This is an automated email from Gerrit. Peter Henn ([email protected]) just uploaded a new patch set to Gerrit, which you can find at http://openocd.zylin.com/942
-- gerrit commit 95ee271992905eda70fb983489ae44266954ad76 Author: Peter Henn <[email protected]> Date: Sun Oct 28 22:08:37 2012 +0100 speed up ftdi by reorder to out-in When the ftdi driver calls finally the mpsse_flush function, it first initiate the USB in and finally the corresponding USB out transaction. Because data in is requested too early the USB device will always answer the first USB in by a NAK. That can prevented by a simple reordering of the out and then the in transfer and can improve the Jtag performance for high JTAG clock rates. Change-Id: I17abf1487c914c92e2e447ee6d30562ef629f327 Signed-off-by: Peter Henn <[email protected]> diff --git a/src/jtag/drivers/mpsse.c b/src/jtag/drivers/mpsse.c index d6cbc84..4142969 100644 --- a/src/jtag/drivers/mpsse.c +++ b/src/jtag/drivers/mpsse.c @@ -779,11 +779,8 @@ int mpsse_flush(struct mpsse_ctx *ctx) if (ctx->read_count) { buffer_write_byte(ctx, 0x87); /* SEND_IMMEDIATE */ read_result.done = false; - read_transfer = libusb_alloc_transfer(0); - libusb_fill_bulk_transfer(read_transfer, ctx->usb_dev, ctx->in_ep, ctx->read_chunk, - ctx->read_chunk_size, read_cb, &read_result, - ctx->usb_read_timeout); - retval = libusb_submit_transfer(read_transfer); + /* delay read transaction to ensure the FTDI chip can support us with data + immediately after processing the MPSSE commands in the write transaction */ } struct transfer_result write_result = { .ctx = ctx, .done = false }; @@ -792,6 +789,14 @@ int mpsse_flush(struct mpsse_ctx *ctx) ctx->write_count, write_cb, &write_result, ctx->usb_write_timeout); retval = libusb_submit_transfer(write_transfer); + if (ctx->read_count) { + read_transfer = libusb_alloc_transfer(0); + libusb_fill_bulk_transfer(read_transfer, ctx->usb_dev, ctx->in_ep, ctx->read_chunk, + ctx->read_chunk_size, read_cb, &read_result, + ctx->usb_read_timeout); + retval = libusb_submit_transfer(read_transfer); + } + /* Polling loop, more or less taken from libftdi */ while (!write_result.done || !read_result.done) { retval = libusb_handle_events(ctx->usb_ctx); -- ------------------------------------------------------------------------------ WINDOWS 8 is here. Millions of people. Your app in 30 days. Visit The Windows 8 Center at Sourceforge for all your go to resources. http://windows8center.sourceforge.net/ join-generation-app-and-make-money-coding-fast/ _______________________________________________ OpenOCD-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openocd-devel
