From 9c7f4b63bad758e0a5321b5c220960f4345f1862 Mon Sep 17 00:00:00 2001
From: Suman Anna <s-anna@ti.com>
Date: Fri, 28 May 2021 14:00:50 -0500
Subject: [PATCH] irqchip/irq-pruss-intc: Fix enabling of intc events

PRUSS INTC events are enabled by default once IRQ events are mapped to
channel:host pair. This may cause issues with undesirable IRQs triggering
even before a PRU IRQ is requested which are silently processed by
pruss_intc_irq_handler().

Fix it by masking all events by default except those which are routed to
various PRU cores (Host IRQs 0, 1; 10 through 19 on K3 SoCs), and any
other reserved IRQs routed to other processors. The unmasking of IRQs is
the responsibility of Linux IRQ core when IRQ is actually requested.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/irqchip/irq-pruss-intc.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
index 92fb5780dc10..b3839dbfb738 100644
--- a/drivers/irqchip/irq-pruss-intc.c
+++ b/drivers/irqchip/irq-pruss-intc.c
@@ -101,6 +101,7 @@ struct pruss_intc_match_data {
  * @soc_config: cached PRUSS INTC IP configuration data
  * @dev: PRUSS INTC device pointer
  * @lock: mutex to serialize interrupts mapping
+ * @irqs_reserved: bit-mask of reserved host interrupts
  */
 struct pruss_intc {
 	struct pruss_intc_map_record event_channel[MAX_PRU_SYS_EVENTS];
@@ -111,6 +112,7 @@ struct pruss_intc {
 	const struct pruss_intc_match_data *soc_config;
 	struct device *dev;
 	struct mutex lock; /* PRUSS INTC lock */
+	u8 irqs_reserved;
 };
 
 /**
@@ -178,6 +180,7 @@ static void pruss_intc_update_hmr(struct pruss_intc *intc, u8 ch, u8 host)
 static void pruss_intc_map(struct pruss_intc *intc, unsigned long hwirq)
 {
 	struct device *dev = intc->dev;
+	bool enable_hwirq = false;
 	u8 ch, host, reg_idx;
 	u32 val;
 
@@ -187,6 +190,9 @@ static void pruss_intc_map(struct pruss_intc *intc, unsigned long hwirq)
 
 	ch = intc->event_channel[hwirq].value;
 	host = intc->channel_host[ch].value;
+	enable_hwirq = (host < FIRST_PRU_HOST_INT ||
+			host >= FIRST_PRU_HOST_INT + MAX_NUM_HOST_IRQS ||
+			intc->irqs_reserved & BIT(host - FIRST_PRU_HOST_INT));
 
 	pruss_intc_update_cmr(intc, hwirq, ch);
 
@@ -194,8 +200,10 @@ static void pruss_intc_map(struct pruss_intc *intc, unsigned long hwirq)
 	val = BIT(hwirq  % 32);
 
 	/* clear and enable system event */
-	pruss_intc_write_reg(intc, PRU_INTC_ESR(reg_idx), val);
 	pruss_intc_write_reg(intc, PRU_INTC_SECR(reg_idx), val);
+	/* unmask only events going to various PRU and other cores by default */
+	if (enable_hwirq)
+		pruss_intc_write_reg(intc, PRU_INTC_ESR(reg_idx), val);
 
 	if (++intc->channel_host[ch].ref_count == 1) {
 		pruss_intc_update_hmr(intc, ch, host);
@@ -204,7 +212,8 @@ static void pruss_intc_map(struct pruss_intc *intc, unsigned long hwirq)
 		pruss_intc_write_reg(intc, PRU_INTC_HIEISR, host);
 	}
 
-	dev_dbg(dev, "mapped system_event = %lu channel = %d host = %d",
+	dev_dbg(dev, "mapped%s system_event = %lu channel = %d host = %d",
+		enable_hwirq ? " and enabled" : "",
 		hwirq, ch, host);
 
 	mutex_unlock(&intc->lock);
@@ -268,11 +277,14 @@ static void pruss_intc_init(struct pruss_intc *intc)
 
 	/*
 	 * configure polarity (SIPR register) to active high and
-	 * type (SITR register) to level interrupt for all system events
+	 * type (SITR register) to level interrupt for all system events,
+	 * and disable and clear all the system events
 	 */
 	for (i = 0; i < num_event_type_regs; i++) {
 		pruss_intc_write_reg(intc, PRU_INTC_SIPR(i), 0xffffffff);
 		pruss_intc_write_reg(intc, PRU_INTC_SITR(i), 0);
+		pruss_intc_write_reg(intc, PRU_INTC_ECR(i), 0xffffffff);
+		pruss_intc_write_reg(intc, PRU_INTC_SECR(i), 0xffffffff);
 	}
 
 	/* clear all interrupt channel map registers, 4 events per register */
@@ -524,7 +536,7 @@ static int pruss_intc_probe(struct platform_device *pdev)
 	struct pruss_intc *intc;
 	struct pruss_host_irq_data *host_data;
 	int i, irq, ret;
-	u8 max_system_events, irqs_reserved = 0;
+	u8 max_system_events;
 
 	data = of_device_get_match_data(dev);
 	if (!data)
@@ -545,7 +557,7 @@ static int pruss_intc_probe(struct platform_device *pdev)
 		return PTR_ERR(intc->base);
 
 	ret = of_property_read_u8(dev->of_node, "ti,irqs-reserved",
-				  &irqs_reserved);
+				  &intc->irqs_reserved);
 
 	/*
 	 * The irqs-reserved is used only for some SoC's therefore not having
@@ -564,7 +576,7 @@ static int pruss_intc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	for (i = 0; i < MAX_NUM_HOST_IRQS; i++) {
-		if (irqs_reserved & BIT(i))
+		if (intc->irqs_reserved & BIT(i))
 			continue;
 
 		irq = platform_get_irq_byname(pdev, irq_names[i]);
