To prevent infinite loop when tracking voltage, we calculate the maximum
value for each platform data.
We assume min voltage is 0 and tracking target voltage using
min_volt_shift for each iteration.
The retry_max is 3 times of expeted iteration count.
Signed-off-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
---
drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index cc44a7a9427a..d4c00237e862 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
struct regulator *proc_reg = info->proc_reg;
struct regulator *sram_reg = info->sram_reg;
int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
+ int retry_max;
+
+ /*
+ * We assume min voltage is 0 and tracking target voltage using
+ * min_volt_shift for each iteration.
+ * The retry_max is 3 times of expeted iteration count.
+ */
+ retry_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
+ info->soc_data->proc_max_volt),
+ info->soc_data->min_volt_shift);
pre_vproc = regulator_get_voltage(proc_reg);
if (pre_vproc < 0) {
@@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
pre_vproc = vproc;
pre_vsram = vsram;
+
+ if (--retry_max < 0) {
+ dev_err(info->cpu_dev,
+ "over loop count, failed to set voltage\n");
+ return -EINVAL;
+ }
} while (vproc != new_vproc || vsram != new_vsram);
return 0;
--
2.18.0
