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kernel/linux-imx6_3.14.28/arch/arm/kernel/io.c 1.74 KB
6b13f685e   김민수   BSP 최초 추가
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  #include <linux/export.h>
  #include <linux/types.h>
  #include <linux/io.h>
  #include <linux/spinlock.h>
  
  static DEFINE_RAW_SPINLOCK(__io_lock);
  
  /*
   * Generic atomic MMIO modify.
   *
   * Allows thread-safe access to registers shared by unrelated subsystems.
   * The access is protected by a single MMIO-wide lock.
   */
  void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set)
  {
  	unsigned long flags;
  	u32 value;
  
  	raw_spin_lock_irqsave(&__io_lock, flags);
  	value = readl_relaxed(reg) & ~mask;
  	value |= (set & mask);
  	writel_relaxed(value, reg);
  	raw_spin_unlock_irqrestore(&__io_lock, flags);
  }
  EXPORT_SYMBOL(atomic_io_modify_relaxed);
  
  void atomic_io_modify(void __iomem *reg, u32 mask, u32 set)
  {
  	unsigned long flags;
  	u32 value;
  
  	raw_spin_lock_irqsave(&__io_lock, flags);
  	value = readl_relaxed(reg) & ~mask;
  	value |= (set & mask);
  	writel(value, reg);
  	raw_spin_unlock_irqrestore(&__io_lock, flags);
  }
  EXPORT_SYMBOL(atomic_io_modify);
  
  /*
   * Copy data from IO memory space to "real" memory space.
   * This needs to be optimized.
   */
  void _memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
  {
  	unsigned char *t = to;
  	while (count) {
  		count--;
  		*t = readb(from);
  		t++;
  		from++;
  	}
  }
  
  /*
   * Copy data from "real" memory space to IO memory space.
   * This needs to be optimized.
   */
  void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
  {
  	const unsigned char *f = from;
  	while (count) {
  		count--;
  		writeb(*f, to);
  		f++;
  		to++;
  	}
  }
  
  /*
   * "memset" on IO memory space.
   * This needs to be optimized.
   */
  void _memset_io(volatile void __iomem *dst, int c, size_t count)
  {
  	while (count) {
  		count--;
  		writeb(c, dst);
  		dst++;
  	}
  }
  
  EXPORT_SYMBOL(_memcpy_fromio);
  EXPORT_SYMBOL(_memcpy_toio);
  EXPORT_SYMBOL(_memset_io);