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Initial allocated page must be read/write/non-cacheable

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2909 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo
2010-09-01 23:52:38 +00:00
parent ad6b0be05a
commit ff021347d6
4 changed files with 36 additions and 6 deletions
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include/nuttx/page.h
+16 -2
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@@ -364,12 +364,19 @@ EXTERN bool up_checkmapping(FAR _TCB *tcb);
* available pages are in-use (the typical case), then this function will
* select a page in-use, un-map it, and make it available.
*
* NOTE 2: Allocating and filling a page is a two step process. up_allocpage()
* NOTE 2: If an in-use page is un-mapped, it may be necessary to flush the
* instruction cache in some architectures.
*
* NOTE 3: Allocating and filling a page is a two step process. up_allocpage()
* allocates the page, and up_fillpage() fills it with data from some non-
* volatile storage device. This distinction is made because up_allocpage()
* can probably be implemented in board-independent logic whereas up_fillpage()
* probably must be implemented as board-specific logic.
*
* NOTE 4: The initial mapping of vpage should be read-able and write-
* able (but not cached). No special actions will be required of
* up_fillpage() in order to write into this allocated page.
*
* Input Parameters:
* tcb - A reference to the task control block of the task that needs to
* have a page fill. Architecture-specific logic can retrieve page
@@ -404,12 +411,19 @@ EXTERN int up_allocpage(FAR _TCB *tcb, FAR void **vpage);
* This callback is assumed to occur from an interrupt level when the
* device driver completes the fill operation.
*
* NOTE: Allocating and filling a page is a two step process. up_allocpage()
* NOTE 1: Allocating and filling a page is a two step process. up_allocpage()
* allocates the page, and up_fillpage() fills it with data from some non-
* volatile storage device. This distinction is made because up_allocpage()
* can probably be implemented in board-independent logic whereas up_fillpage()
* probably must be implemented as board-specific logic.
*
* NOTE 2: The initial mapping of vpage will be read-able, write-able,
* but non-cacheable. No special actions will be required of
* up_fillpage() in order to write into this allocated page. If the
* virtual address maps to a text region, however, this function should
* remap the region so that is is read/execute only. It should be made
* cache-able in any case.
*
* Input Parameters:
* tcb - A reference to the task control block of the task that needs to
* have a page fill. Architecture-specific logic can retrieve page