Re: [PATCH 12/14] hwmon: peci: Add dimmtemp driver

Guenter Roeck
2021-07-15T17:56:06Z

On Tue, Jul 13, 2021 at 12:04:45AM +0200, Iwona Winiarska wrote:
> Add peci-dimmtemp driver for Digital Thermal Sensor (DTS) thermal
> readings of DIMMs that are accessible via the processor PECI interface.
>
> The main use case for the driver (and PECI interface) is out-of-band
> management, where we're able to obtain the DTS readings from an external
> entity connected with PECI, e.g. BMC on server platforms.
>
> Co-developed-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
> Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
> drivers/hwmon/peci/Kconfig | 13 +
> drivers/hwmon/peci/Makefile | 2 +
> drivers/hwmon/peci/dimmtemp.c | 508 ++++++++++++++++++++++++++++++++++
> 3 files changed, 523 insertions(+)
> create mode 100644 drivers/hwmon/peci/dimmtemp.c
>
> diff --git a/drivers/hwmon/peci/Kconfig b/drivers/hwmon/peci/Kconfig
> index e10eed68d70a..f2d57efa508b 100644
> --- a/drivers/hwmon/peci/Kconfig
> +++ b/drivers/hwmon/peci/Kconfig
> @@ -14,5 +14,18 @@ config SENSORS_PECI_CPUTEMP
> This driver can also be built as a module. If so, the module
> will be called peci-cputemp.
>
> +config SENSORS_PECI_DIMMTEMP
> + tristate "PECI DIMM temperature monitoring client"
> + depends on PECI
> + select SENSORS_PECI
> + select PECI_CPU
> + help
> + If you say yes here you get support for the generic Intel PECI hwmon
> + driver which provides Digital Thermal Sensor (DTS) thermal readings of
> + DIMM components that are accessible via the processor PECI interface.
> +
> + This driver can also be built as a module. If so, the module
> + will be called peci-dimmtemp.
> +
> config SENSORS_PECI
> tristate
> diff --git a/drivers/hwmon/peci/Makefile b/drivers/hwmon/peci/Makefile
> index e8a0ada5ab1f..191cfa0227f3 100644
> --- a/drivers/hwmon/peci/Makefile
> +++ b/drivers/hwmon/peci/Makefile
> @@ -1,5 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
>
> peci-cputemp-y := cputemp.o
> +peci-dimmtemp-y := dimmtemp.o
>
> obj-$(CONFIG_SENSORS_PECI_CPUTEMP) += peci-cputemp.o
> +obj-$(CONFIG_SENSORS_PECI_DIMMTEMP) += peci-dimmtemp.o
> diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c
> new file mode 100644
> index 000000000000..2fcb8607137a
> --- /dev/null
> +++ b/drivers/hwmon/peci/dimmtemp.c
> @@ -0,0 +1,508 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// Copyright (c) 2018-2021 Intel Corporation
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/hwmon.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +#include <linux/peci.h>
> +#include <linux/peci-cpu.h>
> +#include <linux/units.h>
> +#include <linux/workqueue.h>
> +#include <linux/x86/intel-family.h>
> +
> +#include "common.h"
> +
> +#define DIMM_MASK_CHECK_DELAY_JIFFIES msecs_to_jiffies(5000)
> +#define DIMM_MASK_CHECK_RETRY_MAX 60 /* 60 x 5 secs = 5 minutes */
> +
> +/* Max number of channel ranks and DIMM index per channel */
> +#define CHAN_RANK_MAX_ON_HSX 8
> +#define DIMM_IDX_MAX_ON_HSX 3
> +#define CHAN_RANK_MAX_ON_BDX 4
> +#define DIMM_IDX_MAX_ON_BDX 3
> +#define CHAN_RANK_MAX_ON_BDXD 2
> +#define DIMM_IDX_MAX_ON_BDXD 2
> +#define CHAN_RANK_MAX_ON_SKX 6
> +#define DIMM_IDX_MAX_ON_SKX 2
> +#define CHAN_RANK_MAX_ON_ICX 8
> +#define DIMM_IDX_MAX_ON_ICX 2
> +#define CHAN_RANK_MAX_ON_ICXD 4
> +#define DIMM_IDX_MAX_ON_ICXD 2
> +
> +#define CHAN_RANK_MAX CHAN_RANK_MAX_ON_HSX
> +#define DIMM_IDX_MAX DIMM_IDX_MAX_ON_HSX
> +#define DIMM_NUMS_MAX (CHAN_RANK_MAX * DIMM_IDX_MAX)
> +
> +#define CPU_SEG_MASK GENMASK(23, 16)
> +#define GET_CPU_SEG(x) (((x) & CPU_SEG_MASK) >> 16)
> +#define CPU_BUS_MASK GENMASK(7, 0)
> +#define GET_CPU_BUS(x) ((x) & CPU_BUS_MASK)
> +
> +#define DIMM_TEMP_MAX GENMASK(15, 8)
> +#define DIMM_TEMP_CRIT GENMASK(23, 16)
> +#define GET_TEMP_MAX(x) (((x) & DIMM_TEMP_MAX) >> 8)
> +#define GET_TEMP_CRIT(x) (((x) & DIMM_TEMP_CRIT) >> 16)
> +
> +struct dimm_info {
> + int chan_rank_max;
> + int dimm_idx_max;
> + u8 min_peci_revision;
> +};
> +
> +struct peci_dimmtemp {
> + struct peci_device *peci_dev;
> + struct device *dev;
> + const char *name;
> + const struct dimm_info *gen_info;
> + struct delayed_work detect_work;
> + struct peci_sensor_data temp[DIMM_NUMS_MAX];
> + long temp_max[DIMM_NUMS_MAX];
> + long temp_crit[DIMM_NUMS_MAX];
> + int retry_count;
> + char **dimmtemp_label;
> + DECLARE_BITMAP(dimm_mask, DIMM_NUMS_MAX);
> +};
> +
> +static u8 __dimm_temp(u32 reg, int dimm_order)
> +{
> + return (reg >> (dimm_order * 8)) & 0xff;
> +}
> +
> +static int get_dimm_temp(struct peci_dimmtemp *priv, int dimm_no)
> +{
> + int dimm_order = dimm_no % priv->gen_info->dimm_idx_max;
> + int chan_rank = dimm_no / priv->gen_info->dimm_idx_max;
> + struct peci_device *peci_dev = priv->peci_dev;
> + u8 cpu_seg, cpu_bus, dev, func;
> + u64 offset;
> + u32 data;
> + u16 reg;
> + int ret;
> +
> + if (!peci_sensor_need_update(&priv->temp[dimm_no]))
> + return 0;
> +
> + ret = peci_pcs_read(peci_dev, PECI_PCS_DDR_DIMM_TEMP, chan_rank, &data);
> + if (ret)
> + return ret;
> +

Similar to the cpu driver, the lack of mutex protection needs to be explained.

> + priv->temp[dimm_no].value = __dimm_temp(data, dimm_order) * MILLIDEGREE_PER_DEGREE;
> +
> + switch (peci_dev->info.model) {
> + case INTEL_FAM6_ICELAKE_X:
> + case INTEL_FAM6_ICELAKE_D:
> + ret = peci_ep_pci_local_read(peci_dev, 0, 13, 0, 2, 0xd4, &data);
> + if (ret || !(data & BIT(31)))
> + break; /* Use default or previous value */
> +
> + ret = peci_ep_pci_local_read(peci_dev, 0, 13, 0, 2, 0xd0, &data);
> + if (ret)
> + break; /* Use default or previous value */
> +
> + cpu_seg = GET_CPU_SEG(data);
> + cpu_bus = GET_CPU_BUS(data);
> +
> + /*
> + * Device 26, Offset 224e0: IMC 0 channel 0 -> rank 0
> + * Device 26, Offset 264e0: IMC 0 channel 1 -> rank 1
> + * Device 27, Offset 224e0: IMC 1 channel 0 -> rank 2
> + * Device 27, Offset 264e0: IMC 1 channel 1 -> rank 3
> + * Device 28, Offset 224e0: IMC 2 channel 0 -> rank 4
> + * Device 28, Offset 264e0: IMC 2 channel 1 -> rank 5
> + * Device 29, Offset 224e0: IMC 3 channel 0 -> rank 6
> + * Device 29, Offset 264e0: IMC 3 channel 1 -> rank 7
> + */
> + dev = 0x1a + chan_rank / 2;
> + offset = 0x224e0 + dimm_order * 4;
> + if (chan_rank % 2)
> + offset += 0x4000;
> +
> + ret = peci_mmio_read(peci_dev, 0, cpu_seg, cpu_bus, dev, 0, offset, &data);
> + if (ret)
> + return ret;
> +
> + priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
> + priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
> +
> + break;
> + case INTEL_FAM6_SKYLAKE_X:
> + /*
> + * Device 10, Function 2: IMC 0 channel 0 -> rank 0
> + * Device 10, Function 6: IMC 0 channel 1 -> rank 1
> + * Device 11, Function 2: IMC 0 channel 2 -> rank 2
> + * Device 12, Function 2: IMC 1 channel 0 -> rank 3
> + * Device 12, Function 6: IMC 1 channel 1 -> rank 4
> + * Device 13, Function 2: IMC 1 channel 2 -> rank 5
> + */
> + dev = 10 + chan_rank / 3 * 2 + (chan_rank % 3 == 2 ? 1 : 0);
> + func = chan_rank % 3 == 1 ? 6 : 2;
> + reg = 0x120 + dimm_order * 4;
> +
> + ret = peci_pci_local_read(peci_dev, 2, dev, func, reg, &data);
> + if (ret)
> + return ret;
> +
> + priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
> + priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
> +
> + break;
> + case INTEL_FAM6_BROADWELL_D:
> + /*
> + * Device 10, Function 2: IMC 0 channel 0 -> rank 0
> + * Device 10, Function 6: IMC 0 channel 1 -> rank 1
> + * Device 12, Function 2: IMC 1 channel 0 -> rank 2
> + * Device 12, Function 6: IMC 1 channel 1 -> rank 3
> + */
> + dev = 10 + chan_rank / 2 * 2;
> + func = (chan_rank % 2) ? 6 : 2;
> + reg = 0x120 + dimm_order * 4;
> +
> + ret = peci_pci_local_read(peci_dev, 2, dev, func, reg, &data);
> + if (ret)
> + return ret;
> +
> + priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
> + priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
> +
> + break;
> + case INTEL_FAM6_HASWELL_X:
> + case INTEL_FAM6_BROADWELL_X:
> + /*
> + * Device 20, Function 0: IMC 0 channel 0 -> rank 0
> + * Device 20, Function 1: IMC 0 channel 1 -> rank 1
> + * Device 21, Function 0: IMC 0 channel 2 -> rank 2
> + * Device 21, Function 1: IMC 0 channel 3 -> rank 3
> + * Device 23, Function 0: IMC 1 channel 0 -> rank 4
> + * Device 23, Function 1: IMC 1 channel 1 -> rank 5
> + * Device 24, Function 0: IMC 1 channel 2 -> rank 6
> + * Device 24, Function 1: IMC 1 channel 3 -> rank 7
> + */
> + dev = 20 + chan_rank / 2 + chan_rank / 4;
> + func = chan_rank % 2;
> + reg = 0x120 + dimm_order * 4;
> +
> + ret = peci_pci_local_read(peci_dev, 1, dev, func, reg, &data);
> + if (ret)
> + return ret;
> +
> + priv->temp_max[dimm_no] = GET_TEMP_MAX(data) * MILLIDEGREE_PER_DEGREE;
> + priv->temp_crit[dimm_no] = GET_TEMP_CRIT(data) * MILLIDEGREE_PER_DEGREE;
> +
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + peci_sensor_mark_updated(&priv->temp[dimm_no]);
> +
> + return 0;
> +}
> +
> +static int dimmtemp_read_string(struct device *dev,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel, const char **str)
> +{
> + struct peci_dimmtemp *priv = dev_get_drvdata(dev);
> +
> + if (attr != hwmon_temp_label)
> + return -EOPNOTSUPP;
> +
> + *str = (const char *)priv->dimmtemp_label[channel];
> +
> + return 0;
> +}
> +
> +static int dimmtemp_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + struct peci_dimmtemp *priv = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = get_dimm_temp(priv, channel);
> + if (ret)
> + return ret;
> +
> + switch (attr) {
> + case hwmon_temp_input:
> + *val = priv->temp[channel].value;
> + break;
> + case hwmon_temp_max:
> + *val = priv->temp_max[channel];
> + break;
> + case hwmon_temp_crit:
> + *val = priv->temp_crit[channel];
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static umode_t dimmtemp_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + const struct peci_dimmtemp *priv = data;
> +
> + if (test_bit(channel, priv->dimm_mask))
> + return 0444;
> +
> + return 0;
> +}
> +
> +static const struct hwmon_ops peci_dimmtemp_ops = {
> + .is_visible = dimmtemp_is_visible,
> + .read_string = dimmtemp_read_string,
> + .read = dimmtemp_read,
> +};
> +
> +static int check_populated_dimms(struct peci_dimmtemp *priv)
> +{
> + int chan_rank_max = priv->gen_info->chan_rank_max;
> + int dimm_idx_max = priv->gen_info->dimm_idx_max;
> + int chan_rank, dimm_idx, ret;
> + u64 dimm_mask = 0;
> + u32 pcs;
> +
> + for (chan_rank = 0; chan_rank < chan_rank_max; chan_rank++) {
> + ret = peci_pcs_read(priv->peci_dev, PECI_PCS_DDR_DIMM_TEMP, chan_rank, &pcs);
> + if (ret) {
> + /*
> + * Overall, we expect either success or -EINVAL in
> + * order to determine whether DIMM is populated or not.
> + * For anything else - we fall back to defering the
> + * detection to be performed at a later point in time.
> + */
> + if (ret == -EINVAL)
> + continue;
> + else

else after continue is unnecessary.

> + return -EAGAIN;
> + }
> +
> + for (dimm_idx = 0; dimm_idx < dimm_idx_max; dimm_idx++)
> + if (__dimm_temp(pcs, dimm_idx))
> + dimm_mask |= BIT(chan_rank * dimm_idx_max + dimm_idx);
> + }
> + /*
> + * It's possible that memory training is not done yet. In this case we
> + * defer the detection to be performed at a later point in time.
> + */
> + if (!dimm_mask)
> + return -EAGAIN;
> +
> + dev_dbg(priv->dev, "Scanned populated DIMMs: %#llx\n", dimm_mask);
> +
> + bitmap_from_u64(priv->dimm_mask, dimm_mask);
> +
> + return 0;
> +}
> +
> +static int create_dimm_temp_label(struct peci_dimmtemp *priv, int chan)
> +{
> + int rank = chan / priv->gen_info->dimm_idx_max;
> + int idx = chan % priv->gen_info->dimm_idx_max;
> +
> + priv->dimmtemp_label[chan] = devm_kasprintf(priv->dev, GFP_KERNEL,
> + "DIMM %c%d", 'A' + rank,
> + idx + 1);
> + if (!priv->dimmtemp_label[chan])
> + return -ENOMEM;
> +
> + return 0;
> +}
> +
> +static const u32 peci_dimmtemp_temp_channel_config[] = {
> + [0 ... DIMM_NUMS_MAX - 1] = HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT,
> + 0
> +};
> +
> +static const struct hwmon_channel_info peci_dimmtemp_temp_channel = {
> + .type = hwmon_temp,
> + .config = peci_dimmtemp_temp_channel_config,
> +};
> +
> +static const struct hwmon_channel_info *peci_dimmtemp_temp_info[] = {
> + &peci_dimmtemp_temp_channel,
> + NULL
> +};
> +
> +static const struct hwmon_chip_info peci_dimmtemp_chip_info = {
> + .ops = &peci_dimmtemp_ops,
> + .info = peci_dimmtemp_temp_info,
> +};
> +
> +static int create_dimm_temp_info(struct peci_dimmtemp *priv)
> +{
> + int ret, i, channels;
> + struct device *dev;
> +
> + ret = check_populated_dimms(priv);
> + if (ret == -EAGAIN) {

The only error returned by check_populated_dimms() is -EAGAIN. Checking for
specifically this error here suggests that there may be other (ignored)
errors. The reader has to examine check_populated_dimms() to find out
that -EAGAIN is indeed the only possible error. To avoid confusion, please
only check for ret here.

> + if (priv->retry_count < DIMM_MASK_CHECK_RETRY_MAX) {
> + schedule_delayed_work(&priv->detect_work,
> + DIMM_MASK_CHECK_DELAY_JIFFIES);
> + priv->retry_count++;
> + dev_dbg(priv->dev, "Deferred populating DIMM temp info\n");
> + return ret;
> + }
> +
> + dev_info(priv->dev, "Timeout populating DIMM temp info\n");

If this returns an error, the message needs to be dev_err().

> + return -ETIMEDOUT;
> + }
> +
> + channels = priv->gen_info->chan_rank_max * priv->gen_info->dimm_idx_max;
> +
> + priv->dimmtemp_label = devm_kzalloc(priv->dev, channels * sizeof(char *), GFP_KERNEL);
> + if (!priv->dimmtemp_label)
> + return -ENOMEM;
> +
> + for_each_set_bit(i, priv->dimm_mask, DIMM_NUMS_MAX) {
> + ret = create_dimm_temp_label(priv, i);
> + if (ret)
> + return ret;
> + }
> +
> + dev = devm_hwmon_device_register_with_info(priv->dev, priv->name, priv,
> + &peci_dimmtemp_chip_info, NULL);
> + if (IS_ERR(dev)) {
> + dev_err(priv->dev, "Failed to register hwmon device\n");
> + return PTR_ERR(dev);
> + }
> +
> + dev_dbg(priv->dev, "%s: sensor '%s'\n", dev_name(dev), priv->name);
> +
> + return 0;
> +}
> +
> +static void create_dimm_temp_info_delayed(struct work_struct *work)
> +{
> + struct peci_dimmtemp *priv = container_of(to_delayed_work(work),
> + struct peci_dimmtemp,
> + detect_work);
> + int ret;
> +
> + ret = create_dimm_temp_info(priv);
> + if (ret && ret != -EAGAIN)
> + dev_dbg(priv->dev, "Failed to populate DIMM temp info\n");
> +}
> +
> +static int peci_dimmtemp_probe(struct auxiliary_device *adev, const struct auxiliary_device_id *id)
> +{
> + struct device *dev = &adev->dev;
> + struct peci_device *peci_dev = to_peci_device(dev->parent);
> + struct peci_dimmtemp *priv;
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->name = devm_kasprintf(dev, GFP_KERNEL, "peci_dimmtemp.cpu%d",
> + peci_dev->info.socket_id);
> + if (!priv->name)
> + return -ENOMEM;
> +
> + dev_set_drvdata(dev, priv);
> + priv->dev = dev;
> + priv->peci_dev = peci_dev;
> + priv->gen_info = (const struct dimm_info *)id->driver_data;
> +
> + INIT_DELAYED_WORK(&priv->detect_work, create_dimm_temp_info_delayed);
> +
> + ret = create_dimm_temp_info(priv);
> + if (ret && ret != -EAGAIN) {
> + dev_dbg(dev, "Failed to populate DIMM temp info\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void peci_dimmtemp_remove(struct auxiliary_device *adev)
> +{
> + struct peci_dimmtemp *priv = dev_get_drvdata(&adev->dev);
> +
> + cancel_delayed_work_sync(&priv->detect_work);
> +}
> +
> +static const struct dimm_info dimm_hsx = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_HSX,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_HSX,
> + .min_peci_revision = 0x30,
> +};
> +
> +static const struct dimm_info dimm_bdx = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_BDX,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_BDX,
> + .min_peci_revision = 0x30,
> +};
> +
> +static const struct dimm_info dimm_bdxd = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_BDXD,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_BDXD,
> + .min_peci_revision = 0x30,
> +};
> +
> +static const struct dimm_info dimm_skx = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_SKX,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_SKX,
> + .min_peci_revision = 0x30,
> +};
> +
> +static const struct dimm_info dimm_icx = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_ICX,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_ICX,
> + .min_peci_revision = 0x40,
> +};
> +
> +static const struct dimm_info dimm_icxd = {
> + .chan_rank_max = CHAN_RANK_MAX_ON_ICXD,
> + .dimm_idx_max = DIMM_IDX_MAX_ON_ICXD,
> + .min_peci_revision = 0x40,
> +};
> +
> +static const struct auxiliary_device_id peci_dimmtemp_ids[] = {
> + {
> + .name = "peci_cpu.dimmtemp.hsx",
> + .driver_data = (kernel_ulong_t)&dimm_hsx,
> + },
> + {
> + .name = "peci_cpu.dimmtemp.bdx",
> + .driver_data = (kernel_ulong_t)&dimm_bdx,
> + },
> + {
> + .name = "peci_cpu.dimmtemp.bdxd",
> + .driver_data = (kernel_ulong_t)&dimm_bdxd,
> + },
> + {
> + .name = "peci_cpu.dimmtemp.skx",
> + .driver_data = (kernel_ulong_t)&dimm_skx,
> + },
> + {
> + .name = "peci_cpu.dimmtemp.icx",
> + .driver_data = (kernel_ulong_t)&dimm_icx,
> + },
> + {
> + .name = "peci_cpu.dimmtemp.icxd",
> + .driver_data = (kernel_ulong_t)&dimm_icxd,
> + },
> + { }
> +};
> +MODULE_DEVICE_TABLE(auxiliary, peci_dimmtemp_ids);
> +
> +static struct auxiliary_driver peci_dimmtemp_driver = {
> + .probe = peci_dimmtemp_probe,
> + .remove = peci_dimmtemp_remove,
> + .id_table = peci_dimmtemp_ids,
> +};
> +
> +module_auxiliary_driver(peci_dimmtemp_driver);
> +
> +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
> +MODULE_AUTHOR("Iwona Winiarska <iwona.winiarska@intel.com>");
> +MODULE_DESCRIPTION("PECI dimmtemp driver");
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(PECI_CPU);