Merge patch series "ufs: core: cleanup and threaded irq handler"

Neil Armstrong <neil.armstrong@linaro.org> says:

On systems with a large number request slots and unavailable MCQ,
the current design of the interrupt handler can delay handling of
other subsystems interrupts causing display artifacts, GPU stalls
or system firmware requests timeouts.

Example of errors reported on a loaded system:
 [drm:dpu_encoder_frame_done_timeout:2706] [dpu error]enc32 frame done timeout
 msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 67.5.20.1: hangcheck detected gpu lockup rb 2!
 msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 67.5.20.1:     completed fence: 74285
 msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 67.5.20.1:     submitted fence: 74286
 Error sending AMC RPMH requests (-110)

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250407-topic-ufs-use-threaded-irq-v3-0-08bee980f71e@linaro.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 33 insertions, 16 deletions

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 0534390c2a35..b40660ca2fa6 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -643,9 +643,6 @@ static void ufshcd_print_host_state(struct ufs_hba *hba)
 		"last_hibern8_exit_tstamp at %lld us, hibern8_exit_cnt=%d\n",
 		div_u64(hba->ufs_stats.last_hibern8_exit_tstamp, 1000),
 		hba->ufs_stats.hibern8_exit_cnt);
-	dev_err(hba->dev, "last intr at %lld us, last intr status=0x%x\n",
-		div_u64(hba->ufs_stats.last_intr_ts, 1000),
-		hba->ufs_stats.last_intr_status);
 	dev_err(hba->dev, "error handling flags=0x%x, req. abort count=%d\n",
 		hba->eh_flags, hba->req_abort_count);
 	dev_err(hba->dev, "hba->ufs_version=0x%x, Host capabilities=0x%x, caps=0x%x\n",
@@ -6974,7 +6971,7 @@ static irqreturn_t ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
 }
 
 /**
- * ufshcd_intr - Main interrupt service routine
+ * ufshcd_threaded_intr - Threaded interrupt service routine
  * @irq: irq number
  * @__hba: pointer to adapter instance
  *
@@ -6982,16 +6979,14 @@ static irqreturn_t ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
  *  IRQ_HANDLED - If interrupt is valid
  *  IRQ_NONE    - If invalid interrupt
  */
-static irqreturn_t ufshcd_intr(int irq, void *__hba)
+static irqreturn_t ufshcd_threaded_intr(int irq, void *__hba)
 {
-	u32 intr_status, enabled_intr_status = 0;
+	u32 last_intr_status, intr_status, enabled_intr_status = 0;
 	irqreturn_t retval = IRQ_NONE;
 	struct ufs_hba *hba = __hba;
 	int retries = hba->nutrs;
 
-	intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
-	hba->ufs_stats.last_intr_status = intr_status;
-	hba->ufs_stats.last_intr_ts = local_clock();
+	last_intr_status = intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
 
 	/*
 	 * There could be max of hba->nutrs reqs in flight and in worst case
@@ -7015,7 +7010,7 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
 		dev_err(hba->dev, "%s: Unhandled interrupt 0x%08x (0x%08x, 0x%08x)\n",
 					__func__,
 					intr_status,
-					hba->ufs_stats.last_intr_status,
+					last_intr_status,
 					enabled_intr_status);
 		ufshcd_dump_regs(hba, 0, UFSHCI_REG_SPACE_SIZE, "host_regs: ");
 	}
@@ -7023,6 +7018,29 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
 	return retval;
 }
 
+/**
+ * ufshcd_intr - Main interrupt service routine
+ * @irq: irq number
+ * @__hba: pointer to adapter instance
+ *
+ * Return:
+ *  IRQ_HANDLED     - If interrupt is valid
+ *  IRQ_WAKE_THREAD - If handling is moved to threaded handled
+ *  IRQ_NONE        - If invalid interrupt
+ */
+static irqreturn_t ufshcd_intr(int irq, void *__hba)
+{
+	struct ufs_hba *hba = __hba;
+
+	/* Move interrupt handling to thread when MCQ & ESI are not enabled */
+	if (!hba->mcq_enabled || !hba->mcq_esi_enabled)
+		return IRQ_WAKE_THREAD;
+
+	/* Directly handle interrupts since MCQ ESI handlers does the hard job */
+	return ufshcd_sl_intr(hba, ufshcd_readl(hba, REG_INTERRUPT_STATUS) &
+				   ufshcd_readl(hba, REG_INTERRUPT_ENABLE));
+}
+
 static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag)
 {
 	int err = 0;
@@ -8722,6 +8740,7 @@ static void ufshcd_config_mcq(struct ufs_hba *hba)
 	u32 intrs;
 
 	ret = ufshcd_mcq_vops_config_esi(hba);
+	hba->mcq_esi_enabled = !ret;
 	dev_info(hba->dev, "ESI %sconfigured\n", ret ? "is not " : "");
 
 	intrs = UFSHCD_ENABLE_MCQ_INTRS;
@@ -10581,7 +10600,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
 
 	/* IRQ registration */
-	err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
+	err = devm_request_threaded_irq(dev, irq, ufshcd_intr, ufshcd_threaded_intr,
+					IRQF_ONESHOT | IRQF_SHARED, UFSHCD, hba);
 	if (err) {
 		dev_err(hba->dev, "request irq failed\n");
 		goto out_disable;
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index e3909cc691b2..ec999fa67124 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -501,8 +501,6 @@ struct ufs_event_hist {
 
 /**
  * struct ufs_stats - keeps usage/err statistics
- * @last_intr_status: record the last interrupt status.
- * @last_intr_ts: record the last interrupt timestamp.
  * @hibern8_exit_cnt: Counter to keep track of number of exits,
  *		reset this after link-startup.
  * @last_hibern8_exit_tstamp: Set time after the hibern8 exit.
@@ -510,9 +508,6 @@ struct ufs_event_hist {
  * @event: array with event history.
  */
 struct ufs_stats {
-	u32 last_intr_status;
-	u64 last_intr_ts;
-
 	u32 hibern8_exit_cnt;
 	u64 last_hibern8_exit_tstamp;
 	struct ufs_event_hist event[UFS_EVT_CNT];
@@ -959,6 +954,7 @@ enum ufshcd_mcq_opr {
  *	ufshcd_resume_complete()
  * @mcq_sup: is mcq supported by UFSHC
  * @mcq_enabled: is mcq ready to accept requests
+ * @mcq_esi_enabled: is mcq ESI configured
  * @res: array of resource info of MCQ registers
  * @mcq_base: Multi circular queue registers base address
  * @uhq: array of supported hardware queues
@@ -1127,6 +1123,7 @@ struct ufs_hba {
 	bool mcq_sup;
 	bool lsdb_sup;
 	bool mcq_enabled;
+	bool mcq_esi_enabled;
 	struct ufshcd_res_info res[RES_MAX];
 	void __iomem *mcq_base;
 	struct ufs_hw_queue *uhq;