On Thu, 2013-08-15 at 18:09 +0100, Sudeep KarkadaNagesha wrote:

From: Sudeep KarkadaNagesha <redacted>

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.

 .../...

 
+bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
+{
+	return (int)phys_id == get_hard_smp_processor_id(cpu);
+}

Naming is a bit gross. You might want to make it clearer that
we are talking about CPU IDs in the device-tree here.

+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;
+		}

Missing:          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
 		 */
-		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;
 }

Cheers,
Ben.