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Fri, 30 Jul 2021 15:04:08 -0700 (PDT) Sender: Guenter Roeck Subject: Re: [PATCH 11/14] hwmon: peci: Add cputemp driver To: "Winiarska, Iwona" , "zweiss@equinix.com" Cc: "corbet@lwn.net" , "jae.hyun.yoo@linux.intel.com" , "Lutomirski, Andy" , "linux-hwmon@vger.kernel.org" , "Luck, Tony" , "andrew@aj.id.au" , "mchehab@kernel.org" , "jdelvare@suse.com" , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "devicetree@vger.kernel.org" , "tglx@linutronix.de" , "linux-aspeed@lists.ozlabs.org" , "linux-doc@vger.kernel.org" , "yazen.ghannam@amd.com" , "robh+dt@kernel.org" , "openbmc@lists.ozlabs.org" , "bp@alien8.de" , "linux-arm-kernel@lists.infradead.org" , "pierre-louis.bossart@linux.intel.com" , "andriy.shevchenko@linux.intel.com" , "x86@kernel.org" , "gregkh@linuxfoundation.org" References: <20210712220447.957418-1-iwona.winiarska@intel.com> <20210712220447.957418-12-iwona.winiarska@intel.com> <20210727070651.GP8018@packtop> From: Guenter Roeck Message-ID: <5613c531-5c6a-c2ec-9081-63db50a108b3@roeck-us.net> Date: Fri, 30 Jul 2021 15:04:05 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/30/21 2:51 PM, Winiarska, Iwona wrote: > On Tue, 2021-07-27 at 07:06 +0000, Zev Weiss wrote: >> On Mon, Jul 12, 2021 at 05:04:44PM CDT, Iwona Winiarska wrote: >>> Add peci-cputemp driver for Digital Thermal Sensor (DTS) thermal >>> readings of the processor package and processor cores that are >>> accessible via the 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 >>> Signed-off-by: Jae Hyun Yoo >>> Signed-off-by: Iwona Winiarska >>> Reviewed-by: Pierre-Louis Bossart >>> --- >>> MAINTAINERS                  |   7 + >>> drivers/hwmon/Kconfig        |   2 + >>> drivers/hwmon/Makefile       |   1 + >>> drivers/hwmon/peci/Kconfig   |  18 ++ >>> drivers/hwmon/peci/Makefile  |   5 + >>> drivers/hwmon/peci/common.h  |  46 ++++ >>> drivers/hwmon/peci/cputemp.c | 503 +++++++++++++++++++++++++++++++++++ >>> 7 files changed, 582 insertions(+) >>> create mode 100644 drivers/hwmon/peci/Kconfig >>> create mode 100644 drivers/hwmon/peci/Makefile >>> create mode 100644 drivers/hwmon/peci/common.h >>> create mode 100644 drivers/hwmon/peci/cputemp.c >>> >>> diff --git a/MAINTAINERS b/MAINTAINERS >>> index f47b5f634293..35ba9e3646bd 100644 >>> --- a/MAINTAINERS >>> +++ b/MAINTAINERS >>> @@ -14504,6 +14504,13 @@ L:     platform-driver-x86@vger.kernel.org >>> S:      Maintained >>> F:      drivers/platform/x86/peaq-wmi.c >>> >>> +PECI HARDWARE MONITORING DRIVERS >>> +M:     Iwona Winiarska >>> +R:     Jae Hyun Yoo >>> +L:     linux-hwmon@vger.kernel.org >>> +S:     Supported >>> +F:     drivers/hwmon/peci/ >>> + >>> PECI SUBSYSTEM >>> M:      Iwona Winiarska >>> R:      Jae Hyun Yoo >>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig >>> index e3675377bc5d..61c0e3404415 100644 >>> --- a/drivers/hwmon/Kconfig >>> +++ b/drivers/hwmon/Kconfig >>> @@ -1507,6 +1507,8 @@ config SENSORS_PCF8591 >>>           These devices are hard to detect and rarely found on mainstream >>>           hardware. If unsure, say N. >>> >>> +source "drivers/hwmon/peci/Kconfig" >>> + >>> source "drivers/hwmon/pmbus/Kconfig" >>> >>> config SENSORS_PWM_FAN >>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile >>> index d712c61c1f5e..f52331f212ed 100644 >>> --- a/drivers/hwmon/Makefile >>> +++ b/drivers/hwmon/Makefile >>> @@ -202,6 +202,7 @@ obj-$(CONFIG_SENSORS_WM8350)        += wm8350-hwmon.o >>> obj-$(CONFIG_SENSORS_XGENE)     += xgene-hwmon.o >>> >>> obj-$(CONFIG_SENSORS_OCC)       += occ/ >>> +obj-$(CONFIG_SENSORS_PECI)     += peci/ >>> obj-$(CONFIG_PMBUS)             += pmbus/ >>> >>> ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG >>> diff --git a/drivers/hwmon/peci/Kconfig b/drivers/hwmon/peci/Kconfig >>> new file mode 100644 >>> index 000000000000..e10eed68d70a >>> --- /dev/null >>> +++ b/drivers/hwmon/peci/Kconfig >>> @@ -0,0 +1,18 @@ >>> +# SPDX-License-Identifier: GPL-2.0-only >>> + >>> +config SENSORS_PECI_CPUTEMP >>> +       tristate "PECI CPU 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 >>> +         cputemp driver which provides Digital Thermal Sensor (DTS) thermal >>> +         readings of the CPU package and CPU cores 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-cputemp. >>> + >>> +config SENSORS_PECI >>> +       tristate >>> diff --git a/drivers/hwmon/peci/Makefile b/drivers/hwmon/peci/Makefile >>> new file mode 100644 >>> index 000000000000..e8a0ada5ab1f >>> --- /dev/null >>> +++ b/drivers/hwmon/peci/Makefile >>> @@ -0,0 +1,5 @@ >>> +# SPDX-License-Identifier: GPL-2.0-only >>> + >>> +peci-cputemp-y := cputemp.o >>> + >>> +obj-$(CONFIG_SENSORS_PECI_CPUTEMP)     += peci-cputemp.o >>> diff --git a/drivers/hwmon/peci/common.h b/drivers/hwmon/peci/common.h >>> new file mode 100644 >>> index 000000000000..54580c100d06 >>> --- /dev/null >>> +++ b/drivers/hwmon/peci/common.h >>> @@ -0,0 +1,46 @@ >>> +/* SPDX-License-Identifier: GPL-2.0-only */ >>> +/* Copyright (c) 2021 Intel Corporation */ >>> + >>> +#include >>> + >>> +#ifndef __PECI_HWMON_COMMON_H >>> +#define __PECI_HWMON_COMMON_H >>> + >>> +#define UPDATE_INTERVAL_DEFAULT                HZ >>> + >>> +/** >>> + * struct peci_sensor_data - PECI sensor information >>> + * @valid: flag to indicate the sensor value is valid >>> + * @value: sensor value in milli units >>> + * @last_updated: time of the last update in jiffies >>> + */ >>> +struct peci_sensor_data { >>> +       unsigned int valid; >> >> From what I can see it looks like the 'valid' member here is strictly a >> one-shot has-this-value-ever-been-set indicator, which seems a bit >> wasteful to keep around forever post initialization; couldn't the same >> information be inferred from checking last_updated != 0 or something? > > That's just expressed in jiffies, which means it can overflow (we're just > unlikely to hit it - but IIUC it can happen). > Doing it this way would require making sure that last_updated is never set to 0 > in code that does the update. I don't think it's worth to add more complexity > there just to save a couple of bytes. > Correct. There are ways around that (eg by setting 'last_updated' to some time in the past), but that isn't really worth the trouble. 'valid' should be bool, though, not "unsigned int". Guenter >> >>> +       s32 value; >>> +       unsigned long last_updated; >>> +}; >>> + >>> +/** >>> + * peci_sensor_need_update() - check whether sensor update is needed or not >>> + * @sensor: pointer to sensor data struct >>> + * >>> + * Return: true if update is needed, false if not. >>> + */ >>> + >>> +static inline bool peci_sensor_need_update(struct peci_sensor_data *sensor) >>> +{ >>> +       return !sensor->valid || >>> +              time_after(jiffies, sensor->last_updated + >>> UPDATE_INTERVAL_DEFAULT); >>> +} >>> + >>> +/** >>> + * peci_sensor_mark_updated() - mark the sensor is updated >>> + * @sensor: pointer to sensor data struct >>> + */ >>> +static inline void peci_sensor_mark_updated(struct peci_sensor_data >>> *sensor) >>> +{ >>> +       sensor->valid = 1; >>> +       sensor->last_updated = jiffies; >>> +} >>> + >>> +#endif /* __PECI_HWMON_COMMON_H */ >>> diff --git a/drivers/hwmon/peci/cputemp.c b/drivers/hwmon/peci/cputemp.c >>> new file mode 100644 >>> index 000000000000..56a526471687 >>> --- /dev/null >>> +++ b/drivers/hwmon/peci/cputemp.c >>> @@ -0,0 +1,503 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +// Copyright (c) 2018-2021 Intel Corporation >>> + >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +#include "common.h" >>> + >>> +#define CORE_NUMS_MAX          64 >>> + >>> +#define DEFAULT_CHANNEL_NUMS   5 >> >> DEFAULT_ seems like a slightly odd prefix for this (it's not something >> that can really be overridden or anything); would BASE_ perhaps be a bit >> more appropriate? > > Ack. > >> >>> +#define CORETEMP_CHANNEL_NUMS  CORE_NUMS_MAX >>> +#define CPUTEMP_CHANNEL_NUMS   (DEFAULT_CHANNEL_NUMS + >>> CORETEMP_CHANNEL_NUMS) >>> + >>> +#define TEMP_TARGET_FAN_TEMP_MASK      GENMASK(15, 8) >>> +#define TEMP_TARGET_REF_TEMP_MASK      GENMASK(23, 16) >>> +#define TEMP_TARGET_TJ_OFFSET_MASK     GENMASK(29, 24) >>> + >>> +#define DTS_MARGIN_MASK                GENMASK(15, 0) >>> +#define PCS_MODULE_TEMP_MASK   GENMASK(15, 0) >>> + >>> +#define DTS_FIXED_POINT_FRACTION       64 >>> + >>> +struct resolved_cores_reg { >>> +       u8 bus; >>> +       u8 dev; >>> +       u8 func; >>> +       u8 offset; >>> +}; >>> + >>> +struct cpu_info { >>> +       struct resolved_cores_reg *reg; >>> +       u8 min_peci_revision; >> >> As with the dimmtemp driver, min_peci_revision appears unused here, >> though in this case if it were removed there'd only be one (pointer) >> member left in struct cpu_info, so we could perhaps remove it as well >> and then also a level of indirection in peci_cputemp_ids/cpu_{hsx,icx} >> too? > > As I mentioned in reply to previous patch comment, it'll be used to validate if > PECI device revision matches driver requirements. > >> >>> +}; >>> + >>> +struct peci_cputemp { >>> +       struct peci_device *peci_dev; >>> +       struct device *dev; >>> +       const char *name; >>> +       const struct cpu_info *gen_info; >>> +       struct { >>> +               struct peci_sensor_data die; >>> +               struct peci_sensor_data dts; >>> +               struct peci_sensor_data tcontrol; >>> +               struct peci_sensor_data tthrottle; >>> +               struct peci_sensor_data tjmax; >>> +               struct peci_sensor_data core[CORETEMP_CHANNEL_NUMS]; >>> +       } temp; >>> +       const char **coretemp_label; >>> +       DECLARE_BITMAP(core_mask, CORE_NUMS_MAX); >>> +}; >>> + >>> +enum cputemp_channels { >>> +       channel_die, >>> +       channel_dts, >>> +       channel_tcontrol, >>> +       channel_tthrottle, >>> +       channel_tjmax, >>> +       channel_core, >>> +}; >>> + >>> +static const char *cputemp_label[DEFAULT_CHANNEL_NUMS] = { >> >> static const char * const cputemp_label?  (That is, const pointer to >> const char, rather than non-const pointer to const char.) > > Ack. > >> >>> +       "Die", >>> +       "DTS", >>> +       "Tcontrol", >>> +       "Tthrottle", >>> +       "Tjmax", >>> +}; >>> + >>> +static int get_temp_targets(struct peci_cputemp *priv) >>> +{ >>> +       s32 tthrottle_offset, tcontrol_margin; >>> +       u32 pcs; >>> +       int ret; >>> + >>> +       /* >>> +        * Just use only the tcontrol marker to determine if target values >>> need >>> +        * update. >>> +        */ >>> +       if (!peci_sensor_need_update(&priv->temp.tcontrol)) >>> +               return 0; >>> + >>> +       ret = peci_pcs_read(priv->peci_dev, PECI_PCS_TEMP_TARGET, 0, &pcs); >>> +       if (ret) >>> +               return ret; >>> + >>> +       priv->temp.tjmax.value = FIELD_GET(TEMP_TARGET_REF_TEMP_MASK, pcs) * >>> MILLIDEGREE_PER_DEGREE; >>> + >>> +       tcontrol_margin = FIELD_GET(TEMP_TARGET_FAN_TEMP_MASK, pcs); >>> +       tcontrol_margin = sign_extend32(tcontrol_margin, 7) * >>> MILLIDEGREE_PER_DEGREE; >>> +       priv->temp.tcontrol.value = priv->temp.tjmax.value - >>> tcontrol_margin; >>> + >>> +       tthrottle_offset = FIELD_GET(TEMP_TARGET_TJ_OFFSET_MASK, pcs) * >>> MILLIDEGREE_PER_DEGREE; >>> +       priv->temp.tthrottle.value = priv->temp.tjmax.value - >>> tthrottle_offset; >>> + >>> +       peci_sensor_mark_updated(&priv->temp.tcontrol); >>> + >>> +       return 0; >>> +} >>> + >>> +/* >>> + * Processors return a value of DTS reading in S10.6 fixed point format >>> + * (sign, 10 bits signed integer value, 6 bits fractional). >> >> This parenthetical reads to me like it's describing 17 bits -- I'm not a >> PECI expert, but from my reading of the (somewhat skimpy) docs I've got >> on it I'd suggest a description more like "sign, 9-bit magnitude, 6-bit >> fraction". > > You're right, adding "sign" here was not intentional. > I'll change it to: > "16 bits: sign, 9-bit magnitude, 6-bit fraction" > or > "16 bits: 10-bit signed magnitude, 6-bit fraction" > > Thanks > -Iwona >