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Message-ID: <8d158880-1e6a-5fdd-dae7-a7647794eb60@roeck-us.net>
Date: Mon, 17 Apr 2023 14:51:12 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Dinh Nguyen <dinh.nguyen@...ux.intel.com>,
linux-hwmon@...r.kernel.org
Cc: dinguyen@...nel.org, devicetree@...r.kernel.org,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
linux-kernel@...r.kernel.org, jdelvare@...e.com,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 3/5] hwmon: (socfpga) Add hardware monitoring support on
SoCFPGA platforms
On 4/17/23 13:55, Dinh Nguyen wrote:
>
> On 4/10/2023 9:44 PM, Guenter Roeck wrote:
>> On 4/10/23 08:33, dinh.nguyen@...ux.intel.com wrote:
>>> From: Dinh Nguyen <dinh.nguyen@...ux.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@...ux.intel.com>
>>> Signed-off-by: Dinh Nguyen <dinh.nguyen@...ux.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.
>
This ...
>>
>>> + 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
... and this contradict each other. If bit 31 indicates an error,
this can not be a signed 32-bit value.
Guenter
>>> + * 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
>
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