Commit '635ce0db8956 ("soc: qcom: pmic_glink: don't traverse clients
list without a lock")' moved the pmic_glink client list under a
spinlock, as it is accessed by the rpmsg/glink callback, which in turn
is invoked from IRQ context.
This means that ucsi_unregister() is now called from IRQ context, which
isn't feasible as it's expecting a sleepable context. An effort is under
way to get GLINK to invoke its callbacks in a sleepable context, but
until then lets schedule the unregistration.
A side effect of this is that ucsi_unregister() can now happen
after the remote processor, and thereby the communication link with it, is
gone. pmic_glink_send() is amended with a check to avoid the resulting NULL
pointer dereference.
This does however result in the user being informed about this error by
the following entry in the kernel log:
ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5
Fixes: 635ce0db8956 ("soc: qcom: pmic_glink: don't traverse clients list without a lock")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Tested-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
---
drivers/soc/qcom/pmic_glink.c | 10 +++++++++-
drivers/usb/typec/ucsi/ucsi_glink.c | 27 ++++++++++++++++++++++-----
2 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
index 58ec91767d79..e4747f1d3da5 100644
--- a/drivers/soc/qcom/pmic_glink.c
+++ b/drivers/soc/qcom/pmic_glink.c
@@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_register_client);
int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
{
struct pmic_glink *pg = client->pg;
+ int ret;
- return rpmsg_send(pg->ept, data, len);
+ mutex_lock(&pg->state_lock);
+ if (!pg->ept)
+ ret = -ECONNRESET;
+ else
+ ret = rpmsg_send(pg->ept, data, len);
+ mutex_unlock(&pg->state_lock);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(pmic_glink_send);
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
index ac53a81c2a81..bb6244f21e0a 100644
--- a/drivers/usb/typec/ucsi/ucsi_glink.c
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -68,6 +68,9 @@ struct pmic_glink_ucsi {
struct work_struct notify_work;
struct work_struct register_work;
+ spinlock_t state_lock;
+ bool ucsi_registered;
+ bool pd_running;
u8 read_buf[UCSI_BUF_SIZE];
};
@@ -244,8 +247,20 @@ static void pmic_glink_ucsi_notify(struct work_struct *work)
static void pmic_glink_ucsi_register(struct work_struct *work)
{
struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work);
+ unsigned long flags;
+ bool pd_running;
- ucsi_register(ucsi->ucsi);
+ spin_lock_irqsave(&ucsi->state_lock, flags);
+ pd_running = ucsi->pd_running;
+ spin_unlock_irqrestore(&ucsi->state_lock, flags);
+
+ if (!ucsi->ucsi_registered && pd_running) {
+ ucsi_register(ucsi->ucsi);
+ ucsi->ucsi_registered = true;
+ } else if (ucsi->ucsi_registered && !pd_running) {
+ ucsi_unregister(ucsi->ucsi);
+ ucsi->ucsi_registered = false;
+ }
}
static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
@@ -269,11 +284,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
static void pmic_glink_ucsi_pdr_notify(void *priv, int state)
{
struct pmic_glink_ucsi *ucsi = priv;
+ unsigned long flags;
- if (state == SERVREG_SERVICE_STATE_UP)
- schedule_work(&ucsi->register_work);
- else if (state == SERVREG_SERVICE_STATE_DOWN)
- ucsi_unregister(ucsi->ucsi);
+ spin_lock_irqsave(&ucsi->state_lock, flags);
+ ucsi->pd_running = state == SERVREG_SERVICE_STATE_UP;
+ spin_unlock_irqrestore(&ucsi->state_lock, flags);
+ schedule_work(&ucsi->register_work);
}
static void pmic_glink_ucsi_destroy(void *data)
@@ -320,6 +336,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register);
init_completion(&ucsi->read_ack);
init_completion(&ucsi->write_ack);
+ spin_lock_init(&ucsi->state_lock);
mutex_init(&ucsi->lock);
ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);
--
2.34.1
