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 <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

2 files changed, 0 insertions, 60 deletions

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;