1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c
new file mode 100644
index 000000000..05507606b
--- /dev/null
+++ b/drivers/usb/gadget/config.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * usb/gadget/config.c -- simplify building config descriptors
+ *
+ * Copyright (C) 2003 David Brownell
+ */
+
+#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>
+#include <linux/usb/otg.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_descriptor_header **ssp)
+{
+	struct usb_gadget *g = f->config->cdev->gadget;
+
+	/* super-speed-plus descriptor falls back to super-speed one,
+	 * if such a descriptor was provided, thus avoiding a NULL
+	 * pointer dereference if a 5gbps capable gadget is used with
+	 * a 10gbps capable config (device port + cable + host port)
+	 */
+	if (!ssp)
+		ssp = ss;
+
+	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;
+	}
+	if (ssp && gadget_is_superspeed_plus(g)) {
+		f->ssp_descriptors = usb_copy_descriptors(ssp);
+		if (!f->ssp_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);
+	f->fs_descriptors = NULL;
+	usb_free_descriptors(f->hs_descriptors);
+	f->hs_descriptors = NULL;
+	usb_free_descriptors(f->ss_descriptors);
+	f->ss_descriptors = NULL;
+	usb_free_descriptors(f->ssp_descriptors);
+	f->ssp_descriptors = NULL;
+}
+EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
+
+struct usb_descriptor_header *usb_otg_descriptor_alloc(
+				struct usb_gadget *gadget)
+{
+	struct usb_descriptor_header *otg_desc;
+	unsigned length = 0;
+
+	if (gadget->otg_caps && (gadget->otg_caps->otg_rev >= 0x0200))
+		length = sizeof(struct usb_otg20_descriptor);
+	else
+		length = sizeof(struct usb_otg_descriptor);
+
+	otg_desc = kzalloc(length, GFP_KERNEL);
+	return otg_desc;
+}
+EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc);
+
+int usb_otg_descriptor_init(struct usb_gadget *gadget,
+		struct usb_descriptor_header *otg_desc)
+{
+	struct usb_otg_descriptor *otg1x_desc;
+	struct usb_otg20_descriptor *otg20_desc;
+	struct usb_otg_caps *otg_caps = gadget->otg_caps;
+	u8 otg_attributes = 0;
+
+	if (!otg_desc)
+		return -EINVAL;
+
+	if (otg_caps && otg_caps->otg_rev) {
+		if (otg_caps->hnp_support)
+			otg_attributes |= USB_OTG_HNP;
+		if (otg_caps->srp_support)
+			otg_attributes |= USB_OTG_SRP;
+		if (otg_caps->adp_support && (otg_caps->otg_rev >= 0x0200))
+			otg_attributes |= USB_OTG_ADP;
+	} else {
+		otg_attributes = USB_OTG_SRP | USB_OTG_HNP;
+	}
+
+	if (otg_caps && (otg_caps->otg_rev >= 0x0200)) {
+		otg20_desc = (struct usb_otg20_descriptor *)otg_desc;
+		otg20_desc->bLength = sizeof(struct usb_otg20_descriptor);
+		otg20_desc->bDescriptorType = USB_DT_OTG;
+		otg20_desc->bmAttributes = otg_attributes;
+		otg20_desc->bcdOTG = cpu_to_le16(otg_caps->otg_rev);
+	} else {
+		otg1x_desc = (struct usb_otg_descriptor *)otg_desc;
+		otg1x_desc->bLength = sizeof(struct usb_otg_descriptor);
+		otg1x_desc->bDescriptorType = USB_DT_OTG;
+		otg1x_desc->bmAttributes = otg_attributes;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_descriptor_init);