arch/unicore32/mm/ioremap.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/arch/unicore32/mm/ioremap.c
  *
  * Code specific to PKUnity SoC and UniCore ISA
  *
  * Copyright (C) 2001-2010 GUAN Xue-tao
  *
  * Re-map IO memory to kernel address space so that we can access it.
  *
  * This allows a driver to remap an arbitrary region of bus memory into
  * virtual space.  One should *only* use readl, writel, memcpy_toio and
  * so on with such remapped areas.
  *
  * Because UniCore only has a 32-bit address space we can't address the
  * whole of the (physical) PCI space at once.  PCI huge-mode addressing
  * allows us to circumvent this restriction by splitting PCI space into
  * two 2GB chunks and mapping only one at a time into processor memory.
  * We use MMU protection domains to trap any attempt to access the bank
  * that is not currently mapped.  (This isn't fully implemented yet.)
  */
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <linux/io.h>

 #include <asm/cputype.h>
 #include <asm/cacheflush.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <linux/sizes.h>

 #include <mach/map.h>
 #include "mm.h"

 /*
  * Used by ioremap() and iounmap() code to mark (super)section-mapped
  * I/O regions in vm_struct->flags field.
  */
 #define VM_UNICORE_SECTION_MAPPING	0x80000000

 int ioremap_page(unsigned long virt, unsigned long phys,
 		 const struct mem_type *mtype)
 {
 	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
 				  __pgprot(mtype->prot_pte));
 }
 EXPORT_SYMBOL(ioremap_page);

 /*
  * Section support is unsafe on SMP - If you iounmap and ioremap a region,
  * the other CPUs will not see this change until their next context switch.
  * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
  * which requires the new ioremap'd region to be referenced, the CPU will
  * reference the _old_ region.
  *
  * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
  * mask the size back to 4MB aligned or we will overflow in the loop below.
  */
 static void unmap_area_sections(unsigned long virt, unsigned long size)
 {
 	unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
 	pgd_t *pgd;

 	flush_cache_vunmap(addr, end);
 	pgd = pgd_offset_k(addr);
 	do {
 		pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);

 		pmd = *pmdp;
 		if (!pmd_none(pmd)) {
 			/*
 			 * Clear the PMD from the page table, and
 			 * increment the kvm sequence so others
 			 * notice this change.
 			 *
 			 * Note: this is still racy on SMP machines.
 			 */
 			pmd_clear(pmdp);

 			/*
 			 * Free the page table, if there was one.
 			 */
 			if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
 				pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
 		}

 		addr += PGDIR_SIZE;
 		pgd++;
 	} while (addr < end);

 	flush_tlb_kernel_range(virt, end);
 }

 static int
 remap_area_sections(unsigned long virt, unsigned long pfn,
 		    size_t size, const struct mem_type *type)
 {
 	unsigned long addr = virt, end = virt + size;
 	pgd_t *pgd;

 	/*
 	 * Remove and free any PTE-based mapping, and
 	 * sync the current kernel mapping.
 	 */
 	unmap_area_sections(virt, size);

 	pgd = pgd_offset_k(addr);
 	do {
 		pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);

 		set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
 		pfn += SZ_4M >> PAGE_SHIFT;
 		flush_pmd_entry(pmd);

 		addr += PGDIR_SIZE;
 		pgd++;
 	} while (addr < end);

 	return 0;
 }

 void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
 	unsigned long offset, size_t size, unsigned int mtype, void *caller)
 {
 	const struct mem_type *type;
 	int err;
 	unsigned long addr;
 	struct vm_struct *area;

 	/*
 	 * High mappings must be section aligned
 	 */
 	if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
 		return NULL;

 	/*
 	 * Don't allow RAM to be mapped
 	 */
 	if (pfn_valid(pfn)) {
 		WARN(1, "BUG: Your driver calls ioremap() on\n"
 			"system memory.  This leads to architecturally\n"
 			"unpredictable behaviour, and ioremap() will fail in\n"
 			"the next kernel release. Please fix your driver.\n");
 		return NULL;
 	}

 	type = get_mem_type(mtype);
 	if (!type)
 		return NULL;

 	/*
 	 * Page align the mapping size, taking account of any offset.
 	 */
 	size = PAGE_ALIGN(offset + size);

 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
 	if (!area)
 		return NULL;
 	addr = (unsigned long)area->addr;

 	if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
 		area->flags |= VM_UNICORE_SECTION_MAPPING;
 		err = remap_area_sections(addr, pfn, size, type);
 	} else
 		err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
 					 __pgprot(type->prot_pte));

 	if (err) {
 		vunmap((void *)addr);
 		return NULL;
 	}

 	flush_cache_vmap(addr, addr + size);
 	return (void __iomem *) (offset + addr);
 }

 void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
 	unsigned int mtype, void *caller)
 {
 	unsigned long last_addr;
 	unsigned long offset = phys_addr & ~PAGE_MASK;
 	unsigned long pfn = __phys_to_pfn(phys_addr);

 	/*
 	 * Don't allow wraparound or zero size
 	 */
 	last_addr = phys_addr + size - 1;
 	if (!size || last_addr < phys_addr)
 		return NULL;

 	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
 }

 /*
  * Remap an arbitrary physical address space into the kernel virtual
  * address space. Needed when the kernel wants to access high addresses
  * directly.
  *
  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  * have to convert them into an offset in a page-aligned mapping, but the
  * caller shouldn't need to know that small detail.
  */
 void __iomem *
 __uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
 		  unsigned int mtype)
 {
 	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
 			__builtin_return_address(0));
 }
 EXPORT_SYMBOL(__uc32_ioremap_pfn);

 void __iomem *
 __uc32_ioremap(unsigned long phys_addr, size_t size)
 {
 	return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
 			__builtin_return_address(0));
 }
 EXPORT_SYMBOL(__uc32_ioremap);

 void __uc32_iounmap(volatile void __iomem *io_addr)
 {
 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 	struct vm_struct *vm;

 	/*
 	 * If this is a section based mapping we need to handle it
 	 * specially as the VM subsystem does not know how to handle
 	 * such a beast. We need the lock here b/c we need to clear
 	 * all the mappings before the area can be reclaimed
 	 * by someone else.
 	 */
 	vm = find_vm_area(addr);
 	if (vm && (vm->flags & VM_IOREMAP) &&
 		(vm->flags & VM_UNICORE_SECTION_MAPPING))
 		unmap_area_sections((unsigned long)vm->addr, vm->size);

 	vunmap(addr);
 }
 EXPORT_SYMBOL(__uc32_iounmap);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* linux/arch/unicore32/mm/ioremap.c
	*
	* Code specific to PKUnity SoC and UniCore ISA
	*
	* Copyright (C) 2001-2010 GUAN Xue-tao
	*
	* Re-map IO memory to kernel address space so that we can access it.
	*
	* This allows a driver to remap an arbitrary region of bus memory into
	* virtual space. One should only use readl, writel, memcpy_toio and
	* so on with such remapped areas.
	*
	* Because UniCore only has a 32-bit address space we can't address the
	* whole of the (physical) PCI space at once. PCI huge-mode addressing
	* allows us to circumvent this restriction by splitting PCI space into
	* two 2GB chunks and mapping only one at a time into processor memory.
	* We use MMU protection domains to trap any attempt to access the bank
	* that is not currently mapped. (This isn't fully implemented yet.)
	*/
	#include <linux/module.h>
	#include <linux/errno.h>
	#include <linux/mm.h>
	#include <linux/vmalloc.h>
	#include <linux/io.h>

	#include <asm/cputype.h>
	#include <asm/cacheflush.h>
	#include <asm/mmu_context.h>
	#include <asm/pgalloc.h>
	#include <asm/tlbflush.h>
	#include <linux/sizes.h>

	#include <mach/map.h>
	#include "mm.h"

	/*
	* Used by ioremap() and iounmap() code to mark (super)section-mapped
	* I/O regions in vm_struct->flags field.
	*/
	#define VM_UNICORE_SECTION_MAPPING 0x80000000

	int ioremap_page(unsigned long virt, unsigned long phys,
	const struct mem_type *mtype)
	{
	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
	__pgprot(mtype->prot_pte));
	}
	EXPORT_SYMBOL(ioremap_page);

	/*
	* Section support is unsafe on SMP - If you iounmap and ioremap a region,
	* the other CPUs will not see this change until their next context switch.
	* Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
	* which requires the new ioremap'd region to be referenced, the CPU will
	* reference the _old_ region.
	*
	* Note that get_vm_area_caller() allocates a guard 4K page, so we need to
	* mask the size back to 4MB aligned or we will overflow in the loop below.
	*/
	static void unmap_area_sections(unsigned long virt, unsigned long size)
	{
	unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
	pgd_t *pgd;

	flush_cache_vunmap(addr, end);
	pgd = pgd_offset_k(addr);
	do {
	pmd_t pmd, pmdp = pmd_offset((pud_t )pgd, addr);

	pmd = *pmdp;
	if (!pmd_none(pmd)) {
	/*
	* Clear the PMD from the page table, and
	* increment the kvm sequence so others
	* notice this change.
	*
	* Note: this is still racy on SMP machines.
	*/
	pmd_clear(pmdp);

	/*
	* Free the page table, if there was one.
	*/
	if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
	pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
	}

	addr += PGDIR_SIZE;
	pgd++;
	} while (addr < end);

	flush_tlb_kernel_range(virt, end);
	}

	static int
	remap_area_sections(unsigned long virt, unsigned long pfn,
	size_t size, const struct mem_type *type)
	{
	unsigned long addr = virt, end = virt + size;
	pgd_t *pgd;

	/*
	* Remove and free any PTE-based mapping, and
	* sync the current kernel mapping.
	*/
	unmap_area_sections(virt, size);

	pgd = pgd_offset_k(addr);
	do {
	pmd_t pmd = pmd_offset((pud_t )pgd, addr);

	set_pmd(pmd, __pmd(__pfn_to_phys(pfn) \| type->prot_sect));
	pfn += SZ_4M >> PAGE_SHIFT;
	flush_pmd_entry(pmd);

	addr += PGDIR_SIZE;
	pgd++;
	} while (addr < end);

	return 0;
	}

	void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
	unsigned long offset, size_t size, unsigned int mtype, void *caller)
	{
	const struct mem_type *type;
	int err;
	unsigned long addr;
	struct vm_struct *area;

	/*
	* High mappings must be section aligned
	*/
	if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
	return NULL;

	/*
	* Don't allow RAM to be mapped
	*/
	if (pfn_valid(pfn)) {
	WARN(1, "BUG: Your driver calls ioremap() on\n"
	"system memory. This leads to architecturally\n"
	"unpredictable behaviour, and ioremap() will fail in\n"
	"the next kernel release. Please fix your driver.\n");
	return NULL;
	}

	type = get_mem_type(mtype);
	if (!type)
	return NULL;

	/*
	* Page align the mapping size, taking account of any offset.
	*/
	size = PAGE_ALIGN(offset + size);

	area = get_vm_area_caller(size, VM_IOREMAP, caller);
	if (!area)
	return NULL;
	addr = (unsigned long)area->addr;

	if (!((__pfn_to_phys(pfn) \| size \| addr) & ~PMD_MASK)) {
	area->flags \|= VM_UNICORE_SECTION_MAPPING;
	err = remap_area_sections(addr, pfn, size, type);
	} else
	err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
	__pgprot(type->prot_pte));

	if (err) {
	vunmap((void *)addr);
	return NULL;
	}

	flush_cache_vmap(addr, addr + size);
	return (void __iomem *) (offset + addr);
	}

	void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
	unsigned int mtype, void *caller)
	{
	unsigned long last_addr;
	unsigned long offset = phys_addr & ~PAGE_MASK;
	unsigned long pfn = __phys_to_pfn(phys_addr);

	/*
	* Don't allow wraparound or zero size
	*/
	last_addr = phys_addr + size - 1;
	if (!size \|\| last_addr < phys_addr)
	return NULL;

	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
	}

	/*
	* Remap an arbitrary physical address space into the kernel virtual
	* address space. Needed when the kernel wants to access high addresses
	* directly.
	*
	* NOTE! We need to allow non-page-aligned mappings too: we will obviously
	* have to convert them into an offset in a page-aligned mapping, but the
	* caller shouldn't need to know that small detail.
	*/
	void __iomem *
	__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
	unsigned int mtype)
	{
	return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(__uc32_ioremap_pfn);

	void __iomem *
	__uc32_ioremap(unsigned long phys_addr, size_t size)
	{
	return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(__uc32_ioremap);

	void __uc32_iounmap(volatile void __iomem *io_addr)
	{
	void addr = (void )(PAGE_MASK & (unsigned long)io_addr);
	struct vm_struct *vm;

	/*
	* If this is a section based mapping we need to handle it
	* specially as the VM subsystem does not know how to handle
	* such a beast. We need the lock here b/c we need to clear
	* all the mappings before the area can be reclaimed
	* by someone else.
	*/
	vm = find_vm_area(addr);
	if (vm && (vm->flags & VM_IOREMAP) &&
	(vm->flags & VM_UNICORE_SECTION_MAPPING))
	unmap_area_sections((unsigned long)vm->addr, vm->size);

	vunmap(addr);
	}
	EXPORT_SYMBOL(__uc32_iounmap);