linux-kernel - [RFC PATCH] of: platform: Skip mapping of interrupts in of_device

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Date:   Thu,  9 Dec 2021 00:10:56 +0000
From:   Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        Prabhakar <prabhakar.csengg@...il.com>,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [RFC PATCH] of: platform: Skip mapping of interrupts in of_device_alloc()

of_device_alloc() in early boot stage creates a interrupt mapping if
there exists a "interrupts" property in the node.

For hierarchical interrupt domains using "interrupts" property in the node
bypassed the hierarchical setup and messed up the irq setup.

This patch adds a check in of_device_alloc() to skip interrupt mapping if
"not-interrupt-producer" property is present in the node. This allows
nodes to describe the interrupts using "interrupts" property.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
Hi All,

Spawning from discussion [1], here is simple patch (not the ideal probably
welcome for suggestions) from stopping the OF code from creating a map for
the interrupts when using "interrupts" property.

[1] https://lore.kernel.org/lkml/87pmqrck2m.wl-maz@kernel.org/
    T/#mbd1e47c1981082aded4b32a52e2c04291e515508

Cheers,
Prabhakar
---
 drivers/of/platform.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b3faf89744aa..629776ca1721 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -114,7 +114,7 @@ struct platform_device *of_device_alloc(struct device_node *np,
 				  struct device *parent)
 {
 	struct platform_device *dev;
-	int rc, i, num_reg = 0, num_irq;
+	int rc, i, num_reg = 0, num_irq = 0;
 	struct resource *res, temp_res;
 
 	dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
@@ -124,7 +124,14 @@ struct platform_device *of_device_alloc(struct device_node *np,
 	/* count the io and irq resources */
 	while (of_address_to_resource(np, num_reg, &temp_res) == 0)
 		num_reg++;
-	num_irq = of_irq_count(np);
+
+	/*
+	 * we don't want to map the interrupts of hierarchical interrupt domain
+	 * into the parent domain yet. This will be the job of the hierarchical
+	 * interrupt driver code to map the interrupts as and when needed.
+	 */
+	if (!of_property_read_bool(np, "not-interrupt-producer"))
+		num_irq = of_irq_count(np);
 
 	/* Populate the resource table */
 	if (num_irq || num_reg) {
@@ -140,7 +147,7 @@ struct platform_device *of_device_alloc(struct device_node *np,
 			rc = of_address_to_resource(np, i, res);
 			WARN_ON(rc);
 		}
-		if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
+		if (num_irq && of_irq_to_resource_table(np, res, num_irq) != num_irq)
 			pr_debug("not all legacy IRQ resources mapped for %pOFn\n",
 				 np);
 	}
-- 
2.17.1