drivers/irqchip/irq-alpine-msi.c

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

File Facts

System
Linux kernel
Corpus path
drivers/irqchip/irq-alpine-msi.c
Extension
.c
Size
6694 bytes
Lines
247
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 alpine_msix_data {
	spinlock_t	msi_map_lock;
	phys_addr_t	addr;
	u32		spi_first;	/* The SGI number that MSIs start */
	u32		num_spis;	/* The number of SGIs for MSIs */
	unsigned long	*msi_map;
};

static int alpine_msix_allocate_sgi(struct alpine_msix_data *priv, int num_req)
{
	int first;

	guard(spinlock)(&priv->msi_map_lock);
	first = bitmap_find_next_zero_area(priv->msi_map, priv->num_spis, 0, num_req, 0);
	if (first >= priv->num_spis)
		return -ENOSPC;

	bitmap_set(priv->msi_map, first, num_req);
	return priv->spi_first + first;
}

static void alpine_msix_free_sgi(struct alpine_msix_data *priv, unsigned int sgi, int num_req)
{
	int first = sgi - priv->spi_first;

	guard(spinlock)(&priv->msi_map_lock);
	bitmap_clear(priv->msi_map, first, num_req);
}

static void alpine_msix_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
	struct alpine_msix_data *priv = irq_data_get_irq_chip_data(data);
	phys_addr_t msg_addr = priv->addr;

	msg_addr |= (data->hwirq << 3);
	msg->address_hi = upper_32_bits(msg_addr);
	msg->address_lo = lower_32_bits(msg_addr);
	msg->data = 0;
}

static struct irq_chip middle_irq_chip = {
	.name			= "alpine_msix_middle",
	.irq_mask		= irq_chip_mask_parent,
	.irq_unmask		= irq_chip_unmask_parent,
	.irq_eoi		= irq_chip_eoi_parent,
	.irq_set_affinity	= irq_chip_set_affinity_parent,
	.irq_compose_msi_msg	= alpine_msix_compose_msi_msg,
};

static int alpine_msix_gic_domain_alloc(struct irq_domain *domain, unsigned int virq, int sgi)
{
	struct irq_fwspec fwspec;
	struct irq_data *d;
	int ret;

	if (!is_of_node(domain->parent->fwnode))
		return -EINVAL;

	fwspec.fwnode = domain->parent->fwnode;
	fwspec.param_count = 3;
	fwspec.param[0] = 0;
	fwspec.param[1] = sgi;
	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;

	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
	if (ret)
		return ret;

	d = irq_domain_get_irq_data(domain->parent, virq);
	d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
	return 0;
}

static int alpine_msix_middle_domain_alloc(struct irq_domain *domain, unsigned int virq,
					   unsigned int nr_irqs, void *args)
{
	struct alpine_msix_data *priv = domain->host_data;
	int sgi, err, i;

	sgi = alpine_msix_allocate_sgi(priv, nr_irqs);
	if (sgi < 0)
		return sgi;

	for (i = 0; i < nr_irqs; i++) {
		err = alpine_msix_gic_domain_alloc(domain, virq + i, sgi + i);
		if (err)
			goto err_sgi;

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

Annotation

Implementation Notes