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author | Grant Likely <grant.likely@secretlab.ca> | 2011-04-28 20:27:21 (GMT) |
---|---|---|
committer | Grant Likely <grant.likely@secretlab.ca> | 2011-05-23 15:30:20 (GMT) |
commit | 93c02ab40ae6e06cb24d14845d9f008fdd24f43d (patch) | |
tree | a8caf072ce7409eceb8178e952b7536bbd289460 /arch/arm/kernel | |
parent | 6291319d4864848efc7b5d81389e2404fb478cb9 (diff) | |
download | linux-93c02ab40ae6e06cb24d14845d9f008fdd24f43d.tar.xz |
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>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r-- | arch/arm/kernel/devtree.c | 98 | ||||
-rw-r--r-- | arch/arm/kernel/setup.c | 23 |
2 files changed, 117 insertions, 4 deletions
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 75e3df8..a701e42 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -21,6 +21,8 @@ #include <asm/setup.h> #include <asm/page.h> +#include <asm/mach/arch.h> +#include <asm/mach-types.h> void __init early_init_dt_add_memory_arch(u64 base, u64 size) { @@ -32,6 +34,102 @@ void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align) return alloc_bootmem_align(size, align); } +void __init arm_dt_memblock_reserve(void) +{ + u64 *reserve_map, base, size; + + if (!initial_boot_params) + return; + + /* Reserve the dtb region */ + memblock_reserve(virt_to_phys(initial_boot_params), + be32_to_cpu(initial_boot_params->totalsize)); + + /* + * Process the reserve map. This will probably overlap the initrd + * and dtb locations which are already reserved, but overlaping + * doesn't hurt anything + */ + reserve_map = ((void*)initial_boot_params) + + be32_to_cpu(initial_boot_params->off_mem_rsvmap); + while (1) { + base = be64_to_cpup(reserve_map++); + size = be64_to_cpup(reserve_map++); + if (!size) + break; + memblock_reserve(base, size); + } +} + +/** + * setup_machine_fdt - Machine setup when an dtb was passed to the kernel + * @dt_phys: physical address of dt blob + * + * If a dtb was passed to the kernel in r2, then use it to choose the + * correct machine_desc and to setup the system. + */ +struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) +{ + struct boot_param_header *devtree; + struct machine_desc *mdesc, *mdesc_best = NULL; + unsigned int score, mdesc_score = ~1; + unsigned long dt_root; + const char *model; + + devtree = phys_to_virt(dt_phys); + + /* check device tree validity */ + if (be32_to_cpu(devtree->magic) != OF_DT_HEADER) + return NULL; + + /* Search the mdescs for the 'best' compatible value match */ + initial_boot_params = devtree; + dt_root = of_get_flat_dt_root(); + for_each_machine_desc(mdesc) { + score = of_flat_dt_match(dt_root, mdesc->dt_compat); + if (score > 0 && score < mdesc_score) { + mdesc_best = mdesc; + mdesc_score = score; + } + } + if (!mdesc_best) { + const char *prop; + long size; + + early_print("\nError: unrecognized/unsupported " + "device tree compatible list:\n[ "); + + prop = of_get_flat_dt_prop(dt_root, "compatible", &size); + while (size > 0) { + early_print("'%s' ", prop); + size -= strlen(prop) + 1; + prop += strlen(prop) + 1; + } + early_print("]\n\n"); + + dump_machine_table(); /* does not return */ + } + + model = of_get_flat_dt_prop(dt_root, "model", NULL); + if (!model) + model = of_get_flat_dt_prop(dt_root, "compatible", NULL); + if (!model) + model = "<unknown>"; + pr_info("Machine: %s, model: %s\n", mdesc_best->name, model); + + /* Retrieve various information from the /chosen node */ + of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line); + /* Initialize {size,address}-cells info */ + of_scan_flat_dt(early_init_dt_scan_root, NULL); + /* Setup memory, calling early_init_dt_add_memory_arch */ + of_scan_flat_dt(early_init_dt_scan_memory, NULL); + + /* Change machine number to match the mdesc we're using */ + __machine_arch_type = mdesc_best->nr; + + return mdesc_best; +} + /** * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq# * 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 @@ static void __init cacheid_init(void) */ 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 @@ void cpu_init(void) : "r14"); } -static void __init dump_machine_table(void) +void __init dump_machine_table(void) { struct machine_desc *p; @@ -837,8 +839,17 @@ static struct machine_desc * __init setup_machine_tags(unsigned int nr) 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 @@ void __init setup_arch(char **cmdline_p) 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 @@ void __init setup_arch(char **cmdline_p) paging_init(mdesc); request_standard_resources(mdesc); + unflatten_device_tree(); + #ifdef CONFIG_SMP if (is_smp()) smp_init_cpus(); |