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| author | Tomas Vanek <vanekt@fbl.cz> | 2018-02-21 22:19:58 +0100 |
|---|---|---|
| committer | Tomas Vanek <vanekt@fbl.cz> | 2018-04-04 21:26:59 +0100 |
| commit | 7829bb701f1d9b294c627142911529ca34a1120b (patch) | |
| tree | bca4a31e3a78104d04bcada718bd6b3e4105ed83 /src | |
| parent | a28dea0fe429339e4f8d356fbff19cb17350c9ca (diff) | |
| download | riscv-openocd-7829bb701f1d9b294c627142911529ca34a1120b.zip riscv-openocd-7829bb701f1d9b294c627142911529ca34a1120b.tar.gz riscv-openocd-7829bb701f1d9b294c627142911529ca34a1120b.tar.bz2 | |
drivers/kitprog: workaround KitProg firmware bug of missing ZLP
KitProg firmware does not send a zero length packet at the end of the bulk-in
transmission of a length divisible by a bulk packet size. This is inconsistent
with the USB specification and results in jtag_libusb_bulk_read()
waits forever when a transmission of specific size is received.
Limit bulk read size to expected number of bytes for problematic tranfer sizes.
Use 1 second timeout as the last resort.
Change-Id: Ice80306424afd76e9fbc6851911ffd5109c84501
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4426
Tested-by: jenkins
Reviewed-by: Bohdan Tymkiv <bhdt@cypress.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/jtag/drivers/kitprog.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/jtag/drivers/kitprog.c b/src/jtag/drivers/kitprog.c index db5b62e..522eb17 100644 --- a/src/jtag/drivers/kitprog.c +++ b/src/jtag/drivers/kitprog.c @@ -741,12 +741,22 @@ static int kitprog_swd_run_queue(void) break; } - /* We use the maximum buffer size here because the KitProg sometimes - * doesn't like bulk reads of fewer than 62 bytes. (?!?!) + /* KitProg firmware does not send a zero length packet + * after the bulk-in transmission of a length divisible by bulk packet + * size (64 bytes) as required by the USB specification. + * Therefore libusb would wait for continuation of transmission. + * Workaround: Limit bulk read size to expected number of bytes + * for problematic tranfer sizes. Otherwise use the maximum buffer + * size here because the KitProg sometimes doesn't like bulk reads + * of fewer than 62 bytes. (?!?!) */ + size_t read_count_workaround = SWD_MAX_BUFFER_LENGTH; + if (read_count % 64 == 0) + read_count_workaround = read_count; + ret = jtag_libusb_bulk_read(kitprog_handle->usb_handle, BULK_EP_IN | LIBUSB_ENDPOINT_IN, (char *)buffer, - SWD_MAX_BUFFER_LENGTH, 0); + read_count_workaround, 1000); if (ret > 0) { /* Handle garbage data by offsetting the initial read index */ if ((unsigned int)ret > read_count) |