dfu: add write error handling

Fix calls to dfu_write() and dfu_flush() to detect errors in the I/O
itself. This could happen due to problems with the storage medium, or
simply when trying to write a FAT/ext file that is larger than the buffer
dfu_mmc.c maintains for this purpose.

Signal the error by switching the DFU state/status. This will be picked
up by the DFU client when it sends the next DFU request. Note that errors
can't simply be returned from e.g. dnload_request_complete(), since that
function has no way to pass errors back to the DFU client; a call to
dnload_request_complete() simply means that a USB OUT completed.

This error state/status needs to be cleared when the next DFU client
connects. While there is a DFU_CLRSTATUS request, no DFU client seems to
send this. Hence, clear this when selecting the USB alternate setting on
the USB interface.

Finally, dfu.c relies on a call to dfu_flush() to clear up the internal
state of the write transaction. Now that errors in dfu_write() are
detected, dfu_flush() may no longer be called for every transaction.
Separate out the cleanup code into a new function, and call it whenever
dfu_write() fails, as well as from any call to dfu_flush().

Signed-off-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/drivers/usb/gadget/f_dfu.c b/drivers/usb/gadget/f_dfu.c
index 859fe82..9863dec 100644
--- a/drivers/usb/gadget/f_dfu.c
+++ b/drivers/usb/gadget/f_dfu.c
@@ -162,17 +162,27 @@ static void dfu_set_poll_timeout(struct dfu_status *dstat, unsigned int ms)
 static void dnload_request_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_dfu *f_dfu = req->context;
+	int ret;
 
-	dfu_write(dfu_get_entity(f_dfu->altsetting), req->buf,
-		  req->length, f_dfu->blk_seq_num);
+	ret = dfu_write(dfu_get_entity(f_dfu->altsetting), req->buf,
+			req->length, f_dfu->blk_seq_num);
+	if (ret) {
+		f_dfu->dfu_status = DFU_STATUS_errUNKNOWN;
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+	}
 }
 
 static void dnload_request_flush(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_dfu *f_dfu = req->context;
+	int ret;
 
-	dfu_flush(dfu_get_entity(f_dfu->altsetting), req->buf,
-		  req->length, f_dfu->blk_seq_num);
+	ret = dfu_flush(dfu_get_entity(f_dfu->altsetting), req->buf,
+			req->length, f_dfu->blk_seq_num);
+	if (ret) {
+		f_dfu->dfu_status = DFU_STATUS_errUNKNOWN;
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+	}
 }
 
 static inline int dfu_get_manifest_timeout(struct dfu_entity *dfu)
@@ -770,6 +780,8 @@ static int dfu_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	debug("%s: intf:%d alt:%d\n", __func__, intf, alt);
 
 	f_dfu->altsetting = alt;
+	f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+	f_dfu->dfu_status = DFU_STATUS_OK;
 
 	return 0;
 }