Re: [PATCH v2 2/3] hwmon: xgene: Add hwmon driver

[Hoan Tran]

Hi Guenter,

On Sat, Jul 16, 2016 at 9:35 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On 07/11/2016 05:30 PM, Hoan Tran wrote:
>>
>> This patch adds hardware temperature and power reading support for
>> APM X-Gene SoC using the mailbox communication interface.
>>
>> Signed-off-by: Hoan Tran <hotran@xxxxxxx>
>> ---
>>   Documentation/hwmon/xgene-hwmon |  30 ++
>>   drivers/hwmon/Kconfig           |   7 +
>>   drivers/hwmon/Makefile          |   1 +
>>   drivers/hwmon/xgene-hwmon.c     | 772
>> ++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 810 insertions(+)
>>   create mode 100644 Documentation/hwmon/xgene-hwmon
>>   create mode 100644 drivers/hwmon/xgene-hwmon.c
>>
>> diff --git a/Documentation/hwmon/xgene-hwmon
>> b/Documentation/hwmon/xgene-hwmon
>> new file mode 100644
>> index 0000000..6ec50ed
>> --- /dev/null
>> +++ b/Documentation/hwmon/xgene-hwmon
>> @@ -0,0 +1,30 @@
>> +Kernel driver xgene-hwmon
>> +========================
>> +
>> +Supported chips:
>> + * APM X-Gene SoC
>> +
>> +Description
>> +-----------
>> +
>> +This driver adds hardware temperature and power reading support for
>> +APM X-Gene SoC using the mailbox communication interface.
>> +For device tree, it is the standard DT mailbox.
>> +For ACPI, it is the PCC mailbox.
>> +
>> +The following sensors are supported
>> +
>> +  * Temperature
>> +    - SoC on-die temperature in milli-degree C
>> +    - Alarm when high/over temperature occurs
>> +  * Power
>> +    - CPU power in uW
>> +    - IO power in uW
>> +
>> +sysfs-Interface
>> +---------------
>> +
>> +temp0_input - SoC on-die temperature (milli-degree C)
>> +temp0_critical_alarm - An 1 would indicates on-die temperature exceeded
>> threshold
>> +power0_input - CPU power in (uW)
>> +power1_input - IO power in (uW)
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index ff94007..55218c6 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -1787,6 +1787,13 @@ config SENSORS_ULTRA45
>>           This driver provides support for the Ultra45 workstation
>> environmental
>>           sensors.
>>
>> +config SENSORS_XGENE
>> +       tristate "APM X-Gene SoC hardware monitoring driver"
>> +       depends on XGENE_SLIMPRO_MBOX || PCC
>> +       help
>> +         If you say yes here you get support for the temperature
>> +         and power sensors for APM X-Gene SoC.
>> +
>>   if ACPI
>>
>>   comment "ACPI drivers"
>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>> index 2ef5b7c..a2460dd 100644
>> --- a/drivers/hwmon/Makefile
>> +++ b/drivers/hwmon/Makefile
>> @@ -162,6 +162,7 @@ obj-$(CONFIG_SENSORS_W83L785TS)     += w83l785ts.o
>>   obj-$(CONFIG_SENSORS_W83L786NG)       += w83l786ng.o
>>   obj-$(CONFIG_SENSORS_WM831X)  += wm831x-hwmon.o
>>   obj-$(CONFIG_SENSORS_WM8350)  += wm8350-hwmon.o
>> +obj-$(CONFIG_SENSORS_XGENE)    += xgene-hwmon.o
>>
>>   obj-$(CONFIG_PMBUS)           += pmbus/
>>
>> diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
>> new file mode 100644
>> index 0000000..03917e3
>> --- /dev/null
>> +++ b/drivers/hwmon/xgene-hwmon.c
>> @@ -0,0 +1,772 @@
>> +/*
>> + * APM X-Gene SoC Hardware Monitoring Driver
>> + *
>> + * Copyright (c) 2016, Applied Micro Circuits Corporation
>> + * Author: Loc Ho <lho@xxxxxxx>
>> + *         Hoan Tran <hotran@xxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License as
>> + * published by the Free Software Foundation; either version 2 of
>> + * the License, or (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, see <http://www.gnu.org/licenses/>.
>> + *
>> + * This driver provides the following features:
>> + *  - Retrieve CPU total power (uW)
>> + *  - Retrieve IO total power (uW)
>> + *  - Retrieve SoC temperature (milli-degree C) and alarm
>> + */
>> +#include <linux/acpi.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/hwmon-sysfs.h>
>> +#include <linux/kfifo.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/mailbox_controller.h>
>> +#include <linux/mailbox_client.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <acpi/acpi_io.h>
>> +#include <acpi/pcc.h>
>> +
>
> Please order include files alphabetically.
>
>> +/* SLIMpro message defines */
>> +#define MSG_TYPE_DBG                   0
>> +#define MSG_TYPE_ERR                   7
>> +#define MSG_TYPE_PWRMGMT               9
>
>
> Are those only used in this driver ?

MSG_TYPE_DBG is used by another driver, i2c_xgene_slimpro. Others are
only used by this driver.

>
>
>> +#define MSG_TYPE(v)                    (((v) & 0xF0000000) >> 28)
>> +#define MSG_TYPE_SET(v)                        (((v) << 28) & 0xF0000000)
>> +#define MSG_SUBTYPE(v)                 (((v) & 0x0F000000) >> 24)
>> +#define MSG_SUBTYPE_SET(v)             (((v) << 24) & 0x0F000000)
>> +
>> +#define DBG_SUBTYPE_SENSOR_READ                4
>> +#define SENSOR_RD_MSG                  0x04FFE902
>> +#define SENSOR_RD_EN_ADDR(a)           ((a) & 0x000FFFFF)
>> +#define PMD_PWR_REG                    0x20
>> +#define PMD_PWR_MW_REG                 0x26
>> +#define SOC_PWR_REG                    0x21
>> +#define SOC_PWR_MW_REG                 0x27
>> +#define SOC_TEMP_REG                   0x10
>> +
>> +#define TEMP_NEGATIVE_BIT              8
>> +
>> +#define PWRMGMT_SUBTYPE_TPC            1
>> +#define TPC_ALARM                      2
>> +#define TPC_GET_ALARM                  3
>> +#define TPC_CMD(v)                     (((v) & 0x00FF0000) >> 16)
>> +#define TPC_CMD_SET(v)                 (((v) << 16) & 0x00FF0000)
>> +#define TPC_EN_MSG(hndl, cmd, type) \
>> +       (MSG_TYPE_SET(MSG_TYPE_PWRMGMT) | \
>> +       MSG_SUBTYPE_SET(hndl) | TPC_CMD_SET(cmd) | type)
>> +
>> +/* PCC defines */
>> +#define PCC_SIGNATURE_MASK             0x50424300
>> +#define PCCC_GENERATE_DB_INT           BIT(15)
>> +#define PCCS_CMD_COMPLETE              BIT(0)
>> +#define PCCS_SCI_DOORBEL               BIT(1)
>> +#define PCCS_PLATFORM_NOTIFICATION     BIT(3)
>> +/*
>> + * Arbitrary retries in case the remote processor is slow to respond
>> + * to PCC commands
>> + */
>> +#define PCC_NUM_RETRIES                        500
>> +
>> +#define ASYNC_MSG_FIFO_SIZE            16
>> +#define MBOX_OP_TIMEOUTMS              1000
>> +
>> +#define WATT_TO_mWATT(x)               ((x) * 1000)
>> +#define mWATT_TO_uWATT(x)              ((x) * 1000)
>> +#define CELSIUS_TO_mCELSIUS(x)         ((x) * 1000)
>> +
>> +#define to_xgene_hwmon_dev(cl)         \
>> +       container_of(cl, struct xgene_hwmon_dev, mbox_client)
>> +
>> +struct slimpro_resp_msg {
>> +       u32 msg;
>> +       u32 param1;
>> +       u32 param2;
>> +} __packed;
>> +
>> +struct xgene_hwmon_dev {
>> +       struct device           *dev;
>> +       struct mbox_chan        *mbox_chan;
>> +       struct mbox_client      mbox_client;
>> +       int                     mbox_idx;
>> +
>> +       spinlock_t              kfifo_lock;
>> +       struct mutex            rd_mutex;
>> +       struct completion       rd_complete;
>> +       int                     resp_pending;
>> +       struct slimpro_resp_msg sync_msg;
>> +
>> +       struct work_struct      workq;
>> +       struct kfifo_rec_ptr_1  async_msg_fifo;
>> +
>> +       struct device           *hwmon_dev;
>> +       bool                    temp_critical_alarm;
>> +
>> +       phys_addr_t             comm_base_addr;
>> +       void                    *pcc_comm_addr;
>> +       u64                     usecs_lat;
>> +};
>> +
>> +/*
>> + * This function tests and clears a bitmask then returns its old value
>> + */
>> +static u16 xgene_word_tst_and_clr(u16 *addr, u16 mask)
>> +{
>> +       u16 ret, val;
>> +
>> +       val = readw_relaxed(addr);
>> +       ret = val & mask;
>> +       val &= ~mask;
>> +       writew_relaxed(val, addr);
>> +
>> +       return ret;
>> +}
>> +
>> +static int xgene_hwmon_decode_temp(u32 val)
>
>
> The "hwmon" in the function names does not really add any value.
> I would suggest to drop it.
>
>> +{
>> +       unsigned long temp = val;
>> +
>> +       /* Convert 9 bit signed temperature to integer */
>> +       if (test_and_clear_bit(TEMP_NEGATIVE_BIT, &temp))
>> +               return (temp - 256);
>> +       else
>
>
> else after return is unnecessary.
> I would suggest to use sign_extend32(val, TEMP_NEGATIVE_BIT).

That's a good suggestion. I'll use sign_extend32().

>
>
>> +               return temp;
>> +}
>> +
>> +static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
>> +{
>> +       struct acpi_pcct_shared_memory *generic_comm_base =
>> ctx->pcc_comm_addr;
>> +       void *ptr = generic_comm_base + 1;
>> +       int rc, i;
>> +       u16 val;
>> +
>> +       mutex_lock(&ctx->rd_mutex);
>> +       init_completion(&ctx->rd_complete);
>> +       ctx->resp_pending = true;
>> +
>> +       /* Write signature for subspace */
>> +       writel_relaxed(PCC_SIGNATURE_MASK | ctx->mbox_idx,
>> +                      &generic_comm_base->signature);
>> +
>> +       /* Write to the shared command region */
>> +       writew_relaxed(MSG_TYPE(msg[0]) | PCCC_GENERATE_DB_INT,
>> +                      &generic_comm_base->command);
>> +
>> +       /* Flip CMD COMPLETE bit */
>> +       val = readw_relaxed(&generic_comm_base->status);
>> +       val &= ~PCCS_CMD_COMPLETE;
>> +       writew_relaxed(val, &generic_comm_base->status);
>> +
>> +       /* Copy the message to the PCC comm space */
>> +       for (i = 0; i < sizeof(struct slimpro_resp_msg) / 4; i++)
>> +               writel_relaxed(msg[i], ptr + i * 4);
>> +
>> +       /* Ring the doorbell */
>> +       rc = mbox_send_message(ctx->mbox_chan, msg);
>> +       if (rc < 0) {
>> +               dev_err(ctx->dev, "Mailbox send error %d\n", rc);
>> +               goto err;
>> +       }
>> +       if (!wait_for_completion_timeout(&ctx->rd_complete,
>> +
>> usecs_to_jiffies(ctx->usecs_lat))) {
>> +               dev_err(ctx->dev, "Mailbox operation timed out\n");
>> +               rc = -ETIMEDOUT;
>> +               goto err;
>> +       }
>> +
>> +       /* Check for invalid data */
>> +       if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
>> +               rc = -EINVAL;
>> +               goto err;
>> +       }
>> +
>> +       msg[0] = ctx->sync_msg.msg;
>> +       msg[1] = ctx->sync_msg.param1;
>> +       msg[2] = ctx->sync_msg.param2;
>> +
>> +err:
>> +       mbox_chan_txdone(ctx->mbox_chan, 0);
>> +       ctx->resp_pending = false;
>> +       mutex_unlock(&ctx->rd_mutex);
>> +       return rc;
>> +}
>> +
>> +static int xgene_hwmon_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
>> +{
>> +       int rc;
>> +
>> +       mutex_lock(&ctx->rd_mutex);
>> +       init_completion(&ctx->rd_complete);
>> +       ctx->resp_pending = true;
>> +
>> +       rc = mbox_send_message(ctx->mbox_chan, msg);
>> +       if (rc < 0) {
>> +               dev_err(ctx->dev, "Mailbox send error %d\n", rc);
>> +               goto err;
>> +       }
>> +
>> +       if (!wait_for_completion_timeout(&ctx->rd_complete,
>> +
>> msecs_to_jiffies(MBOX_OP_TIMEOUTMS))) {
>> +               dev_err(ctx->dev, "Mailbox operation timed out\n");
>> +               rc = -ETIMEDOUT;
>> +               goto err;
>> +       }
>> +
>> +       /* Check for invalid data */
>> +       if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
>> +               rc = -EINVAL;
>> +               goto err;
>> +       }
>> +
>> +       msg[0] = ctx->sync_msg.msg;
>> +       msg[1] = ctx->sync_msg.param1;
>> +       msg[2] = ctx->sync_msg.param2;
>> +
>> +err:
>> +       ctx->resp_pending = false;
>> +       mutex_unlock(&ctx->rd_mutex);
>> +       return rc;
>> +}
>> +
>> +static int xgene_hwmon_reg_map_rd(struct xgene_hwmon_dev *ctx, u32 addr,
>> +                                 u32 *data)
>> +{
>> +       u32 msg[3];
>> +       int rc;
>> +
>> +       msg[0] = SENSOR_RD_MSG;
>> +       msg[1] = SENSOR_RD_EN_ADDR(addr);
>> +       msg[2] = 0;
>> +
>> +       if (acpi_disabled)
>> +               rc = xgene_hwmon_rd(ctx, msg);
>> +       else
>> +               rc = xgene_hwmon_pcc_rd(ctx, msg);
>> +
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       *data = msg[1];
>> +
>> +       return rc;
>> +}
>> +
>> +static int xgene_hwmon_get_notification_msg(struct xgene_hwmon_dev *ctx,
>> +                                           u32 *amsg)
>> +{
>> +       u32 msg[3];
>> +       int rc;
>> +
>> +       msg[0] = TPC_EN_MSG(PWRMGMT_SUBTYPE_TPC, TPC_GET_ALARM, 0);
>> +       msg[1] = 0;
>> +       msg[2] = 0;
>> +
>> +       rc = xgene_hwmon_pcc_rd(ctx, msg);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       amsg[0] = msg[0];
>> +       amsg[1] = msg[1];
>> +       amsg[2] = msg[2];
>> +
>> +       return rc;
>> +}
>> +
>> +static int xgene_hwmon_get_cpu_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
>> +{
>> +       u32 watt, mwatt;
>> +       int rc;
>> +
>> +       rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_REG, &watt);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_MW_REG, &mwatt);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       *val = WATT_TO_mWATT(watt) + mwatt;
>> +       return 0;
>> +}
>> +
>> +static int xgene_hwmon_get_io_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
>> +{
>> +       u32 watt, mwatt;
>> +       int rc;
>> +
>> +       rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_REG, &watt);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_MW_REG, &mwatt);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       *val = WATT_TO_mWATT(watt) + mwatt;
>> +       return 0;
>> +}
>> +
>> +static int xgene_hwmon_get_temp(struct xgene_hwmon_dev *ctx, u32 *val)
>> +{
>> +       return xgene_hwmon_reg_map_rd(ctx, SOC_TEMP_REG, val);
>> +}
>> +
>> +/*
>> + * Sensor temperature/power functions
>> + */
>> +static ssize_t xgene_hwmon_show_temp(struct device *dev,
>> +                                    struct device_attribute *attr,
>> +                                    char *buf)
>> +{
>> +       struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
>> +       int rc, temp;
>> +       u32 val;
>> +
>> +       rc = xgene_hwmon_get_temp(ctx, &val);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       temp = xgene_hwmon_decode_temp(val);
>> +
>> +       return snprintf(buf, PAGE_SIZE, "%d\n",
>> CELSIUS_TO_mCELSIUS(temp));
>> +}
>> +
>> +static ssize_t xgene_hwmon_show_temp_label(struct device *dev,
>> +                                          struct device_attribute *attr,
>> +                                          char *buf)
>> +{
>> +       return snprintf(buf, PAGE_SIZE, "SoC Temperature\n");
>> +}
>> +
>> +static ssize_t
>> +xgene_hwmon_show_temp_critical_alarm(struct device *dev,
>> +                                    struct device_attribute *devattr,
>> +                                    char *buf)
>> +{
>> +       struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
>> +
>> +       return snprintf(buf, PAGE_SIZE, "%d\n", ctx->temp_critical_alarm);
>> +}
>> +
>> +
>> +static ssize_t xgene_hwmon_show_cpu_pwr_label(struct device *dev,
>> +                                             struct device_attribute
>> *attr,
>> +                                             char *buf)
>> +{
>> +       return snprintf(buf, PAGE_SIZE, "CPU power\n");
>> +}
>> +
>> +static ssize_t xgene_hwmon_show_io_pwr_label(struct device *dev,
>> +                                             struct device_attribute
>> *attr,
>> +                                             char *buf)
>> +{
>> +       return snprintf(buf, PAGE_SIZE, "IO power\n");
>> +}
>> +
>> +static ssize_t xgene_hwmon_show_cpu_pwr(struct device *dev,
>> +                                       struct device_attribute *attr,
>> +                                       char *buf)
>> +{
>> +       struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
>> +       u32 val;
>> +       int rc;
>> +
>> +       rc = xgene_hwmon_get_cpu_pwr(ctx, &val);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
>> +}
>> +
>> +static ssize_t xgene_hwmon_show_io_pwr(struct device *dev,
>> +                                      struct device_attribute *attr,
>> +                                      char *buf)
>> +{
>> +       struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
>> +       u32 val;
>> +       int rc;
>> +
>> +       rc = xgene_hwmon_get_io_pwr(ctx, &val);
>> +       if (rc < 0)
>> +               return rc;
>> +
>> +       return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
>> +}
>> +
>> +static SENSOR_DEVICE_ATTR(temp0_label, S_IRUGO,
>> xgene_hwmon_show_temp_label,
>> +                         NULL, 0);
>> +static SENSOR_DEVICE_ATTR(temp0_input, S_IRUGO, xgene_hwmon_show_temp,
>> +                         NULL, 0);
>> +static SENSOR_DEVICE_ATTR(temp0_critical_alarm, S_IRUGO,
>> +                         xgene_hwmon_show_temp_critical_alarm, NULL, 0);
>> +
>> +static SENSOR_DEVICE_ATTR(power0_label, S_IRUGO,
>> +                         xgene_hwmon_show_cpu_pwr_label, NULL, 0);
>> +static SENSOR_DEVICE_ATTR(power0_input, S_IRUGO,
>> xgene_hwmon_show_cpu_pwr,
>> +                         NULL, 0);
>> +
>> +static SENSOR_DEVICE_ATTR(power1_label, S_IRUGO,
>> +                         xgene_hwmon_show_io_pwr_label, NULL, 1);
>> +static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, xgene_hwmon_show_io_pwr,
>> +                         NULL, 1);
>> +
>
>
> Temperature and power attributes start with index 1. You don't use the index
> value in
> SENSOR_DEVICE_ATTR(), so DEVCIE_ATTR_RO() might be a better choice.

Yes, I'll use DEVICE_ATTR_RO() and start with index 1.

>
>> +static struct attribute *xgene_hwmon_attrs[] = {
>> +       &sensor_dev_attr_temp0_label.dev_attr.attr,
>> +       &sensor_dev_attr_temp0_input.dev_attr.attr,
>> +       &sensor_dev_attr_temp0_critical_alarm.dev_attr.attr,
>> +       &sensor_dev_attr_power0_label.dev_attr.attr,
>> +       &sensor_dev_attr_power0_input.dev_attr.attr,
>> +       &sensor_dev_attr_power1_label.dev_attr.attr,
>> +       &sensor_dev_attr_power1_input.dev_attr.attr,
>> +       NULL,
>> +};
>> +ATTRIBUTE_GROUPS(xgene_hwmon);
>> +
>> +static int xgene_hwmon_tpc_alarm(struct xgene_hwmon_dev *ctx,
>> +                                struct slimpro_resp_msg *amsg)
>> +{
>> +       char name[40];
>> +
>> +       ctx->temp_critical_alarm = amsg->param2 ? true : false;
>
>
> You could use !!amsg->param2, or simply rely on the compiler and C standard
> to auto-convert the integer to boolean.
>
>> +       snprintf(name, sizeof(name), "temp0_critical_alarm");
>> +       sysfs_notify(&ctx->dev->kobj, NULL, name);
>
>
> Why not just use "temp0_critical_alarm" (or rather "temp1_critical_alarm")
> as parameter to sysfs_notify() ?
>
>
>> +
>> +       return 0;
>> +}
>> +
>> +static void xgene_hwmon_process_pwrmsg(struct xgene_hwmon_dev *ctx,
>> +                                      struct slimpro_resp_msg *amsg)
>> +{
>> +       if ((MSG_SUBTYPE(amsg->msg) == PWRMGMT_SUBTYPE_TPC) &&
>> +           (TPC_CMD(amsg->msg) == TPC_ALARM))
>> +               xgene_hwmon_tpc_alarm(ctx, amsg);
>> +}
>> +
>> +/*
>> + * This function is called to process async work queue
>> + */
>> +static void xgene_hwmon_evt_work(struct work_struct *work)
>> +{
>> +       struct slimpro_resp_msg amsg;
>> +       struct xgene_hwmon_dev *ctx;
>> +       int ret;
>> +
>> +       ctx = container_of(work, struct xgene_hwmon_dev, workq);
>> +       while (kfifo_out_spinlocked(&ctx->async_msg_fifo, &amsg,
>> +                                   sizeof(struct slimpro_resp_msg),
>> +                                   &ctx->kfifo_lock)) {
>> +               /*
>> +                * If PCC, send a consumer command to Platform to get info
>> +                * If Slimpro Mailbox, get message from specific FIFO
>> +                */
>> +               if (!acpi_disabled) {
>> +                       ret = xgene_hwmon_get_notification_msg(ctx,
>> +                                                              (u32
>> *)&amsg);
>> +                       if (ret < 0)
>> +                               continue;
>> +               }
>> +
>> +               if (MSG_TYPE(amsg.msg) == MSG_TYPE_PWRMGMT)
>> +                       xgene_hwmon_process_pwrmsg(ctx, &amsg);
>> +       }
>> +}
>> +
>> +/*
>> + * This function is called when the SLIMpro Mailbox received a message
>> + */
>> +static void xgene_hwmon_rx_cb(struct mbox_client *cl, void *msg)
>> +{
>> +       struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
>> +       struct slimpro_resp_msg amsg;
>> +
>> +       /*
>> +        * Response message format:
>> +        * msg[0] is the return code of the operation
>> +        * msg[1] is the first parameter word
>> +        * msg[2] is the second parameter word
>> +        *
>> +        * As message only supports dword size, just assign it.
>> +        */
>> +
>> +       /* Check for sync query */
>> +       if (ctx->resp_pending &&
>> +           ((MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_ERR) ||
>> +            (MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_DBG &&
>> +             MSG_SUBTYPE(((u32 *) msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
>> +            (MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_PWRMGMT &&
>> +             MSG_SUBTYPE(((u32 *) msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
>> +             TPC_CMD(((u32 *) msg)[0]) == TPC_ALARM))) {
>> +               ctx->sync_msg.msg = ((u32 *) msg)[0];
>> +               ctx->sync_msg.param1 = ((u32 *) msg)[1];
>> +               ctx->sync_msg.param2 = ((u32 *) msg)[2];
>> +
>> +               /* Operation waiting for response */
>> +               complete(&ctx->rd_complete);
>> +
>> +               return;
>> +       }
>> +
>> +       amsg.msg   = ((u32 *) msg)[0];
>> +       amsg.param1 = ((u32 *) msg)[1];
>> +       amsg.param2 = ((u32 *) msg)[2];
>> +
>> +       /* Enqueue to the FIFO */
>> +       kfifo_in_spinlocked(&ctx->async_msg_fifo, &amsg,
>> +                           sizeof(struct slimpro_resp_msg),
>> &ctx->kfifo_lock);
>> +       /* Schedule the bottom handler */
>> +       schedule_work(&ctx->workq);
>> +}
>> +
>> +/*
>> + * This function is called when the PCC Mailbox received a message
>> + */
>> +static void xgene_hwmon_pcc_rx_cb(struct mbox_client *cl, void *msg)
>> +{
>> +       struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
>> +       struct acpi_pcct_shared_memory *generic_comm_base =
>> ctx->pcc_comm_addr;
>> +       struct slimpro_resp_msg amsg;
>> +
>> +       msg = generic_comm_base + 1;
>> +       /* Check if platform sends interrupt */
>> +       if (!xgene_word_tst_and_clr(&generic_comm_base->status,
>> +                                   PCCS_SCI_DOORBEL))
>> +               return;
>> +
>> +       /*
>> +        * Response message format:
>> +        * msg[0] is the return code of the operation
>> +        * msg[1] is the first parameter word
>> +        * msg[2] is the second parameter word
>> +        *
>> +        * As message only supports dword size, just assign it.
>> +        */
>> +
>> +       /* Check for sync query */
>> +       if (ctx->resp_pending &&
>> +           ((MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_ERR) ||
>> +            (MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_DBG &&
>> +             MSG_SUBTYPE(((u32 *) msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
>> +            (MSG_TYPE(((u32 *) msg)[0]) == MSG_TYPE_PWRMGMT &&
>> +             MSG_SUBTYPE(((u32 *) msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
>> +             TPC_CMD(((u32 *) msg)[0]) == TPC_ALARM))) {
>> +
>> +               /* Check if platform completes command */
>> +               if (xgene_word_tst_and_clr(&generic_comm_base->status,
>> +                                           PCCS_CMD_COMPLETE)) {
>> +                       ctx->sync_msg.msg = ((u32 *) msg)[0];
>> +                       ctx->sync_msg.param1 = ((u32 *) msg)[1];
>> +                       ctx->sync_msg.param2 = ((u32 *) msg)[2];
>> +
>> +                       /* Operation waiting for response */
>> +                       complete(&ctx->rd_complete);
>> +
>> +                       return;
>> +               }
>> +       }
>> +
>> +       /*
>> +        * Platform notifies interrupt to OSPM.
>> +        * OPSM schedules a consumer command to get this information
>> +        * in a workqueue. Platform must wait until OSPM has issued
>> +        * a consumer command that serves this notification.
>> +        */
>> +
>> +       /* Enqueue to the FIFO */
>> +       kfifo_in_spinlocked(&ctx->async_msg_fifo, &amsg,
>> +                           sizeof(struct slimpro_resp_msg),
>> &ctx->kfifo_lock);
>> +       /* Schedule the bottom handler */
>> +       schedule_work(&ctx->workq);
>> +}
>> +
>> +static void xgene_hwmon_tx_done(struct mbox_client *cl, void *msg, int
>> ret)
>> +{
>> +       if (ret) {
>> +               dev_dbg(cl->dev, "TX did not complete: CMD sent:%x,
>> ret:%d\n",
>> +                       *(u16 *) msg, ret);
>> +       } else {
>> +               dev_dbg(cl->dev, "TX completed. CMD sent:%x, ret:%d\n",
>> +                       *(u16 *) msg, ret);
>
>
> Please run your patch through checkoatch --strict. I would like to see
> at least the following messages resolved.
>
> "No space is necessary after a cast"
> "Blank lines aren't necessary after an open brace '{'"
> "Please don't use multiple blank lines"
> "Alignment should match open parenthesis"
> "line over 80 characters" (with precedence over continuation line alignment)
>
>
>> +       }
>> +}
>> +
>> +static int xgene_hwmon_probe(struct platform_device *pdev)
>> +{
>> +       struct xgene_hwmon_dev *ctx;
>> +       struct mbox_client *cl;
>> +       int rc;
>> +
>> +       ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
>> +       if (!ctx)
>> +               return -ENOMEM;
>> +
>> +       ctx->dev = &pdev->dev;
>> +       platform_set_drvdata(pdev, ctx);
>> +       cl = &ctx->mbox_client;
>> +
>> +       /* Request mailbox channel */
>> +       cl->dev = &pdev->dev;
>> +       cl->tx_done = xgene_hwmon_tx_done;
>> +       cl->tx_block = false;
>> +       cl->tx_tout = MBOX_OP_TIMEOUTMS;
>> +       cl->knows_txdone = false;
>> +       if (acpi_disabled) {
>> +               cl->rx_callback = xgene_hwmon_rx_cb;
>> +               ctx->mbox_chan = mbox_request_channel(cl, 0);
>> +               if (IS_ERR(ctx->mbox_chan)) {
>> +                       dev_err(&pdev->dev,
>> +                               "SLIMpro mailbox channel request
>> failed\n");
>> +                       return -ENODEV;
>> +               }
>> +       } else {
>> +               struct acpi_pcct_hw_reduced *cppc_ss;
>> +
>> +               if (device_property_read_u32(&pdev->dev, "pcc-channel",
>> +                                            &ctx->mbox_idx)) {
>> +                       dev_err(&pdev->dev, "no pcc-channel property\n");
>> +                       return -ENODEV;
>> +               }
>> +
>> +               cl->rx_callback = xgene_hwmon_pcc_rx_cb;
>> +               ctx->mbox_chan = pcc_mbox_request_channel(cl,
>> ctx->mbox_idx);
>> +               if (IS_ERR(ctx->mbox_chan)) {
>> +                       dev_err(&pdev->dev,
>> +                               "PPC channel request failed\n");
>> +                       return -ENODEV;
>> +               }
>> +
>> +               /*
>> +                * The PCC mailbox controller driver should
>> +                * have parsed the PCCT (global table of all
>> +                * PCC channels) and stored pointers to the
>> +                * subspace communication region in con_priv.
>> +                */
>> +               cppc_ss = ctx->mbox_chan->con_priv;
>> +               if (!cppc_ss) {
>> +                       dev_err(&pdev->dev, "PPC subspace not found\n");
>> +                       rc = -ENODEV;
>> +                       goto out_mbox_free;
>> +               }
>> +
>> +               if (!ctx->mbox_chan->mbox->txdone_irq) {
>> +                       dev_err(&pdev->dev, "PCC IRQ not supported\n");
>> +                       rc = -ENODEV;
>> +                       goto out_mbox_free;
>> +               }
>> +
>> +               /*
>> +                * This is the shared communication region
>> +                * for the OS and Platform to communicate over.
>> +                */
>> +               ctx->comm_base_addr = cppc_ss->base_address;
>> +               if (ctx->comm_base_addr) {
>> +                       ctx->pcc_comm_addr =
>> +
>> acpi_os_ioremap(ctx->comm_base_addr,
>> +                                                       cppc_ss->length);
>> +               } else {
>> +                       dev_err(&pdev->dev, "Failed to get PCC comm
>> region\n");
>> +                       rc = -ENODEV;
>> +                       goto out_mbox_free;
>> +               }
>> +
>> +               if (!ctx->pcc_comm_addr) {
>> +                       dev_err(&pdev->dev,
>> +                               "Failed to ioremap PCC comm region\n");
>> +                       rc = -ENOMEM;
>> +                       goto out_mbox_free;
>> +               }
>> +
>> +               /*
>> +                * cppc_ss->latency is just a Nominal value. In reality
>> +                * the remote processor could be much slower to reply.
>> +                * So add an arbitrary amount of wait on top of Nominal.
>> +                */
>> +               ctx->usecs_lat = PCC_NUM_RETRIES * cppc_ss->latency;
>> +       }
>> +
>> +       spin_lock_init(&ctx->kfifo_lock);
>> +       mutex_init(&ctx->rd_mutex);
>> +
>> +       rc = kfifo_alloc(&ctx->async_msg_fifo,
>> +                        sizeof(struct slimpro_resp_msg) *
>> ASYNC_MSG_FIFO_SIZE,
>> +                        GFP_KERNEL);
>> +       if (rc)
>> +               goto out_mbox_free;
>> +
>> +       INIT_WORK(&ctx->workq, xgene_hwmon_evt_work);
>> +
>> +       ctx->hwmon_dev = devm_hwmon_device_register_with_groups(ctx->dev,
>> +
>> "apm_xgene",
>> +                                                               ctx,
>> +
>> xgene_hwmon_groups);
>
>
> Using the devm_ function here would, on remove, result in the mailbox and
> kfifo
> being removed before the hwmon driver is removed. This might result in race
> conditions. You have two options: Use devm_add_action() to remove those in
> sequence,
> or use hwmon_device_register_with_groups() and remove the hwmon device
> explicitly
> (and first) in the remove function.

Yes, I'll use hwmon_device_register_with_groups().

Thanks
Hoan

>
> Note that you don't have to store hwmon_dev in ctx if you use
> devm_add_action()
> and devm_hwmon_device_register_with_groups().
>
>
>> +       if (IS_ERR(ctx->hwmon_dev)) {
>> +               dev_err(&pdev->dev, "Failed to register HW monitor
>> device\n");
>> +               rc = PTR_ERR(ctx->hwmon_dev);
>> +               goto out;
>> +       }
>> +
>> +       dev_info(&pdev->dev, "APM X-Gene SoC HW monitor driver
>> registered\n");
>> +
>> +       return rc;
>> +
>> +out:
>> +       kfifo_free(&ctx->async_msg_fifo);
>> +out_mbox_free:
>> +       if (acpi_disabled)
>> +               mbox_free_channel(ctx->mbox_chan);
>> +       else
>> +               pcc_mbox_free_channel(ctx->mbox_chan);
>> +
>> +       return rc;
>> +}
>> +
>> +static int xgene_hwmon_remove(struct platform_device *pdev)
>> +{
>> +       struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
>> +
>> +       kfifo_free(&ctx->async_msg_fifo);
>> +       if (acpi_disabled)
>> +               mbox_free_channel(ctx->mbox_chan);
>> +       else
>> +               pcc_mbox_free_channel(ctx->mbox_chan);
>> +
>> +       return 0;
>> +}
>> +
>> +#ifdef CONFIG_ACPI
>> +static const struct acpi_device_id xgene_hwmon_acpi_match[] = {
>> +       {"APMC0D29", 0},
>> +       {},
>> +};
>> +MODULE_DEVICE_TABLE(acpi, xgene_hwmon_acpi_match);
>> +#endif
>> +
>> +static const struct of_device_id xgene_hwmon_of_match[] = {
>> +       {.compatible = "apm,xgene-slimpro-hwmon"},
>> +       {}
>> +};
>> +MODULE_DEVICE_TABLE(of, xgene_hwmon_of_match);
>> +
>> +static struct platform_driver xgene_hwmon_driver __refdata = {
>> +       .probe = xgene_hwmon_probe,
>> +       .remove = xgene_hwmon_remove,
>> +       .driver = {
>> +               .name = "xgene-slimpro-hwmon",
>> +               .of_match_table = xgene_hwmon_of_match,
>> +               .acpi_match_table = ACPI_PTR(xgene_hwmon_acpi_match),
>> +       },
>> +};
>> +module_platform_driver(xgene_hwmon_driver);
>> +
>> +MODULE_DESCRIPTION("APM X-Gene SoC hardware monitor");
>> +MODULE_LICENSE("GPL");
>>
>