drivers/irqchip/irq-loongson-pch-msi.c

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

File Facts

System
Linux kernel
Corpus path
drivers/irqchip/irq-loongson-pch-msi.c
Extension
.c
Size
7220 bytes
Lines
293
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 pch_msi_data {
	struct mutex	msi_map_lock;
	phys_addr_t	doorbell;
	u32		irq_first;	/* The vector number that MSIs starts */
	u32		num_irqs;	/* The number of vectors for MSIs */
	unsigned long	*msi_map;
};

static struct fwnode_handle *pch_msi_handle[MAX_IO_PICS];

static int pch_msi_allocate_hwirq(struct pch_msi_data *priv, int num_req)
{
	int first;

	mutex_lock(&priv->msi_map_lock);

	first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
					get_count_order(num_req));
	if (first < 0) {
		mutex_unlock(&priv->msi_map_lock);
		return -ENOSPC;
	}

	mutex_unlock(&priv->msi_map_lock);

	return priv->irq_first + first;
}

static void pch_msi_free_hwirq(struct pch_msi_data *priv,
				int hwirq, int num_req)
{
	int first = hwirq - priv->irq_first;

	mutex_lock(&priv->msi_map_lock);
	bitmap_release_region(priv->msi_map, first, get_count_order(num_req));
	mutex_unlock(&priv->msi_map_lock);
}

static void pch_msi_compose_msi_msg(struct irq_data *data,
					struct msi_msg *msg)
{
	struct pch_msi_data *priv = irq_data_get_irq_chip_data(data);

	msg->address_hi = upper_32_bits(priv->doorbell);
	msg->address_lo = lower_32_bits(priv->doorbell);
	msg->data = data->hwirq;
}

static struct irq_chip middle_irq_chip = {
	.name			= "PCH MSI",
	.irq_mask		= irq_chip_mask_parent,
	.irq_unmask		= irq_chip_unmask_parent,
	.irq_ack		= irq_chip_ack_parent,
	.irq_set_affinity	= irq_chip_set_affinity_parent,
	.irq_compose_msi_msg	= pch_msi_compose_msi_msg,
};

static int pch_msi_parent_domain_alloc(struct irq_domain *domain,
					unsigned int virq, int hwirq)
{
	struct irq_fwspec fwspec;

	fwspec.fwnode = domain->parent->fwnode;
	fwspec.param_count = 1;
	fwspec.param[0] = hwirq;

	return irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
}

static int pch_msi_middle_domain_alloc(struct irq_domain *domain,
					   unsigned int virq,
					   unsigned int nr_irqs, void *args)
{
	struct pch_msi_data *priv = domain->host_data;
	int hwirq, err, i;

	hwirq = pch_msi_allocate_hwirq(priv, nr_irqs);
	if (hwirq < 0)
		return hwirq;

	for (i = 0; i < nr_irqs; i++) {
		err = pch_msi_parent_domain_alloc(domain, virq + i, hwirq + i);
		if (err)
			goto err_hwirq;

		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
					      &middle_irq_chip, priv);
	}

	return 0;

Annotation

Implementation Notes