drivers/irqchip/irq-loongson-htpic.c

Source file repositories/reference/linux-study-clean/drivers/irqchip/irq-loongson-htpic.c

File Facts

System
Linux kernel
Corpus path
drivers/irqchip/irq-loongson-htpic.c
Extension
.c
Size
3143 bytes
Lines
151
Domain
Driver Families
Bucket
drivers/irqchip
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct loongson_htpic {
	void __iomem *base;
	struct irq_domain *domain;
};

static struct loongson_htpic *htpic;

static void htpic_irq_dispatch(struct irq_desc *desc)
{
	struct loongson_htpic *priv = irq_desc_get_handler_data(desc);
	struct irq_chip *chip = irq_desc_get_chip(desc);
	uint32_t pending;

	chained_irq_enter(chip, desc);
	pending = readl(priv->base);
	/* Ack all IRQs at once, otherwise IRQ flood might happen */
	writel(pending, priv->base);

	if (!pending)
		spurious_interrupt();

	while (pending) {
		int bit = __ffs(pending);

		if (unlikely(bit > 15)) {
			spurious_interrupt();
			break;
		}

		generic_handle_domain_irq(priv->domain, bit);
		pending &= ~BIT(bit);
	}
	chained_irq_exit(chip, desc);
}

static void htpic_reg_init(void)
{
	int i;

	for (i = 0; i < HTINT_NUM_VECTORS; i++) {
		/* Disable all HT Vectors */
		writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4);
		/* Read back to force write */
		(void) readl(htpic->base + i * 0x4);
		/* Ack all possible pending IRQs */
		writel(GENMASK(31, 0), htpic->base + i * 0x4);
	}

	/* Enable 16 vectors for PIC */
	writel(0xffff, htpic->base + HTINT_EN_OFF);
}

static void htpic_resume(void *data)
{
	htpic_reg_init();
}

static const struct syscore_ops htpic_syscore_ops = {
	.resume		= htpic_resume,
};

static struct syscore htpic_syscore = {
	.ops = &htpic_syscore_ops,
};

static int __init htpic_of_init(struct device_node *node, struct device_node *parent)
{
	unsigned int parent_irq[4];
	int i, err;
	int num_parents = 0;

	if (htpic) {
		pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n");
		return -ENODEV;
	}

	htpic = kzalloc_obj(*htpic);
	if (!htpic)
		return -ENOMEM;

	htpic->base = of_iomap(node, 0);
	if (!htpic->base) {
		err = -ENODEV;
		goto out_free;
	}

	htpic->domain = __init_i8259_irqs(node);
	if (!htpic->domain) {
		pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n");
		err = -ENOMEM;

Annotation

Implementation Notes