linux-kernel - Re: [PATCH v2 2/2] irqchip: Add StarFive external interrupt controller

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Date: Tue, 13 Feb 2024 10:03:12 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: Changhuang Liang <changhuang.liang@...rfivetech.com>, Rob Herring
 <robh+dt@...nel.org>, Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
 Philipp Zabel <p.zabel@...gutronix.de>
Cc: Ley Foon Tan <leyfoon.tan@...rfivetech.com>, Jack Zhu
 <jack.zhu@...rfivetech.com>, Changhuang Liang
 <changhuang.liang@...rfivetech.com>, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org
Subject: Re: [PATCH v2 2/2] irqchip: Add StarFive external interrupt controller

On Mon, Jan 29 2024 at 21:58, Changhuang Liang wrote:
> +
> +struct starfive_irq_chip {
> +	void __iomem *base;
> +	struct irq_domain *root_domain;
> +	struct clk *clk;
> +};

https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#struct-declarations-and-initializers

Please.

> +static void starfive_intc_mod(struct starfive_irq_chip *irqc, u32 reg, u32 mask, u32 data)
> +{
> +	u32 value;
> +
> +	value = ioread32(irqc->base + reg) & ~mask;
> +	data &= mask;

Why?

> +	data |= value;
> +	iowrite32(data, irqc->base + reg);

How is this serialized against concurrent invocations of this code on
different CPUs for different interrupts?

It's not and this requires a raw_spinlock for protection.

> +}
> +
> +static void starfive_intc_unmask(struct irq_data *d)
> +{
> +	struct starfive_irq_chip *irqc = irq_data_get_irq_chip_data(d);
> +
> +	starfive_intc_mod(irqc, STARFIVE_INTC_SRC0_MASK, BIT(d->hwirq), 0);
> +}
> +
> +static void starfive_intc_mask(struct irq_data *d)
> +{
> +	struct starfive_irq_chip *irqc = irq_data_get_irq_chip_data(d);
> +
> +	starfive_intc_mod(irqc, STARFIVE_INTC_SRC0_MASK, BIT(d->hwirq), BIT(d->hwirq));
> +}
> +
> +static struct irq_chip intc_dev = {
> +	.name = "starfive jh8100 intc",
> +	.irq_unmask = starfive_intc_unmask,
> +	.irq_mask = starfive_intc_mask,
> +};

See documentation please.

> +static int starfive_intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)
> +{
> +	irq_domain_set_info(d, irq, hwirq, &intc_dev, d->host_data,
> +			    handle_level_irq, NULL, NULL);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops starfive_intc_domain_ops = {
> +	.xlate = irq_domain_xlate_onecell,
> +	.map = starfive_intc_map,
> +};

Ditto.

> +static void starfive_intc_irq_handler(struct irq_desc *desc)
> +{
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	struct starfive_irq_chip *irqc = irq_data_get_irq_handler_data(&desc->irq_data);

https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#variable-declarations

> +	unsigned long value = 0;

Pointless initialization

> +	int hwirq;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	value = ioread32(irqc->base + STARFIVE_INTC_SRC0_INT);
> +	while (value) {
> +		hwirq = ffs(value) - 1;
> +
> +		generic_handle_domain_irq(irqc->root_domain, hwirq);
> +
> +		starfive_intc_mod(irqc, STARFIVE_INTC_SRC0_CLEAR, BIT(hwirq), BIT(hwirq));
> +		starfive_intc_mod(irqc, STARFIVE_INTC_SRC0_CLEAR, BIT(hwirq), 0);
> +
> +		clear_bit(hwirq, &value);
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +static int __init starfive_intc_init(struct device_node *intc,
> +				     struct device_node *parent)
> +{
> +	struct starfive_irq_chip *irqc;
> +	struct reset_control *rst;
> +	int ret;
> +	int parent_irq;

See Documentation

> +	irqc = kzalloc(sizeof(*irqc), GFP_KERNEL);
> +	if (!irqc)
> +		return -ENOMEM;
> +
> +	irqc->base = of_iomap(intc, 0);
> +	if (!irqc->base) {
> +		pr_err("Unable to map IC registers\n");
> +		ret = -ENXIO;
> +		goto err_free;
> +	}
> +
> +	rst = of_reset_control_get_exclusive(intc, NULL);
> +	if (IS_ERR(rst)) {
> +		pr_err("Unable to get reset control %pe\n", rst);
> +		ret = PTR_ERR(rst);
> +		goto err_unmap;
> +	}
> +
> +	irqc->clk = of_clk_get(intc, 0);
> +	if (IS_ERR(irqc->clk)) {
> +		pr_err("Unable to get clock\n");
> +		ret = PTR_ERR(irqc->clk);
> +		goto err_rst;
> +	}
> +
> +	ret = reset_control_deassert(rst);
> +	if (ret)
> +		goto err_clk;
> +
> +	ret = clk_prepare_enable(irqc->clk);
> +	if (ret)
> +		goto err_clk;
> +
> +	irqc->root_domain = irq_domain_add_linear(intc, STARFIVE_INTC_SRC_IRQ_NUM,
> +						  &starfive_intc_domain_ops, irqc);
> +	if (!irqc->root_domain) {
> +		pr_err("Unable to create IRQ domain\n");
> +		ret = -EINVAL;
> +		goto err_clk;
> +	}
> +
> +	parent_irq = of_irq_get(intc, 0);
> +	if (parent_irq < 0) {
> +		pr_err("Failed to get main IRQ: %d\n", parent_irq);
> +		ret = parent_irq;
> +		goto err_clk;

Leaks the interrupt domain, no?

Thanks,

        tglx