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Commit bc4f94d8 authored by Russell King's avatar Russell King
Browse files

ARM: outer cache: add documentation of outer cache functions 



Add some documentation to cover the outer cache functions so that their
requirements can be better understood.  Of particular note are the
flush_all() and disable() methods which must not be called except in
very specific circumstances.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent d453ef75

arch/arm/include/asm/outercache.h

+47 −1
Original line number Diff line number Diff line
@@ -39,35 +39,75 @@ struct outer_cache_fns { 
extern struct outer_cache_fns outer_cache;



#ifdef CONFIG_OUTER_CACHE



/**

 * outer_inv_range - invalidate range of outer cache lines

 * @start: starting physical address, inclusive

 * @end: end physical address, exclusive

 */

static inline void outer_inv_range(phys_addr_t start, phys_addr_t end)

{

	if (outer_cache.inv_range)

		outer_cache.inv_range(start, end);

}



/**

 * outer_clean_range - clean dirty outer cache lines

 * @start: starting physical address, inclusive

 * @end: end physical address, exclusive

 */

static inline void outer_clean_range(phys_addr_t start, phys_addr_t end)

{

	if (outer_cache.clean_range)

		outer_cache.clean_range(start, end);

}



/**

 * outer_flush_range - clean and invalidate outer cache lines

 * @start: starting physical address, inclusive

 * @end: end physical address, exclusive

 */

static inline void outer_flush_range(phys_addr_t start, phys_addr_t end)

{

	if (outer_cache.flush_range)

		outer_cache.flush_range(start, end);

}



/**

 * outer_flush_all - clean and invalidate all cache lines in the outer cache

 *

 * Note: depending on implementation, this may not be atomic - it must

 * only be called with interrupts disabled and no other active outer

 * cache masters.

 *

 * It is intended that this function is only used by implementations

 * needing to override the outer_cache.disable() method due to security.

 * (Some implementations perform this as a clean followed by an invalidate.)

 */

static inline void outer_flush_all(void)

{

	if (outer_cache.flush_all)

		outer_cache.flush_all();

}



/**

 * outer_disable - clean, invalidate and disable the outer cache

 *

 * Disable the outer cache, ensuring that any data contained in the outer

 * cache is pushed out to lower levels of system memory.  The note and

 * conditions above concerning outer_flush_all() applies here.

 */

static inline void outer_disable(void)

{

	if (outer_cache.disable)

		outer_cache.disable();

}



/**

 * outer_resume - restore the cache configuration and re-enable outer cache

 *

 * Restore any configuration that the cache had when previously enabled,

 * and re-enable the outer cache.

 */

static inline void outer_resume(void)

{

	if (outer_cache.resume)
@@ -89,6 +129,12 @@ static inline void outer_resume(void) { } 
#endif



#ifdef CONFIG_OUTER_CACHE_SYNC

/**

 * outer_sync - perform a sync point for outer cache

 *

 * Ensure that all outer cache operations are complete and any store

 * buffers are drained.

 */

static inline void outer_sync(void)

{

	if (outer_cache.sync)