Re: [PATCH 1/4] Irqchip: Ingenic: Change interrupt handling form cascade to chained_irq.

From: Zhou Yanjie
Date: Sun Jan 27 2019 - 09:50:45 EST


My fault, in the function "generic_handle_irq" should use "bit" instead of "__fls(irq_reg)".
It will be fixed in the v2.

On 2019å01æ27æ 18:21, Marc Zyngier wrote:
On Sat, 26 Jan 2019 15:38:40 +0000,
Zhou Yanjie <zhouyanjie@xxxxxxxx> wrote:
The interrupt handling method is changed from old-style cascade to
chained_irq which is more appropriate. Also, it can process the
corner situation that more than one irq is coming to a single
chip at the same time.

Signed-off-by: Zhou Yanjie <zhouyanjie@xxxxxxxx>
---
drivers/irqchip/irq-ingenic.c | 49 ++++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 24 deletions(-)

diff --git a/drivers/irqchip/irq-ingenic.c b/drivers/irqchip/irq-ingenic.c
index 2ff0898..2713ec4 100644
--- a/drivers/irqchip/irq-ingenic.c
+++ b/drivers/irqchip/irq-ingenic.c
@@ -1,16 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@xxxxxxxxxx>
- * JZ4740 platform IRQ support
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 675 Mass Ave, Cambridge, MA 02139, USA.
- *
+ * Ingenic XBurst platform IRQ support
*/
#include <linux/errno.h>
@@ -19,6 +10,7 @@
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
#include <linux/irqchip/ingenic.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
@@ -41,22 +33,35 @@ struct ingenic_intc_data {
#define JZ_REG_INTC_PENDING 0x10
#define CHIP_SIZE 0x20
-static irqreturn_t intc_cascade(int irq, void *data)
+static void ingenic_chained_handle_irq(struct irq_desc *desc)
{
- struct ingenic_intc_data *intc = irq_get_handler_data(irq);
- uint32_t irq_reg;
+ struct ingenic_intc_data *intc = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ bool have_irq = false;
+ u32 pending;
unsigned i;
+ chained_irq_enter(chip, desc);
for (i = 0; i < intc->num_chips; i++) {
- irq_reg = readl(intc->base + (i * CHIP_SIZE) +
+ pending = readl(intc->base + (i * CHIP_SIZE) +
JZ_REG_INTC_PENDING);
- if (!irq_reg)
+ if (!pending)
continue;
- generic_handle_irq(__fls(irq_reg) + (i * 32) + JZ4740_IRQ_BASE);
+ have_irq = true;
+ while (pending) {
+ int bit = __ffs(pending);
So 'bit' is the least significant bit in the pending word,

+
+ generic_handle_irq(__fls(pending) + (i * 32) +
and here you handle the *most significant* bit,

+ JZ4740_IRQ_BASE);
+ pending &= ~BIT(bit);
yet it is the least significant bit that you clear. I am tempted to
say that you have never tested this code with more than a single
interrupt.

Thanks,

M.