Re: [PATCH 02/15] x86: Add device tree support
From: Sebastian Andrzej Siewior
Date: Mon Jan 03 2011 - 07:21:11 EST
Grant Likely wrote:
+extern char cmd_line[COMMAND_LINE_SIZE];
+/* This number is used when no interrupt has been assigned */
+#define NO_IRQ (-1)
0 means NO_IRQ on x86 and most architectures. I will change this when
I pick up the patch.
cat /proc/interrupts
CPU0
0: 40 IO-APIC-edge timer
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 577d06b..26f2c9a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -113,6 +113,7 @@
#endif
#include <asm/mce.h>
#include <asm/alternative.h>
+#include <asm/prom.h>
/*
* end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
@@ -445,6 +446,9 @@ static void __init parse_setup_data(void)
case SETUP_E820_EXT:
parse_e820_ext(data);
break;
+ case SETUP_DTB:
+ add_dtb(pa_data);
+ break;
Why is the physical address being passed in when the virtual address
is needed to be stored in initial_boot_params by add_dtb()?
add_dtb() changes it via phys_to_virt() so it is stored as virtual. I
can't touch this memory that early in the boot process so it is passed as
phys. phys_to_virt() isn't working (yet) so you need a fixmap or an
early_ioremap(). Earlier I used the device tree very late so the
phys_to_virt() memory was working.
Later in the series add_dtb() stores it in a custom u64 variable because I
might have to use the built-in dtb, I have to relocate the dtb (so the
boot loader does not have to care about kernel's memory layout) and I have
to use it "early" so I create a fixmap for it.
The dtb is not usable before the ->get_config() hook (x86_dtb_get_config,
patch #5) is called. After that initial_boot_params is set and can be used.
default:
break;
}
--
1.7.3.2
Sebastian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/