linux-kernel - [PATCH 3/3] irqchip/irq-pruss-intc: Fix processing of IEP interrupts

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Date:   Tue, 19 Sep 2023 11:49:00 +0530
From:   MD Danish Anwar <danishanwar@...com>
To:     Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>,
        Suman Anna <s-anna@...com>,
        David Lechner <david@...hnology.com>,
        Roger Quadros <rogerq@...nel.org>,
        "Andrew F. Davis" <afd@...com>, Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
CC:     <linux-kernel@...r.kernel.org>, <srk@...com>, <danishanwar@...com>,
        <r-gunasekaran@...com>, <vigneshr@...com>
Subject: [PATCH 3/3] irqchip/irq-pruss-intc: Fix processing of IEP interrupts

From: Suman Anna <s-anna@...com>

It was discovered that IEP capture/compare IRQs (event #7 on all SoCs
and event #56 on K3 SoCs) are always triggered twice when PPS is
generated and CMP hit event detected by IEP.

An example of the problem is:
  pruss_intc_irq_handler
   generic_handle_irq
    handle_level_irq
      mask_ack_irq -> IRQ 7 masked and asked in INTC,
                      but it's not yet cleared on HW level
      handle_irq_event()
        <threaded on RT>
           icss_iep_cap_cmp_handler() -> IRQ 7 is actually processed in HW
        irq_finalize_oneshot()
         unmask_irq()
           pruss_intc_irq_unmask() -> IRQ 7 status is still observed as set

The solution is to actually ack these IRQs from pruss_intc_irq_unmask()
after the IRQ source is cleared in HW.

No public errata available for this yet.

Fixes: 04e2d1e06978 ("irqchip/irq-pruss-intc: Add a PRUSS irqchip driver for PRUSS interrupts")

Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
Signed-off-by: Suman Anna <s-anna@...com>
Signed-off-by: MD Danish Anwar <danishanwar@...com>
---
 drivers/irqchip/irq-pruss-intc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
index 3cf684ede564..9907847dbda8 100644
--- a/drivers/irqchip/irq-pruss-intc.c
+++ b/drivers/irqchip/irq-pruss-intc.c
@@ -70,6 +70,8 @@
 #define MAX_PRU_SYS_EVENTS 160
 #define MAX_PRU_CHANNELS 20
 
+#define MAX_PRU_INT_EVENTS	64
+
 /**
  * struct pruss_intc_map_record - keeps track of actual mapping state
  * @value: The currently mapped value (channel or host)
@@ -85,10 +87,13 @@ struct pruss_intc_map_record {
  * @num_system_events: number of input system events handled by the PRUSS INTC
  * @num_host_events: number of host events (which is equal to number of
  *		     channels) supported by the PRUSS INTC
+ * @quirky_events: bitmask of events that need quirky IRQ handling (limited to
+ *		   (internal sources only for now, so 64 bits suffice)
  */
 struct pruss_intc_match_data {
 	u8 num_system_events;
 	u8 num_host_events;
+	u64 quirky_events;
 };
 
 /**
@@ -304,6 +309,10 @@ static void pruss_intc_irq_ack(struct irq_data *data)
 	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
 	unsigned int hwirq = data->hwirq;
 
+	if (hwirq < MAX_PRU_INT_EVENTS &&
+	    intc->soc_config->quirky_events & BIT_ULL(hwirq))
+		return;
+
 	pruss_intc_write_reg(intc, PRU_INTC_SICR, hwirq);
 }
 
@@ -320,6 +329,9 @@ static void pruss_intc_irq_unmask(struct irq_data *data)
 	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
 	unsigned int hwirq = data->hwirq;
 
+	if (hwirq < MAX_PRU_INT_EVENTS &&
+	    intc->soc_config->quirky_events & BIT_ULL(hwirq))
+		pruss_intc_write_reg(intc, PRU_INTC_SICR, hwirq);
 	pruss_intc_write_reg(intc, PRU_INTC_EISR, hwirq);
 }
 
@@ -644,11 +656,13 @@ static int pruss_intc_remove(struct platform_device *pdev)
 static const struct pruss_intc_match_data pruss_intc_data = {
 	.num_system_events = 64,
 	.num_host_events = 10,
+	.quirky_events = BIT_ULL(7), /* IEP capture/compare event */
 };
 
 static const struct pruss_intc_match_data icssg_intc_data = {
 	.num_system_events = 160,
 	.num_host_events = 20,
+	.quirky_events = BIT_ULL(7) | BIT_ULL(56), /* IEP{0,1} capture/compare events */
 };
 
 static const struct of_device_id pruss_intc_of_match[] = {
-- 
2.34.1