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drivers/pn53x_usb: rework timeout usage

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This commit is contained in:
Romuald Conty 2011-09-22 16:21:22 +00:00
parent 481fb4943f
commit 87c13825af
1 changed files with 56 additions and 6 deletions
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62
libnfc/drivers/pn53x_usb.c
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@ -65,6 +65,37 @@ Thanks to d18c7db and Okko for example code
#define DRIVER_DATA(pnd) ((struct pn53x_usb_data*)(pnd->driver_data))
/* This modified from some GNU example _not_ to overwrite y */
int timeval_subtract(struct timeval *result,
const struct timeval *x,
const struct timeval *y)
{
struct timeval tmp;
tmp.tv_sec = y->tv_sec;
tmp.tv_usec = y->tv_usec;
/* Perform the carry for the later subtraction */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
tmp.tv_usec -= 1000000 * nsec;
tmp.tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
tmp.tv_usec += 1000000 * nsec;
tmp.tv_sec -= nsec;
}
/* Compute the time remaining to wait.
tv_usec is certainly positive. */
result->tv_sec = x->tv_sec - tmp.tv_sec;
result->tv_usec = x->tv_usec - tmp.tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < tmp.tv_sec;
}
typedef enum {
UNKNOWN,
NXP_PN531,
@ -99,7 +130,8 @@ pn53x_usb_bulk_read (struct pn53x_usb_data *data, byte_t abtRx[], const size_t s
if (res > 0) {
LOG_HEX ("RX", abtRx, res);
} else if (res < 0) {
log_put (LOG_CATEGORY, NFC_PRIORITY_ERROR, "Unable to read from USB (%s)", _usb_strerror (res));
if (res != -USB_TIMEDOUT)
log_put (LOG_CATEGORY, NFC_PRIORITY_ERROR, "Unable to read from USB (%s)", _usb_strerror (res));
}
return res;
}
@ -462,9 +494,6 @@ pn53x_usb_receive (nfc_device_t * pnd, byte_t * pbtData, const size_t szDataLen,
switch (CHIP_DATA (pnd)->ui8LastCommand) {
case InDataExchange:
case TgGetData:
if (!timeout)
delayed_reply = true;
break;
case InJumpForDEP:
case TgInitAsTarget:
delayed_reply = true;
@ -480,12 +509,33 @@ pn53x_usb_receive (nfc_device_t * pnd, byte_t * pbtData, const size_t szDataLen,
* If no timeout is specified but the command is blocking, force a 250ms
* timeout to allow breaking the loop if the user wants to stop it.
*/
struct timeval fixed_timeout = {
const struct timeval fixed_timeout = {
.tv_sec = 0,
.tv_usec = 250000,
};
struct timeval remaining_time, usb_timeout;
if (timeout) {
remaining_time = *timeout;
}
read:
res = pn53x_usb_bulk_read (DRIVER_DATA (pnd), abtRxBuf, sizeof (abtRxBuf), (delayed_reply && !timeout) ? &fixed_timeout : timeout);
if (timeout) {
// A user-provided timeout is set, we have to cut it in multiple chunk to be able to keep an nfc_abort_command() mecanism
struct timeval tmp;
if (1 == timeval_subtract (&tmp, &remaining_time, &fixed_timeout)) {
// The subtraction result is negative
usb_timeout = remaining_time;
remaining_time.tv_sec = 0;
remaining_time.tv_usec = 0;
} else {
usb_timeout = fixed_timeout;
remaining_time = tmp;
}
} else {
// No user-provided timeout, we will wait infinitely but we need nfc_abort_command() mecanism.
usb_timeout = fixed_timeout;
}
res = pn53x_usb_bulk_read (DRIVER_DATA (pnd), abtRxBuf, sizeof (abtRxBuf), &usb_timeout);
if (delayed_reply && (res == -USB_TIMEDOUT)) {
if (DRIVER_DATA (pnd)->abort_flag) {