From da844a81779e2bb263eca4ecb1046541fdb11cf8 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Sun, 4 Nov 2012 00:30:13 +0400 Subject: xtensa: add device trees support Device trees allow specification of hardware topology and device parameters at runtime instead of hard-coding them in platform setup code. This allows running single binary kernel on a range of compatible boards. New boot parameters tag BP_TAG_FDT is allocated and a pointer to flat device tree is passed in it. Note that current interrupt mapping scheme uses single cell for interrupt identification. That means that IRQ numbers used in DTS must be CPU internal IRQ numbers, not external. It is possible to extend interrupt identification to two cells, and use second cell to tell external IRQ numbers form internal. That would allow to use single DTS on multiple boards with different mapping of external IRQ numbers. Signed-off-by: Max Filippov Signed-off-by: Chris Zankel --- arch/xtensa/include/asm/bootparam.h | 1 + arch/xtensa/include/asm/prom.h | 6 ++++++ 2 files changed, 7 insertions(+) create mode 100644 arch/xtensa/include/asm/prom.h (limited to 'arch/xtensa/include') diff --git a/arch/xtensa/include/asm/bootparam.h b/arch/xtensa/include/asm/bootparam.h index 9983f2c1b7ee..057077e96c98 100644 --- a/arch/xtensa/include/asm/bootparam.h +++ b/arch/xtensa/include/asm/bootparam.h @@ -22,6 +22,7 @@ #define BP_TAG_MEMORY 0x1003 /* memory addr and size (bp_meminfo) */ #define BP_TAG_SERIAL_BAUSRATE 0x1004 /* baud rate of current console. */ #define BP_TAG_SERIAL_PORT 0x1005 /* serial device of current console */ +#define BP_TAG_FDT 0x1006 /* flat device tree addr */ #define BP_TAG_FIRST 0x7B0B /* first tag with a version number */ #define BP_TAG_LAST 0x7E0B /* last tag */ diff --git a/arch/xtensa/include/asm/prom.h b/arch/xtensa/include/asm/prom.h new file mode 100644 index 000000000000..f3d7cd2c0de7 --- /dev/null +++ b/arch/xtensa/include/asm/prom.h @@ -0,0 +1,6 @@ +#ifndef _XTENSA_ASM_PROM_H +#define _XTENSA_ASM_PROM_H + +#define HAVE_ARCH_DEVTREE_FIXUPS + +#endif /* _XTENSA_ASM_PROM_H */ -- cgit v1.2.3