linux/arch/arm64/mm/ioremap.c

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/mm.h>
#include <linux/io.h>

void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
			   unsigned long prot)
{
	unsigned long last_addr = phys_addr + size - 1;

	/* Don't allow outside PHYS_MASK */
	if (last_addr & ~PHYS_MASK)
		return NULL;

	/* Don't allow RAM to be mapped. */
	if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr))))
		return NULL;

	return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
}
EXPORT_SYMBOL(ioremap_prot);

/*
 * Must be called after early_fixmap_init
 */
void __init early_ioremap_init(void)
{
	early_ioremap_setup();
}

bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
				 unsigned long flags)
{
	unsigned long pfn = PHYS_PFN(offset);

	return pfn_is_map_memory(pfn);
}