LXR linux/arch/arm/kernel/io.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/export.h>
   3#include <linux/types.h>
   4#include <linux/io.h>
   5#include <linux/spinlock.h>
   6
   7static DEFINE_RAW_SPINLOCK(__io_lock);
   8
   9/*
  10 * Generic atomic MMIO modify.
  11 *
  12 * Allows thread-safe access to registers shared by unrelated subsystems.
  13 * The access is protected by a single MMIO-wide lock.
  14 */
  15void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set)
  16{
  17        unsigned long flags;
  18        u32 value;
  19
  20        raw_spin_lock_irqsave(&__io_lock, flags);
  21        value = readl_relaxed(reg) & ~mask;
  22        value |= (set & mask);
  23        writel_relaxed(value, reg);
  24        raw_spin_unlock_irqrestore(&__io_lock, flags);
  25}
  26EXPORT_SYMBOL(atomic_io_modify_relaxed);
  27
  28void atomic_io_modify(void __iomem *reg, u32 mask, u32 set)
  29{
  30        unsigned long flags;
  31        u32 value;
  32
  33        raw_spin_lock_irqsave(&__io_lock, flags);
  34        value = readl_relaxed(reg) & ~mask;
  35        value |= (set & mask);
  36        writel(value, reg);
  37        raw_spin_unlock_irqrestore(&__io_lock, flags);
  38}
  39EXPORT_SYMBOL(atomic_io_modify);
  40
  41/*
  42 * Copy data from IO memory space to "real" memory space.
  43 * This needs to be optimized.
  44 */
  45void _memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
  46{
  47        unsigned char *t = to;
  48        while (count) {
  49                count--;
  50                *t = readb(from);
  51                t++;
  52                from++;
  53        }
  54}
  55EXPORT_SYMBOL(_memcpy_fromio);
  56
  57/*
  58 * Copy data from "real" memory space to IO memory space.
  59 * This needs to be optimized.
  60 */
  61void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
  62{
  63        const unsigned char *f = from;
  64        while (count) {
  65                count--;
  66                writeb(*f, to);
  67                f++;
  68                to++;
  69        }
  70}
  71EXPORT_SYMBOL(_memcpy_toio);
  72
  73/*
  74 * "memset" on IO memory space.
  75 * This needs to be optimized.
  76 */
  77void _memset_io(volatile void __iomem *dst, int c, size_t count)
  78{
  79        while (count) {
  80                count--;
  81                writeb(c, dst);
  82                dst++;
  83        }
  84}
  85EXPORT_SYMBOL(_memset_io);
  86