diff options
| author | Lasse Dalegaard <dalegaard@gmail.com> | 2021-10-27 11:02:10 +0100 |
|---|---|---|
| committer | KevinOConnor <kevin@koconnor.net> | 2021-10-27 11:10:17 -0400 |
| commit | de331802365020f3a13ab6ffa97a3c96609af161 (patch) | |
| tree | feb397ea53070da6eb82e7f7c5a60359fc44e90c /src | |
| parent | aa481fd9c3fc915537a51966320773fcf7008e7b (diff) | |
| download | kutter-de331802365020f3a13ab6ffa97a3c96609af161.tar.gz kutter-de331802365020f3a13ab6ffa97a3c96609af161.tar.xz kutter-de331802365020f3a13ab6ffa97a3c96609af161.zip | |
rp2040: add barrier in usb_read_ep0_setup
Some versions of gcc, in some cases, decide that it is OK to move the
read to `INTR` to right after clearing the `SETUP_REC` bit of
`SIE_STATUS`, instead of after the `memcpy`.
The rp2040 datasheet doesn't appear to say anything about how quickly
the `SETUP_REC` bit will be cleared in `INTR`, but regardless the
compiler should not be re-ordering the read like this.
Here we force the correct ordering using a memory barrier.
Signed-off-by: Lasse Dalegaard <dalegaard@gmail.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/rp2040/usbserial.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/rp2040/usbserial.c b/src/rp2040/usbserial.c index 3cd2e9d8..030f4752 100644 --- a/src/rp2040/usbserial.c +++ b/src/rp2040/usbserial.c @@ -96,6 +96,7 @@ usb_read_ep0_setup(void *data, uint_fast8_t max_len) | USB_BUF_CTRL_AVAIL | DPBUF_SIZE); usb_hw->sie_status = USB_SIE_STATUS_SETUP_REC_BITS; memcpy(data, (void*)usb_dpram->setup_packet, max_len); + barrier(); if (usb_hw->intr & USB_INTR_SETUP_REQ_BITS) { // Raced with next setup packet usb_notify_ep0(); |