Re: [PATCH] thermal: qoriq: Only enable sites that actually exist

From: Daniel Lezcano
Date: Tue Nov 30 2021 - 10:17:32 EST



Hi Sebastian,

thanks for the fix.

On 29/11/2021 12:02, Sebastian Krzyszkowiak wrote:
> On i.MX8MQ, enabling monitoring sites that aren't connected to anything
> can cause unwanted side effects on some units. This seems to happen
> once some of these sites report out-of-range readings and results in
> sensor misbehavior, such as thermal zone readings getting stuck or even
> suddenly reporting an impossibly high value, triggering emergency
> shutdowns.
>
> The datasheet lists all non-existent sites as "reserved" and doesn't
> make any guarantees about being able to enable them at all, so let's
> not do that.

The description of what does the patch is missing here.

> Fixes: 45038e03d633 ("thermal: qoriq: Enable all sensors before registering them")
>
> Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@xxxxxxx>
> ---
> drivers/thermal/qoriq_thermal.c | 63 ++++++++++++++++++++++-----------
> 1 file changed, 43 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
> index 73049f9bea25..ef0848849ee2 100644
> --- a/drivers/thermal/qoriq_thermal.c
> +++ b/drivers/thermal/qoriq_thermal.c
> @@ -32,7 +32,6 @@
> #define TMR_DISABLE 0x0
> #define TMR_ME 0x80000000
> #define TMR_ALPF 0x0c000000
> -#define TMR_MSITE_ALL GENMASK(15, 0)
>
> #define REGS_TMTMIR 0x008 /* Temperature measurement interval Register */
> #define TMTMIR_DEFAULT 0x0000000f
> @@ -129,33 +128,51 @@ static const struct thermal_zone_of_device_ops tmu_tz_ops = {
> static int qoriq_tmu_register_tmu_zone(struct device *dev,
> struct qoriq_tmu_data *qdata)
> {
> - int id;
> + int ret = 0;
> + struct device_node *np, *child, *sensor_np;
>
> - if (qdata->ver == TMU_VER1) {
> - regmap_write(qdata->regmap, REGS_TMR,
> - TMR_MSITE_ALL | TMR_ME | TMR_ALPF);
> - } else {
> - regmap_write(qdata->regmap, REGS_V2_TMSR, TMR_MSITE_ALL);
> - regmap_write(qdata->regmap, REGS_TMR, TMR_ME | TMR_ALPF_V2);
> - }
> + np = of_find_node_by_name(NULL, "thermal-zones");
> + if (!np)
> + return -ENODEV;
> +
> + sensor_np = of_node_get(dev->of_node);
>
> - for (id = 0; id < SITES_MAX; id++) {
> + for_each_available_child_of_node(np, child) {
> struct thermal_zone_device *tzd;
> - struct qoriq_sensor *sensor = &qdata->sensor[id];
> - int ret;
> + struct qoriq_sensor *sensor;
> + int id, site;
> +
> + ret = thermal_zone_of_get_sensor_id(child, sensor_np, &id);
> +
> + if (ret < 0) {
> + dev_err(dev, "failed to get valid sensor id: %d\n", ret);
> + of_node_put(child);
> + break;
> + }
>
> + sensor = &qdata->sensor[id];
> sensor->id = id;
>
> + /* Enable monitoring */
> + if (qdata->ver == TMU_VER1) {
> + site = 0x1 << (15 - id);
> + regmap_update_bits(qdata->regmap, REGS_TMR,
> + site | TMR_ME | TMR_ALPF,
> + site | TMR_ME | TMR_ALPF);
> + } else {
> + site = 0x1 << id;
> + regmap_update_bits(qdata->regmap, REGS_V2_TMSR, site, site);
> + regmap_write(qdata->regmap, REGS_TMR, TMR_ME | TMR_ALPF_V2);
> + }

Why not create the site mask in the loop and then call once the block
above out this loop?

> tzd = devm_thermal_zone_of_sensor_register(dev, id,
> sensor,
> &tmu_tz_ops);
> - ret = PTR_ERR_OR_ZERO(tzd);
> - if (ret) {
> - if (ret == -ENODEV)
> - continue;
> -
> - regmap_write(qdata->regmap, REGS_TMR, TMR_DISABLE);
> - return ret;
> + if (IS_ERR(tzd)) {
> + ret = PTR_ERR(tzd);
> + dev_err(dev, "failed to register thermal zone: %d\n", ret);
> + of_node_put(child);
> + break;
> }
>
> if (devm_thermal_add_hwmon_sysfs(tzd))
> @@ -164,7 +181,13 @@ static int qoriq_tmu_register_tmu_zone(struct device *dev,
>
> }
>
> - return 0;
> + of_node_put(sensor_np);
> + of_node_put(np);
> +
> + if (ret)
> + regmap_write(qdata->regmap, REGS_TMR, TMR_DISABLE);
> +
> + return ret;
> }
>
> static int qoriq_tmu_calibration(struct device *dev,
>


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