drivers:misc: ti-st: protect registrations
Concurrent access to UART2/combo-interface by multiple protocol drivers such
as BT, FM and GPS caused issues during firmware download failure cases or
cases when the firmware download took longer than usual.
This was because of un-safe access to protos_registered & st_states.
Protecting this will also make the registration complete callback un-safe for
sleep.
Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/misc/ti-st/st_core.c b/drivers/misc/ti-st/st_core.c
index ba168a7..2b62232 100644
--- a/drivers/misc/ti-st/st_core.c
+++ b/drivers/misc/ti-st/st_core.c
@@ -137,6 +137,8 @@
* st_reg_complete -
* to call registration complete callbacks
* of all protocol stack drivers
+ * This function is being called with spin lock held, protocol drivers are
+ * only expected to complete their waits and do nothing more than that.
*/
void st_reg_complete(struct st_data_s *st_gdata, char err)
{
@@ -538,11 +540,12 @@
set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
st_recv = st_kim_recv;
+ /* enable the ST LL - to set default chip state */
+ st_ll_enable(st_gdata);
+
/* release lock previously held - re-locked below */
spin_unlock_irqrestore(&st_gdata->lock, flags);
- /* enable the ST LL - to set default chip state */
- st_ll_enable(st_gdata);
/* this may take a while to complete
* since it involves BT fw download
*/
@@ -553,10 +556,13 @@
(test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
pr_err(" KIM failure complete callback ");
st_reg_complete(st_gdata, err);
+ clear_bit(ST_REG_PENDING, &st_gdata->st_state);
}
return -EINVAL;
}
+ spin_lock_irqsave(&st_gdata->lock, flags);
+
clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
st_recv = st_int_recv;
@@ -576,10 +582,10 @@
if (st_gdata->is_registered[new_proto->chnl_id] == true) {
pr_err(" proto %d already registered ",
new_proto->chnl_id);
+ spin_unlock_irqrestore(&st_gdata->lock, flags);
return -EALREADY;
}
- spin_lock_irqsave(&st_gdata->lock, flags);
add_channel_to_table(st_gdata, new_proto);
st_gdata->protos_registered++;
new_proto->write = st_write;
@@ -619,7 +625,7 @@
spin_lock_irqsave(&st_gdata->lock, flags);
- if (st_gdata->list[proto->chnl_id] == NULL) {
+ if (st_gdata->is_registered[proto->chnl_id] == false) {
pr_err(" chnl_id %d not registered", proto->chnl_id);
spin_unlock_irqrestore(&st_gdata->lock, flags);
return -EPROTONOSUPPORT;
@@ -629,6 +635,10 @@
remove_channel_from_table(st_gdata, proto);
spin_unlock_irqrestore(&st_gdata->lock, flags);
+ /* paranoid check */
+ if (st_gdata->protos_registered < ST_EMPTY)
+ st_gdata->protos_registered = ST_EMPTY;
+
if ((st_gdata->protos_registered == ST_EMPTY) &&
(!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
pr_info(" all chnl_ids unregistered ");