xref: /openbmc/linux/arch/ia64/mm/ioremap.c (revision c900529f3d9161bfde5cca0754f83b4d3c3e0220)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.
 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
 */

#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <asm/io.h>
#include <asm/meminit.h>

static inline void __iomem *
__ioremap_uc(unsigned long phys_addr)
{
	return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
}

void __iomem *
early_ioremap (unsigned long phys_addr, unsigned long size)
{
	u64 attr;
	attr = kern_mem_attribute(phys_addr, size);
	if (attr & EFI_MEMORY_WB)
		return (void __iomem *) phys_to_virt(phys_addr);
	return __ioremap_uc(phys_addr);
}

void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
			   unsigned long flags)
{
	u64 attr;
	unsigned long gran_base, gran_size;
	unsigned long page_base;

	/*
	 * For things in kern_memmap, we must use the same attribute
	 * as the rest of the kernel.  For more details, see
	 * Documentation/arch/ia64/aliasing.rst.
	 */
	attr = kern_mem_attribute(phys_addr, size);
	if (attr & EFI_MEMORY_WB)
		return (void __iomem *) phys_to_virt(phys_addr);
	else if (attr & EFI_MEMORY_UC)
		return __ioremap_uc(phys_addr);

	/*
	 * Some chipsets don't support UC access to memory.  If
	 * WB is supported for the whole granule, we prefer that.
	 */
	gran_base = GRANULEROUNDDOWN(phys_addr);
	gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
	if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
		return (void __iomem *) phys_to_virt(phys_addr);

	/*
	 * WB is not supported for the whole granule, so we can't use
	 * the region 7 identity mapping.  If we can safely cover the
	 * area with kernel page table mappings, we can use those
	 * instead.
	 */
	page_base = phys_addr & PAGE_MASK;
	size = PAGE_ALIGN(phys_addr + size) - page_base;
	if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB)
		return generic_ioremap_prot(phys_addr, size, __pgprot(flags));

	return __ioremap_uc(phys_addr);
}
EXPORT_SYMBOL(ioremap_prot);

void __iomem *
ioremap_uc(unsigned long phys_addr, unsigned long size)
{
	if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
		return NULL;

	return __ioremap_uc(phys_addr);
}
EXPORT_SYMBOL(ioremap_uc);

void
early_iounmap (volatile void __iomem *addr, unsigned long size)
{
}

void iounmap(volatile void __iomem *addr)
{
	if (REGION_NUMBER(addr) == RGN_GATE)
		vunmap((void *) ((unsigned long) addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);