linux-kernel - [tip: irq/core] genirq/generic_chip: Make irq_remove_generic

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Date:   Fri, 27 Oct 2023 07:24:00 -0000
From:   "tip-bot2 for Herve Codina" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Herve Codina <herve.codina@...tlin.com>,
        Thomas Gleixner <tglx@...utronix.de>, stable@...r.kernel.org,
        x86@...nel.org, linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/core] genirq/generic_chip: Make irq_remove_generic_chip()
 irqdomain aware

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     5e7afb2eb7b2a7c81e9f608cbdf74a07606fd1b5
Gitweb:        https://git.kernel.org/tip/5e7afb2eb7b2a7c81e9f608cbdf74a07606fd1b5
Author:        Herve Codina <herve.codina@...tlin.com>
AuthorDate:    Tue, 24 Oct 2023 17:03:35 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 27 Oct 2023 09:15:44 +02:00

genirq/generic_chip: Make irq_remove_generic_chip() irqdomain aware

irq_remove_generic_chip() calculates the Linux interrupt number for removing the
handler and interrupt chip based on gc::irq_base as a linear function of
the bit positions of set bits in the @msk argument.

When the generic chip is present in an irq domain, i.e. created with a call
to irq_alloc_domain_generic_chips(), gc::irq_base contains not the base
Linux interrupt number.  It contains the base hardware interrupt for this
chip. It is set to 0 for the first chip in the domain, 0 + N for the next
chip, where $N is the number of hardware interrupts per chip.

That means the Linux interrupt number cannot be calculated based on
gc::irq_base for irqdomain based chips without a domain map lookup, which
is currently missing.

Rework the code to take the irqdomain case into account and calculate the
Linux interrupt number by a irqdomain lookup of the domain specific
hardware interrupt number.

[ tglx: Massage changelog. Reshuffle the logic and add a proper comment. ]

Fixes: cfefd21e693d ("genirq: Add chip suspend and resume callbacks")
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20231024150335.322282-1-herve.codina@bootlin.com

---
 kernel/irq/generic-chip.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index 81ecca0..d39a40b 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -548,21 +548,34 @@ EXPORT_SYMBOL_GPL(irq_setup_alt_chip);
 void irq_remove_generic_chip(struct irq_chip_generic *gc, u32 msk,
 			     unsigned int clr, unsigned int set)
 {
-	unsigned int i = gc->irq_base;
+	unsigned int i, virq;
 
 	raw_spin_lock(&gc_lock);
 	list_del(&gc->list);
 	raw_spin_unlock(&gc_lock);
 
-	for (; msk; msk >>= 1, i++) {
+	for (i = 0; msk; msk >>= 1, i++) {
 		if (!(msk & 0x01))
 			continue;
 
+		/*
+		 * Interrupt domain based chips store the base hardware
+		 * interrupt number in gc::irq_base. Otherwise gc::irq_base
+		 * contains the base Linux interrupt number.
+		 */
+		if (gc->domain) {
+			virq = irq_find_mapping(gc->domain, gc->irq_base + i);
+			if (!virq)
+				continue;
+		} else {
+			virq = gc->irq_base + i;
+		}
+
 		/* Remove handler first. That will mask the irq line */
-		irq_set_handler(i, NULL);
-		irq_set_chip(i, &no_irq_chip);
-		irq_set_chip_data(i, NULL);
-		irq_modify_status(i, clr, set);
+		irq_set_handler(virq, NULL);
+		irq_set_chip(virq, &no_irq_chip);
+		irq_set_chip_data(virq, NULL);
+		irq_modify_status(virq, clr, set);
 	}
 }
 EXPORT_SYMBOL_GPL(irq_remove_generic_chip);