arch/csky/include/asm/io.h

Source file repositories/reference/linux-study-clean/arch/csky/include/asm/io.h

File Facts

System
Linux kernel
Corpus path
arch/csky/include/asm/io.h
Extension
.h
Size
1367 bytes
Lines
44
Domain
Architecture Layer
Bucket
arch/csky
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef __ASM_CSKY_IO_H
#define __ASM_CSKY_IO_H

#include <linux/pgtable.h>
#include <linux/types.h>

/*
 * I/O memory access primitives. Reads are ordered relative to any
 * following Normal memory access. Writes are ordered relative to any prior
 * Normal memory access.
 *
 * For CACHEV1 (807, 810), store instruction could fast retire, so we need
 * another mb() to prevent st fast retire.
 *
 * For CACHEV2 (860), store instruction with PAGE_ATTR_NO_BUFFERABLE won't
 * fast retire.
 */
#define readb(c)		({ u8  __v = readb_relaxed(c); rmb(); __v; })
#define readw(c)		({ u16 __v = readw_relaxed(c); rmb(); __v; })
#define readl(c)		({ u32 __v = readl_relaxed(c); rmb(); __v; })

#ifdef CONFIG_CPU_HAS_CACHEV2
#define writeb(v,c)		({ wmb(); writeb_relaxed((v),(c)); })
#define writew(v,c)		({ wmb(); writew_relaxed((v),(c)); })
#define writel(v,c)		({ wmb(); writel_relaxed((v),(c)); })
#else
#define writeb(v,c)		({ wmb(); writeb_relaxed((v),(c)); mb(); })
#define writew(v,c)		({ wmb(); writew_relaxed((v),(c)); mb(); })
#define writel(v,c)		({ wmb(); writel_relaxed((v),(c)); mb(); })
#endif

/*
 * I/O memory mapping functions.
 */
#define ioremap_wc(addr, size) \
	ioremap_prot((addr), (size), \
		__pgprot((_PAGE_IOREMAP & ~_CACHE_MASK) | _CACHE_UNCACHED))

#include <asm-generic/io.h>

#endif /* __ASM_CSKY_IO_H */

Annotation

Implementation Notes