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authorPavan Savoy <pavan_savoy@ti.com>2011-12-15 10:38:20 -0600
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-04 15:21:03 -0800
commitbfb88d6c91a2cf507ff7763ebec94d72b4c98b07 (patch)
treeddb098bbb0ee412d6121d2e22061850d602b0a30
parent1ff97647f066aef72ae68042c9abc4a837a12e6d (diff)
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>
-rw-r--r--drivers/misc/ti-st/st_core.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/drivers/misc/ti-st/st_core.c b/drivers/misc/ti-st/st_core.c
index ba168a7d54d4..2b62232c2c6a 100644
--- a/drivers/misc/ti-st/st_core.c
+++ b/drivers/misc/ti-st/st_core.c
@@ -137,6 +137,8 @@ void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
* 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 @@ long st_register(struct st_proto_s *new_proto)
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 @@ long st_register(struct st_proto_s *new_proto)
(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 @@ long st_register(struct st_proto_s *new_proto)
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 @@ long st_unregister(struct st_proto_s *proto)
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 @@ long st_unregister(struct st_proto_s *proto)
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 ");