From mboxrd@z Thu Jan 1 00:00:00 1970 From: grant.likely@secretlab.ca (Grant Likely) Date: Mon, 31 Jan 2011 14:04:11 -0700 Subject: [PATCH v2 4/6] arm/dt: probe for platforms via the device tree In-Reply-To: <20110131203626.15105.64302.stgit@localhost6.localdomain6> References: <20110131203626.15105.64302.stgit@localhost6.localdomain6> Message-ID: <20110131210410.15105.63595.stgit@localhost6.localdomain6> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. It also creates arm_unflatten_device_tree() which copies the dtb into an allocated buffer and unflattens it into the live-tree representation. 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 ] Signed-off-by: Grant Likely --- arch/arm/include/asm/mach/arch.h | 2 + arch/arm/include/asm/prom.h | 11 +++++ arch/arm/include/asm/setup.h | 1 arch/arm/kernel/devtree.c | 87 ++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/setup.c | 10 +++- arch/arm/mm/init.c | 8 +++ 6 files changed, 117 insertions(+), 2 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..6ba62a8 100644 --- a/arch/arm/include/asm/prom.h +++ b/arch/arm/include/asm/prom.h @@ -21,5 +21,16 @@ static inline void irq_dispose_mapping(unsigned int virq) return; } +extern void arm_unflatten_device_tree(void); +extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys); + +#else /* CONFIG_OF */ + +static void arm_unflatten_device_tree(void) { } +static inline struct machine_desc *setup_machine_fdt(unsigned int dt_phys) +{ + return NULL; +} + #endif /* CONFIG_OF */ #endif /* ASMARM_PROM_H */ diff --git a/arch/arm/include/asm/setup.h b/arch/arm/include/asm/setup.h index 06c4d0e..1cec82a 100644 --- a/arch/arm/include/asm/setup.h +++ b/arch/arm/include/asm/setup.h @@ -222,6 +222,7 @@ extern struct meminfo meminfo; #define bank_phys_size(bank) (bank)->size extern int arm_add_memory(unsigned long start, unsigned long size); +extern char cmd_line[COMMAND_LINE_SIZE]; #endif /* __KERNEL__ */ diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index ac48da2..07b75bb 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -21,6 +21,7 @@ #include #include +#include void __init early_init_dt_add_memory_arch(u64 base, u64 size) { @@ -45,3 +46,89 @@ 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; + +/** + * arm_unflatten_device_tree - Copy dtb into a safe area and unflatten it. + * + * Copies the dtb out of initial memory and into an allocated block so that + * it doesn't get overwritten by the kernel and then unflatten it into the + * live tree representation. + */ +void __init arm_unflatten_device_tree(void) +{ + struct boot_param_header *devtree; + u32 dtb_size; + + if (!initial_boot_params) + return; + + /* Save the dtb to an allocated buffer */ + dtb_size = be32_to_cpu(initial_boot_params->totalsize); + devtree = early_init_dt_alloc_memory_arch(dtb_size, SZ_4K); + if (!devtree) { + printk("Unable to allocate memory for device tree\n"); + while(1); + } + pr_info("relocating device tree from 0x%p to 0x%p, length 0x%x\n", + initial_boot_params, devtree, dtb_size); + memmove(devtree, initial_boot_params, dtb_size); + initial_boot_params = devtree; + + unflatten_device_tree(); +} + +/** + * 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 = phys_to_virt(dt_phys); + struct machine_desc *mdesc, *mdesc_best = NULL; + unsigned int score, mdesc_score = ~1; + unsigned long dt_root; + const char *model; + + /* check device tree validity */ + if (!dt_phys || 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 = ""; + 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); + + return mdesc_best; +} diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index cbc1836..68e0204 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -42,6 +43,7 @@ #include #include +#include #include #include #include @@ -125,7 +127,7 @@ EXPORT_SYMBOL(elf_platform); static const char *cpu_name; static const char *machine_name; -static char __initdata cmd_line[COMMAND_LINE_SIZE]; +char cmd_line[COMMAND_LINE_SIZE]; struct machine_desc *machine_desc __initdata; static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE; @@ -838,7 +840,9 @@ 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; @@ -859,6 +863,8 @@ void __init setup_arch(char **cmdline_p) paging_init(mdesc); request_standard_resources(mdesc); + arm_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 5164069..62ff2e8 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -71,6 +71,14 @@ static int __init parse_tag_initrd2(const struct tag *tag) __tagtable(ATAG_INITRD2, parse_tag_initrd2); +#ifdef CONFIG_OF_FLATTREE +void __init early_init_dt_setup_initrd_arch(unsigned long start, unsigned long end) +{ + phys_initrd_start = start; + phys_initrd_size = end - start + 1; +} +#endif /* CONFIG_OF_FLATTREE */ + /* * This keeps memory configuration data used by a couple memory * initialization functions, as well as show_mem() for the skipping