Message-ID: <87r1ao23fp.wl-maz@kernel.org>
Date:   Tue, 07 Dec 2021 09:02:18 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Qin Jian <qinjian@...lus1.com>
Cc:     robh+dt@...nel.org, mturquette@...libre.com, sboyd@...nel.org,
        tglx@...utronix.de, p.zabel@...gutronix.de, linux@...linux.org.uk,
        broonie@...nel.org, arnd@...db.de,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        wells.lu@...plus.com
Subject: Re: [PATCH v5 08/10] irqchip: Add Sunplus SP7021 interrupt controller driver

On Fri, 03 Dec 2021 07:34:25 +0000,
Qin Jian <qinjian@...lus1.com> wrote:
> 
> Add interrupt controller driver for Sunplus SP7021 SoC.
> 
> This is the interrupt controller in P-chip which collects all interrupt
> sources in P-chip and routes them to parent interrupt controller in C-chip.
> 
> Signed-off-by: Qin Jian <qinjian@...lus1.com>
> ---
>  MAINTAINERS                       |   1 +
>  drivers/irqchip/Kconfig           |   9 +
>  drivers/irqchip/Makefile          |   1 +
>  drivers/irqchip/irq-sp7021-intc.c | 284 ++++++++++++++++++++++++++++++
>  4 files changed, 295 insertions(+)
>  create mode 100644 drivers/irqchip/irq-sp7021-intc.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6b3bbe021..febbd97bf 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2665,6 +2665,7 @@ F:	Documentation/devicetree/bindings/clock/sunplus,sp7021-clkc.yaml
>  F:	Documentation/devicetree/bindings/interrupt-controller/sunplus,sp7021-intc.yaml
>  F:	Documentation/devicetree/bindings/reset/sunplus,reset.yaml
>  F:	drivers/clk/clk-sp7021.c
> +F:	drivers/irqchip/irq-sp7021-intc.c
>  F:	drivers/reset/reset-sunplus.c
>  F:	include/dt-bindings/clock/sp-sp7021.h
>  F:	include/dt-bindings/reset/sp-sp7021.h
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index aca7b595c..b9429b8d0 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -602,4 +602,13 @@ config APPLE_AIC
>  	  Support for the Apple Interrupt Controller found on Apple Silicon SoCs,
>  	  such as the M1.
>  
> +config SUNPLUS_SP7021_INTC
> +	bool "Sunplus SP7021 interrupt controller"
> +	help
> +	  Support for the Sunplus SP7021 Interrupt Controller IP core.
> +	  SP7021 SoC has 2 Chips: C-Chip & P-Chip. This is used as a
> +	  chained controller, routing all interrupt source in P-Chip to
> +	  the primary controller on C-Chip.
> +	  This is selected automatically by platform config.
> +
>  endmenu
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index f88cbf36a..75411f654 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -116,3 +116,4 @@ obj-$(CONFIG_MACH_REALTEK_RTL)		+= irq-realtek-rtl.o
>  obj-$(CONFIG_WPCM450_AIC)		+= irq-wpcm450-aic.o
>  obj-$(CONFIG_IRQ_IDT3243X)		+= irq-idt3243x.o
>  obj-$(CONFIG_APPLE_AIC)			+= irq-apple-aic.o
> +obj-$(CONFIG_SUNPLUS_SP7021_INTC)	+= irq-sp7021-intc.o
> diff --git a/drivers/irqchip/irq-sp7021-intc.c b/drivers/irqchip/irq-sp7021-intc.c
> new file mode 100644
> index 000000000..beabc64d5
> --- /dev/null
> +++ b/drivers/irqchip/irq-sp7021-intc.c
> @@ -0,0 +1,284 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +/*
> + * Copyright (C) Sunplus Technology Co., Ltd.
> + *       All rights reserved.
> + */
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/io.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +
> +#define SP_INTC_HWIRQ_MIN	0
> +#define SP_INTC_HWIRQ_MAX	223
> +
> +#define SP_INTC_NR_IRQS		(SP_INTC_HWIRQ_MAX - SP_INTC_HWIRQ_MIN + 1)
> +#define SP_INTC_NR_GROUPS	DIV_ROUND_UP(SP_INTC_NR_IRQS, 32)
> +#define SP_INTC_REG_SIZE	(SP_INTC_NR_GROUPS * 4)
> +
> +/* REG_GROUP_0 regs */
> +#define REG_INTR_TYPE		(sp_intc.g0)
> +#define REG_INTR_POLARITY	(REG_INTR_TYPE     + SP_INTC_REG_SIZE)
> +#define REG_INTR_PRIORITY	(REG_INTR_POLARITY + SP_INTC_REG_SIZE)
> +#define REG_INTR_MASK		(REG_INTR_PRIORITY + SP_INTC_REG_SIZE)
> +
> +/* REG_GROUP_1 regs */
> +#define REG_INTR_CLEAR		(sp_intc.g1)
> +#define REG_MASKED_EXT1		(REG_INTR_CLEAR    + SP_INTC_REG_SIZE)
> +#define REG_MASKED_EXT0		(REG_MASKED_EXT1   + SP_INTC_REG_SIZE)
> +#define REG_INTR_GROUP		(REG_INTR_CLEAR    + 31 * 4)
> +
> +#define GROUP_MASK			(BIT(SP_INTC_NR_GROUPS) - 1)
> +#define GROUP_SHIFT_EXT1	(0)
> +#define GROUP_SHIFT_EXT0	(8)
> +
> +/*
> + * When GPIO_INT0~7 set to edge trigger, doesn't work properly.
> + * WORKAROUND: change it to level trigger, and toggle the polarity
> + * at ACK/Handler to make the HW work.
> + */
> +#define GPIO_INT0_HWIRQ		120
> +#define GPIO_INT7_HWIRQ		127
> +#define IS_GPIO_INT(irq)	\
> +({ \
> +	u32 i = irq; \
> +	(i >= GPIO_INT0_HWIRQ) && (i <= GPIO_INT7_HWIRQ); \
> +})
> +
> +/* index of states */
> +enum {
> +	_IS_EDGE = 0,
> +	_IS_LOW,
> +	_IS_ACTIVE
> +};
> +
> +#define STATE_BIT(irq, idx)			(((irq) - GPIO_INT0_HWIRQ) * 3 + (idx))
> +#define ASSIGN_STATE(irq, idx, v)	assign_bit(STATE_BIT(irq, idx), sp_intc.states, v)
> +#define TEST_STATE(irq, idx)		test_bit(STATE_BIT(irq, idx), sp_intc.states)
> +
> +static struct sp_intctl {
> +	/*
> +	 * REG_GROUP_0: include type/polarity/priority/mask regs.
> +	 * REG_GROUP_1: include clear/masked_ext0/masked_ext1/group regs.
> +	 */
> +	void __iomem *g0; // REG_GROUP_0 base
> +	void __iomem *g1; // REG_GROUP_1 base
> +
> +	struct irq_domain *domain;
> +	raw_spinlock_t lock;
> +
> +	/*
> +	 * store GPIO_INT states
> +	 * each interrupt has 3 states: is_edge, is_low, is_active
> +	 */
> +	DECLARE_BITMAP(states, (GPIO_INT7_HWIRQ - GPIO_INT0_HWIRQ + 1) * 3);
> +} sp_intc;
> +
> +static struct irq_chip sp_intc_chip;
> +
> +static void sp_intc_assign_bit(u32 hwirq, void __iomem *base, bool value)
> +{
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&sp_intc.lock, flags);
> +	__assign_bit(hwirq, base, value);

__assign_bit() on an MMIO mapping? No. Why do you think we have
separate MMIO accessors?

> +	raw_spin_unlock_irqrestore(&sp_intc.lock, flags);
> +}
> +
> +static void sp_intc_ack_irq(struct irq_data *d)
> +{
> +	u32 hwirq = d->hwirq;
> +
> +	if (unlikely(IS_GPIO_INT(hwirq) && TEST_STATE(hwirq, _IS_EDGE))) { // WORKAROUND
> +		sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, !TEST_STATE(hwirq, _IS_LOW));
> +		ASSIGN_STATE(hwirq, _IS_ACTIVE, true);
> +	}
> +
> +	sp_intc_assign_bit(hwirq, REG_INTR_CLEAR, 1);
> +}
> +
> +static void sp_intc_mask_irq(struct irq_data *d)
> +{
> +	sp_intc_assign_bit(d->hwirq, REG_INTR_MASK, 0);
> +}
> +
> +static void sp_intc_unmask_irq(struct irq_data *d)
> +{
> +	sp_intc_assign_bit(d->hwirq, REG_INTR_MASK, 1);
> +}
> +
> +static int sp_intc_set_type(struct irq_data *d, unsigned int type)
> +{
> +	u32 hwirq = d->hwirq;
> +	bool is_edge = !(type & IRQ_TYPE_LEVEL_MASK);
> +	bool is_low = (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_EDGE_FALLING);
> +
> +	irq_set_handler_locked(d, is_edge ? handle_edge_irq : handle_level_irq);
> +
> +	if (unlikely(IS_GPIO_INT(hwirq) && is_edge)) { // WORKAROUND
> +		/* store states */
> +		ASSIGN_STATE(hwirq, _IS_EDGE, is_edge);
> +		ASSIGN_STATE(hwirq, _IS_LOW, is_low);
> +		ASSIGN_STATE(hwirq, _IS_ACTIVE, false);
> +		/* change to level */
> +		is_edge = false;
> +	}
> +
> +	sp_intc_assign_bit(hwirq, REG_INTR_TYPE, is_edge);
> +	sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, is_low);
> +
> +	return 0;
> +}
> +
> +static int sp_intc_get_ext_irq(int ext_num)
> +{
> +	void __iomem *base = ext_num ? REG_MASKED_EXT1 : REG_MASKED_EXT0;
> +	u32 shift = ext_num ? GROUP_SHIFT_EXT1 : GROUP_SHIFT_EXT0;
> +	u32 groups;
> +	u32 pending_group;
> +	u32 group;
> +	u32 pending_irq;
> +
> +	groups = readl_relaxed(REG_INTR_GROUP);
> +	pending_group = (groups >> shift) & GROUP_MASK;
> +	if (!pending_group)
> +		return -1;
> +
> +	group = fls(pending_group) - 1;
> +	pending_irq = readl_relaxed(base + group * 4);
> +	if (!pending_irq)
> +		return -1;
> +
> +	return (group * 32) + fls(pending_irq) - 1;
> +}
> +
> +static void sp_intc_handle_ext_cascaded(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	int ext_num = (int)irq_desc_get_handler_data(desc);
> +	int hwirq;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	while ((hwirq = sp_intc_get_ext_irq(ext_num)) >= 0) {
> +		if (unlikely(IS_GPIO_INT(hwirq) && TEST_STATE(hwirq, _IS_ACTIVE))) { // WORKAROUND
> +			ASSIGN_STATE(hwirq, _IS_ACTIVE, false);
> +			sp_intc_assign_bit(hwirq, REG_INTR_POLARITY, TEST_STATE(hwirq, _IS_LOW));
> +		} else {
> +			generic_handle_domain_irq(sp_intc.domain, hwirq);
> +		}
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +#ifdef CONFIG_SMP
> +static int sp_intc_set_affinity(struct irq_data *d, const struct cpumask *mask, bool force)
> +{
> +	return -EINVAL;
> +}
> +#endif
> +
> +static struct irq_chip sp_intc_chip = {
> +	.name = "sp_intc",
> +	.irq_ack = sp_intc_ack_irq,
> +	.irq_mask = sp_intc_mask_irq,
> +	.irq_unmask = sp_intc_unmask_irq,
> +	.irq_set_type = sp_intc_set_type,
> +#ifdef CONFIG_SMP
> +	.irq_set_affinity = sp_intc_set_affinity,
> +#endif
> +};
> +
> +static int sp_intc_irq_domain_map(struct irq_domain *domain,
> +				  unsigned int irq, irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_and_handler(irq, &sp_intc_chip, handle_level_irq);
> +	irq_set_chip_data(irq, &sp_intc_chip);
> +	irq_set_noprobe(irq);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops sp_intc_dm_ops = {
> +	.xlate = irq_domain_xlate_twocell,
> +	.map = sp_intc_irq_domain_map,
> +};
> +
> +static int sp_intc_irq_map(struct device_node *node, int i)
> +{
> +	unsigned int irq;
> +
> +	irq = irq_of_parse_and_map(node, i);
> +	if (!irq)
> +		return -ENOENT;
> +
> +	irq_set_chained_handler_and_data(irq, sp_intc_handle_ext_cascaded, (void *)i);
> +
> +	return 0;
> +}
> +
> +void sp_intc_set_ext(u32 hwirq, int ext_num)
> +{
> +	sp_intc_assign_bit(hwirq, REG_INTR_PRIORITY, !ext_num);
> +}
> +EXPORT_SYMBOL_GPL(sp_intc_set_ext);

No way. We don't export random symbols without a good justification,
and you didn't give any.

> +
> +int __init sp_intc_init_dt(struct device_node *node, struct device_node *parent)

This should be static.

> +{
> +	int i, ret;
> +
> +	sp_intc.g0 = of_iomap(node, 0);
> +	if (!sp_intc.g0)
> +		return -ENXIO;
> +
> +	sp_intc.g1 = of_iomap(node, 1);
> +	if (!sp_intc.g1) {
> +		ret = -ENXIO;
> +		goto out_unmap0;
> +	}
> +
> +	ret = sp_intc_irq_map(node, 0); // EXT_INT0
> +	if (ret)
> +		goto out_unmap1;
> +
> +	ret = sp_intc_irq_map(node, 1); // EXT_INT1
> +	if (ret)
> +		goto out_unmap1;
> +
> +	/* initial regs */
> +	for (i = 0; i < SP_INTC_NR_GROUPS; i++) {
> +		/* all mask */
> +		writel_relaxed(0, REG_INTR_MASK + i * 4);
> +		/* all edge */
> +		writel_relaxed(~0, REG_INTR_TYPE + i * 4);
> +		/* all high-active */
> +		writel_relaxed(0, REG_INTR_POLARITY + i * 4);
> +		/* all EXT_INT0 */
> +		writel_relaxed(~0, REG_INTR_PRIORITY + i * 4);
> +		/* all clear */
> +		writel_relaxed(~0, REG_INTR_CLEAR + i * 4);
> +	}
> +
> +	sp_intc.domain = irq_domain_add_linear(node, SP_INTC_NR_IRQS,
> +					       &sp_intc_dm_ops, &sp_intc);
> +	if (!sp_intc.domain) {
> +		ret = -ENOMEM;
> +		goto out_unmap1;
> +	}
> +
> +	raw_spin_lock_init(&sp_intc.lock);
> +
> +	return 0;
> +
> +out_unmap1:
> +	iounmap(sp_intc.g1);
> +out_unmap0:
> +	iounmap(sp_intc.g0);
> +
> +	return ret;
> +}
> +
> +IRQCHIP_DECLARE(sp_intc, "sunplus,sp7021-intc", sp_intc_init_dt);

	M.

-- 
Without deviation from the norm, progress is not possible.

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