pseries/drc-info: Search DRC properties for CPU indexes

pseries/drc-info: Provide parallel routines to convert between
drc_index and CPU numbers at runtime, using the older device-tree
properties ("ibm,drc-indexes", "ibm,drc-names", "ibm,drc-types"
and "ibm,drc-power-domains"), or the new property "ibm,drc-info".
Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/prom.h

@@ -80,6 +80,21 @@ extern void of_instantiate_rtc(void);
 
 extern int of_get_ibm_chip_id(struct device_node *np);
 
+struct of_drc_info {
+	char *drc_type;
+	char *drc_name_prefix;
+	u32 drc_index_start;
+	u32 drc_name_suffix_start;
+	u32 num_sequential_elems;
+	u32 sequential_inc;
+	u32 drc_power_domain;
+	u32 last_drc_index;
+};
+
+extern int of_read_drc_info_cell(struct property **prop,
+			const __be32 **curval, struct of_drc_info *data);
+
+
 /*
  * There are two methods for telling firmware what our capabilities are.
  * Newer machines have an "ibm,client-architecture-support" method on the

arch/powerpc/platforms/pseries/of_helpers.c

@@ -3,6 +3,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <asm/prom.h>
 
 #include "of_helpers.h"
 
@@ -37,3 +38,62 @@ struct device_node *pseries_of_derive_parent(const char *path)
 		kfree(parent_path);
 	return parent ? parent : ERR_PTR(-EINVAL);
 }
+
+
+/* Helper Routines to convert between drc_index to cpu numbers */
+
+int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
+			struct of_drc_info *data)
+{
+	const char *p;
+	const __be32 *p2;
+
+	if (!data)
+		return -EINVAL;
+
+	/* Get drc-type:encode-string */
+	p = data->drc_type = (char*) (*curval);
+	p = of_prop_next_string(*prop, p);
+	if (!p)
+		return -EINVAL;
+
+	/* Get drc-name-prefix:encode-string */
+	data->drc_name_prefix = (char *)p;
+	p = of_prop_next_string(*prop, p);
+	if (!p)
+		return -EINVAL;
+
+	/* Get drc-index-start:encode-int */
+	p2 = (const __be32 *)p;
+	p2 = of_prop_next_u32(*prop, p2, &data->drc_index_start);
+	if (!p2)
+		return -EINVAL;
+
+	/* Get drc-name-suffix-start:encode-int */
+	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
+	if (!p2)
+		return -EINVAL;
+
+	/* Get number-sequential-elements:encode-int */
+	p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
+	if (!p2)
+		return -EINVAL;
+
+	/* Get sequential-increment:encode-int */
+	p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
+	if (!p2)
+		return -EINVAL;
+
+	/* Get drc-power-domain:encode-int */
+	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
+	if (!p2)
+		return -EINVAL;
+
+	/* Should now know end of current entry */
+	(*curval) = (void *)p2;
+	data->last_drc_index = data->drc_index_start +
+		((data->num_sequential_elems - 1) * data->sequential_inc);
+
+	return 0;
+}
+EXPORT_SYMBOL(of_read_drc_info_cell);

arch/powerpc/platforms/pseries/pseries_energy.c

@@ -22,6 +22,7 @@
 #include <asm/page.h>
 #include <asm/hvcall.h>
 #include <asm/firmware.h>
+#include <asm/prom.h>
 
 
 #define MODULE_VERS "1.0"
@@ -38,26 +39,58 @@ static int sysfs_entries;
 static u32 cpu_to_drc_index(int cpu)
 {
 	struct device_node *dn = NULL;
-	const int *indexes;
-	int i;
+	int thread_index;
 	int rc = 1;
 	u32 ret = 0;
 
 	dn = of_find_node_by_path("/cpus");
 	if (dn == NULL)
 		goto err;
+
+	/* Convert logical cpu number to core number */
+	thread_index = cpu_core_index_of_thread(cpu);
+
+	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
+		struct property *info = NULL;
+		struct of_drc_info drc;
+		int j;
+		u32 num_set_entries;
+		const __be32 *value;
+
+		info = of_find_property(dn, "ibm,drc-info", NULL);
+		if (info == NULL)
+			goto err_of_node_put;
+
+		value = of_prop_next_u32(info, NULL, &num_set_entries);
+		if (!value)
+			goto err_of_node_put;
+
+		for (j = 0; j < num_set_entries; j++) {
+
+			of_read_drc_info_cell(&info, &value, &drc);
+			if (strncmp(drc.drc_type, "CPU", 3))
+				goto err;
+
+			if (thread_index < drc.last_drc_index)
+				break;
+		}
+
+		ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
+	} else {
+		const __be32 *indexes;
+
 		indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
 		if (indexes == NULL)
 			goto err_of_node_put;
-	/* Convert logical cpu number to core number */
-	i = cpu_core_index_of_thread(cpu);
+
 		/*
 		 * The first element indexes[0] is the number of drc_indexes
-	 * returned in the list.  Hence i+1 will get the drc_index
-	 * corresponding to core number i.
+		 * returned in the list.  Hence thread_index+1 will get the
+		 * drc_index corresponding to core number thread_index.
 		 */
-	WARN_ON(i > indexes[0]);
-	ret = indexes[i + 1];
+		ret = indexes[thread_index + 1];
+	}
+
 	rc = 0;
 
 err_of_node_put:
@@ -72,12 +105,48 @@ static int drc_index_to_cpu(u32 drc_index)
 {
 	struct device_node *dn = NULL;
 	const int *indexes;
-	int i, cpu = 0;
+	int thread_index = 0, cpu = 0;
 	int rc = 1;
 
 	dn = of_find_node_by_path("/cpus");
 	if (dn == NULL)
 		goto err;
+
+	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
+		struct property *info = NULL;
+		struct of_drc_info drc;
+		int j;
+		u32 num_set_entries;
+		const __be32 *value;
+
+		info = of_find_property(dn, "ibm,drc-info", NULL);
+		if (info == NULL)
+			goto err_of_node_put;
+
+		value = of_prop_next_u32(info, NULL, &num_set_entries);
+		if (!value)
+			goto err_of_node_put;
+
+		for (j = 0; j < num_set_entries; j++) {
+
+			of_read_drc_info_cell(&info, &value, &drc);
+			if (strncmp(drc.drc_type, "CPU", 3))
+				goto err;
+
+			if (drc_index > drc.last_drc_index) {
+				cpu += drc.num_sequential_elems;
+				continue;
+			}
+			cpu += ((drc_index - drc.drc_index_start) /
+				drc.sequential_inc);
+
+			thread_index = cpu_first_thread_of_core(cpu);
+			rc = 0;
+			break;
+		}
+	} else {
+		unsigned long int i;
+
 		indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
 		if (indexes == NULL)
 			goto err_of_node_put;
@@ -91,15 +160,16 @@ static int drc_index_to_cpu(u32 drc_index)
 				break;
 		}
 		/* Convert core number to logical cpu number */
-	cpu = cpu_first_thread_of_core(i);
+		thread_index = cpu_first_thread_of_core(i);
 		rc = 0;
+	}
 
 err_of_node_put:
 	of_node_put(dn);
 err:
 	if (rc)
 		printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
-	return cpu;
+	return thread_index;
 }
 
 /*