From 819d596568d82ffb85b0b5989a1567810fe66098 Mon Sep 17 00:00:00 2001 From: Sudeep KarkadaNagesha Date: Thu, 15 Aug 2013 13:34:18 +0100 Subject: powerpc: refactor of_get_cpu_node to support other architectures Currently different drivers requiring to access cpu device node are parsing the device tree themselves. Since the ordering in the DT need not match the logical cpu ordering, the parsing logic needs to consider that. However, this has resulted in lots of code duplication and in some cases even incorrect logic. It's better to consolidate them by adding support for getting cpu device node for a given logical cpu index in DT core library. However logical to physical index mapping can be architecture specific. PowerPC has it's own implementation to get the cpu node for a given logical index. This patch refactors the current implementation of of_get_cpu_node. This in preparation to move the implementation to DT core library. It separates out the logical to physical mapping so that a default matching of the physical id to the logical cpu index can be added when moved to common code. Architecture specific code can override it. Cc: Rob Herring Cc: Grant Likely Acked-by: Benjamin Herrenschmidt Signed-off-by: Sudeep KarkadaNagesha --- arch/powerpc/kernel/prom.c | 76 ++++++++++++++++++++++++++++------------------ 1 file changed, 47 insertions(+), 29 deletions(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index eb23ac92abb9..f7b8c0be982e 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -865,45 +865,63 @@ static int __init prom_reconfig_setup(void) __initcall(prom_reconfig_setup); #endif +bool arch_match_cpu_phys_id(int cpu, u64 phys_id) +{ + return (int)phys_id == get_hard_smp_processor_id(cpu); +} + +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; +} + /* Find the device node for a given logical cpu number, also returns the cpu * local thread number (index in ibm,interrupt-server#s) if relevant and * asked for (non NULL) */ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread) { - int hardid; - struct device_node *np; + struct device_node *cpun, *cpus; - hardid = get_hard_smp_processor_id(cpu); + cpus = of_find_node_by_path("/cpus"); + if (!cpus) { + pr_warn("Missing cpus node, bailing out\n"); + return NULL; + } - for_each_node_by_type(np, "cpu") { - const u32 *intserv; - unsigned int plen, t; + for_each_child_of_node(cpus, cpun) { + if (of_node_cmp(cpun->type, "cpu")) + continue; - /* Check for ibm,ppc-interrupt-server#s. If it doesn't exist - * fallback to "reg" property and assume no threads + /* 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. */ - intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", - &plen); - if (intserv == NULL) { - const u32 *reg = of_get_property(np, "reg", NULL); - if (reg == NULL) - continue; - if (*reg == hardid) { - if (thread) - *thread = 0; - return np; - } - } else { - plen /= sizeof(u32); - for (t = 0; t < plen; t++) { - if (hardid == intserv[t]) { - if (thread) - *thread = t; - return np; - } - } - } + if (__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; } -- cgit v1.2.3 From 183912d352a242a276a7877852f107459a13aff9 Mon Sep 17 00:00:00 2001 From: Sudeep KarkadaNagesha Date: Thu, 15 Aug 2013 14:01:40 +0100 Subject: of: move of_get_cpu_node implementation to DT core library This patch moves the generalized implementation of of_get_cpu_node from PowerPC to DT core library, thereby adding support for retrieving cpu node for a given logical cpu index on any architecture. The CPU subsystem can now use this function to assign of_node in the cpu device while registering CPUs. It is recommended to use these helper function only in pre-SMP/early initialisation stages to retrieve CPU device node pointers in logical ordering. Once the cpu devices are registered, it can be retrieved easily from cpu device of_node which avoids unnecessary parsing and matching. Cc: Benjamin Herrenschmidt Cc: Grant Likely Acked-by: Rob Herring Signed-off-by: Sudeep KarkadaNagesha --- arch/powerpc/include/asm/prom.h | 3 -- arch/powerpc/kernel/prom.c | 57 ------------------------- drivers/of/base.c | 95 +++++++++++++++++++++++++++++++++++++++++ include/linux/cpu.h | 1 + include/linux/of.h | 7 +++ 5 files changed, 103 insertions(+), 60 deletions(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h index bc2da154f68b..ac204e022922 100644 --- a/arch/powerpc/include/asm/prom.h +++ b/arch/powerpc/include/asm/prom.h @@ -43,9 +43,6 @@ void of_parse_dma_window(struct device_node *dn, const void *dma_window_prop, extern void kdump_move_device_tree(void); -/* CPU OF node matching */ -struct device_node *of_get_cpu_node(int cpu, unsigned int *thread); - /* cache lookup */ struct device_node *of_find_next_cache_node(struct device_node *np); diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index f7b8c0be982e..1c14cd4a5e05 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -870,63 +870,6 @@ bool arch_match_cpu_phys_id(int cpu, u64 phys_id) return (int)phys_id == get_hard_smp_processor_id(cpu); } -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; -} - -/* Find the device node for a given logical cpu number, also returns the cpu - * local thread number (index in ibm,interrupt-server#s) if relevant and - * asked for (non 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 (__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); - #if defined(CONFIG_DEBUG_FS) && defined(DEBUG) static struct debugfs_blob_wrapper flat_dt_blob; diff --git a/drivers/of/base.c b/drivers/of/base.c index 5c5427918eb2..605afa9fbe5e 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 +#include #include #include #include @@ -230,6 +231,100 @@ 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 */ diff --git a/include/linux/cpu.h b/include/linux/cpu.h index ab0eade73039..3dfed2b9ae2e 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -28,6 +28,7 @@ struct cpu { extern int register_cpu(struct cpu *cpu, int num); extern struct device *get_cpu_device(unsigned cpu); extern bool cpu_is_hotpluggable(unsigned cpu); +extern bool arch_match_cpu_phys_id(int cpu, u64 phys_id); extern int cpu_add_dev_attr(struct device_attribute *attr); extern void cpu_remove_dev_attr(struct device_attribute *attr); diff --git a/include/linux/of.h b/include/linux/of.h index 1fd08ca23106..c0bb2f188048 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -266,6 +266,7 @@ extern int of_device_is_available(const struct device_node *device); extern const void *of_get_property(const struct device_node *node, const char *name, int *lenp); +extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread); #define for_each_property_of_node(dn, pp) \ for (pp = dn->properties; pp != NULL; pp = pp->next) @@ -459,6 +460,12 @@ static inline const void *of_get_property(const struct device_node *node, return NULL; } +static inline struct device_node *of_get_cpu_node(int cpu, + unsigned int *thread) +{ + return NULL; +} + static inline int of_property_read_u64(const struct device_node *np, const char *propname, u64 *out_value) { -- cgit v1.2.3