powerpc/cpufreq: Add pr_warn() on OPAL firmware failures
Cpufreq depends on platform firmware to implement PStates. In case of
platform firmware failure, cpufreq should not panic host kernel with
BUG_ON(). Less severe pr_warn() will suffice.
Add firmware_has_feature(FW_FEATURE_OPALv3) check to
skip probing for device-tree on non-powernv platforms.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index bb1d08d..379c083 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -28,6 +28,7 @@
#include <linux/of.h>
#include <asm/cputhreads.h>
+#include <asm/firmware.h>
#include <asm/reg.h>
#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
@@ -98,7 +99,11 @@
return -ENODEV;
}
- WARN_ON(len_ids != len_freqs);
+ if (len_ids != len_freqs) {
+ pr_warn("Entries in ibm,pstate-ids and "
+ "ibm,pstate-frequencies-mhz does not match\n");
+ }
+
nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
if (!nr_pstates) {
pr_warn("No PStates found\n");
@@ -131,7 +136,12 @@
int i;
i = powernv_pstate_info.max - pstate_id;
- BUG_ON(i >= powernv_pstate_info.nr_pstates || i < 0);
+ if (i >= powernv_pstate_info.nr_pstates || i < 0) {
+ pr_warn("PState id %d outside of PState table, "
+ "reporting nominal id %d instead\n",
+ pstate_id, powernv_pstate_info.nominal);
+ i = powernv_pstate_info.max - powernv_pstate_info.nominal;
+ }
return powernv_freqs[i].frequency;
}
@@ -321,6 +331,10 @@
{
int rc = 0;
+ /* Don't probe on pseries (guest) platforms */
+ if (!firmware_has_feature(FW_FEATURE_OPALv3))
+ return -ENODEV;
+
/* Discover pstates from device tree and init */
rc = init_powernv_pstates();
if (rc) {