diff options
| author | Julius Werner <jwerner@chromium.org> | 2013-08-27 15:48:32 -0700 |
|---|---|---|
| committer | Isaac Christensen <isaac.christensen@se-eng.com> | 2014-08-13 00:04:14 +0200 |
| commit | b8fad3d02986222fa162d455eca2ffe807b6a15a (patch) | |
| tree | f6beaf474faa9f4a9a4a611abb52774e7d0906ed /payloads/libpayload/include | |
| parent | 4498f6a6e57aa3bc1ed9449e3ad153b1a60c4eb6 (diff) | |
| download | coreboot-b8fad3d02986222fa162d455eca2ffe807b6a15a.tar.xz | |
arm: libpayload: Add cache coherent DMA memory definition and management
This patch adds a mechanism to set aside a region of cache-coherent
(i.e. usually uncached) virtual memory, which can be used to communicate
with DMA devices without automatic cache snooping (common on ARM)
without the need of explicit flush/invalidation instructions in the
driver code.
This works by setting aside said region in the (board-specific) page
table setup, as exemplary done in this patch for the Snow and Pit
boards. It uses a new mechanism for adding board-specific Coreboot table
entries to describe this region in an entry with the LB_DMA tag.
Libpayload's memory allocator is enhanced to be able to operate on
distinct types/regions of memory. It provides dma_malloc() and
dma_memalign() functions for use in drivers, which by default just
operate on the same heap as their traditional counterparts. However, if
the Coreboot table parsing code finds a CB_DMA section, further requests
through the dma_xxx() functions will return memory from the region
described therein instead.
Change-Id: Ia9c249249e936bbc3eb76e7b4822af2230ffb186
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/167155
(cherry picked from commit d142ccdcd902a9d6ab4d495fbe6cbe85c61a5f01)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6622
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Diffstat (limited to 'payloads/libpayload/include')
| -rw-r--r-- | payloads/libpayload/include/coreboot_tables.h | 1 | ||||
| -rw-r--r-- | payloads/libpayload/include/stdlib.h | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/payloads/libpayload/include/coreboot_tables.h b/payloads/libpayload/include/coreboot_tables.h index 5132d50261..e20249d627 100644 --- a/payloads/libpayload/include/coreboot_tables.h +++ b/payloads/libpayload/include/coreboot_tables.h @@ -187,6 +187,7 @@ struct cb_gpios { #define CB_TAG_VDAT 0x0015 #define CB_TAG_VBNV 0x0019 #define CB_TAG_VBOOT_HANDOFF 0x0020 +#define CB_TAG_DMA 0x0022 struct lb_range { uint32_t tag; uint32_t size; diff --git a/payloads/libpayload/include/stdlib.h b/payloads/libpayload/include/stdlib.h index 92a13e38e7..8c8c200873 100644 --- a/payloads/libpayload/include/stdlib.h +++ b/payloads/libpayload/include/stdlib.h @@ -112,6 +112,9 @@ void *calloc(size_t nmemb, size_t size); void *realloc(void *ptr, size_t size); void *memalign(size_t align, size_t size); #endif +void init_dma_memory(void *start, u32 size); +void *dma_malloc(size_t size); +void *dma_memalign(size_t align, size_t size); /** @} */ /** |