arm/dt: probe for platforms via the device tree
If a dtb is passed to the kernel then the kernel needs to iterate
through compiled-in mdescs looking for one that matches and move the
dtb data to a safe location before it gets accidentally overwritten by
the kernel.
This patch creates a new function, setup_machine_fdt() which is
analogous to the setup_machine_atags() created in the previous patch.
It does all the early setup needed to use a device tree machine
description.
v5: - Print warning with neither dtb nor atags are passed to the kernel
- Fix bug in setting of __machine_arch_type to the selected machine,
not just the last machine in the list.
Reported-by: Tixy <tixy@yxit.co.uk>
- Copy command line directly into boot_command_line instead of cmd_line
v4: - Dump some output when a matching machine_desc cannot be found
v3: - Added processing of reserved list.
- Backed out the v2 change that copied instead of reserved the
dtb. dtb is reserved again and the real problem was fixed by
using alloc_bootmem_align() for early allocation of RAM for
unflattening the tree.
- Moved cmd_line and initrd changes to earlier patch to make series
bisectable.
v2: Changed to save the dtb by copying into an allocated buffer.
- Since the dtb will very likely be passed in the first 16k of ram
where the interrupt vectors live, memblock_reserve() is
insufficient to protect the dtb data.
[based on work originally written by Jeremy Kerr <jeremy.kerr@canonical.com>]
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 42c2f0c..05db25e 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -20,6 +20,7 @@
#include <linux/screen_info.h>
#include <linux/init.h>
#include <linux/kexec.h>
+#include <linux/of_fdt.h>
#include <linux/crash_dump.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
@@ -42,6 +43,7 @@
#include <asm/cachetype.h>
#include <asm/tlbflush.h>
+#include <asm/prom.h>
#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
@@ -309,7 +311,7 @@
*/
extern struct proc_info_list *lookup_processor_type(unsigned int);
-static void __init early_print(const char *str, ...)
+void __init early_print(const char *str, ...)
{
extern void printascii(const char *);
char buf[256];
@@ -439,7 +441,7 @@
: "r14");
}
-static void __init dump_machine_table(void)
+void __init dump_machine_table(void)
{
struct machine_desc *p;
@@ -837,8 +839,17 @@
if (tags->hdr.tag != ATAG_CORE)
convert_to_tag_list(tags);
#endif
- if (tags->hdr.tag != ATAG_CORE)
+
+ if (tags->hdr.tag != ATAG_CORE) {
+#if defined(CONFIG_OF)
+ /*
+ * If CONFIG_OF is set, then assume this is a reasonably
+ * modern system that should pass boot parameters
+ */
+ early_print("Warning: Neither atags nor dtb found\n");
+#endif
tags = (struct tag *)&init_tags;
+ }
if (mdesc->fixup)
mdesc->fixup(mdesc, tags, &from, &meminfo);
@@ -864,7 +875,9 @@
unwind_init();
setup_processor();
- mdesc = setup_machine_tags(machine_arch_type);
+ mdesc = setup_machine_fdt(__atags_pointer);
+ if (!mdesc)
+ mdesc = setup_machine_tags(machine_arch_type);
machine_desc = mdesc;
machine_name = mdesc->name;
@@ -887,6 +900,8 @@
paging_init(mdesc);
request_standard_resources(mdesc);
+ unflatten_device_tree();
+
#ifdef CONFIG_SMP
if (is_smp())
smp_init_cpus();