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usb: gadget: Support already-mapped DMA SGs

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Add a new 'sg_was_mapped' field to the struct usb_request. This field
can be used to indicate that the scatterlist associated to the USB
transfer has already been mapped into the DMA space, and it does not
have to be done internally.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20240130122340.54813-2-paul@crapouillou.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paul Cercueil 2024-01-30 13:23:37 +01:00 committed by Greg Kroah-Hartman
parent 7ad818eef6
commit 99f638dd49
2 changed files with 8 additions and 1 deletions
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7
drivers/usb/gadget/udc/core.c
View File

@ -903,6 +903,11 @@ int usb_gadget_map_request_by_dev(struct device *dev,
if (req->length == 0)
return 0;
if (req->sg_was_mapped) {
req->num_mapped_sgs = req->num_sgs;
return 0;
}
if (req->num_sgs) {
int mapped;
@ -948,7 +953,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_map_request);
void usb_gadget_unmap_request_by_dev(struct device *dev,
struct usb_request *req, int is_in)
{
if (req->length == 0)
if (req->length == 0 || req->sg_was_mapped)
return;
if (req->num_mapped_sgs) {

2
include/linux/usb/gadget.h
View File

@ -52,6 +52,7 @@ struct usb_ep;
* @short_not_ok: When reading data, makes short packets be
* treated as errors (queue stops advancing till cleanup).
* @dma_mapped: Indicates if request has been mapped to DMA (internal)
* @sg_was_mapped: Set if the scatterlist has been mapped before the request
* @complete: Function called when request completes, so this request and
* its buffer may be re-used. The function will always be called with
* interrupts disabled, and it must not sleep.
@ -111,6 +112,7 @@ struct usb_request {
unsigned zero:1;
unsigned short_not_ok:1;
unsigned dma_mapped:1;
unsigned sg_was_mapped:1;
void (*complete)(struct usb_ep *ep,
struct usb_request *req);