CHERRY-PICK: USB-console: Don't wait in interrupt contexts

Previously the USB console code would wait for up to
30 ms for the USB packet buffer to become available
for transmission, even if it was called from an interrupt
context.  This doesn't work because, even if we were OK
with waiting this long in interrupt contexts, which we are
not, we rightly assert that we are not in an interrupt
context in task_wait_event, which usleep calls.

This solution is a quick fix to only wait when not called
from within an interrupt context.  The correct solution
is likely to decouple the printf code from directly calling
the console driver code, instead we should place a queue
between the driver and printf logic.

Signed-off-by: Anton Staaf <robotboy@chromium.org>

BRANCH=None
BUG=None
TEST=make buildall -j
     Enable USB console on discovery board and manually test.

Change-Id: I8f6f820fefc970d84db2b637a1504193be4fd9ce
Original-Change-Id: I5b6f7bbb77f75132c75935f8fda01e652a236ae0
Reviewed-on: https://chromium-review.googlesource.com/225867
Tested-by: Anton Staaf <robotboy@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Anton Staaf <robotboy@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/229155
Reviewed-by: Mohammed Habibulla <moch@chromium.org>
Commit-Queue: Mohammed Habibulla <moch@chromium.org>
Tested-by: Mohammed Habibulla <moch@chromium.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/chip/stm32/usb_console.c b/chip/stm32/usb_console.c
index a8b219bb87..47e31711e0 100644
--- a/chip/stm32/usb_console.c
+++ b/chip/stm32/usb_console.c
@@ -146,7 +146,8 @@ static int usb_wait_console(void)
 	 */
 	if (last_tx_ok) {
 		while (usb_console_tx_valid() || !is_reset) {
-			if (timestamp_expired(deadline, NULL)) {
+			if (timestamp_expired(deadline, NULL) ||
+			    in_interrupt_context()) {
 				last_tx_ok = 0;
 				return EC_ERROR_TIMEOUT;
 			}