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Message-ID: <20260108050103.126008-1-pshete@nvidia.com>
Date: Thu, 8 Jan 2026 05:01:03 +0000
From: Prathamesh Shete <pshete@...dia.com>
To: <thierry.reding@...il.com>, <jonathanh@...dia.com>,
<ulf.hansson@...aro.org>, <chleroy@...nel.org>, <jirislaby@...nel.org>,
<haotienh@...dia.com>, <linux-tegra@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
CC: <pshete@...dia.com>, <petlozup@...dia.com>
Subject: [PATCH] soc/tegra: pmc: Fix unsafe generic_handle_irq() call
Currently, when resuming from system suspend on Tegra platforms,
the following warning is observed:
WARNING: CPU: 0 PID: 14459 at kernel/irq/irqdesc.c:666
Call trace:
handle_irq_desc+0x20/0x58 (P)
tegra186_pmc_wake_syscore_resume+0xe4/0x15c
syscore_resume+0x3c/0xb8
suspend_devices_and_enter+0x510/0x540
pm_suspend+0x16c/0x1d8
The warning occurs because generic_handle_irq() is being called from
a non-interrupt context which is considered as unsafe.
Fix this warning by deferring generic_handle_irq() call to an IRQ work
which gets executed in hard IRQ context where generic_handle_irq()
can be called safely.
When PREEMPT_RT kernels are used, regular IRQ work (initialized with
init_irq_work) is deferred to run in per-CPU kthreads in preemptible
context rather than hard IRQ context. Hence, use the IRQ_WORK_INIT_HARD
variant so that with PREEMPT_RT kernels, the IRQ work is processed in
hardirq context instead of being deferred to a thread which is required
for calling generic_handle_irq().
On non-PREEMPT_RT kernels, both init_irq_work() and IRQ_WORK_INIT_HARD()
execute in IRQ context, so this change has no functional impact for
standard kernel configurations.
Signed-off-by: Petlozu Pravareshwar <petlozup@...dia.com>
Signed-off-by: Prathamesh Shete <pshete@...dia.com>
---
drivers/soc/tegra/pmc.c | 106 ++++++++++++++++++++++++++++------------
1 file changed, 76 insertions(+), 30 deletions(-)
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index f3760a3b3026..a0cc276e235a 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -28,6 +28,7 @@
#include <linux/iopoll.h>
#include <linux/irqdomain.h>
#include <linux/irq.h>
+#include <linux/irq_work.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/of_clk.h>
@@ -336,6 +337,8 @@ struct tegra_wake_event {
}, \
}
+#define TEGRA_PMC_MAX_WAKE_VECTORS 4
+
struct tegra_pmc_soc {
unsigned int num_powergates;
const char *const *powergates;
@@ -468,6 +471,10 @@ struct tegra_pmc {
unsigned long *wake_sw_status_map;
unsigned long *wake_cntrl_level_map;
struct syscore syscore;
+
+ /* Pending wake IRQ processing */
+ u32 pending_wake_status[TEGRA_PMC_MAX_WAKE_VECTORS];
+ struct irq_work pending_wake_irq_work;
};
static struct tegra_pmc *pmc = &(struct tegra_pmc) {
@@ -1905,8 +1912,59 @@ static int tegra_pmc_parse_dt(struct tegra_pmc *pmc, struct device_node *np)
return 0;
}
+/* translate sc7 wake sources back into IRQs to catch edge triggered wakeups */
+static void tegra186_pmc_wake_irq_work_handler(struct irq_work *work)
+{
+ struct tegra_pmc *pmc = container_of(work, struct tegra_pmc,
+ pending_wake_irq_work);
+ unsigned int i, wake;
+ unsigned long pending_wake_status;
+
+ for (i = 0; i < pmc->soc->max_wake_vectors; i++) {
+ pending_wake_status = pmc->pending_wake_status[i];
+
+ for_each_set_bit(wake, &pending_wake_status, 32) {
+ irq_hw_number_t hwirq = wake + (i * 32);
+ struct irq_desc *desc;
+ unsigned int irq;
+
+ irq = irq_find_mapping(pmc->domain, hwirq);
+ if (!irq) {
+ dev_warn(pmc->dev, "No IRQ found for WAKE%lu!\n",
+ hwirq);
+ continue;
+ }
+
+ dev_dbg(pmc->dev,
+ "Resume caused by WAKE%lu mapped to IRQ %d\n",
+ hwirq, irq);
+
+ desc = irq_to_desc(irq);
+ if (!desc) {
+ dev_warn(pmc->dev,
+ "No descriptor found for IRQ %d\n",
+ irq);
+ continue;
+ }
+
+ if (!desc->action || !desc->action->name)
+ continue;
+
+ generic_handle_irq(irq);
+ }
+
+ pmc->pending_wake_status[i] = 0;
+ }
+}
+
static int tegra_pmc_init(struct tegra_pmc *pmc)
{
+ if (pmc->soc->max_wake_vectors > TEGRA_PMC_MAX_WAKE_VECTORS) {
+ dev_err(pmc->dev, "max_wake_vectors (%u) exceeds maximum (%u)\n",
+ pmc->soc->max_wake_vectors, TEGRA_PMC_MAX_WAKE_VECTORS);
+ return -EINVAL;
+ }
+
if (pmc->soc->max_wake_events > 0) {
pmc->wake_type_level_map = bitmap_zalloc(pmc->soc->max_wake_events, GFP_KERNEL);
if (!pmc->wake_type_level_map)
@@ -1923,6 +1981,12 @@ static int tegra_pmc_init(struct tegra_pmc *pmc)
pmc->wake_cntrl_level_map = bitmap_zalloc(pmc->soc->max_wake_events, GFP_KERNEL);
if (!pmc->wake_cntrl_level_map)
return -ENOMEM;
+
+ /* Initialize IRQ work for processing wake IRQs
+ * Must use HARD_IRQ variant to run in hard IRQ context on PREEMPT_RT
+ * because we call generic_handle_irq() which requires hard IRQ context.
+ */
+ pmc->pending_wake_irq_work = IRQ_WORK_INIT_HARD(tegra186_pmc_wake_irq_work_handler);
}
if (pmc->soc->init)
@@ -3129,47 +3193,29 @@ static void wke_clear_wake_status(struct tegra_pmc *pmc)
}
}
-/* translate sc7 wake sources back into IRQs to catch edge triggered wakeups */
-static void tegra186_pmc_process_wake_events(struct tegra_pmc *pmc, unsigned int index,
- unsigned long status)
-{
- unsigned int wake;
-
- dev_dbg(pmc->dev, "Wake[%d:%d] status=%#lx\n", (index * 32) + 31, index * 32, status);
-
- for_each_set_bit(wake, &status, 32) {
- irq_hw_number_t hwirq = wake + 32 * index;
- struct irq_desc *desc;
- unsigned int irq;
-
- irq = irq_find_mapping(pmc->domain, hwirq);
-
- desc = irq_to_desc(irq);
- if (!desc || !desc->action || !desc->action->name) {
- dev_dbg(pmc->dev, "Resume caused by WAKE%ld, IRQ %d\n", hwirq, irq);
- continue;
- }
-
- dev_dbg(pmc->dev, "Resume caused by WAKE%ld, %s\n", hwirq, desc->action->name);
- generic_handle_irq(irq);
- }
-}
-
static void tegra186_pmc_wake_syscore_resume(void *data)
{
- u32 status, mask;
+ u32 mask;
unsigned int i;
for (i = 0; i < pmc->soc->max_wake_vectors; i++) {
mask = readl(pmc->wake + WAKE_AOWAKE_TIER2_ROUTING(i));
- status = readl(pmc->wake + WAKE_AOWAKE_STATUS_R(i)) & mask;
-
- tegra186_pmc_process_wake_events(pmc, i, status);
+ pmc->pending_wake_status[i] = readl(pmc->wake + WAKE_AOWAKE_STATUS_R(i)) & mask;
}
+ /* Schedule IRQ work to process wake IRQs (if any) */
+ irq_work_queue(&pmc->pending_wake_irq_work);
}
static int tegra186_pmc_wake_syscore_suspend(void *data)
{
+ unsigned int i;
+
+ /* Check if there are unhandled wake IRQs */
+ for (i = 0; i < pmc->soc->max_wake_vectors; i++)
+ if (pmc->pending_wake_status[i])
+ dev_warn(pmc->dev,
+ "Unhandled wake IRQs pending vector[%u]: 0x%x\n",
+ i, pmc->pending_wake_status[i]);
wke_read_sw_wake_status(pmc);
/* flip the wakeup trigger for dual-edge triggered pads
--
2.25.1
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