[PATCH v11 5/8] cpufreq: amd-pstate: Bail out if min/max/nominal_freq is 0

[Perry Yuan]

The amd-pstate driver cannot work when the min_freq, nominal_freq or
the max_freq is zero. When this happens it is prudent to error out
early on rather than waiting failing at the time of the governor
initialization.

Acked-by: Huang Rui <ray.huang@xxxxxxx>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
---
 drivers/cpufreq/amd-pstate.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 3836d62b54ef..960fead0b83e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -839,9 +839,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	nominal_freq = READ_ONCE(cpudata->nominal_freq);
 	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
 
-	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
-		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
-			min_freq, max_freq);
+	if (min_freq <= 0 || max_freq <= 0 ||
+	    nominal_freq <= 0 || min_freq > max_freq) {
+		dev_err(dev,
+			"min_freq(%d) or max_freq(%d) or nominal_freq (%d) value is incorrect, check _CPC in ACPI tables\n",
+			min_freq, max_freq, nominal_freq);
 		ret = -EINVAL;
 		goto free_cpudata1;
 	}
@@ -1299,9 +1301,11 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	max_freq = READ_ONCE(cpudata->max_freq);
 	nominal_freq = READ_ONCE(cpudata->nominal_freq);
 	lowest_nonlinear_freq = READ_ONCE(cpudata->lowest_nonlinear_freq);
-	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
-		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
-				min_freq, max_freq);
+	if (min_freq <= 0 || max_freq <= 0 ||
+	    nominal_freq <= 0 || min_freq > max_freq) {
+		dev_err(dev,
+			"min_freq(%d) or max_freq(%d) or nominal_freq(%d) value is incorrect, check _CPC in ACPI tables\n",
+			min_freq, max_freq, nominal_freq);
 		ret = -EINVAL;
 		goto free_cpudata1;
 	}
-- 
2.34.1