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
   7 static 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  */
  15 void 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 }
  26 EXPORT_SYMBOL(atomic_io_modify_relaxed);
  27
  28 void 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 }
  39 EXPORT_SYMBOL(atomic_io_modify);
  40
  41 /*
  42  * Copy data from IO memory space to "real" memory space.
  43  * This needs to be optimized.
  44  */
  45 void _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 }
  55 EXPORT_SYMBOL(_memcpy_fromio);
  56
  57 /*
  58  * Copy data from "real" memory space to IO memory space.
  59  * This needs to be optimized.
  60  */
  61 void _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 }
  71 EXPORT_SYMBOL(_memcpy_toio);
  72
  73 /*
  74  * "memset" on IO memory space.
  75  * This needs to be optimized.
  76  */
  77 void _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 }
  85 EXPORT_SYMBOL(_memset_io);