Re: [PATCH v7 01/12] irqchip: Add driver for Loongson I/O Local Interrupt Controller

On 2020-03-25 11:25, Paul Cercueil wrote:

Hi Jiaxun,


Le mer. 25 mars 2020 à 10:28, Jiaxun Yang [off-list ref] a 
écrit :

quoted

This controller appeared on Loongson family of chips as the primary
package interrupt source.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Huacai Chen <redacted>
Signed-off-by: Huacai Chen <redacted>
Reviewed-by: Marc Zyngier <maz@kernel.org>
---
v4-v5:
	Resolve suggestions from maz:
		- Remove DT validation
		- Simplify unnucessary functions & variables
---
 drivers/irqchip/Kconfig                |   9 +
 drivers/irqchip/Makefile               |   1 +
 drivers/irqchip/irq-loongson-liointc.c | 261 
+++++++++++++++++++++++++
 3 files changed, 271 insertions(+)
 create mode 100644 drivers/irqchip/irq-loongson-liointc.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 6d397732138d..c609eaa319d2 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig

@@ -513,4 +513,13 @@ config EXYNOS_IRQ_COMBINER
 	  Say yes here to add support for the IRQ combiner devices embedded
 	  in Samsung Exynos chips.

+config LOONGSON_LIOINTC
+	bool "Loongson Local I/O Interrupt Controller"
+	depends on MACH_LOONGSON64
+	default y
+	select IRQ_DOMAIN
+	select GENERIC_IRQ_CHIP
+	help
+	  Support for the Loongson Local I/O Interrupt Controller.
+
 endmenu

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index eae0d78cbf22..5e7678efdfe6 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile

@@ -105,3 +105,4 @@ obj-$(CONFIG_MADERA_IRQ)		+= irq-madera.o
 obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
 obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
 obj-$(CONFIG_TI_SCI_INTA_IRQCHIP)	+= irq-ti-sci-inta.o
+obj-$(CONFIG_LOONGSON_LIOINTC)		+= irq-loongson-liointc.o

diff --git a/drivers/irqchip/irq-loongson-liointc.c 

b/drivers/irqchip/irq-loongson-liointc.c
new file mode 100644
index 000000000000..18de2c09ece4

--- /dev/null
+++ b/drivers/irqchip/irq-loongson-liointc.c

@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
+ *  Loongson Local IO Interrupt Controller support
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/irqchip.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/smp.h>
+#include <linux/irqchip/chained_irq.h>
+
+#include <boot_param.h>
+
+#define LIOINTC_CHIP_IRQ	32
+#define LIOINTC_NUM_PARENT 4
+
+#define LIOINTC_INTC_CHIP_START	0x20
+
+#define LIOINTC_REG_INTC_STATUS	(LIOINTC_INTC_CHIP_START + 0x20)
+#define LIOINTC_REG_INTC_EN_STATUS	(LIOINTC_INTC_CHIP_START + 0x04)
+#define LIOINTC_REG_INTC_ENABLE	(LIOINTC_INTC_CHIP_START + 0x08)
+#define LIOINTC_REG_INTC_DISABLE	(LIOINTC_INTC_CHIP_START + 0x0c)
+#define LIOINTC_REG_INTC_POL	(LIOINTC_INTC_CHIP_START + 0x10)
+#define LIOINTC_REG_INTC_EDGE	(LIOINTC_INTC_CHIP_START + 0x14)
+
+#define LIOINTC_SHIFT_INTx	4
+
+struct liointc_handler_data {
+	struct liointc_priv	*priv;
+	u32			parent_int_map;
+};
+
+struct liointc_priv {
+	struct irq_chip_generic		*gc;
+	struct liointc_handler_data	handler[LIOINTC_NUM_PARENT];
+	u8				map_cache[LIOINTC_CHIP_IRQ];
+};
+
+static void liointc_chained_handle_irq(struct irq_desc *desc)
+{
+	struct liointc_handler_data *handler = 

irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irq_chip_generic *gc = handler->priv->gc;
+	u32 pending;
+
+	chained_irq_enter(chip, desc);
+
+	pending = readl(gc->reg_base + LIOINTC_REG_INTC_STATUS);
+
+	if (!pending)
+		spurious_interrupt();
+
+	while (pending) {
+		int bit = __ffs(pending);
+
+		generic_handle_irq(irq_find_mapping(gc->domain, bit));
+		pending &= ~BIT(bit);
+	}

Consider using the for_each_set_bit() macro from <linux/bitops.h>.
See drivers/irqchip/irq-ingenic-tcu.c for instance.

which would require changing the pending type to be unsigned long.
Open-coding these if fine if it helps keeping the type system 
consistent.

         M.
-- 
Jazz is not dead. It just smells funny...

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