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authorStephan Gerhold <stephan@gerhold.net>2021-07-12 15:57:03 +0200
committerBjorn Andersson <bjorn.andersson@linaro.org>2021-08-04 22:20:09 -0500
commite3d4571955050736bbf3eda0a9538a09d9fcfce8 (patch)
tree7919def3bbbe9f9eebe32f1483e79f485c6fc2b7 /drivers/soc
parentc73a6852b42c8c80cc46590dbbcfa6c448fdbc63 (diff)
soc: qcom: smsm: Fix missed interrupts if state changes while masked
The SMSM driver detects interrupt edges by tracking the last state it has seen (and has triggered the interrupt handler for). This works fine, but only if the interrupt does not change state while masked. For example, if an interrupt is unmasked while the state is HIGH, the stored last_value for that interrupt might still be LOW. Then, when the remote processor triggers smsm_intr() we assume that nothing has changed, even though the state might have changed from HIGH to LOW. Attempt to fix this by checking the current remote state before unmasking an IRQ. Use atomic operations to avoid the interrupt handler from interfering with the unmask function. This fixes modem crashes in some edge cases with the BAM-DMUX driver. Specifically, the BAM-DMUX interrupt handler is not called for the HIGH -> LOW smsm state transition if the BAM-DMUX driver is loaded (and therefore unmasks the interrupt) after the modem was already started: qcom-q6v5-mss 4080000.remoteproc: fatal error received: a2_task.c:3188: Assert FALSE failed: A2 DL PER deadlock timer expired waiting for Apps ACK Fixes: c97c4090ff72 ("soc: qcom: smsm: Add driver for Qualcomm SMSM") Signed-off-by: Stephan Gerhold <stephan@gerhold.net> Link: https://lore.kernel.org/r/20210712135703.324748-2-stephan@gerhold.net Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Diffstat (limited to 'drivers/soc')
-rw-r--r--drivers/soc/qcom/smsm.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index a48f9db98836..ef15d014c03a 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -109,7 +109,7 @@ struct smsm_entry {
DECLARE_BITMAP(irq_enabled, 32);
DECLARE_BITMAP(irq_rising, 32);
DECLARE_BITMAP(irq_falling, 32);
- u32 last_value;
+ unsigned long last_value;
u32 *remote_state;
u32 *subscription;
@@ -204,8 +204,7 @@ static irqreturn_t smsm_intr(int irq, void *data)
u32 val;
val = readl(entry->remote_state);
- changed = val ^ entry->last_value;
- entry->last_value = val;
+ changed = val ^ xchg(&entry->last_value, val);
for_each_set_bit(i, entry->irq_enabled, 32) {
if (!(changed & BIT(i)))
@@ -264,6 +263,12 @@ static void smsm_unmask_irq(struct irq_data *irqd)
struct qcom_smsm *smsm = entry->smsm;
u32 val;
+ /* Make sure our last cached state is up-to-date */
+ if (readl(entry->remote_state) & BIT(irq))
+ set_bit(irq, &entry->last_value);
+ else
+ clear_bit(irq, &entry->last_value);
+
set_bit(irq, entry->irq_enabled);
if (entry->subscription) {