Use integer rounding for the computation of prescaler.
Improve the test of prescaler range, knowing its value would be
decremented before being written in TPIU ACPR.
Change-Id: I041dde1dca41323904e36a6b6975028a6de902b3
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5909
Tested-by: jenkins
uint16_t *prescaler)
{
struct stlink_usb_handle_s *h = handle;
uint16_t *prescaler)
{
struct stlink_usb_handle_s *h = handle;
if (enabled && (!(h->version.flags & STLINK_F_HAS_TRACE) ||
pin_protocol != TPIU_PIN_PROTOCOL_ASYNC_UART)) {
if (enabled && (!(h->version.flags & STLINK_F_HAS_TRACE) ||
pin_protocol != TPIU_PIN_PROTOCOL_ASYNC_UART)) {
if (!*trace_freq)
*trace_freq = max_trace_freq;
if (!*trace_freq)
*trace_freq = max_trace_freq;
- presc = traceclkin_freq / *trace_freq;
-
- if (traceclkin_freq % *trace_freq > 0)
- presc++;
+ unsigned int presc = (traceclkin_freq + *trace_freq / 2) / *trace_freq;
+ if (presc == 0 || presc > TPIU_ACPR_MAX_SWOSCALER + 1) {
+ LOG_ERROR("SWO frequency is not suitable. Please choose a different "
+ "frequency.");
+ return ERROR_FAIL;
+ }
- if (presc > TPIU_ACPR_MAX_SWOSCALER) {
+ /* Probe's UART speed must be within 3% of the TPIU's SWO baud rate. */
+ unsigned int max_deviation = (traceclkin_freq * 3) / 100;
+ if (presc * *trace_freq < traceclkin_freq - max_deviation ||
+ presc * *trace_freq > traceclkin_freq + max_deviation) {
LOG_ERROR("SWO frequency is not suitable. Please choose a different "
"frequency.");
return ERROR_FAIL;
LOG_ERROR("SWO frequency is not suitable. Please choose a different "
"frequency.");
return ERROR_FAIL;