Messages in this thread Patch in this message | | | Subject | [PATCH v3 4/6] arm/dt: probe for platforms via the device tree | From | Grant Likely <> | Date | Sat, 12 Feb 2011 01:14:48 -0700 |
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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.
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>] Signed-off-by: Grant Likely <grant.likely@secretlab.ca> --- arch/arm/include/asm/mach/arch.h | 2 + arch/arm/include/asm/prom.h | 12 +++++ arch/arm/kernel/devtree.c | 89 ++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/setup.c | 8 +++ arch/arm/mm/init.c | 2 + 5 files changed, 112 insertions(+), 1 deletions(-)
diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h index 3a0893a..2ed24e7 100644 --- a/arch/arm/include/asm/mach/arch.h +++ b/arch/arm/include/asm/mach/arch.h @@ -22,6 +22,8 @@ struct machine_desc { unsigned int nr; /* architecture number */ const char *name; /* architecture name */ unsigned long boot_params; /* tagged list */ + const char **dt_compat; /* array of device tree + * 'compatible' strings */ unsigned int nr_irqs; /* number of IRQs */ diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h index 8f1037f..11b8708 100644 --- a/arch/arm/include/asm/prom.h +++ b/arch/arm/include/asm/prom.h @@ -21,5 +21,17 @@ static inline void irq_dispose_mapping(unsigned int virq) return; } +extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys); +extern void arm_dt_memblock_reserve(void); + +#else /* CONFIG_OF */ + +static inline struct machine_desc *setup_machine_fdt(unsigned int dt_phys) +{ + return NULL; +} + +static inline void arm_dt_memblock_reserve(void) { } + #endif /* CONFIG_OF */ #endif /* ASMARM_PROM_H */ diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 75e3df8..f5b6f1d 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 +34,33 @@ 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); + } +} + /** * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq# * @@ -45,3 +74,63 @@ unsigned int irq_create_of_mapping(struct device_node *controller, return intspec[0]; } EXPORT_SYMBOL_GPL(irq_create_of_mapping); + +extern struct machine_desc __arch_info_begin, __arch_info_end; + +/** + * 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 (mdesc = &__arch_info_begin; mdesc < &__arch_info_end; 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) { + printk("Machine not supported, unable to continue.\n"); + while (1); + } + + 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, NULL); + /* 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); + /* Save command line for /proc/cmdline */ + strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE); + + /* Change machine number to match the mdesc we're using */ + __machine_arch_type = mdesc->nr; + + return mdesc_best; +} diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 7bc7a27..3d737a0 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> @@ -875,7 +877,9 @@ 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; @@ -896,6 +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(); diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index a2ba1d1..8e3387c 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -22,6 +22,7 @@ #include <linux/sort.h> #include <asm/mach-types.h> +#include <asm/prom.h> #include <asm/sections.h> #include <asm/setup.h> #include <asm/sizes.h> @@ -322,6 +323,7 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc) #endif arm_mm_memblock_reserve(); + arm_dt_memblock_reserve(); /* reserve any platform specific memblock areas */ if (mdesc->reserve)
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