cpu: Add iterators for "present" CPUs

Some code path want to look at all the CPUs that are "present",
which means they have been enabled by HB/Cronus and can be accessed
via XSCOMs, even if they haven't called in yet.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

core/cpu.c

@@ -494,6 +494,20 @@ struct cpu_thread *first_available_cpu(void)
 	return next_available_cpu(NULL);
 }
 
+struct cpu_thread *next_present_cpu(struct cpu_thread *cpu)
+{
+	do {
+		cpu = next_cpu(cpu);
+	} while(cpu && !cpu_is_present(cpu));
+
+	return cpu;
+}
+
+struct cpu_thread *first_present_cpu(void)
+{
+	return next_present_cpu(NULL);
+}
+
 u8 get_available_nr_cores_in_chip(u32 chip_id)
 {
 	struct cpu_thread *core;

include/cpu.h

@@ -165,6 +165,11 @@ extern struct cpu_thread *next_cpu(struct cpu_thread *cpu);
  *          this API standpoint.
  */
 
+static inline bool cpu_is_present(struct cpu_thread *cpu)
+{
+	return cpu->state >= cpu_state_present;
+}
+
 static inline bool cpu_is_available(struct cpu_thread *cpu)
 {
 	return cpu->state == cpu_state_active ||
@@ -173,13 +178,18 @@ static inline bool cpu_is_available(struct cpu_thread *cpu)
 
 extern struct cpu_thread *first_available_cpu(void);
 extern struct cpu_thread *next_available_cpu(struct cpu_thread *cpu);
+extern struct cpu_thread *first_present_cpu(void);
+extern struct cpu_thread *next_present_cpu(struct cpu_thread *cpu);
 
 #define for_each_cpu(cpu)	\
 	for (cpu = first_cpu(); cpu; cpu = next_cpu(cpu))
 
 #define for_each_available_cpu(cpu)	\
 	for (cpu = first_available_cpu(); cpu; cpu = next_available_cpu(cpu))
 
+#define for_each_present_cpu(cpu)	\
+	for (cpu = first_present_cpu(); cpu; cpu = next_present_cpu(cpu))
+
 extern struct cpu_thread *first_available_core_in_chip(u32 chip_id);
 extern struct cpu_thread *next_available_core_in_chip(struct cpu_thread *cpu, u32 chip_id);
 extern u8 get_available_nr_cores_in_chip(u32 chip_id);