Re: [PATCH v2 13/15] hwmon: peci: Add dimmtemp driver

["Winiarska, Iwona" <iwona.winiarska@intel.com>]

On Tue, 2021-08-03 at 08:39 -0700, Guenter Roeck wrote:
> On Tue, Aug 03, 2021 at 01:31:32PM +0200, Iwona Winiarska wrote:
> > Add peci-dimmtemp driver for Temperature Sensor on DIMM readings 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 thermal 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>
> > ---
> > Note that the timeout was completely removed - we're going to probe
> > for detected DIMMs every 5 seconds until we reach "stable" state of
> > either getting correct DIMM data or getting all -EINVAL (which
> > suggest that the CPU doesn't have any DIMMs).
> > 
> >  drivers/hwmon/peci/Kconfig    |  13 +
> >  drivers/hwmon/peci/Makefile   |   2 +
> >  drivers/hwmon/peci/dimmtemp.c | 614 ++++++++++++++++++++++++++++++++++
> >  3 files changed, 629 insertions(+)
> >  create mode 100644 drivers/hwmon/peci/dimmtemp.c
> > 
> > diff --git a/drivers/hwmon/peci/Kconfig b/drivers/hwmon/peci/Kconfig
> > index e10eed68d70a..9d32a57badfe 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 Temperature Sensor on DIMM readings 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..6264c29bb6c0
> > --- /dev/null
> > +++ b/drivers/hwmon/peci/dimmtemp.c
> > @@ -0,0 +1,614 @@
> > +// 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)
> > +
> > +/* 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 peci_dimmtemp;
> > +
> > +struct dimm_info {
> > +       int chan_rank_max;
> > +       int dimm_idx_max;
> > +       u8 min_peci_revision;
> > +       int (*read_thresholds)(struct peci_dimmtemp *priv, int dimm_order,
> > +                              int chan_rank, u32 *data);
> > +};
> > +
> > +struct peci_dimm_thresholds {
> > +       long temp_max;
> > +       long temp_crit;
> > +       struct peci_sensor_state state;
> > +};
> > +
> > +enum peci_dimm_threshold_type {
> > +       temp_max_type,
> > +       temp_crit_type,
> > +};
> > +
> > +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 {
> > +               struct peci_sensor_data temp;
> > +               struct peci_dimm_thresholds thresholds;
> > +       } dimm[DIMM_NUMS_MAX];
> > +       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, long
> > *val)
> > +{
> > +       int dimm_order = dimm_no % priv->gen_info->dimm_idx_max;
> > +       int chan_rank = dimm_no / priv->gen_info->dimm_idx_max;
> > +       u32 data;
> > +       int ret;
> 
>         int ret = 0;
> 
> > +
> > +       mutex_lock(&priv->dimm[dimm_no].temp.state.lock);
> > +       if (!peci_sensor_need_update(&priv->dimm[dimm_no].temp.state))
> > +               goto skip_update;
> > +
> > +       ret = peci_pcs_read(priv->peci_dev, PECI_PCS_DDR_DIMM_TEMP,
> > chan_rank, &data);
> > +       if (ret) {
> > +               mutex_unlock(&priv->dimm[dimm_no].temp.state.lock);
> > +               return ret;
> > +       }
> 
>         if (ret)
>                 goto unlock;
> 
> > +
> > +       priv->dimm[dimm_no].temp.value = __dimm_temp(data, dimm_order) *
> > MILLIDEGREE_PER_DEGREE;
> > +
> > +       peci_sensor_mark_updated(&priv->dimm[dimm_no].temp.state);
> > +
> > +skip_update:
> > +       *val = priv->dimm[dimm_no].temp.value;
> 
> unlock:
> > +       mutex_unlock(&priv->dimm[dimm_no].temp.state.lock);
> > +       return 0;
> 
>         return ret;

Ack.

> 
> > +}
> > +
> > +static int update_thresholds(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;
> > +       u32 data;
> > +       int ret;
> > +
> > +       if (!peci_sensor_need_update(&priv->dimm[dimm_no].thresholds.state))
> > +               return 0;
> > +
> > +       ret = priv->gen_info->read_thresholds(priv, dimm_order, chan_rank,
> > &data);
> > +       if (ret == -ENODATA) /* Use default or previous value */
> > +               return 0;
> > +       if (ret)
> > +               return ret;
> > +
> > +       priv->dimm[dimm_no].thresholds.temp_max = GET_TEMP_MAX(data) *
> > MILLIDEGREE_PER_DEGREE;
> > +       priv->dimm[dimm_no].thresholds.temp_crit = GET_TEMP_CRIT(data) *
> > MILLIDEGREE_PER_DEGREE;
> > +
> > +       peci_sensor_mark_updated(&priv->dimm[dimm_no].thresholds.state);
> > +
> > +       return 0;
> > +}
> > +
> > +static int get_dimm_thresholds(struct peci_dimmtemp *priv, enum
> > peci_dimm_threshold_type type,
> > +                              int dimm_no, long *val)
> > +{
> > +       int ret;
> > +
> > +       mutex_lock(&priv->dimm[dimm_no].thresholds.state.lock);
> > +       ret = update_thresholds(priv, dimm_no);
> > +       if (ret)
> > +               goto unlock;
> > +
> > +       switch (type) {
> > +       case temp_max_type:
> > +               *val = priv->dimm[dimm_no].thresholds.temp_max;
> > +               break;
> > +       case temp_crit_type:
> > +               *val = priv->dimm[dimm_no].thresholds.temp_crit;
> > +               break;
> > +       default:
> > +               ret = -EOPNOTSUPP;
> > +               break;
> > +       }
> > +unlock:
> > +       mutex_unlock(&priv->dimm[dimm_no].thresholds.state.lock);
> > +
> > +       return ret;
> > +}
> > +
> > +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);
> > +
> > +       switch (attr) {
> > +       case hwmon_temp_input:
> > +               return get_dimm_temp(priv, channel, val);
> > +       case hwmon_temp_max:
> > +               return get_dimm_thresholds(priv, temp_max_type, channel,
> > val);
> > +       case hwmon_temp_crit:
> > +               return get_dimm_thresholds(priv, temp_crit_type, channel,
> > val);
> > +       default:
> > +               break;
> > +       }
> > +
> > +       return -EOPNOTSUPP;
> > +}
> > +
> > +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;
> > +       u32 chan_rank_empty = 0;
> > +       u64 dimm_mask = 0;
> > +       int chan_rank, dimm_idx, ret;
> > +       u32 pcs;
> > +
> > +       BUILD_BUG_ON(CHAN_RANK_MAX > 32);
> > +       BUILD_BUG_ON(DIMM_NUMS_MAX > 64);
> 
> I don't immediately see the value of those build bugs. What happens if
> CHAN_RANK_MAX > 32 or DIMM_NUMS_MAX > 64 ? Where do those limits come
> from ?

Supported HW doesn't come near the limit for now - it's just an "artificial"
limit imposed by variables we're using (u64 for dimm_mask and u32 for
chan_rank_empty).

> 
> > +       if (chan_rank_max * dimm_idx_max > DIMM_NUMS_MAX) {
> > +               WARN_ONCE(1, "Unsupported number of DIMMs");
> 
> Maybe display the values (chan_rank_max and dimm_idx_max).

Ok.

> 
> > +               return -EINVAL;
> > +       }
> > +
> > +       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
> 
> Why " - " ?

Hum... No idea after reading it now.
I'll drop it.

Thank you
-Iwona

> 
> > +                        * detection to be performed at a later point in
> > time.
> > +                        */
> > +                       if (ret == -EINVAL) {
> > +                               chan_rank_empty |= BIT(chan_rank);
> > +                               continue;
> > +                       }
> > +
> > +                       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);
> > +       }
> > +
> > +       /* If we got all -EINVALs, it means that the CPU doesn't have any
> > DIMMs. */
> > +       if (chan_rank_empty == GENMASK(chan_rank_max - 1, 0))
> > +               return -ENODEV;
> > +
> > +       /*
> > +        * 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;
> > +
> > +       /*
> > +        * We expect to either find populated DIMMs and carry on with
> > creating
> > +        * sensors, or find out that there are no DIMMs populated.
> > +        * All other states mean that the platform never reached the state
> > that
> > +        * allows to check DIMM state - causing us to retry later on.
> > +        */
> > +       ret = check_populated_dimms(priv);
> > +       if (ret == -ENODEV) {
> > +               dev_dbg(priv->dev, "No DIMMs found\n");
> > +               return 0;
> > +       } else if (ret) {
> > +               schedule_delayed_work(&priv->detect_work,
> > DIMM_MASK_CHECK_DELAY_JIFFIES);
> > +               dev_dbg(priv->dev, "Deferred populating DIMM temp info\n");
> > +               return ret;
> > +       }
> > +
> > +       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;
> > +               mutex_init(&priv->dimm[i].thresholds.state.lock);
> > +               mutex_init(&priv->dimm[i].temp.state.lock);
> > +       }
> > +
> > +       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_err(priv->dev, "Failed to populate DIMM temp info\n");
> > +}
> > +
> > +static void remove_delayed_work(void *_priv)
> > +{
> > +       struct peci_dimmtemp *priv = _priv;
> > +
> > +       cancel_delayed_work_sync(&priv->detect_work);
> > +}
> > +
> > +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;
> > +
> > +       priv->dev = dev;
> > +       priv->peci_dev = peci_dev;
> > +       priv->gen_info = (const struct dimm_info *)id->driver_data;
> > +
> > +       /*
> > +        * This is just a sanity check. Since we're using commands that are
> > +        * guaranteed to be supported on a given platform, we should never
> > see
> > +        * revision lower than expected.
> > +        */
> > +       if (peci_dev->info.peci_revision < priv->gen_info-
> > >min_peci_revision)
> > +               dev_warn(priv->dev,
> > +                        "Unexpected PECI revision %#x, some features may be
> > unavailable\n",
> > +                        peci_dev->info.peci_revision);
> > +
> > +       INIT_DELAYED_WORK(&priv->detect_work,
> > create_dimm_temp_info_delayed);
> > +
> > +       ret = devm_add_action_or_reset(priv->dev, remove_delayed_work,
> > priv);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = create_dimm_temp_info(priv);
> > +       if (ret && ret != -EAGAIN) {
> > +               dev_err(dev, "Failed to populate DIMM temp info\n");
> > +               return ret;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int
> > +read_thresholds_hsx(struct peci_dimmtemp *priv, int dimm_order, int
> > chan_rank, u32 *data)
> > +{
> > +       u8 dev, func;
> > +       u16 reg;
> > +       int ret;
> > +
> > +       /*
> > +        * 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(priv->peci_dev, 1, dev, func, reg, data);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
> > +}
> > +
> > +static int
> > +read_thresholds_bdxd(struct peci_dimmtemp *priv, int dimm_order, int
> > chan_rank, u32 *data)
> > +{
> > +       u8 dev, func;
> > +       u16 reg;
> > +       int ret;
> > +
> > +       /*
> > +        * 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(priv->peci_dev, 2, dev, func, reg, data);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
> > +}
> > +
> > +static int
> > +read_thresholds_skx(struct peci_dimmtemp *priv, int dimm_order, int
> > chan_rank, u32 *data)
> > +{
> > +       u8 dev, func;
> > +       u16 reg;
> > +       int ret;
> > +
> > +       /*
> > +        * 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(priv->peci_dev, 2, dev, func, reg, data);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
> > +}
> > +
> > +static int
> > +read_thresholds_icx(struct peci_dimmtemp *priv, int dimm_order, int
> > chan_rank, u32 *data)
> > +{
> > +       u32 reg_val;
> > +       u64 offset;
> > +       int ret;
> > +       u8 dev;
> > +
> > +       ret = peci_ep_pci_local_read(priv->peci_dev, 0, 13, 0, 2, 0xd4,
> > &reg_val);
> > +       if (ret || !(reg_val & BIT(31)))
> > +               return -ENODATA; /* Use default or previous value */
> > +
> > +       ret = peci_ep_pci_local_read(priv->peci_dev, 0, 13, 0, 2, 0xd0,
> > &reg_val);
> > +       if (ret)
> > +               return -ENODATA; /* Use default or previous value */
> > +
> > +       /*
> > +        * 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 = 26 + chan_rank / 2;
> > +       offset = 0x224e0 + dimm_order * 4 + (chan_rank % 2) * 0x4000;
> > +
> > +       ret = peci_mmio_read(priv->peci_dev, 0, GET_CPU_SEG(reg_val),
> > GET_CPU_BUS(reg_val),
> > +                            dev, 0, offset, data);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return 0;
> > +}
> > +
> > +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 = 0x33,
> > +       .read_thresholds = &read_thresholds_hsx,
> > +};
> > +
> > +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 = 0x33,
> > +       .read_thresholds = &read_thresholds_hsx,
> > +};
> > +
> > +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 = 0x33,
> > +       .read_thresholds = &read_thresholds_bdxd,
> > +};
> > +
> > +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 = 0x33,
> > +       .read_thresholds = &read_thresholds_skx,
> > +};
> > +
> > +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,
> > +       .read_thresholds = &read_thresholds_icx,
> > +};
> > +
> > +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,
> > +       .read_thresholds = &read_thresholds_icx,
> > +};
> > +
> > +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,
> > +       .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);