of: Make cpu node handling more portable.

Use for_each_node_by_type() to iterate all cpu nodes in the
system.

Provide and overridable function arch_find_n_match_cpu_physical_id,
which sees if the given device node matches 'cpu' and if so sets
'*thread' when non-NULL to the cpu thread number within the core.

The default implementation behaves the same as the existing code.

Add a sparc64 implementation.

Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

3 files changed, 84 insertions, 17 deletions

diff --git a/arch/sparc/kernel/prom_64.c b/arch/sparc/kernel/prom_64.c
index d397d7fc5c28..6b39125eb927 100644
--- a/arch/sparc/kernel/prom_64.c
+++ b/arch/sparc/kernel/prom_64.c
@@ -373,6 +373,59 @@ static const char *get_mid_prop(void)
         return (tlb_type == spitfire ? "upa-portid" : "portid");
 }
 
+bool arch_find_n_match_cpu_physical_id(struct device_node *cpun,
+                                       int cpu, unsigned int *thread)
+{
+        const char *mid_prop = get_mid_prop();
+        int this_cpu_id;
+
+        /* On hypervisor based platforms we interrogate the 'reg'
+         * property.  On everything else we look for a 'upa-portis',
+         * 'portid', or 'cpuid' property.
+         */
+
+        if (tlb_type == hypervisor) {
+                struct property *prop = of_find_property(cpun, "reg", NULL);
+                u32 *regs;
+
+                if (!prop) {
+                        pr_warn("CPU node missing reg property\n");
+                        return false;
+                }
+                regs = prop->value;
+                this_cpu_id = regs[0] & 0x0fffffff;
+        } else {
+                this_cpu_id = of_getintprop_default(cpun, mid_prop, -1);
+
+                if (this_cpu_id < 0) {
+                        mid_prop = "cpuid";
+                        this_cpu_id = of_getintprop_default(cpun, mid_prop, -1);
+                }
+                if (this_cpu_id < 0) {
+                        pr_warn("CPU node missing cpu ID property\n");
+                        return false;
+                }
+        }
+        if (this_cpu_id == cpu) {
+                if (thread) {
+                        int proc_id = cpu_data(cpu).proc_id;
+
+                        /* On sparc64, the cpu thread information is obtained
+                         * either from OBP or the machine description.  We've
+                         * actually probed this information already long before
+                         * this interface gets called so instead of interrogating
+                         * both the OF node and the MDESC again, just use what
+                         * we discovered already.
+                         */
+                        if (proc_id < 0)
+                                proc_id = 0;
+                        *thread = proc_id;
+                }
+                return true;
+        }
+        return false;
+}
+
 static void *of_iterate_over_cpus(void *(*func)(struct device_node *, int, int), int arg)
 {
         struct device_node *dp;
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 7d4c70f859e3..e4c99453adf1 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -280,6 +280,31 @@ static bool __of_find_n_match_cpu_property(struct device_node *cpun,
         return false;
 }
 
+/*
+ * arch_find_n_match_cpu_physical_id - See if the given device node is
+ * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
+ * else false.  If 'thread' is non-NULL, the local thread number within the
+ * core is returned in it.
+ */
+bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
+                                              int cpu, unsigned int *thread)
+{
+        /* 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 true;
+
+        if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))
+                return true;
+
+        return false;
+}
+
 /**
  * of_get_cpu_node - Get device node associated with the given logical CPU
  *
@@ -300,24 +325,10 @@ static bool __of_find_n_match_cpu_property(struct device_node *cpun,
  */
 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)
-                return NULL;
+        struct device_node *cpun;
 
-        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))
+        for_each_node_by_type(cpun, "cpu") {
+                if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
                         return cpun;
         }
         return NULL;
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 801ff9e73679..fbd25c3c2923 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -18,6 +18,7 @@
 #include <linux/cpumask.h>
 
 struct device;
+struct device_node;
 
 struct cpu {
         int node_id;            /* The node which contains the CPU */
@@ -29,6 +30,8 @@ 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 bool arch_find_n_match_cpu_physical_id(struct device_node *cpun,
+                                              int cpu, unsigned int *thread);
 
 extern int cpu_add_dev_attr(struct device_attribute *attr);
 extern void cpu_remove_dev_attr(struct device_attribute *attr);