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-rw-r--r--src/include/bootstate.h8
-rw-r--r--src/lib/hardwaremain.c137
2 files changed, 126 insertions, 19 deletions
diff --git a/src/include/bootstate.h b/src/include/bootstate.h
index f732d1e1a2..0370c36067 100644
--- a/src/include/bootstate.h
+++ b/src/include/bootstate.h
@@ -156,6 +156,14 @@ int boot_state_sched_on_entry(struct boot_state_callback *bscb,
int boot_state_sched_on_exit(struct boot_state_callback *bscb,
boot_state_t state);
+/* Block/Unblock the (state, seq) pair from transitioning. Returns 0 on
+ * success < 0 when the phase of the (state,seq) has already ran. */
+int boot_state_block(boot_state_t state, boot_state_sequence_t seq);
+int boot_state_unblock(boot_state_t state, boot_state_sequence_t seq);
+/* Block/Unblock current state phase from transitioning. */
+void boot_state_current_block(void);
+void boot_state_current_unblock(void);
+
/* Entry into the boot state machine. */
void hardwaremain(int boot_complete);
diff --git a/src/lib/hardwaremain.c b/src/lib/hardwaremain.c
index 8e5481e398..39aae6d83f 100644
--- a/src/lib/hardwaremain.c
+++ b/src/lib/hardwaremain.c
@@ -72,10 +72,18 @@ struct boot_state_times {
struct mono_time samples[MAX_TIME_SAMPLES];
};
+/* The prologue (BS_ON_ENTRY) and epilogue (BS_ON_EXIT) of a state can be
+ * blocked from transitioning to the next (state,seq) pair. When the blockers
+ * field is 0 a transition may occur. */
+struct boot_phase {
+ struct boot_state_callback *callbacks;
+ int blockers;
+};
+
struct boot_state {
const char *name;
boot_state_t id;
- struct boot_state_callback *seq_callbacks[2];
+ struct boot_phase phases[2];
boot_state_t (*run_state)(void *arg);
void *arg;
int complete : 1;
@@ -89,7 +97,7 @@ struct boot_state {
{ \
.name = #state_, \
.id = state_, \
- .seq_callbacks = { NULL, NULL }, \
+ .phases = { { NULL, 0 }, { NULL, 0 } }, \
.run_state = run_func_, \
.arg = NULL, \
.complete = 0, \
@@ -299,29 +307,55 @@ static void bs_run_timers(int drain) {}
static void bs_call_callbacks(struct boot_state *state,
boot_state_sequence_t seq)
{
- while (state->seq_callbacks[seq] != NULL) {
- struct boot_state_callback *bscb;
+ struct boot_phase *phase = &state->phases[seq];
+
+ while (1) {
+ if (phase->callbacks != NULL) {
+ struct boot_state_callback *bscb;
- /* Remove the first callback. */
- bscb = state->seq_callbacks[seq];
- state->seq_callbacks[seq] = bscb->next;
- bscb->next = NULL;
+ /* Remove the first callback. */
+ bscb = phase->callbacks;
+ phase->callbacks = bscb->next;
+ bscb->next = NULL;
#if BOOT_STATE_DEBUG
- printk(BS_DEBUG_LVL, "BS: callback (%p) @ %s.\n",
- bscb, bscb->location);
+ printk(BS_DEBUG_LVL, "BS: callback (%p) @ %s.\n",
+ bscb, bscb->location);
#endif
- bscb->callback(bscb->arg);
+ bscb->callback(bscb->arg);
+
+ continue;
+ }
+
+ /* All callbacks are complete and there are no blockers for
+ * this state. Therefore, this part of the state is complete. */
+ if (!phase->blockers)
+ break;
+
+ /* Something is blocking this state from transitioning. As
+ * there are no more callbacks a pending timer needs to be
+ * ran to unblock the state. */
+ bs_run_timers(0);
}
}
-static void bs_walk_state_machine(boot_state_t current_state_id)
+/* Keep track of the current state. */
+static struct state_tracker {
+ boot_state_t state_id;
+ boot_state_sequence_t seq;
+} current_phase = {
+ .state_id = BS_PRE_DEVICE,
+ .seq = BS_ON_ENTRY,
+};
+
+static void bs_walk_state_machine(void)
{
while (1) {
struct boot_state *state;
+ boot_state_t next_id;
- state = &boot_states[current_state_id];
+ state = &boot_states[current_phase.state_id];
if (state->complete) {
printk(BIOS_EMERG, "BS: %s state already executed.\n",
@@ -335,17 +369,25 @@ static void bs_walk_state_machine(boot_state_t current_state_id)
bs_sample_time(state);
- bs_call_callbacks(state, BS_ON_ENTRY);
+ bs_call_callbacks(state, current_phase.seq);
+ /* Update the current sequence so that any calls to block the
+ * current state from the run_state() function will place a
+ * block on the correct phase. */
+ current_phase.seq = BS_ON_EXIT;
bs_sample_time(state);
- current_state_id = state->run_state(state->arg);
+ next_id = state->run_state(state->arg);
printk(BS_DEBUG_LVL, "BS: Exiting %s state.\n", state->name);
bs_sample_time(state);
- bs_call_callbacks(state, BS_ON_EXIT);
+ bs_call_callbacks(state, current_phase.seq);
+
+ /* Update the current phase with new state id and sequence. */
+ current_phase.state_id = next_id;
+ current_phase.seq = BS_ON_ENTRY;
bs_sample_time(state);
@@ -367,8 +409,8 @@ static int boot_state_sched_callback(struct boot_state *state,
return -1;
}
- bscb->next = state->seq_callbacks[seq];
- state->seq_callbacks[seq] = bscb;
+ bscb->next = state->phases[seq].callbacks;
+ state->phases[seq].callbacks = bscb;
return 0;
}
@@ -433,7 +475,64 @@ void hardwaremain(int boot_complete)
/* FIXME: Is there a better way to handle this? */
init_timer();
- bs_walk_state_machine(BS_PRE_DEVICE);
+ bs_walk_state_machine();
+
die("Boot state machine failure.\n");
}
+
+int boot_state_block(boot_state_t state, boot_state_sequence_t seq)
+{
+ struct boot_phase *bp;
+
+ /* Blocking a previously ran state is not appropriate. */
+ if (current_phase.state_id > state ||
+ (current_phase.state_id == state && current_phase.seq > seq) ) {
+ printk(BIOS_WARNING,
+ "BS: Completed state (%d, %d) block attempted.\n",
+ state, seq);
+ return -1;
+ }
+
+ bp = &boot_states[state].phases[seq];
+ bp->blockers++;
+
+ return 0;
+}
+
+int boot_state_unblock(boot_state_t state, boot_state_sequence_t seq)
+{
+ struct boot_phase *bp;
+
+ /* Blocking a previously ran state is not appropriate. */
+ if (current_phase.state_id > state ||
+ (current_phase.state_id == state && current_phase.seq > seq) ) {
+ printk(BIOS_WARNING,
+ "BS: Completed state (%d, %d) unblock attempted.\n",
+ state, seq);
+ return -1;
+ }
+
+ bp = &boot_states[state].phases[seq];
+
+ if (bp->blockers == 0) {
+ printk(BIOS_WARNING,
+ "BS: Unblock attempted on non-blocked state (%d, %d).\n",
+ state, seq);
+ return -1;
+ }
+
+ bp->blockers--;
+
+ return 0;
+}
+
+void boot_state_current_block(void)
+{
+ boot_state_block(current_phase.state_id, current_phase.seq);
+}
+
+void boot_state_current_unblock(void)
+{
+ boot_state_unblock(current_phase.state_id, current_phase.seq);
+}