USB: gadget: mtp: Add module parameter for Rx transfer length
The Rx request transfer length is 16K bytes by default. The test
results indicate that larger transfers improve write speeds. Add
provision for specifying Rx transfer length at runtime.
echo -n 1048576 > /sys/module/g_android/parameters/mtp_rx_req_len
The above command can be used to set Rx transfer length to 1MB. If
the memory allocation is failed, fallback to the default length.
CRs-Fixed: 429212
Change-Id: I74d5da09437c25e9f1772f7cd49aecb8e4fedcf2
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
diff --git a/drivers/usb/gadget/f_mtp.c b/drivers/usb/gadget/f_mtp.c
index 82ffbba..0c0d58a 100644
--- a/drivers/usb/gadget/f_mtp.c
+++ b/drivers/usb/gadget/f_mtp.c
@@ -67,6 +67,9 @@
#define MTP_RESPONSE_OK 0x2001
#define MTP_RESPONSE_DEVICE_BUSY 0x2019
+unsigned int mtp_rx_req_len = MTP_BULK_BUFFER_SIZE;
+module_param(mtp_rx_req_len, uint, S_IRUGO | S_IWUSR);
+
static const char mtp_shortname[] = "mtp_usb";
struct mtp_dev {
@@ -493,10 +496,27 @@
req->complete = mtp_complete_in;
mtp_req_put(dev, &dev->tx_idle, req);
}
+
+ /*
+ * The RX buffer should be aligned to EP max packet for
+ * some controllers. At bind time, we don't know the
+ * operational speed. Hence assuming super speed max
+ * packet size.
+ */
+ if (mtp_rx_req_len % 1024)
+ mtp_rx_req_len = MTP_BULK_BUFFER_SIZE;
+
+retry_rx_alloc:
for (i = 0; i < RX_REQ_MAX; i++) {
- req = mtp_request_new(dev->ep_out, MTP_BULK_BUFFER_SIZE);
- if (!req)
- goto fail;
+ req = mtp_request_new(dev->ep_out, mtp_rx_req_len);
+ if (!req) {
+ if (mtp_rx_req_len <= MTP_BULK_BUFFER_SIZE)
+ goto fail;
+ for (; i > 0; i--)
+ mtp_request_free(dev->rx_req[i], dev->ep_out);
+ mtp_rx_req_len = MTP_BULK_BUFFER_SIZE;
+ goto retry_rx_alloc;
+ }
req->complete = mtp_complete_out;
dev->rx_req[i] = req;
}
@@ -526,7 +546,7 @@
DBG(cdev, "mtp_read(%d)\n", count);
- if (count > MTP_BULK_BUFFER_SIZE)
+ if (count > mtp_rx_req_len)
return -EINVAL;
if (!IS_ALIGNED(count, dev->ep_out->maxpacket))
@@ -554,7 +574,7 @@
requeue_req:
/* queue a request */
req = dev->rx_req[0];
- req->length = MTP_BULK_BUFFER_SIZE;
+ req->length = mtp_rx_req_len;
dev->rx_done = 0;
ret = usb_ep_queue(dev->ep_out, req, GFP_KERNEL);
if (ret < 0) {
@@ -832,7 +852,7 @@
cur_buf = (cur_buf + 1) % RX_REQ_MAX;
/* some h/w expects size to be aligned to ep's MTU */
- read_req->length = MTP_BULK_BUFFER_SIZE;
+ read_req->length = mtp_rx_req_len;
dev->rx_done = 0;
ret = usb_ep_queue(dev->ep_out, read_req, GFP_KERNEL);