nios2: I/O Mapping

/*

 * Copyright (C) 2014 Altera Corporation

 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>

 * Copyright (C) 2004 Microtronix Datacom Ltd.

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License. See the file "COPYING" in the main directory of this archive

 * for more details.

 */

#ifndef _ASM_NIOS2_IO_H

#define _ASM_NIOS2_IO_H

#include <asm/pgtable-bits.h>

#include <asm-generic/iomap.h>

/* PCI is not supported in nios2, set this to 0. */

#define IO_SPACE_LIMIT 0

#define readb_relaxed(addr)	readb(addr)

#define readw_relaxed(addr)	readw(addr)

#define readl_relaxed(addr)	readl(addr)

#define writeb_relaxed(x, addr)	writeb(x, addr)

#define writew_relaxed(x, addr)	writew(x, addr)

#define writel_relaxed(x, addr)	writel(x, addr)

#include <asm-generic/io.h>

extern void __iomem *__ioremap(unsigned long physaddr, unsigned long size,

			unsigned long cacheflag);

extern void __iounmap(void __iomem *addr);

static inline void __iomem *ioremap(unsigned long physaddr, unsigned long size)

{

	return __ioremap(physaddr, size, 0);

}

static inline void __iomem *ioremap_nocache(unsigned long physaddr,

						unsigned long size)

{

	return __ioremap(physaddr, size, 0);

}

static inline void iounmap(void __iomem *addr)

{

	__iounmap(addr);

}

/* Pages to physical address... */

# define page_to_phys(page)	virt_to_phys(page_to_virt(page))

# define page_to_bus(page)	page_to_virt(page)

/* Macros used for converting between virtual and physical mappings. */

# define phys_to_virt(vaddr)	\

	((void *)((unsigned long)(vaddr) | CONFIG_NIOS2_KERNEL_REGION_BASE))

/* Clear top 3 bits */

# define virt_to_phys(vaddr)	\

	((unsigned long)((unsigned long)(vaddr) & ~0xE0000000))

#endif /* _ASM_NIOS2_IO_H */

/*

 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>

 * Copyright (C) 2009 Wind River Systems Inc

 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com

 * Copyright (C) 2004 Microtronix Datacom Ltd.

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License. See the file "COPYING" in the main directory of this archive

 * for more details.

 */

#include <linux/export.h>

#include <linux/sched.h>

#include <linux/mm.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/io.h>

#include <asm/cacheflush.h>

#include <asm/tlbflush.h>

static inline void remap_area_pte(pte_t *pte, unsigned long address,

				unsigned long size, unsigned long phys_addr,

				unsigned long flags)

{

	unsigned long end;

	unsigned long pfn;

	pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ

				| _PAGE_WRITE | flags);

	address &= ~PMD_MASK;

	end = address + size;

	if (end > PMD_SIZE)

		end = PMD_SIZE;

	if (address >= end)

		BUG();

	pfn = PFN_DOWN(phys_addr);

	do {

		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 {

		pud_t *pud;

		pmd_t *pmd;

		error = -ENOMEM;

		pud = pud_alloc(&init_mm, dir, 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,

			unsigned long cacheflag)

{

	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;

	if (!size || last_addr < phys_addr)

		return NULL;

	/* Don't allow anybody to remap normal RAM that we're using */

	if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) {

		char *t_addr, *t_end;

		struct page *page;

		t_addr = __va(phys_addr);

		t_end = t_addr + (size - 1);

		for (page = virt_to_page(t_addr);

			page <= virt_to_page(t_end); page++)

			if (!PageReserved(page))

				return NULL;

	}

	/*

	 * Map uncached objects in the low part of address space to

	 * CONFIG_NIOS2_IO_REGION_BASE

	 */

	if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&

	    IS_MAPPABLE_UNCACHEABLE(last_addr) &&

	    !(cacheflag & _PAGE_CACHED))

		return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);

	/* Mappings have to be page-aligned */

	offset = phys_addr & ~PAGE_MASK;

	phys_addr &= PAGE_MASK;

	size = PAGE_ALIGN(last_addr + 1) - phys_addr;

	/* Ok, go for it */

	area = get_vm_area(size, VM_IOREMAP);

	if (!area)

		return NULL;

	addr = area->addr;

	if (remap_area_pages((unsigned long) addr, phys_addr, size,

		cacheflag)) {

		vunmap(addr);

		return NULL;

	}

	return (void __iomem *) (offset + (char *)addr);

}

EXPORT_SYMBOL(__ioremap);

/*

 * __iounmap unmaps nearly everything, so be careful

 * it doesn't free currently pointer/page tables anymore but it

 * wasn't used anyway and might be added later.

 */

void __iounmap(void __iomem *addr)

{

	struct vm_struct *p;

	if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE)

		return;

	p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));

	if (!p)

		pr_err("iounmap: bad address %p\n", addr);

	kfree(p);

}

EXPORT_SYMBOL(__iounmap);