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 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/arch/arm/mm/ioremap.c
  *
  * Re-map IO memory to kernel address space so that we can access it.
  *
  * (C) Copyright 1995 1996 Linus Torvalds
  *
  * Hacked for ARM by Phil Blundell <philb@gnu.org>
  * Hacked to allow all architectures to build, and various cleanups
  * by Russell King
  *
  * 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 the ARM 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 <linux/sizes.h>
 #include <linux/memblock.h>
 
 #include <asm/cp15.h>
 #include <asm/cputype.h>
 #include <asm/cacheflush.h>
 #include <asm/early_ioremap.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/set_memory.h>
 #include <asm/system_info.h>
 
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
 #include "mm.h"
 
 
 LIST_HEAD(static_vmlist);
 
 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
             size_t size, unsigned int mtype)
 {
     struct static_vm *svm;
     struct vm_struct *vm;
 
     list_for_each_entry(svm, &static_vmlist, list) {
         vm = &svm->vm;
         if (!(vm->flags & VM_ARM_STATIC_MAPPING))
             continue;
         if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
             continue;
 
         if (vm->phys_addr > paddr ||
             paddr + size - 1 > vm->phys_addr + vm->size - 1)
             continue;
 
         return svm;
     }
 
     return NULL;
 }
 
 struct static_vm *find_static_vm_vaddr(void *vaddr)
 {
     struct static_vm *svm;
     struct vm_struct *vm;
 
     list_for_each_entry(svm, &static_vmlist, list) {
         vm = &svm->vm;
 
         /* static_vmlist is ascending order */
         if (vm->addr > vaddr)
             break;
 
         if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
             return svm;
     }
 
     return NULL;
 }
 
 void __init add_static_vm_early(struct static_vm *svm)
 {
     struct static_vm *curr_svm;
     struct vm_struct *vm;
     void *vaddr;
 
     vm = &svm->vm;
     vm_area_add_early(vm);
     vaddr = vm->addr;
 
     list_for_each_entry(curr_svm, &static_vmlist, list) {
         vm = &curr_svm->vm;
 
         if (vm->addr > vaddr)
             break;
     }
     list_add_tail(&svm->list, &curr_svm->list);
 }
 
 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);
 
 void __check_vmalloc_seq(struct mm_struct *mm)
 {
     int seq;
 
     do {
         seq = atomic_read(&init_mm.context.vmalloc_seq);
         memcpy(pgd_offset(mm, VMALLOC_START),
                pgd_offset_k(VMALLOC_START),
                sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
                     pgd_index(VMALLOC_START)));
         /*
          * Use a store-release so that other CPUs that observe the
          * counter's new value are guaranteed to see the results of the
          * memcpy as well.
          */
         atomic_set_release(&mm->context.vmalloc_seq, seq);
     } while (seq != atomic_read(&init_mm.context.vmalloc_seq));
 }
 
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 /*
  * 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 1MB 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_1M - 1));
     pmd_t *pmdp = pmd_off_k(addr);
 
     do {
         pmd_t pmd = *pmdp;
 
         if (!pmd_none(pmd)) {
             /*
              * Clear the PMD from the page table, and
              * increment the vmalloc sequence so others
              * notice this change.
              *
              * Note: this is still racy on SMP machines.
              */
             pmd_clear(pmdp);
             atomic_inc_return_release(&init_mm.context.vmalloc_seq);
 
             /*
              * 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 += PMD_SIZE;
         pmdp += 2;
     } while (addr < end);
 
     /*
      * Ensure that the active_mm is up to date - we want to
      * catch any use-after-iounmap cases.
      */
     check_vmalloc_seq(current->active_mm);
 
     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;
     pmd_t *pmd = pmd_off_k(addr);
 
     /*
      * Remove and free any PTE-based mapping, and
      * sync the current kernel mapping.
      */
     unmap_area_sections(virt, size);
 
     do {
         pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
         pfn += SZ_1M >> PAGE_SHIFT;
         pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
         pfn += SZ_1M >> PAGE_SHIFT;
         flush_pmd_entry(pmd);
 
         addr += PMD_SIZE;
         pmd += 2;
     } while (addr < end);
 
     return 0;
 }
 
 static int
 remap_area_supersections(unsigned long virt, unsigned long pfn,
              size_t size, const struct mem_type *type)
 {
     unsigned long addr = virt, end = virt + size;
     pmd_t *pmd = pmd_off_k(addr);
 
     /*
      * Remove and free any PTE-based mapping, and
      * sync the current kernel mapping.
      */
     unmap_area_sections(virt, size);
     do {
         unsigned long super_pmd_val, i;
 
         super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
                 PMD_SECT_SUPER;
         super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
 
         for (i = 0; i < 8; i++) {
             pmd[0] = __pmd(super_pmd_val);
             pmd[1] = __pmd(super_pmd_val);
             flush_pmd_entry(pmd);
 
             addr += PMD_SIZE;
             pmd += 2;
         }
 
         pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
     } while (addr < end);
 
     return 0;
 }
 #endif
 
 static void __iomem * __arm_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;
     phys_addr_t paddr = __pfn_to_phys(pfn);
 
 #ifndef CONFIG_ARM_LPAE
     /*
      * High mappings must be supersection aligned
      */
     if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
         return NULL;
 #endif
 
     type = get_mem_type(mtype);
     if (!type)
         return NULL;
 
     /*
      * Page align the mapping size, taking account of any offset.
      */
     size = PAGE_ALIGN(offset + size);
 
     /*
      * Try to reuse one of the static mapping whenever possible.
      */
     if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
         struct static_vm *svm;
 
         svm = find_static_vm_paddr(paddr, size, mtype);
         if (svm) {
             addr = (unsigned long)svm->vm.addr;
             addr += paddr - svm->vm.phys_addr;
             return (void __iomem *) (offset + addr);
         }
     }
 
     /*
      * Don't allow RAM to be mapped with mismatched attributes - this
      * causes problems with ARMv6+
      */
     if (WARN_ON(memblock_is_map_memory(PFN_PHYS(pfn)) &&
             mtype != MT_MEMORY_RW))
         return NULL;
 
     area = get_vm_area_caller(size, VM_IOREMAP, caller);
     if (!area)
         return NULL;
     addr = (unsigned long)area->addr;
     area->phys_addr = paddr;
 
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
     if (DOMAIN_IO == 0 &&
         (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
            cpu_is_xsc3()) && pfn >= 0x100000 &&
            !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
         area->flags |= VM_ARM_SECTION_MAPPING;
         err = remap_area_supersections(addr, pfn, size, type);
     } else if (!((paddr | size | addr) & ~PMD_MASK)) {
         area->flags |= VM_ARM_SECTION_MAPPING;
         err = remap_area_sections(addr, pfn, size, type);
     } else
 #endif
         err = ioremap_page_range(addr, addr + size, paddr,
                      __pgprot(type->prot_pte));
 
     if (err) {
         vunmap((void *)addr);
         return NULL;
     }
 
     flush_cache_vmap(addr, addr + size);
     return (void __iomem *) (offset + addr);
 }
 
 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
     unsigned int mtype, void *caller)
 {
     phys_addr_t 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 __arm_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 *
 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
           unsigned int mtype)
 {
     return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
                     __builtin_return_address(0));
 }
 EXPORT_SYMBOL(__arm_ioremap_pfn);
 
 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
                       unsigned int, void *) =
     __arm_ioremap_caller;
 
 void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 {
     return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
                    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap);
 
 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
 {
     return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
                    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
 
 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 {
     return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
                    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_wc);
 
 /*
  * Remap an arbitrary physical address space into the kernel virtual
  * address space as memory. Needed when the kernel wants to execute
  * code in external memory. This is needed for reprogramming source
  * clocks that would affect normal memory for example. Please see
  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
  */
 void __iomem *
 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
 {
     unsigned int mtype;
 
     if (cached)
         mtype = MT_MEMORY_RWX;
     else
         mtype = MT_MEMORY_RWX_NONCACHED;
 
     return __arm_ioremap_caller(phys_addr, size, mtype,
             __builtin_return_address(0));
 }
 
 void __arm_iomem_set_ro(void __iomem *ptr, size_t size)
 {
     set_memory_ro((unsigned long)ptr, PAGE_ALIGN(size) / PAGE_SIZE);
 }
 
 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 {
     return (__force void *)arch_ioremap_caller(phys_addr, size,
                            MT_MEMORY_RW,
                            __builtin_return_address(0));
 }
 
 void iounmap(volatile void __iomem *io_addr)
 {
     void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
     struct static_vm *svm;
 
     /* If this is a static mapping, we must leave it alone */
     svm = find_static_vm_vaddr(addr);
     if (svm)
         return;
 
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
     {
         struct vm_struct *vm;
 
         vm = find_vm_area(addr);
 
         /*
          * 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.
          */
         if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
             unmap_area_sections((unsigned long)vm->addr, vm->size);
     }
 #endif
 
     vunmap(addr);
 }
 EXPORT_SYMBOL(iounmap);
 
 #if defined(CONFIG_PCI) || IS_ENABLED(CONFIG_PCMCIA)
 static int pci_ioremap_mem_type = MT_DEVICE;
 
 void pci_ioremap_set_mem_type(int mem_type)
 {
     pci_ioremap_mem_type = mem_type;
 }
 
 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
 {
     unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
 
     if (!(res->flags & IORESOURCE_IO))
         return -EINVAL;
 
     if (res->end > IO_SPACE_LIMIT)
         return -EINVAL;
 
     return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr,
                   __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
 }
 EXPORT_SYMBOL(pci_remap_iospace);
 
 void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
 {
     return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
                    __builtin_return_address(0));
 }
 EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
 #endif
 
 /*
  * 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 memblock_is_map_memory(pfn);
 }

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