Re: [PATCH v2 13/15] hwmon: peci: Add dimmtemp driver
From: Guenter Roeck
Date: Wed Aug 04 2021 - 13:33:43 EST
On 8/4/21 3:46 AM, Winiarska, Iwona wrote:
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@xxxxxxxxxxxxxxx>
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxxxxxxxx>
Signed-off-by: Iwona Winiarska <iwona.winiarska@xxxxxxxxx>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
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).
Please use a value derived from the size of those variables for the check
to clarify and explain the constraints.
Thanks,
Guenter