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| author | Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> | 2011-11-10 16:38:29 +0100 |
|---|---|---|
| committer | Jonas Bonn <jonas@southpole.se> | 2012-02-17 09:55:22 +0100 |
| commit | dec830189e1e192a80f574243a2dc31bdc1c4fc5 (patch) | |
| tree | 864ae5fd9b3975805195eb2b0396d80e6a408425 /arch/openrisc | |
| parent | arch/openrisc/mm/init.c: trivial: use BUG_ON (diff) | |
| download | linux-dec830189e1e192a80f574243a2dc31bdc1c4fc5.tar.xz linux-dec830189e1e192a80f574243a2dc31bdc1c4fc5.zip | |
openrisc: enable passing of flattened device tree pointer
This patch enables passing a fdt pointer to the kernel.
This makes for the kernel parameter API:
void kernel(unsigned int fdt);
which, in accordance with the OpenRISC ABI results in:
r3 = pointer to fdt
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Diffstat (limited to 'arch/openrisc')
| -rw-r--r-- | arch/openrisc/kernel/head.S | 17 | ||||
| -rw-r--r-- | arch/openrisc/kernel/setup.c | 18 |
2 files changed, 25 insertions, 10 deletions
diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index c75018d22644..1088b5fca3bd 100644 --- a/arch/openrisc/kernel/head.S +++ b/arch/openrisc/kernel/head.S @@ -26,6 +26,7 @@ #include <asm/cache.h> #include <asm/spr_defs.h> #include <asm/asm-offsets.h> +#include <linux/of_fdt.h> #define tophys(rd,rs) \ l.movhi rd,hi(-KERNELBASE) ;\ @@ -440,6 +441,9 @@ _dispatch_do_ipage_fault: __HEAD .global _start _start: + /* save kernel parameters */ + l.or r25,r0,r3 /* pointer to fdt */ + /* * ensure a deterministic start */ @@ -471,7 +475,6 @@ _start: CLEAR_GPR(r22) CLEAR_GPR(r23) CLEAR_GPR(r24) - CLEAR_GPR(r25) CLEAR_GPR(r26) CLEAR_GPR(r27) CLEAR_GPR(r28) @@ -565,6 +568,18 @@ enable_mmu: // reset the simulation counters l.nop 5 + /* check fdt header magic word */ + l.lwz r3,0(r25) /* load magic from fdt into r3 */ + l.movhi r4,hi(OF_DT_HEADER) + l.ori r4,r4,lo(OF_DT_HEADER) + l.sfeq r3,r4 + l.bf _fdt_found + l.nop + /* magic number mismatch, set fdt pointer to null */ + l.or r25,r0,r0 +_fdt_found: + /* pass fdt pointer to or32_early_setup in r3 */ + l.or r3,r0,r25 LOAD_SYMBOL_2_GPR(r24, or32_early_setup) l.jalr r24 l.nop diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c index 1422f747f52b..bf5eba22ce9e 100644 --- a/arch/openrisc/kernel/setup.c +++ b/arch/openrisc/kernel/setup.c @@ -207,18 +207,18 @@ void __init setup_cpuinfo(void) * Handles the pointer to the device tree that this kernel is to use * for establishing the available platform devices. * - * For now, this is limited to using the built-in device tree. In the future, - * it is intended that this function will take a pointer to the device tree - * that is potentially built-in, but potentially also passed in by the - * bootloader, or discovered by some equally clever means... + * Falls back on built-in device tree in case null pointer is passed. */ -void __init or32_early_setup(void) +void __init or32_early_setup(unsigned int fdt) { - - early_init_devtree(__dtb_start); - - printk(KERN_INFO "Compiled-in FDT at 0x%p\n", __dtb_start); + if (fdt) { + early_init_devtree((void*) fdt); + printk(KERN_INFO "FDT at 0x%08x\n", fdt); + } else { + early_init_devtree(__dtb_start); + printk(KERN_INFO "Compiled-in FDT at %p\n", __dtb_start); + } } static int __init openrisc_device_probe(void) |