arch/mips/pci/pci-generic.c

Source file repositories/reference/linux-study-clean/arch/mips/pci/pci-generic.c

File Facts

System
Linux kernel
Corpus path
arch/mips/pci/pci-generic.c
Extension
.c
Size
1830 bytes
Lines
67
Domain
Architecture Layer
Bucket
arch/mips
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2016 Imagination Technologies
 * Author: Paul Burton <paul.burton@mips.com>
 *
 * pcibios_align_resource taken from arch/arm/kernel/bios32.c.
 */

#include <linux/pci.h>

/*
 * We need to avoid collisions with `mirrored' VGA ports
 * and other strange ISA hardware, so we always want the
 * addresses to be allocated in the 0x000-0x0ff region
 * modulo 0x400.
 *
 * Why? Because some silly external IO cards only decode
 * the low 10 bits of the IO address. The 0x00-0xff region
 * is reserved for motherboard devices that decode all 16
 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
 * but we want to try to avoid allocating at 0x2900-0x2bff
 * which might have be mirrored at 0x0100-0x03ff..
 */
resource_size_t pcibios_align_resource(void *data, const struct resource *res,
				       const struct resource *empty_res,
				       resource_size_t size, resource_size_t align)
{
	struct pci_dev *dev = data;
	resource_size_t start = res->start;
	struct pci_host_bridge *host_bridge;

	if (res->flags & IORESOURCE_IO && start & 0x300)
		start = (start + 0x3ff) & ~0x3ff;

	host_bridge = pci_find_host_bridge(dev->bus);

	if (host_bridge->align_resource)
		return host_bridge->align_resource(dev, res,
				start, size, align);

	if (res->flags & IORESOURCE_MEM)
		return pci_align_resource(dev, res, empty_res, size, align);

	return start;
}

void pcibios_fixup_bus(struct pci_bus *bus)
{
	pci_read_bridge_bases(bus);
}

#ifdef pci_remap_iospace
int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
{
	unsigned long vaddr;

	if (res->start != 0) {
		WARN_ONCE(1, "resource start address is not zero\n");
		return -ENODEV;
	}

	vaddr = (unsigned long)ioremap(phys_addr, resource_size(res));
	set_io_port_base(vaddr);
	return 0;
}
#endif

Annotation

Implementation Notes