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

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