On Wed, Apr 22, 2015 at 06:21:42PM +0530, Keerthy wrote:
> 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.
>
applying to my -fixes branch. next time, please make sure you have the
correct linux-pm address so we can track the patch in our patchwork.
BR,
Eduardo Valentin
> Signed-off-by: Keerthy <j-keerthy@xxxxxx>
> ---
> .../thermal/ti-soc-thermal/omap5-thermal-data.c | 3 +-
> drivers/thermal/ti-soc-thermal/ti-bandgap.c | 41 +++++++++++++++++++++-
> drivers/thermal/ti-soc-thermal/ti-bandgap.h | 4 ++-
> 3 files changed, 45 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c b/drivers/thermal/ti-soc-thermal/omap5-thermal-data.c
> index eff0c80..79ff70c 100644
> --- 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 8fdddb6..08a2155 100644
> --- 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 b2da3fc..0c52f7a 100644
> --- 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)
>
> --
> 1.9.1
>
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