arch/nios2/mm/ioremap.c

Source file repositories/reference/linux-study-clean/arch/nios2/mm/ioremap.c

File Facts

System
Linux kernel
Corpus path
arch/nios2/mm/ioremap.c
Extension
.c
Size
4573 bytes
Lines
189
Domain
Architecture Layer
Bucket
arch/nios2
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration 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

if (!pte_none(*pte)) {
			pr_err("remap_area_pte: page already exists\n");
			BUG();
		}
		set_pte(pte, pfn_pte(pfn, pgprot));
		address += PAGE_SIZE;
		pfn++;
		pte++;
	} while (address && (address < end));
}

static inline int remap_area_pmd(pmd_t *pmd, unsigned long address,
				unsigned long size, unsigned long phys_addr,
				unsigned long flags)
{
	unsigned long end;

	address &= ~PGDIR_MASK;
	end = address + size;
	if (end > PGDIR_SIZE)
		end = PGDIR_SIZE;
	phys_addr -= address;
	if (address >= end)
		BUG();
	do {
		pte_t *pte = pte_alloc_kernel(pmd, address);

		if (!pte)
			return -ENOMEM;
		remap_area_pte(pte, address, end - address, address + phys_addr,
			flags);
		address = (address + PMD_SIZE) & PMD_MASK;
		pmd++;
	} while (address && (address < end));
	return 0;
}

static int remap_area_pages(unsigned long address, unsigned long phys_addr,
				unsigned long size, unsigned long flags)
{
	int error;
	pgd_t *dir;
	unsigned long end = address + size;

	phys_addr -= address;
	dir = pgd_offset(&init_mm, address);
	flush_cache_all();
	if (address >= end)
		BUG();
	do {
		p4d_t *p4d;
		pud_t *pud;
		pmd_t *pmd;

		error = -ENOMEM;
		p4d = p4d_alloc(&init_mm, dir, address);
		if (!p4d)
			break;
		pud = pud_alloc(&init_mm, p4d, address);
		if (!pud)
			break;
		pmd = pmd_alloc(&init_mm, pud, address);
		if (!pmd)
			break;
		if (remap_area_pmd(pmd, address, end - address,
			phys_addr + address, flags))
			break;
		error = 0;
		address = (address + PGDIR_SIZE) & PGDIR_MASK;
		dir++;
	} while (address && (address < end));
	flush_tlb_all();
	return error;
}

#define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL)

/*
 * Map some physical address range into the kernel address space.
 */
void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
{
	struct vm_struct *area;
	unsigned long offset;
	unsigned long last_addr;
	void *addr;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;

Annotation

Implementation Notes