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
   6 static 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  */
  14 void 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 }
  25 EXPORT_SYMBOL(atomic_io_modify_relaxed);
  26
  27 void 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 }
  38 EXPORT_SYMBOL(atomic_io_modify);
  39
  40 /*
  41  * Copy data from IO memory space to "real" memory space.
  42  * This needs to be optimized.
  43  */
  44 void _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 }
  54
  55 /*
  56  * Copy data from "real" memory space to IO memory space.
  57  * This needs to be optimized.
  58  */
  59 void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
  60 {
  61         const unsigned char *f = from;
  62         while (count) {
  63                 count--;
  64                 writeb(*f, to);
  65                 f++;
  66                 to++;
  67         }
  68 }
  69
  70 /*
  71  * "memset" on IO memory space.
  72  * This needs to be optimized.
  73  */
  74 void _memset_io(volatile void __iomem *dst, int c, size_t count)
  75 {
  76         while (count) {
  77                 count--;
  78                 writeb(c, dst);
  79                 dst++;
  80         }
  81 }
  82
  83 EXPORT_SYMBOL(_memcpy_fromio);
  84 EXPORT_SYMBOL(_memcpy_toio);
  85 EXPORT_SYMBOL(_memset_io);