From a4c39c41bf3592684e36fa0dbbd4ab1a31f969b9 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Thu, 19 Jun 2008 17:52:25 -0700 Subject: [PATCH] usb gadget: descriptor copying support Define three new descriptor manipulation utilities, for use when setting up functions that may have multiple instances: usb_copy_descriptors() to copy a vector of descriptors usb_free_descriptors() to free the copy usb_find_endpoint() to find a copied version These will be used as follows. Functions will continue to have static tables of descriptors they update, now used as __initdata templates. When a function creates a new instance, it patches those tables with relevant interface and string IDs, plus endpoint assignments. Then it copies those morphed descriptors, associates the copies with the new function instance, and records the endpoint descriptors to use when activating the endpoints. When initialization is done, only the copies remain in memory. The copies are freed on driver removal. This ensures that each instance has descriptors which hold the right instance-specific data. Two instances in the same configuration will obviously never share the same interface IDs or use the same endpoints. Instances in different configurations won't do so either, which means this is slightly less memory-efficient in some cases. This also includes a bugfix to the epautoconf code that shows up with this usage model. It must replace the previous endpoint number when updating the template descriptors, not just mask in a few more bits. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/config.c | 76 ++++++++++++++++++++++++++++++++- drivers/usb/gadget/epautoconf.c | 1 + include/linux/usb/gadget.h | 19 +++++++++ 3 files changed, 95 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c index a4e54b2743..1ca1c32639 100644 --- a/drivers/usb/gadget/config.c +++ b/drivers/usb/gadget/config.c @@ -96,7 +96,7 @@ int usb_gadget_config_buf( /* config descriptor first */ if (length < USB_DT_CONFIG_SIZE || !desc) return -EINVAL; - *cp = *config; + *cp = *config; /* then interface/endpoint/class/vendor/... */ len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8*)buf, @@ -115,3 +115,77 @@ int usb_gadget_config_buf( return len; } +/** + * 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 **__init +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; +} + +/** + * usb_find_endpoint - find a copy of an endpoint descriptor + * @src: original vector of descriptors + * @copy: copy of @src + * @ep: endpoint descriptor found in @src + * + * This returns the copy of the @match descriptor made for @copy. Its + * intended use is to help remembering the endpoint descriptor to use + * when enabling a given endpoint. + */ +struct usb_endpoint_descriptor *__init +usb_find_endpoint( + struct usb_descriptor_header **src, + struct usb_descriptor_header **copy, + struct usb_endpoint_descriptor *match +) +{ + while (*src) { + if (*src == (void *) match) + return (void *)*copy; + src++; + copy++; + } + return NULL; +} diff --git a/drivers/usb/gadget/epautoconf.c b/drivers/usb/gadget/epautoconf.c index 8bdad221fa..9462e30192 100644 --- a/drivers/usb/gadget/epautoconf.c +++ b/drivers/usb/gadget/epautoconf.c @@ -159,6 +159,7 @@ ep_matches ( /* MATCH!! */ /* report address */ + desc->bEndpointAddress &= USB_DIR_IN; if (isdigit (ep->name [2])) { u8 num = simple_strtol (&ep->name [2], NULL, 10); desc->bEndpointAddress |= num; diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index cf468fbdbf..0ebedaec07 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -858,6 +858,25 @@ int usb_descriptor_fillbuf(void *, unsigned, int usb_gadget_config_buf(const struct usb_config_descriptor *config, void *buf, unsigned buflen, const struct usb_descriptor_header **desc); +/* copy a NULL-terminated vector of descriptors */ +struct usb_descriptor_header **usb_copy_descriptors( + struct usb_descriptor_header **); + +/* return copy of endpoint descriptor given original descriptor set */ +struct usb_endpoint_descriptor *usb_find_endpoint( + struct usb_descriptor_header **src, + struct usb_descriptor_header **copy, + struct usb_endpoint_descriptor *match); + +/** + * usb_free_descriptors - free descriptors returned by usb_copy_descriptors() + * @v: vector of descriptors + */ +static inline void usb_free_descriptors(struct usb_descriptor_header **v) +{ + kfree(v); +} + /*-------------------------------------------------------------------------*/ /* utility wrapping a simple endpoint selection policy */ -- 2.39.5