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author | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-04-18 14:34:34 -0300 |
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committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-07-15 09:20:26 -0300 |
commit | 8ea0afa3b801e9fe3ff676c3e60e74afa1a0848a (patch) | |
tree | 443bd51a72db01596ceacd710567060706201d75 /Documentation/xtensa/booting.rst | |
parent | b0a4aa950c68b5010831ecfc450510c64e4d80ba (diff) | |
download | linux-8ea0afa3b801e9fe3ff676c3e60e74afa1a0848a.tar.bz2 |
docs: xtensa: convert to ReST
Rename the xtensa documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/xtensa/booting.rst')
-rw-r--r-- | Documentation/xtensa/booting.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/xtensa/booting.rst b/Documentation/xtensa/booting.rst new file mode 100644 index 000000000000..e1b83707e5b6 --- /dev/null +++ b/Documentation/xtensa/booting.rst @@ -0,0 +1,22 @@ +===================================== +Passing boot parameters to the kernel +===================================== + +Boot parameters are represented as a TLV list in the memory. Please see +arch/xtensa/include/asm/bootparam.h for definition of the bp_tag structure and +tag value constants. First entry in the list must have type BP_TAG_FIRST, last +entry must have type BP_TAG_LAST. The address of the first list entry is +passed to the kernel in the register a2. The address type depends on MMU type: + +- For configurations without MMU, with region protection or with MPU the + address must be the physical address. +- For configurations with region translarion MMU or with MMUv3 and CONFIG_MMU=n + the address must be a valid address in the current mapping. The kernel will + not change the mapping on its own. +- For configurations with MMUv2 the address must be a virtual address in the + default virtual mapping (0xd0000000..0xffffffff). +- For configurations with MMUv3 and CONFIG_MMU=y the address may be either a + virtual or physical address. In either case it must be within the default + virtual mapping. It is considered physical if it is within the range of + physical addresses covered by the default KSEG mapping (XCHAL_KSEG_PADDR.. + XCHAL_KSEG_PADDR + XCHAL_KSEG_SIZE), otherwise it is considered virtual. |