diff options
Diffstat (limited to 'drivers/of/base.c')
| -rw-r--r-- | drivers/of/base.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c index 5c5427918eb..e486e416d5a 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -18,6 +18,7 @@ * 2 of the License, or (at your option) any later version. */ #include <linux/ctype.h> +#include <linux/cpu.h> #include <linux/module.h> #include <linux/of.h> #include <linux/spinlock.h> @@ -32,6 +33,7 @@ struct device_node *of_allnodes; EXPORT_SYMBOL(of_allnodes); struct device_node *of_chosen; struct device_node *of_aliases; +static struct device_node *of_stdout; DEFINE_MUTEX(of_aliases_mutex); @@ -230,6 +232,100 @@ const void *of_get_property(const struct device_node *np, const char *name, } EXPORT_SYMBOL(of_get_property); +/* + * arch_match_cpu_phys_id - Match the given logical CPU and physical id + * + * @cpu: logical cpu index of a core/thread + * @phys_id: physical identifier of a core/thread + * + * CPU logical to physical index mapping is architecture specific. + * However this __weak function provides a default match of physical + * id to logical cpu index. phys_id provided here is usually values read + * from the device tree which must match the hardware internal registers. + * + * Returns true if the physical identifier and the logical cpu index + * correspond to the same core/thread, false otherwise. + */ +bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id) +{ + return (u32)phys_id == cpu; +} + +/** + * Checks if the given "prop_name" property holds the physical id of the + * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not + * NULL, local thread number within the core is returned in it. + */ +static bool __of_find_n_match_cpu_property(struct device_node *cpun, + const char *prop_name, int cpu, unsigned int *thread) +{ + const __be32 *cell; + int ac, prop_len, tid; + u64 hwid; + + ac = of_n_addr_cells(cpun); + cell = of_get_property(cpun, prop_name, &prop_len); + if (!cell) + return false; + prop_len /= sizeof(*cell); + for (tid = 0; tid < prop_len; tid++) { + hwid = of_read_number(cell, ac); + if (arch_match_cpu_phys_id(cpu, hwid)) { + if (thread) + *thread = tid; + return true; + } + cell += ac; + } + return false; +} + +/** + * of_get_cpu_node - Get device node associated with the given logical CPU + * + * @cpu: CPU number(logical index) for which device node is required + * @thread: if not NULL, local thread number within the physical core is + * returned + * + * The main purpose of this function is to retrieve the device node for the + * given logical CPU index. It should be used to initialize the of_node in + * cpu device. Once of_node in cpu device is populated, all the further + * references can use that instead. + * + * CPU logical to physical index mapping is architecture specific and is built + * before booting secondary cores. This function uses arch_match_cpu_phys_id + * which can be overridden by architecture specific implementation. + * + * Returns a node pointer for the logical cpu if found, else NULL. + */ +struct device_node *of_get_cpu_node(int cpu, unsigned int *thread) +{ + struct device_node *cpun, *cpus; + + cpus = of_find_node_by_path("/cpus"); + if (!cpus) { + pr_warn("Missing cpus node, bailing out\n"); + return NULL; + } + + for_each_child_of_node(cpus, cpun) { + if (of_node_cmp(cpun->type, "cpu")) + continue; + /* Check for non-standard "ibm,ppc-interrupt-server#s" property + * for thread ids on PowerPC. If it doesn't exist fallback to + * standard "reg" property. + */ + if (IS_ENABLED(CONFIG_PPC) && + __of_find_n_match_cpu_property(cpun, + "ibm,ppc-interrupt-server#s", cpu, thread)) + return cpun; + if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread)) + return cpun; + } + return NULL; +} +EXPORT_SYMBOL(of_get_cpu_node); + /** Checks if the given "compat" string matches one of the strings in * the device's "compatible" property */ @@ -1595,6 +1691,15 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) of_chosen = of_find_node_by_path("/chosen"); if (of_chosen == NULL) of_chosen = of_find_node_by_path("/chosen@0"); + + if (of_chosen) { + const char *name; + + name = of_get_property(of_chosen, "linux,stdout-path", NULL); + if (name) + of_stdout = of_find_node_by_path(name); + } + of_aliases = of_find_node_by_path("/aliases"); if (!of_aliases) return; @@ -1703,3 +1808,19 @@ const char *of_prop_next_string(struct property *prop, const char *cur) return curv; } EXPORT_SYMBOL_GPL(of_prop_next_string); + +/** + * of_device_is_stdout_path - check if a device node matches the + * linux,stdout-path property + * + * Check if this device node matches the linux,stdout-path property + * in the chosen node. return true if yes, false otherwise. + */ +int of_device_is_stdout_path(struct device_node *dn) +{ + if (!of_stdout) + return false; + + return of_stdout == dn; +} +EXPORT_SYMBOL_GPL(of_device_is_stdout_path); |