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driver/at86rf2xx: Fix possible race condition where at86rf2xx_configure returns to the wrong state if waited on finished state in at86rf2xx_setstate #7115

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Merged
thomaseichinger merged 1 commit into from
Jun 26, 2017
Merged

driver/at86rf2xx: Fix possible race condition where at86rf2xx_configure returns to the wrong state if waited on finished state in at86rf2xx_setstate #7115

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14 changes: 3 additions & 11 deletions drivers/at86rf2xx/at86rf2xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -136,18 +136,10 @@ size_t at86rf2xx_send(at86rf2xx_t *dev, uint8_t *data, size_t len)

void at86rf2xx_tx_prepare(at86rf2xx_t *dev)
{
uint8_t state;

dev->pending_tx++;
/* make sure ongoing transmissions are finished */
do {
state = at86rf2xx_get_status(dev);
} while (state == AT86RF2XX_STATE_BUSY_RX_AACK ||
state == AT86RF2XX_STATE_BUSY_TX_ARET);
if (state != AT86RF2XX_STATE_TX_ARET_ON) {
dev->idle_state = state;
}
at86rf2xx_set_state(dev, AT86RF2XX_STATE_TX_ARET_ON);

dev->idle_state = at86rf2xx_set_state(dev, AT86RF2XX_STATE_TX_ARET_ON);

dev->tx_frame_len = IEEE802154_FCS_LEN;
}

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28 changes: 13 additions & 15 deletions drivers/at86rf2xx/at86rf2xx_getset.c
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Expand Up @@ -444,29 +444,25 @@ static inline void _set_state(at86rf2xx_t *dev, uint8_t state, uint8_t cmd)
dev->state = state;
}

void at86rf2xx_set_state(at86rf2xx_t *dev, uint8_t state)
uint8_t at86rf2xx_set_state(at86rf2xx_t *dev, uint8_t state)
{
uint8_t old_state = at86rf2xx_get_status(dev);

if (state == old_state) {
return;
}

if (state == AT86RF2XX_STATE_FORCE_TRX_OFF) {
_set_state(dev, AT86RF2XX_STATE_TRX_OFF, state);
return;
}
uint8_t old_state;

/* make sure there is no ongoing transmission, or state transition already
* in progress */
while (old_state == AT86RF2XX_STATE_BUSY_RX_AACK ||
old_state == AT86RF2XX_STATE_BUSY_TX_ARET ||
old_state == AT86RF2XX_STATE_IN_PROGRESS) {
do {
old_state = at86rf2xx_get_status(dev);
} while (old_state == AT86RF2XX_STATE_BUSY_RX_AACK ||
old_state == AT86RF2XX_STATE_BUSY_TX_ARET ||
old_state == AT86RF2XX_STATE_IN_PROGRESS);

if (state == AT86RF2XX_STATE_FORCE_TRX_OFF) {
_set_state(dev, AT86RF2XX_STATE_TRX_OFF, state);
return old_state;
}

if (state == old_state) {
return;
return old_state;
}

/* we need to go via PLL_ON if we are moving between RX_AACK_ON <-> TX_ARET_ON */
Expand All @@ -493,6 +489,8 @@ void at86rf2xx_set_state(at86rf2xx_t *dev, uint8_t state)
} else {
_set_state(dev, state, state);
}

return old_state;
}

void at86rf2xx_reset_state_machine(at86rf2xx_t *dev)
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6 changes: 2 additions & 4 deletions drivers/at86rf2xx/at86rf2xx_internal.c
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Expand Up @@ -147,10 +147,8 @@ void at86rf2xx_hardware_reset(at86rf2xx_t *dev)

void at86rf2xx_configure_phy(at86rf2xx_t *dev)
{
uint8_t state = at86rf2xx_get_status(dev);

/* we must be in TRX_OFF before changing the PHY configuration */
at86rf2xx_set_state(dev, AT86RF2XX_STATE_TRX_OFF);
uint8_t prev_state = at86rf2xx_set_state(dev, AT86RF2XX_STATE_TRX_OFF);

#ifdef MODULE_AT86RF212B
/* The TX power register must be updated after changing the channel if
Expand Down Expand Up @@ -200,7 +198,7 @@ void at86rf2xx_configure_phy(at86rf2xx_t *dev)
#endif

/* Return to the state we had before reconfiguring */
at86rf2xx_set_state(dev, state);
at86rf2xx_set_state(dev, prev_state);
}

#if defined(MODULE_AT86RF233) || defined(MODULE_AT86RF231)
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4 changes: 3 additions & 1 deletion drivers/include/at86rf2xx.h
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Expand Up @@ -385,8 +385,10 @@ void at86rf2xx_set_option(at86rf2xx_t *dev, uint16_t option, bool state);
*
* @param[in] dev device to change state of
* @param[in] state the targeted new state
*
* @return the previous state before the new state was set
*/
void at86rf2xx_set_state(at86rf2xx_t *dev, uint8_t state);
uint8_t at86rf2xx_set_state(at86rf2xx_t *dev, uint8_t state);

/**
* @brief Reset the internal state machine to TRX_OFF mode.
Expand Down