thermal: ti-soc-thermal: OMAP5: Implement Workaround for Errata i813

DESCRIPTION

Spurious Thermal Alert: Talert can happen randomly while the device remains
under the temperature limit defined for this event to trig. This spurious
event is caused by a incorrect re-synchronization between clock domains.
The comparison between configured threshold and current temperature value
can happen while the value is transitioning (metastable), thus causing
inappropriate event generation. No spurious event occurs as long as the
threshold value stays unchanged. Spurious event can be generated while a
thermal alert threshold is modified in
CONTROL_BANDGAP_THRESHOLD_MPU/GPU/CORE/DSPEVE/IVA_n.

WORKAROUND

Spurious event generation can be avoided by performing following sequence
when the threshold is modified:
1. Mask the hot/cold events at the thermal IP level.
2. Modify Threshold.
3. Unmask the hot/cold events at the thermal IP level.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

diff --git a/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c b/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c
index eff0c80fd4af50110cde6b4dc5cba3500787e91e..79ff70c446ba195ef893125b377567ff4ac2e58b 100644 (file)
--- a/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c
+++ b/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c
@@ -319,7 +319,8 @@ const struct ti_bandgap_data omap5430_data = {
                        TI_BANDGAP_FEATURE_FREEZE_BIT |
                        TI_BANDGAP_FEATURE_TALERT |
                        TI_BANDGAP_FEATURE_COUNTER_DELAY |
-                       TI_BANDGAP_FEATURE_HISTORY_BUFFER,
+                       TI_BANDGAP_FEATURE_HISTORY_BUFFER |
+                       TI_BANDGAP_FEATURE_ERRATA_813,
        .fclock_name = "l3instr_ts_gclk_div",
        .div_ck_name = "l3instr_ts_gclk_div",
        .conv_table = omap5430_adc_to_temp,

diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
index 9747523858a10a05de402128c4993a76fe5bcc14..bc14dc874594e4d9fd37a68874bb6adb6eb4b562 100644 (file)
--- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
+++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
@@ -445,7 +445,7 @@ static int ti_bandgap_update_alert_threshold(struct ti_bandgap *bgp, int id,
 {
        struct temp_sensor_data *ts_data = bgp->conf->sensors[id].ts_data;
        struct temp_sensor_registers *tsr;
-       u32 thresh_val, reg_val, t_hot, t_cold;
+       u32 thresh_val, reg_val, t_hot, t_cold, ctrl;
        int err = 0;
 
        tsr = bgp->conf->sensors[id].registers;
@@ -477,8 +477,47 @@ static int ti_bandgap_update_alert_threshold(struct ti_bandgap *bgp, int id,
                  ~(tsr->threshold_thot_mask | tsr->threshold_tcold_mask);
        reg_val |= (t_hot << __ffs(tsr->threshold_thot_mask)) |
                   (t_cold << __ffs(tsr->threshold_tcold_mask));
+
+       /**
+        * Errata i813:
+        * Spurious Thermal Alert: Talert can happen randomly while the device
+        * remains under the temperature limit defined for this event to trig.
+        * This spurious event is caused by a incorrect re-synchronization
+        * between clock domains. The comparison between configured threshold
+        * and current temperature value can happen while the value is
+        * transitioning (metastable), thus causing inappropriate event
+        * generation. No spurious event occurs as long as the threshold value
+        * stays unchanged. Spurious event can be generated while a thermal
+        * alert threshold is modified in
+        * CONTROL_BANDGAP_THRESHOLD_MPU/GPU/CORE/DSPEVE/IVA_n.
+        */
+
+       if (TI_BANDGAP_HAS(bgp, ERRATA_813)) {
+               /* Mask t_hot and t_cold events at the IP Level */
+               ctrl = ti_bandgap_readl(bgp, tsr->bgap_mask_ctrl);
+
+               if (hot)
+                       ctrl &= ~tsr->mask_hot_mask;
+               else
+                       ctrl &= ~tsr->mask_cold_mask;
+
+               ti_bandgap_writel(bgp, ctrl, tsr->bgap_mask_ctrl);
+       }
+
+       /* Write the threshold value */
        ti_bandgap_writel(bgp, reg_val, tsr->bgap_threshold);
 
+       if (TI_BANDGAP_HAS(bgp, ERRATA_813)) {
+               /* Unmask t_hot and t_cold events at the IP Level */
+               ctrl = ti_bandgap_readl(bgp, tsr->bgap_mask_ctrl);
+               if (hot)
+                       ctrl |= tsr->mask_hot_mask;
+               else
+                       ctrl |= tsr->mask_cold_mask;
+
+               ti_bandgap_writel(bgp, ctrl, tsr->bgap_mask_ctrl);
+       }
+
        if (err) {
                dev_err(bgp->dev, "failed to reprogram thot threshold\n");
                err = -EIO;

diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.h b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
index b2da3fc42b510019e5bdbda21034f9d16770f951..0c52f7afba00b5335adbeba60cd31f547d2256a3 100644 (file)
--- a/drivers/thermal/ti-soc-thermal/ti-bandgap.h
+++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
@@ -320,7 +320,8 @@ struct ti_temp_sensor {
  *
  * TI_BANDGAP_FEATURE_ERRATA_814 - used to workaorund when the bandgap device
  *     has Errata 814
- *
+ * TI_BANDGAP_FEATURE_ERRATA_813 - used to workaorund when the bandgap device
+ *     has Errata 813
  * TI_BANDGAP_HAS(b, f) - macro to check if a bandgap device is capable of a
  *      specific feature (above) or not. Return non-zero, if yes.
  */
@@ -335,6 +336,7 @@ struct ti_temp_sensor {
 #define TI_BANDGAP_FEATURE_COUNTER_DELAY       BIT(8)
 #define TI_BANDGAP_FEATURE_HISTORY_BUFFER      BIT(9)
 #define TI_BANDGAP_FEATURE_ERRATA_814          BIT(10)
+#define TI_BANDGAP_FEATURE_ERRATA_813          BIT(11)
 #define TI_BANDGAP_HAS(b, f)                   \
                        ((b)->conf->features & TI_BANDGAP_FEATURE_ ## f)