linux-kernel - [PATCH 3/3] amba: Properly handle device probe without IRQ domain

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Date:   Mon, 16 Aug 2021 15:46:19 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     <linux-kernel@...r.kernel.org>, Rob Herring <robh+dt@...nel.org>,
        "Frank Rowand" <frowand.list@...il.com>
CC:     <devicetree@...r.kernel.org>, Russell King <linux@...linux.org.uk>,
        "Linus Walleij" <linus.walleij@...aro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Ruizhe Lin <linruizhe@...wei.com>
Subject: [PATCH 3/3] amba: Properly handle device probe without IRQ domain

of_amba_device_create() uses irq_of_parse_and_map() to translate
a DT interrupt specification into a Linux virtual interrupt number.

But it doesn't properly handle the case where the interrupt controller
is not yet available, eg, when pl011 interrupt is connected to MBIGEN
interrupt controller, because the mbigen initialization is too late,
which will lead to no IRQ due to no IRQ domain found, log is shown below,
  "irq: no irq domain found for uart0 !"

use of_irq_get() to return -EPROBE_DEFER as above, and in the function
amba_device_try_add()/amba_device_add(), it will properly handle in such
case, also return 0 in other fail cases to be consistent as before.

Cc: Russell King <linux@...linux.org.uk>
Cc: Rob Herring <robh+dt@...nel.org>
Cc: Frank Rowand <frowand.list@...il.com>
Reported-by: Ruizhe Lin <linruizhe@...wei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 drivers/amba/bus.c    | 27 +++++++++++++++++++++++++++
 drivers/of/platform.c |  6 +-----
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 36f2f42c8014..720aa6cdd402 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -19,6 +19,7 @@
 #include <linux/clk/clk-conf.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
+#include <linux/of_irq.h>
 
 #include <asm/irq.h>
 
@@ -371,12 +372,38 @@ static void amba_device_release(struct device *dev)
 	kfree(d);
 }
 
+static int of_amba_device_decode_irq(struct amba_device *dev)
+{
+	struct device_node *node = dev->dev.of_node;
+	int i, irq = 0;
+
+	if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
+		/* Decode the IRQs and address ranges */
+		for (i = 0; i < AMBA_NR_IRQS; i++) {
+			irq = of_irq_get(node, i);
+			if (irq < 0) {
+				if (irq == -EPROBE_DEFER)
+					return irq;
+				irq = 0;
+			}
+
+			dev->irq[i] = irq;
+		}
+	}
+
+	return 0;
+}
+
 static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
 {
 	u32 size;
 	void __iomem *tmp;
 	int i, ret;
 
+	ret = of_amba_device_decode_irq(dev);
+	if (ret)
+		goto err_out;
+
 	ret = request_resource(parent, &dev->res);
 	if (ret)
 		goto err_out;
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 74afbb7a4f5e..32d5ff8df747 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -222,7 +222,7 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 {
 	struct amba_device *dev;
 	const void *prop;
-	int i, ret;
+	int ret;
 
 	pr_debug("Creating amba device %pOF\n", node);
 
@@ -253,10 +253,6 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 	if (prop)
 		dev->periphid = of_read_ulong(prop, 1);
 
-	/* Decode the IRQs and address ranges */
-	for (i = 0; i < AMBA_NR_IRQS; i++)
-		dev->irq[i] = irq_of_parse_and_map(node, i);
-
 	ret = of_address_to_resource(node, 0, &dev->res);
 	if (ret) {
 		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
-- 
2.26.2