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Message-ID: <a3e966f8-8e9d-7081-1665-9d2e87acb310@linux.intel.com>
Date:   Mon, 17 Apr 2023 15:55:31 -0500
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Subject: Re: [PATCH 3/5] hwmon: (socfpga) Add hardware monitoring support on
 SoCFPGA platforms
To:     Guenter Roeck <linux@roeck-us.net>, linux-hwmon@vger.kernel.org
Cc:     dinguyen@kernel.org, devicetree@vger.kernel.org,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-kernel@vger.kernel.org, jdelvare@suse.com,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
References: <20230410153314.27127-1-dinh.nguyen@linux.intel.com>
 <20230410153314.27127-3-dinh.nguyen@linux.intel.com>
 <09730359-8731-e21e-3335-bf60ba7f1280@roeck-us.net>
Content-Language: en-US
From:   Dinh Nguyen <dinh.nguyen@linux.intel.com>
In-Reply-To: <09730359-8731-e21e-3335-bf60ba7f1280@roeck-us.net>
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On 4/10/2023 9:44 PM, Guenter Roeck wrote:
> On 4/10/23 08:33, dinh.nguyen@linux.intel.com wrote:
>> From: Dinh Nguyen <dinh.nguyen@linux.intel.com>
>>
>> The driver supports 64-bit SoCFPGA platforms for temperature and voltage
>> reading using the platform's SDM(Secure Device Manager). The driver
>> also uses the Stratix10 Service layer driver.
>>
>> This driver only supports OF SoCFPGA 64-bit platforms.
>>
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Signed-off-by: Dinh Nguyen <dinh.nguyen@linux.intel.com>
>> ---
>>   Documentation/hwmon/index.rst                 |   1 +
>>   Documentation/hwmon/socfpga-hwmon.rst         |  30 ++
>>   drivers/firmware/stratix10-svc.c              |  18 +-
>
> Changes outside the hwmon subsystem need to be in a separate patch.

will separate...

>
>> drivers/hwmon/Kconfig                         |  11 +
>>   drivers/hwmon/Makefile                        |   1 +
>>   drivers/hwmon/socfpga-hwmon.c                 | 406 ++++++++++++++++++
>>   include/linux/firmware/intel/stratix10-smc.h  |  34 ++
>>   .../firmware/intel/stratix10-svc-client.h     |   6 +
>>   8 files changed, 506 insertions(+), 1 deletion(-)
>>   create mode 100644 Documentation/hwmon/socfpga-hwmon.rst
>>   create mode 100644 drivers/hwmon/socfpga-hwmon.c
>>
>>
...
>> +
>> +enum hwmon_type_op {
>> +    SOCFPGA_HWMON_TYPE_TEMP,
>> +    SOCFPGA_HWMON_TYPE_VOLT,
>> +    SOCFPGA_HWMON_TYPE_MAX
>
> Unused define

Removed.

>
>> +};
>> +
>> +static const char *const hwmon_types_str[] = { "temperature", 
>> "voltage" };
>> +
>> +static umode_t socfpga_is_visible(const void *dev,
>> +                  enum hwmon_sensor_types type,
>> +                  u32 attr, int chan)
>> +{
>> +    switch (type) {
>> +    case hwmon_temp:
>> +    case hwmon_in:
>> +        return 0444;
>> +    default:
>> +        return 0;
>> +    }
>> +}
>> +
>> +static void socfpga_smc_callback(struct stratix10_svc_client *client,
>> +                      struct stratix10_svc_cb_data *data)
>> +{
>> +    struct socfpga_hwmon_priv *priv = client->priv;
>> +    struct arm_smccc_res *res = data->kaddr1;
>> +
>> +    if (data->status == BIT(SVC_STATUS_OK))    {
>> +        if (priv->msg.command == COMMAND_HWMON_READTEMP)
>> +            priv->temperature.value = res->a0;
>> +        else
>> +            priv->voltage.value = res->a0;
>> +    } else
>> +        dev_err(client->dev, "%s returned 0x%lX\n", __func__, res->a0);
>> +
>
> Missing { } in else branch. Please run checkpatch --strict and fix
> continuation line alignment issues as well as unbalanced if/else
> reports.
Will do.
>
>> +    complete(&priv->completion);
>> +}
>> +
>> +static int socfpga_hwmon_send(struct socfpga_hwmon_priv *priv)
>> +{
>> +    int ret;
>> +
>> +    priv->client.receive_cb = socfpga_smc_callback;
>> +
>> +    ret = stratix10_svc_send(priv->chan, &priv->msg);
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    if (!wait_for_completion_timeout(&priv->completion, 
>> HWMON_TIMEOUT)) {
>> +        dev_err(priv->client.dev, "SMC call timeout!\n");
>> +        return -ETIMEDOUT;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int socfpga_hwmon_err_to_errno(struct socfpga_hwmon_priv *priv)
>> +{
>> +    int value = priv->temperature.value;
>> +
>> +    if (!(value & ETEMP_ERROR))
>> +        return 0;
>> +
>
> This is odd. int is normally 32 bit, this function is called from
> socfpga_read() for temperatures, which presumably are defined
> as "signed 32-bit fixed point binary". That means that negative
> temperatures would be treated as errors. Please verify.

That's correct, if bit 31 is set, then it indicates an error.

>
>> +    dev_err(priv->client.dev, "temperature sensor code 0x%08x\n", 
>> value);
>> +
>
> Please don't clog the log with such messages.

Removed.

>
>> +    value &= ~ETEMP_ERROR;
>> +    switch (value) {
>> +    case ETEMP_NOT_PRESENT:
>> +        return -ENOENT;
>> +    case ETEMP_CORRUPT:
>> +    case ETEMP_NOT_INITIALIZED:
>> +        return -ENODATA;
>> +    case ETEMP_BUSY:
>> +        return -EBUSY;
>> +    case ETEMP_INACTIVE:
>> +    case ETEMP_TIMEOUT:
>> +    case ETEMP_TOO_OLD:
>> +        return -EAGAIN;
>> +    default:
>> +        /* Unknown error */
>> +        return -EINVAL;
>
> Should be -EIO.
>
Replaced.
>> +    }
>> +}
>> +
>> +static int socfpga_read(struct device *dev, enum hwmon_sensor_types 
>> type,
>> +            u32 attr, int chan, long *val)
>> +{
>> +    struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);
>> +    int ret;
>> +
>> +    mutex_lock(&priv->lock);
>> +    reinit_completion(&priv->completion);
>> +
>> +    switch (type) {
>> +    case hwmon_temp:
>> +        priv->msg.arg[0] = BIT_ULL(priv->temperature.chan[chan]);
>> +        priv->msg.command = COMMAND_HWMON_READTEMP;
>> +        if (socfpga_hwmon_send(priv))
>> +            goto status_done;
>> +
>> +        ret = socfpga_hwmon_err_to_errno(priv);
>> +        if (ret)
>> +            break;
>> +        /*
>> +         * The Temperature Sensor IP core returns the Celsius
>> +         * temperature value in signed 32-bit fixed point binary
>> +         * format, with eight bits below binary point.
>> +         */
>> +        *val = (priv->temperature.value * MILLIDEGREE_PER_DEGREE) / 
>> 256;
>> +        break;
>> +    case hwmon_in: /* Read voltage */
>
> Pointless comment

Removed.

>
>> +        priv->msg.arg[0] = BIT_ULL(priv->voltage.chan[chan]);
>> +        priv->msg.command = COMMAND_HWMON_READVOLT;
>> +        if (socfpga_hwmon_send(priv))
>> +            goto status_done;
>> +
>
> No error check for voltage sensors ?
> Also, unless I am missing something, the error bailout leaves ret
> undefined.
>
There are no error readings for the voltage sensors specified in the 
spec. Will update

the ret value.

>> +        /*
>> +         * The Voltage Sensor IP core returns the sampled voltage
>> +         * in unsigned 32-bit fixed point binary format, with 16 bits
>> +         * below binary point.
>> +         */
>> +        *val = (priv->voltage.value * MILLIVOLT_PER_VOLT) / 65536;
>> +        break;
>> +    default:
>> +        ret = -EOPNOTSUPP;
>> +        break;
>> +    }
>> +
>> +status_done:
>> +    stratix10_svc_done(priv->chan);
>> +    mutex_unlock(&priv->lock);
>> +    return ret;
>> +}
>> +
>> +static int socfpga_read_string(struct device *dev,
>> +                   enum hwmon_sensor_types type, u32 attr,
>> +                   int chan, const char **str)
>> +{
>> +    struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);
>> +
>> +    switch (type) {
>> +    case hwmon_in:
>> +        *str = priv->voltage.names[chan];
>> +        return 0;
>> +    case hwmon_temp:
>> +        *str = priv->temperature.names[chan];
>> +        return 0;
>> +    default:
>> +        return -EOPNOTSUPP;
>> +    }
>> +}
>> +
>> +static const struct hwmon_ops socfpga_ops = {
>> +    .is_visible = socfpga_is_visible,
>> +    .read = socfpga_read,
>> +    .read_string = socfpga_read_string,
>> +};
>> +
>> +static const struct hwmon_channel_info *socfpga_info[] = {
>> +    HWMON_CHANNEL_INFO(temp,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL,
>> +        HWMON_T_INPUT | HWMON_T_LABEL, HWMON_T_INPUT | HWMON_T_LABEL),
>> +    HWMON_CHANNEL_INFO(in,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL,
>> +        HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL),
>> +    NULL
>> +};
>> +
>> +static const struct hwmon_chip_info socfpga_chip_info = {
>> +    .ops = &socfpga_ops,
>> +    .info = socfpga_info,
>> +};
>> +
>> +static int socfpga_add_channel(struct device *dev,  const char *type,
>> +                u32 val, const char *label,
>> +                struct socfpga_hwmon_priv *priv)
>> +{
>> +    int type_index;
>> +    struct socfpga_hwmon_chan *p;
>> +
>> +    type_index = match_string(hwmon_types_str, 
>> ARRAY_SIZE(hwmon_types_str), type);
>> +    switch (type_index) {
>> +    case SOCFPGA_HWMON_TYPE_TEMP:
>> +        p = &priv->temperature;
>> +        break;
>> +    case SOCFPGA_HWMON_TYPE_VOLT:
>> +        p = &priv->voltage;
>> +        break;
>> +    default:
>> +        return -ENODATA;
>> +    }
>> +    if (p->n >= SOCFPGA_HWMON_MAXSENSORS)
>> +        return -ENOSPC;
>> +
>> +    p->names[p->n] = label;
>> +    p->chan[p->n] = val;
>> +    p->n++;
>> +
>> +    return 0;
>> +}
>> +
>> +static int socfpga_probe_child_from_dt(struct device *dev,
>> +                       struct device_node *child,
>> +                       struct socfpga_hwmon_priv *priv)
>> +{
>> +    struct device_node *grandchild;
>> +    const char *label;
>> +    const char *type;
>> +    u32 val;
>> +    int ret;
>> +
>> +    if (of_property_read_string(child, "name", &type))
>> +        return dev_err_probe(dev, -EINVAL, "No type for %pOF\n", 
>> child);
>> +
>> +    for_each_child_of_node(child, grandchild) {
>> +        ret = of_property_read_u32(grandchild, "reg", &val);
>> +        if (ret)
>> +            return dev_err_probe(dev, ret, "missing reg property of 
>> %pOF\n",
>> +                         grandchild);
>> +
>> +        ret = of_property_read_string(grandchild, "label", &label);
>> +        if (ret)
>> +            return dev_err_probe(dev, ret, "missing label propoerty 
>> of %pOF\n",
>> +                         grandchild);
>> +        ret = socfpga_add_channel(dev, type, val, label, priv);
>> +        if (ret == -ENOSPC)
>> +            return dev_err_probe(dev, ret, "too many channels, only 
>> %d supported\n",
>> +                         SOCFPGA_HWMON_MAXSENSORS);
>> +    }
>> +    return 0;
>> +}
>> +
>> +static int socfpga_probe_from_dt(struct device *dev,
>> +                 struct socfpga_hwmon_priv *priv)
>> +{
>> +    const struct device_node *np = dev->of_node;
>> +    struct device_node *child;
>> +    int ret = 0;
>> +
>> +    for_each_child_of_node(np, child) {
>> +        ret = socfpga_probe_child_from_dt(dev, child, priv);
>> +        if (ret)
>> +            break;
>> +    }
>> +    of_node_put(child);
>> +
>> +    return ret;
>> +}
>> +
>> +static int socfpga_hwmon_probe(struct platform_device *pdev)
>> +{
>> +    struct device *dev = &pdev->dev;
>> +    struct device *hwmon_dev;
>> +    struct socfpga_hwmon_priv *priv;
>> +    int ret;
>> +
>> +    priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +    if (!priv)
>> +        return -ENOMEM;
>> +
>> +    priv->client.dev = dev;
>> +    priv->client.priv = priv;
>> +
>> +    ret = socfpga_probe_from_dt(dev, priv);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Unable to probe from device 
>> tree\n");
>> +
>> +    mutex_init(&priv->lock);
>> +    init_completion(&priv->completion);
>> +    hwmon_dev = devm_hwmon_device_register_with_info(dev, 
>> "socfpgahwmon",
>> +                             priv,
>> +                             &socfpga_chip_info,
>> +                             NULL);
>> +    if (IS_ERR(hwmon_dev))
>> +        return PTR_ERR(hwmon_dev);
>> +
>> +    priv->chan = stratix10_svc_request_channel_byname(&priv->client,
>> +                    SVC_CLIENT_HWMON);
>
> This is racy: hwmon attributes exist here, and priv->chan may be 
> accessed before
> it is set.

Fixed in v2.

>
>> +    if (IS_ERR(priv->chan))
>> +        return dev_err_probe(dev, PTR_ERR(priv->chan),
>> +                     "couldn't get service channel %s\n",
>> +                     SVC_CLIENT_RSU);
>> +
>> +    platform_set_drvdata(pdev, priv);
>> +
>> +    return 0;
>> +}
>> +
>> +static int socfpga_hwmon_remove(struct platform_device *pdev)
>> +{
>> +    struct socfpga_hwmon_priv *priv = platform_get_drvdata(pdev);
>> +
>> +    stratix10_svc_free_channel(priv->chan);
>
> This releases the channel before the hwmon device is released.
> Another race condition.

fixed in V2.

Thanks for the review!

Dinh