + + /* count descriptors and their sizes; then add vector size */ + for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++) + bytes += (*tmp)->bLength; + bytes += (n_desc + 1) * sizeof(*tmp); + + mem = kmalloc(bytes, GFP_KERNEL); + if (!mem) + return NULL; + + /* fill in pointers starting at "tmp", + * to descriptors copied starting at "mem"; + * and return "ret" + */ + tmp = mem; + ret = mem; + mem += (n_desc + 1) * sizeof(*tmp); + while (*src) { + memcpy(mem, *src, (*src)->bLength); + *tmp = mem; + tmp++; + mem += (*src)->bLength; + src++; + } + *tmp = NULL; + + return ret; +} +EXPORT_SYMBOL_GPL(usb_copy_descriptors); + +int usb_assign_descriptors(struct usb_function *f, + struct usb_descriptor_header **fs, + struct usb_descriptor_header **hs, + struct usb_descriptor_header **ss) +{ + struct usb_gadget *g = f->config->cdev->gadget; + + if (fs) { + f->fs_descriptors = usb_copy_descriptors(fs); + if (!f->fs_descriptors) + goto err; + } + if (hs && gadget_is_dualspeed(g)) { + f->hs_descriptors = usb_copy_descriptors(hs); + if (!f->hs_descriptors) + goto err; + } + if (ss && gadget_is_superspeed(g)) { + f->ss_descriptors = usb_copy_descriptors(ss); + if (!f->ss_descriptors) + goto err; + } + return 0; +err: + usb_free_all_descriptors(f); + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(usb_assign_descriptors); + +void usb_free_all_descriptors(struct usb_function *f) +{ + usb_free_descriptors(f->fs_descriptors); + usb_free_descriptors(f->hs_descriptors); + usb_free_descriptors(f->ss_descriptors); +} +EXPORT_SYMBOL_GPL(usb_free_all_descriptors); |