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>

drivers/dfu/dfu.c

@@ -147,6 +147,19 @@ static int dfu_write_buffer_drain(struct dfu_entity *dfu)
 	return ret;
 }
 
+void dfu_write_transaction_cleanup(struct dfu_entity *dfu)
+{
+	/* clear everything */
+	dfu_free_buf();
+	dfu->crc = 0;
+	dfu->offset = 0;
+	dfu->i_blk_seq_num = 0;
+	dfu->i_buf_start = dfu_buf;
+	dfu->i_buf_end = dfu_buf;
+	dfu->i_buf = dfu->i_buf_start;
+	dfu->inited = 0;
+}
+
 int dfu_flush(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 {
 	int ret = 0;
@@ -162,23 +175,14 @@ int dfu_flush(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 		printf("\nDFU complete %s: 0x%08x\n", dfu_hash_algo->name,
 		       dfu->crc);
 
-	/* clear everything */
-	dfu_free_buf();
-	dfu->crc = 0;
-	dfu->offset = 0;
-	dfu->i_blk_seq_num = 0;
-	dfu->i_buf_start = dfu_buf;
-	dfu->i_buf_end = dfu_buf;
-	dfu->i_buf = dfu->i_buf_start;
-	dfu->inited = 0;
+	dfu_write_transaction_cleanup(dfu);
 
 	return ret;
 }
 
 int dfu_write(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 {
-	int ret = 0;
-	int tret;
+	int ret;
 
 	debug("%s: name: %s buf: 0x%p size: 0x%x p_num: 0x%x offset: 0x%llx bufoffset: 0x%x\n",
 	      __func__, dfu->name, buf, size, blk_seq_num, dfu->offset,
@@ -202,6 +206,7 @@ int dfu_write(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 	if (dfu->i_blk_seq_num != blk_seq_num) {
 		printf("%s: Wrong sequence number! [%d] [%d]\n",
 		       __func__, dfu->i_blk_seq_num, blk_seq_num);
+		dfu_write_transaction_cleanup(dfu);
 		return -1;
 	}
 
@@ -223,15 +228,18 @@ int dfu_write(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 
 	/* flush buffer if overflow */
 	if ((dfu->i_buf + size) > dfu->i_buf_end) {
-		tret = dfu_write_buffer_drain(dfu);
-		if (ret == 0)
-			ret = tret;
+		ret = dfu_write_buffer_drain(dfu);
+		if (ret) {
+			dfu_write_transaction_cleanup(dfu);
+			return ret;
+		}
 	}
 
 	/* we should be in buffer now (if not then size too large) */
 	if ((dfu->i_buf + size) > dfu->i_buf_end) {
 		error("Buffer overflow! (0x%p + 0x%x > 0x%p)\n", dfu->i_buf,
 		      size, dfu->i_buf_end);
+		dfu_write_transaction_cleanup(dfu);
 		return -1;
 	}
 
@@ -240,12 +248,14 @@ int dfu_write(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 
 	/* if end or if buffer full flush */
 	if (size == 0 || (dfu->i_buf + size) > dfu->i_buf_end) {
-		tret = dfu_write_buffer_drain(dfu);
-		if (ret == 0)
-			ret = tret;
+		ret = dfu_write_buffer_drain(dfu);
+		if (ret) {
+			dfu_write_transaction_cleanup(dfu);
+			return ret;
+		}
 	}
 
-	return ret;
+	return 0;
 }
 
 static int dfu_read_buffer_fill(struct dfu_entity *dfu, void *buf, int size)

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;
 }