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ethercat
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Cherry-picked MR 188 (injection-semaphore) from 1.7.

This commit is contained in:
Florian Pose 2026-03-26 16:41:43 +01:00
parent 98563a2f0d
commit cf19168844
1 changed files with 32 additions and 4 deletions
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36
master/master.c
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@ -61,6 +61,23 @@
rt_mutex_lock_interruptible(lock, 0)
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 12, 47)
#define smp_store_release(p, v) \
do { \
smp_mb(); \
ACCESS_ONCE(*p) = (v); \
} while (0)
#define smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = ACCESS_ONCE(*p); \
smp_mb(); \
___p1; \
})
#endif
#include "master.h"
/****************************************************************************/
@ -195,6 +212,7 @@ int ec_master_init(ec_master_t *master, /**< EtherCAT master */
master->phase = EC_ORPHANED;
master->active = 0;
master->config_changed = 0;
master->injection_seq_fsm = 0;
master->injection_seq_rt = 0;
@ -1596,6 +1614,7 @@ static int ec_master_idle_thread(void *priv_data)
static int ec_master_operation_thread(void *priv_data)
{
ec_master_t *master = (ec_master_t *) priv_data;
unsigned int seq_rt;
EC_MASTER_DBG(master, 1, "Operation thread running"
" with fsm interval = %u us, max data size=%zu\n",
@ -1604,7 +1623,11 @@ static int ec_master_operation_thread(void *priv_data)
while (!kthread_should_stop()) {
ec_datagram_output_stats(&master->fsm_datagram);
if (master->injection_seq_rt == master->injection_seq_fsm) {
/* Use smp_load_acquire() to prevent re-ordering.
* https://gitlab.com/etherlab.org/ethercat/-/work_items/168 */
seq_rt = smp_load_acquire(&master->injection_seq_rt);
if (seq_rt == master->injection_seq_fsm) { // was injected
// output statistics
ec_master_output_stats(master);
@ -1616,7 +1639,9 @@ static int ec_master_operation_thread(void *priv_data)
if (ec_fsm_master_exec(&master->fsm)) {
// Inject datagrams (let the RT thread queue them, see
// ecrt_master_send())
master->injection_seq_fsm++;
// re-ordering-safe version of `master->injection_seq_fsm++`
smp_store_release(&master->injection_seq_fsm,
master->injection_seq_fsm + 1);
}
ec_master_exec_slave_fsms(master);
@ -2436,11 +2461,14 @@ int ecrt_master_send(ec_master_t *master)
{
ec_datagram_t *datagram, *n;
ec_device_index_t dev_idx;
unsigned int seq_fsm;
if (master->injection_seq_rt != master->injection_seq_fsm) {
seq_fsm = smp_load_acquire(&master->injection_seq_fsm);
if (master->injection_seq_rt != seq_fsm) {
// inject datagram produced by master FSM
ec_master_queue_datagram(master, &master->fsm_datagram);
master->injection_seq_rt = master->injection_seq_fsm;
smp_store_release(&master->injection_seq_rt, seq_fsm);
}
ec_master_inject_external_datagrams(master);