There are a couple subtle errors in the mapping between cpu-ids and a
cpus associated drc-index when using the new ibm,drc-info property.
The first is that while drc-info may have been a supported firmware
feature at boot it is possible we have migrated to a CEC with older
firmware that doesn't support the ibm,drc-info property. In that case
the device tree would have been updated after migration to remove the
ibm,drc-info property and replace it with the older style ibm,drc-*
properties for types, indexes, names, and power-domains.
The second is that the first value of the ibm,drc-info property is
the int encoded count of drc-info entries. As such "value" returned
by of_prop_next_u32() is pointing at that count, and not the first
element of the first drc-info entry as is expected by the
of_read_drc_info_cell() helper.
Fix the first by ignoring DRC-INFO firmware feature and instead
testing directly for ibm,drc-info, and then falling back to the
old style ibm,drc-indexes in the case it doesn't exit.
Fix the second by incrementing value to the next element prior to
parsing drc-info entries.
Signed-off-by: Tyrel Datwyler <tyr...@linux.ibm.com>
---
arch/powerpc/platforms/pseries/pseries_energy.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c
b/arch/powerpc/platforms/pseries/pseries_energy.c
index a96874f..09e98d3 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -36,6 +36,7 @@ static int sysfs_entries;
static u32 cpu_to_drc_index(int cpu)
{
struct device_node *dn = NULL;
+ struct property *info;
int thread_index;
int rc = 1;
u32 ret = 0;
@@ -47,20 +48,18 @@ static u32 cpu_to_drc_index(int cpu)
/* 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;
+ info = of_find_property(dn, "ibm,drc-info", NULL);
+ if (info) {
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;
+ else
+ value++;
for (j = 0; j < num_set_entries; j++) {
@@ -110,6 +109,7 @@ static u32 cpu_to_drc_index(int cpu)
static int drc_index_to_cpu(u32 drc_index)
{
struct device_node *dn = NULL;
+ struct property *info;
const int *indexes;
int thread_index = 0, cpu = 0;
int rc = 1;
@@ -117,21 +117,18 @@ static int drc_index_to_cpu(u32 drc_index)
dn = of_find_node_by_path("/cpus");
if (dn == NULL)
goto err;
-
- if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
- struct property *info = NULL;
+ info = of_find_property(dn, "ibm,drc-info", NULL);
+ if (info) {
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;
+ else
+ value++;
for (j = 0; j < num_set_entries; j++) {
--
2.7.4
