FAILED: patch "[PATCH] irqchip/stm32mp-exti: Fix the unit of the hwspinlock timeout" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x d31fbbade43f880b7e59e2b3a72722fe2725d93f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090812-banker-manhandle-d0d6@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d31fbbade43f880b7e59e2b3a72722fe2725d93f Mon Sep 17 00:00:00 2001
From: Ju Nan <[email protected]>
Date: Fri, 21 Aug 2026 10:47:57 +0800
Subject: [PATCH] irqchip/stm32mp-exti: Fix the unit of the hwspinlock timeout

HWSPNLCK_TIMEOUT is passed to hwspin_lock_timeout_in_atomic(), whose timeout argument is in milliseconds, not microseconds:

  atomic_delay += HWSPINLOCK_RETRY_DELAY_US;
  if (atomic_delay > to * 1000)
          return -ETIMEDOUT;

So stm32mp_exti_set_type() asks for a 1 second timeout where the comment next to the macro says it wants 1 millisecond. The semaphore is polled with udelay() from a section that holds chip_data->rlock, a raw_spinlock_t, so preemption stays disabled for the whole wait on every configuration, PREEMPT_RT included.

The hwspinlock core documents this explicitly:

If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the timeout is handled with busy-waiting delays, hence shall not exceed few msecs.

index bf3a2def69ca..a19e91fbd010 100644
@@ -22,7 +22,7 @@
 
 #define IRQS_PER_BANK			32
 
-#define HWSPNLCK_TIMEOUT		1000 /* usec */
+#define HWSPNLCK_TIMEOUT_MS		1
 
 #define EXTI_EnCIDCFGR(n)		(0x180 + (n) * 4)
 #define EXTI_HWCFGR1			0x3f0

@@ -376,7 +376,7 @@ static int stm32mp_exti_set_type(struct irq_data *d, unsigned int type)
 	raw_spin_lock(&chip_data->rlock);
 
 	if (hwlock) {
-		err = hwspin_lock_timeout_in_atomic(hwlock, HWSPNLCK_TIMEOUT);
+		err = hwspin_lock_timeout_in_atomic(hwlock, HWSPNLCK_TIMEOUT_MS);
 		if (err) {
 			pr_err("%s can't get hwspinlock (%d)\n", __func__, err);
 			goto unlock;

From: Antonio Borneo <[email protected]>

[ Upstream commit 350755e2e548ccbe941d045900b57233efa906cb ]

Keep only the code for ARMv7m STM32 MCUs in in stm32-exti.c and split out the code for ARMv7a & ARMv8a STM32MPxxx MPUs into stm32mp-exti.c

Adapt the split to Linux 6.6 without importing the intervening standard-PM, interrupts-extended, secure-event, or RIF changes. Move the existing MPU implementation, including its syscore callbacks and platform remove hook, to irq-stm32mp-exti.c. Keep the MCU-only cleanup from the upstream split. Existing functions are moved or reused; no new functions are introduced.

The stable tree has no STM32MP_EXTI selector, so add it and select the MCU or MPU driver from the corresponding ARM architecture configuration. Keep the timeout unchanged for d31fbbade43f880b7e59e2b3a72722fe2725d93f, which applies cleanly to the split MPU driver with Git's three-way application.

Stable-dep-of: d31fbbade43f ("irqchip/stm32mp-exti: Fix the unit of the hwspinlock timeout")

---
 arch/arm/mach-stm32/Kconfig        |   3 +-
 drivers/irqchip/Kconfig            |   5 +
 drivers/irqchip/Makefile           |   1 +
 drivers/irqchip/irq-stm32-exti.c   | 622 +-------------------------
 drivers/irqchip/irq-stm32mp-exti.c | 694 +++++++++++++++++++++++++++++
 5 files changed, 708 insertions(+), 617 deletions(-)
 create mode 100644 drivers/irqchip/irq-stm32mp-exti.c

index 98145031586f1..9b70f1ab4b081 100644
@@ -11,7 +11,8 @@ menuconfig ARCH_STM32
 	select CLKSRC_STM32
 	select PINCTRL
 	select RESET_CONTROLLER
-	select STM32_EXTI
+	select STM32_EXTI if ARM_SINGLE_ARMV7M
+	select STM32MP_EXTI if ARCH_MULTI_V7
 	help
 	  Support for STMicroelectronics STM32 processors.
 

index 4ff91df769478..c42eead1d02de 100644
@@ -392,6 +392,11 @@ config LS_SCFG_MSI
 config PARTITION_PERCPU
 	bool
 
+config STM32MP_EXTI
+	bool
+	select IRQ_DOMAIN
+	select GENERIC_IRQ_CHIP
+
 config STM32_EXTI
 	bool
 	select IRQ_DOMAIN

index ffd945fe71aa2..96625e7b9c235 100644
@@ -84,6 +84,7 @@ obj-$(CONFIG_MVEBU_SEI)			+= irq-mvebu-sei.o
 obj-$(CONFIG_LS_EXTIRQ)			+= irq-ls-extirq.o
 obj-$(CONFIG_LS_SCFG_MSI)		+= irq-ls-scfg-msi.o
 obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o irq-aspeed-i2c-ic.o irq-aspeed-scu-ic.o
+obj-$(CONFIG_STM32MP_EXTI)		+= irq-stm32mp-exti.o
 obj-$(CONFIG_STM32_EXTI) 		+= irq-stm32-exti.o
 obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
 obj-$(CONFIG_IRQ_UNIPHIER_AIDET)	+= irq-uniphier-aidet.o

2.53.0

From: Ju Nan <[email protected]>

[ Upstream commit d31fbbade43f880b7e59e2b3a72722fe2725d93f ]

HWSPNLCK_TIMEOUT is passed to hwspin_lock_timeout_in_atomic(), whose timeout argument is in milliseconds, not microseconds:

  atomic_delay += HWSPINLOCK_RETRY_DELAY_US;
  if (atomic_delay > to * 1000)
          return -ETIMEDOUT;

So stm32mp_exti_set_type() asks for a 1 second timeout where the comment next to the macro says it wants 1 millisecond. The semaphore is polled with udelay() from a section that holds chip_data->rlock, a raw_spinlock_t, so preemption stays disabled for the whole wait on every configuration, PREEMPT_RT included.

The hwspinlock core documents this explicitly:

If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the timeout is handled with busy-waiting delays, hence shall not exceed few msecs.

---
 drivers/irqchip/irq-stm32mp-exti.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 6f607be9c9c43..b45d66d285cb6 100644
@@ -23,7 +23,7 @@
 
 #define IRQS_PER_BANK			32
 
-#define HWSPNLCK_TIMEOUT		1000 /* usec */
+#define HWSPNLCK_TIMEOUT_MS		1
 
 struct stm32_exti_bank {
 	u32 imr_ofst;

@@ -361,7 +361,7 @@ static int stm32_exti_h_set_type(struct irq_data *d, unsigned int type)
 	raw_spin_lock(&chip_data->rlock);
 
 	if (hwlock) {
-		err = hwspin_lock_timeout_in_atomic(hwlock, HWSPNLCK_TIMEOUT);
+		err = hwspin_lock_timeout_in_atomic(hwlock, HWSPNLCK_TIMEOUT_MS);
 		if (err) {
 			pr_err("%s can't get hwspinlock (%d)\n", __func__, err);
 			goto unlock;

2.53.0