From 8ea0afa3b801e9fe3ff676c3e60e74afa1a0848a Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 18 Apr 2019 14:34:34 -0300 Subject: 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 --- Documentation/xtensa/booting.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/xtensa/booting.rst (limited to 'Documentation/xtensa/booting.rst') 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. -- cgit v1.2.3