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: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2014-03-16 10:52:55 +00:00
parent d453ef752c
commit bc4f94d85c

View file

@ -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)