See below.

On 11/20/2017 09:35 AM, Nathan Fontenot wrote:

On 11/16/2017 02:11 PM, Michael Bringmann wrote:

quoted

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 <redacted>
---
Changes in V4:
  -- Rename of_one_drc_info to of_read_drc_info_cell
  -- Fix some spacing within expressions
  -- Make some style corrections
---
 arch/powerpc/include/asm/prom.h                 |   15 +++
 arch/powerpc/platforms/pseries/of_helpers.c     |   60 ++++++++++
 arch/powerpc/platforms/pseries/pseries_energy.c |  138 ++++++++++++++++++-----
 3 files changed, 185 insertions(+), 28 deletions(-)

...

quoted

+
+		value = info->value;
+		value = (void *)of_prop_next_u32(info, value,
+						&num_set_entries);

Missed this the first time, but setting value twice seems a bit odd.
This should be able to be collapsed into;

		value = (void *)of_prop_next_u32(info, NULL, &num_set_entries);

Okay

quoted

+		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;
+
+			WARN_ON(((thread_index - drc.drc_index_start) %
+					drc.sequential_inc) != 0);

The WARN_ON that you have here, and in the code below, really fell like they
should be in of_read_drc_info_cell. These are checks on reading the info in
the drc-info property.

Remove unnecessary WARN_ON() checks.

quoted

+		}
+
+		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;
+
+		/*
+		 * The first element indexes[0] is the number of drc_indexes
+		 * returned in the list.  Hence thread_index+1 will get the
+		 * drc_index corresponding to core number thread_index.
+		 */
+		WARN_ON(thread_index > indexes[0]);
+		ret = indexes[thread_index + 1];
+	}
+
 	rc = 0;

 err_of_node_put:

@@ -72,34 +111,77 @@ 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;
-	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
-	if (indexes == NULL)
-		goto err_of_node_put;
-	/*
-	 * First element in the array is the number of drc_indexes
-	 * returned.  Search through the list to find the matching
-	 * drc_index and get the core number
-	 */
-	for (i = 0; i < indexes[0]; i++) {
-		if (indexes[i + 1] == drc_index)
+
+	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 = info->value;
+		value = (void *)of_prop_next_u32(info, value,
+						&num_set_entries);

Okay.

Same here as mentioned above.

-Nathan

quoted

+		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;
+
+			WARN_ON(drc_index < drc.drc_index_start);
+			WARN_ON(((drc_index - drc.drc_index_start) %
+					drc.sequential_inc) != 0);
+
+			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;
+		/*
+		 * First element in the array is the number of drc_indexes
+		 * returned.  Search through the list to find the matching
+		 * drc_index and get the core number
+		 */
+		for (i = 0; i < indexes[0]; i++) {
+			if (indexes[i + 1] == drc_index)
+				break;
+		}
+		/* Convert core number to logical cpu number */
+		thread_index = cpu_first_thread_of_core(i);
+		rc = 0;
 	}
-	/* Convert core number to logical cpu number */
-	cpu = 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;
 }

 /*

-- 
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb@linux.vnet.ibm.com