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Diffstat (limited to '')
| -rw-r--r-- | lib/ioremap.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/lib/ioremap.c b/lib/ioremap.c new file mode 100644 index 000000000..517f5853f --- /dev/null +++ b/lib/ioremap.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Re-map IO memory to kernel address space so that we can access it. + * This is needed for high PCI addresses that aren't mapped in the + * 640k-1MB IO memory area on PC's + * + * (C) Copyright 1995 1996 Linus Torvalds + */ +#include <linux/vmalloc.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/io.h> +#include <linux/export.h> +#include <asm/cacheflush.h> +#include <asm/pgtable.h> + +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP +static int __read_mostly ioremap_p4d_capable; +static int __read_mostly ioremap_pud_capable; +static int __read_mostly ioremap_pmd_capable; +static int __read_mostly ioremap_huge_disabled; + +static int __init set_nohugeiomap(char *str) +{ + ioremap_huge_disabled = 1; + return 0; +} +early_param("nohugeiomap", set_nohugeiomap); + +void __init ioremap_huge_init(void) +{ + if (!ioremap_huge_disabled) { + if (arch_ioremap_pud_supported()) + ioremap_pud_capable = 1; + if (arch_ioremap_pmd_supported()) + ioremap_pmd_capable = 1; + } +} + +static inline int ioremap_p4d_enabled(void) +{ + return ioremap_p4d_capable; +} + +static inline int ioremap_pud_enabled(void) +{ + return ioremap_pud_capable; +} + +static inline int ioremap_pmd_enabled(void) +{ + return ioremap_pmd_capable; +} + +#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */ +static inline int ioremap_p4d_enabled(void) { return 0; } +static inline int ioremap_pud_enabled(void) { return 0; } +static inline int ioremap_pmd_enabled(void) { return 0; } +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + +static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, pgprot_t prot) +{ + pte_t *pte; + u64 pfn; + + pfn = phys_addr >> PAGE_SHIFT; + pte = pte_alloc_kernel(pmd, addr); + if (!pte) + return -ENOMEM; + do { + BUG_ON(!pte_none(*pte)); + set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); + pfn++; + } while (pte++, addr += PAGE_SIZE, addr != end); + return 0; +} + +static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, pgprot_t prot) +{ + pmd_t *pmd; + unsigned long next; + + phys_addr -= addr; + pmd = pmd_alloc(&init_mm, pud, addr); + if (!pmd) + return -ENOMEM; + do { + next = pmd_addr_end(addr, end); + + if (ioremap_pmd_enabled() && + ((next - addr) == PMD_SIZE) && + IS_ALIGNED(phys_addr + addr, PMD_SIZE) && + pmd_free_pte_page(pmd, addr)) { + if (pmd_set_huge(pmd, phys_addr + addr, prot)) + continue; + } + + if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot)) + return -ENOMEM; + } while (pmd++, addr = next, addr != end); + return 0; +} + +static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, pgprot_t prot) +{ + pud_t *pud; + unsigned long next; + + phys_addr -= addr; + pud = pud_alloc(&init_mm, p4d, addr); + if (!pud) + return -ENOMEM; + do { + next = pud_addr_end(addr, end); + + if (ioremap_pud_enabled() && + ((next - addr) == PUD_SIZE) && + IS_ALIGNED(phys_addr + addr, PUD_SIZE) && + pud_free_pmd_page(pud, addr)) { + if (pud_set_huge(pud, phys_addr + addr, prot)) + continue; + } + + if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot)) + return -ENOMEM; + } while (pud++, addr = next, addr != end); + return 0; +} + +static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, pgprot_t prot) +{ + p4d_t *p4d; + unsigned long next; + + phys_addr -= addr; + p4d = p4d_alloc(&init_mm, pgd, addr); + if (!p4d) + return -ENOMEM; + do { + next = p4d_addr_end(addr, end); + + if (ioremap_p4d_enabled() && + ((next - addr) == P4D_SIZE) && + IS_ALIGNED(phys_addr + addr, P4D_SIZE)) { + if (p4d_set_huge(p4d, phys_addr + addr, prot)) + continue; + } + + if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot)) + return -ENOMEM; + } while (p4d++, addr = next, addr != end); + return 0; +} + +int ioremap_page_range(unsigned long addr, + unsigned long end, phys_addr_t phys_addr, pgprot_t prot) +{ + pgd_t *pgd; + unsigned long start; + unsigned long next; + int err; + + might_sleep(); + BUG_ON(addr >= end); + + start = addr; + phys_addr -= addr; + pgd = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, end); + err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot); + if (err) + break; + } while (pgd++, addr = next, addr != end); + + flush_cache_vmap(start, end); + + return err; +} |