From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B430C433FE for ; Tue, 26 Apr 2022 15:27:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236449AbiDZPaG (ORCPT ); Tue, 26 Apr 2022 11:30:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347997AbiDZPaG (ORCPT ); Tue, 26 Apr 2022 11:30:06 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF61EAE7F for ; Tue, 26 Apr 2022 08:26:55 -0700 (PDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 23QF2Qqj012745; Tue, 26 Apr 2022 15:26:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=8KiiEsFRGLmpnZe+NPxY9LRvzjIRuH0LaTOwfZxz6W4=; b=WkZTvDILDZy4fIwB5E37jpqc6H3orrb1v5xU+IogDtiVUJc96zanZ1uYPVguN1R5ECI2 vgMF96Jm1mcp6P9fFUaQn4HAfjlhRGVgsZ7N8I89hSERe4F9Ncj9A5bqMcOBc4Skuazo 5gb6IeCZpZeQggvhXqm7ETxhIffoGhdGKT6w4vUmKxqV3NYi6HGR/IjnG8L+fBbFLInr yw4wLwHPvVkIPu6nukdFnNeztkp4k4auyBBvq0iJl9re1PaZSjndy+gg8o3ZJQc8xOI5 w7GD8bEeJJxuxRuHS91cj9flSOiT3yrhL3UZpedX58zKvXZGu+nSeKh8u9vyBAlyEBZg 8A== Received: from ppma03wdc.us.ibm.com (ba.79.3fa9.ip4.static.sl-reverse.com [169.63.121.186]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3fpk1frj91-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 26 Apr 2022 15:26:39 +0000 Received: from pps.filterd (ppma03wdc.us.ibm.com [127.0.0.1]) by ppma03wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 23QFCSA3019960; Tue, 26 Apr 2022 15:26:39 GMT Received: from b03cxnp07027.gho.boulder.ibm.com (b03cxnp07027.gho.boulder.ibm.com [9.17.130.14]) by ppma03wdc.us.ibm.com with ESMTP id 3fm939dw6c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 26 Apr 2022 15:26:39 +0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp07027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 23QFQcJx36438338 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 26 Apr 2022 15:26:38 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2ABB1BE04F; Tue, 26 Apr 2022 15:26:38 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D4F37BE054; Tue, 26 Apr 2022 15:26:37 +0000 (GMT) Received: from [9.211.82.59] (unknown [9.211.82.59]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 26 Apr 2022 15:26:37 +0000 (GMT) Message-ID: Date: Tue, 26 Apr 2022 10:26:37 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH] hwmon (occ): Avoid polling OCC during probe Content-Language: en-US To: Guenter Roeck , linux-hwmon@vger.kernel.org Cc: jdelvare@suse.com, joel@jms.id.au References: <20220426144555.12120-1-eajames@linux.ibm.com> From: Eddie James In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: UTLEQyU2hl_bahsWrn8RngRZ4UHKVHz8 X-Proofpoint-ORIG-GUID: UTLEQyU2hl_bahsWrn8RngRZ4UHKVHz8 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-26_04,2022-04-26_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 spamscore=0 lowpriorityscore=0 clxscore=1015 bulkscore=0 phishscore=0 suspectscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204260096 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On 4/26/22 10:01, Guenter Roeck wrote: > On 4/26/22 07:45, Eddie James wrote: >> Instead of polling the OCC during the probe, use the "occ_active" >> sysfs file to control when the driver polls the OCC for sensor data. >> The reason for this change is that the SBE, which is the device by >> which the driver communicates with the OCC, cannot handle communications >> during certain system state transitions. >> > > This is hackish, to say the least. Why not just instantiate the driver > manually instead if userspace interaction is indeed needed, and there > is no means to auto-instantiate it only after the hardware is ready ? Well, the occ-hwmon platform devices are currently created by the parent FSI occ device (that's a bit of a hack too). I poked through the platform/device/bus interfaces but couldn't work out how to create the device but not probe it, so that userspace could later bind the device to the driver. The current userspace does just that, but it relies on the the initial probe failing since SBE can't handle the communications yet. The error scenario is that the SBE can get into a bad state, so communications shouldn't even be attempted. So to answer your question, there's no reason not to just instantiate the driver manually, but I don't actually know how to do so with these drivers. > > On the other side, what means does userspace have to determine that > the SBE/OCC is ready ? Can't that same mechanism not be used in the > kernel to auto-instantiate the driver ? No it's impossible, it's not just some bit we can check in HW unfortunately, the signal is PLDM (platform level data model) over the network. Thanks for your quick response. Eddie > > Guenter > >> Signed-off-by: Eddie James >> --- >>   drivers/hwmon/occ/common.c | 100 +++++++++++++++++++-------- >>   drivers/hwmon/occ/common.h |   5 +- >>   drivers/hwmon/occ/p8_i2c.c |   2 +- >>   drivers/hwmon/occ/p9_sbe.c |   2 +- >>   drivers/hwmon/occ/sysfs.c  | 137 ++++++++++++++++++++++--------------- >>   5 files changed, 156 insertions(+), 90 deletions(-) >> >> diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c >> index f00cd59f1d19..d78f4bebc718 100644 >> --- a/drivers/hwmon/occ/common.c >> +++ b/drivers/hwmon/occ/common.c >> @@ -1149,44 +1149,75 @@ static void occ_parse_poll_response(struct >> occ *occ) >>           sizeof(*header), size + sizeof(*header)); >>   } >>   -int occ_setup(struct occ *occ, const char *name) >> +int occ_active(struct occ *occ, bool active) >>   { >> -    int rc; >> - >> -    mutex_init(&occ->lock); >> -    occ->groups[0] = &occ->group; >> +    int rc = mutex_lock_interruptible(&occ->lock); >>   -    /* no need to lock */ >> -    rc = occ_poll(occ); >> -    if (rc == -ESHUTDOWN) { >> -        dev_info(occ->bus_dev, "host is not ready\n"); >> -        return rc; >> -    } else if (rc < 0) { >> -        dev_err(occ->bus_dev, >> -            "failed to get OCC poll response=%02x: %d\n", >> -            occ->resp.return_status, rc); >> +    if (rc) >>           return rc; >> -    } >>   -    occ->next_update = jiffies + OCC_UPDATE_FREQUENCY; >> -    occ_parse_poll_response(occ); >> +    if (active) { >> +        if (occ->active) { >> +            rc = -EALREADY; >> +            goto unlock; >> +        } >>   -    rc = occ_setup_sensor_attrs(occ); >> -    if (rc) { >> -        dev_err(occ->bus_dev, "failed to setup sensor attrs: %d\n", >> -            rc); >> -        return rc; >> -    } >> +        occ->error_count = 0; >> +        occ->last_safe = 0; >>   -    occ->hwmon = >> devm_hwmon_device_register_with_groups(occ->bus_dev, name, >> -                                occ, occ->groups); >> -    if (IS_ERR(occ->hwmon)) { >> -        rc = PTR_ERR(occ->hwmon); >> -        dev_err(occ->bus_dev, "failed to register hwmon device: %d\n", >> -            rc); >> -        return rc; >> +        rc = occ_poll(occ); >> +        if (rc < 0) { >> +            dev_err(occ->bus_dev, >> +                "failed to get OCC poll response=%02x: %d\n", >> +                occ->resp.return_status, rc); >> +            goto unlock; >> +        } >> + >> +        occ->active = true; >> +        occ->next_update = jiffies + OCC_UPDATE_FREQUENCY; >> +        occ_parse_poll_response(occ); >> + >> +        rc = occ_setup_sensor_attrs(occ); >> +        if (rc) { >> +            dev_err(occ->bus_dev, >> +                "failed to setup sensor attrs: %d\n", rc); >> +            goto unlock; >> +        } >> + >> +        occ->hwmon = hwmon_device_register_with_groups(occ->bus_dev, >> +                                   "occ", occ, >> +                                   occ->groups); >> +        if (IS_ERR(occ->hwmon)) { >> +            rc = PTR_ERR(occ->hwmon); >> +            occ->hwmon = NULL; >> +            dev_err(occ->bus_dev, >> +                "failed to register hwmon device: %d\n", rc); >> +            goto unlock; >> +        } >> +    } else { >> +        if (!occ->active) { >> +            rc = -EALREADY; >> +            goto unlock; >> +        } >> + >> +        if (occ->hwmon) >> +            hwmon_device_unregister(occ->hwmon); >> +        occ->active = false; >> +        occ->hwmon = NULL; >>       } >>   +unlock: >> +    mutex_unlock(&occ->lock); >> +    return rc; >> +} >> + >> +int occ_setup(struct occ *occ) >> +{ >> +    int rc; >> + >> +    mutex_init(&occ->lock); >> +    occ->groups[0] = &occ->group; >> + >>       rc = occ_setup_sysfs(occ); >>       if (rc) >>           dev_err(occ->bus_dev, "failed to setup sysfs: %d\n", rc); >> @@ -1195,6 +1226,15 @@ int occ_setup(struct occ *occ, const char *name) >>   } >>   EXPORT_SYMBOL_GPL(occ_setup); >>   +void occ_shutdown(struct occ *occ) >> +{ >> +    occ_shutdown_sysfs(occ); >> + >> +    if (occ->hwmon) >> +        hwmon_device_unregister(occ->hwmon); >> +} >> +EXPORT_SYMBOL_GPL(occ_shutdown); >> + >>   MODULE_AUTHOR("Eddie James "); >>   MODULE_DESCRIPTION("Common OCC hwmon code"); >>   MODULE_LICENSE("GPL"); >> diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h >> index 2dd4a4d240c0..64d5ec7e169b 100644 >> --- a/drivers/hwmon/occ/common.h >> +++ b/drivers/hwmon/occ/common.h >> @@ -106,6 +106,7 @@ struct occ { >>       struct attribute_group group; >>       const struct attribute_group *groups[2]; >>   +    bool active; >>       int error;                      /* final transfer error after >> retry */ >>       int last_error;            /* latest transfer error */ >>       unsigned int error_count;       /* number of xfr errors >> observed */ >> @@ -123,9 +124,11 @@ struct occ { >>       u8 prev_mode; >>   }; >>   -int occ_setup(struct occ *occ, const char *name); >> +int occ_active(struct occ *occ, bool active); >> +int occ_setup(struct occ *occ); >>   int occ_setup_sysfs(struct occ *occ); >>   void occ_shutdown(struct occ *occ); >> +void occ_shutdown_sysfs(struct occ *occ); >>   void occ_sysfs_poll_done(struct occ *occ); >>   int occ_update_response(struct occ *occ); >>   diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c >> index 9e61e1fb5142..da39ea28df31 100644 >> --- a/drivers/hwmon/occ/p8_i2c.c >> +++ b/drivers/hwmon/occ/p8_i2c.c >> @@ -223,7 +223,7 @@ static int p8_i2c_occ_probe(struct i2c_client >> *client) >>       occ->poll_cmd_data = 0x10;        /* P8 OCC poll data */ >>       occ->send_cmd = p8_i2c_occ_send_cmd; >>   -    return occ_setup(occ, "p8_occ"); >> +    return occ_setup(occ); >>   } >>     static int p8_i2c_occ_remove(struct i2c_client *client) >> diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c >> index 49b13cc01073..42fc7b97bb34 100644 >> --- a/drivers/hwmon/occ/p9_sbe.c >> +++ b/drivers/hwmon/occ/p9_sbe.c >> @@ -145,7 +145,7 @@ static int p9_sbe_occ_probe(struct >> platform_device *pdev) >>       occ->poll_cmd_data = 0x20;        /* P9 OCC poll data */ >>       occ->send_cmd = p9_sbe_occ_send_cmd; >>   -    rc = occ_setup(occ, "p9_occ"); >> +    rc = occ_setup(occ); >>       if (rc == -ESHUTDOWN) >>           rc = -ENODEV;    /* Host is shutdown, don't spew errors */ >>   diff --git a/drivers/hwmon/occ/sysfs.c b/drivers/hwmon/occ/sysfs.c >> index b2f788a77746..2317301fc1e9 100644 >> --- a/drivers/hwmon/occ/sysfs.c >> +++ b/drivers/hwmon/occ/sysfs.c >> @@ -6,13 +6,13 @@ >>   #include >>   #include >>   #include >> +#include >>   #include >>     #include "common.h" >>     /* OCC status register */ >>   #define OCC_STAT_MASTER            BIT(7) >> -#define OCC_STAT_ACTIVE            BIT(0) >>     /* OCC extended status register */ >>   #define OCC_EXT_STAT_DVFS_OT        BIT(7) >> @@ -22,6 +22,25 @@ >>   #define OCC_EXT_STAT_DVFS_VDD        BIT(3) >>   #define OCC_EXT_STAT_GPU_THROTTLE    GENMASK(2, 0) >>   +static ssize_t occ_active_store(struct device *dev, >> +                struct device_attribute *attr, >> +                const char *buf, size_t count) >> +{ >> +    int rc; >> +    bool active; >> +    struct occ *occ = dev_get_drvdata(dev); >> + >> +    rc = kstrtobool(buf, &active); >> +    if (rc) >> +        return rc; >> + >> +    rc = occ_active(occ, active); >> +    if (rc) >> +        return rc; >> + >> +    return count; >> +} >> + >>   static ssize_t occ_sysfs_show(struct device *dev, >>                     struct device_attribute *attr, char *buf) >>   { >> @@ -31,54 +50,64 @@ static ssize_t occ_sysfs_show(struct device *dev, >>       struct occ_poll_response_header *header; >>       struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); >>   -    rc = occ_update_response(occ); >> -    if (rc) >> -        return rc; >> +    if (occ->active) { >> +        rc = occ_update_response(occ); >> +        if (rc) >> +            return rc; >>   -    header = (struct occ_poll_response_header *)occ->resp.data; >> - >> -    switch (sattr->index) { >> -    case 0: >> -        val = !!(header->status & OCC_STAT_MASTER); >> -        break; >> -    case 1: >> -        val = !!(header->status & OCC_STAT_ACTIVE); >> -        break; >> -    case 2: >> -        val = !!(header->ext_status & OCC_EXT_STAT_DVFS_OT); >> -        break; >> -    case 3: >> -        val = !!(header->ext_status & OCC_EXT_STAT_DVFS_POWER); >> -        break; >> -    case 4: >> -        val = !!(header->ext_status & OCC_EXT_STAT_MEM_THROTTLE); >> -        break; >> -    case 5: >> -        val = !!(header->ext_status & OCC_EXT_STAT_QUICK_DROP); >> -        break; >> -    case 6: >> -        val = header->occ_state; >> -        break; >> -    case 7: >> -        if (header->status & OCC_STAT_MASTER) >> -            val = hweight8(header->occs_present); >> -        else >> +        header = (struct occ_poll_response_header *)occ->resp.data; >> + >> +        switch (sattr->index) { >> +        case 0: >> +            val = !!(header->status & OCC_STAT_MASTER); >> +            break; >> +        case 1: >>               val = 1; >> -        break; >> -    case 8: >> -        val = header->ips_status; >> -        break; >> -    case 9: >> -        val = header->mode; >> -        break; >> -    case 10: >> -        val = !!(header->ext_status & OCC_EXT_STAT_DVFS_VDD); >> -        break; >> -    case 11: >> -        val = header->ext_status & OCC_EXT_STAT_GPU_THROTTLE; >> -        break; >> -    default: >> -        return -EINVAL; >> +            break; >> +        case 2: >> +            val = !!(header->ext_status & OCC_EXT_STAT_DVFS_OT); >> +            break; >> +        case 3: >> +            val = !!(header->ext_status & OCC_EXT_STAT_DVFS_POWER); >> +            break; >> +        case 4: >> +            val = !!(header->ext_status & >> +                 OCC_EXT_STAT_MEM_THROTTLE); >> +            break; >> +        case 5: >> +            val = !!(header->ext_status & OCC_EXT_STAT_QUICK_DROP); >> +            break; >> +        case 6: >> +            val = header->occ_state; >> +            break; >> +        case 7: >> +            if (header->status & OCC_STAT_MASTER) >> +                val = hweight8(header->occs_present); >> +            else >> +                val = 1; >> +            break; >> +        case 8: >> +            val = header->ips_status; >> +            break; >> +        case 9: >> +            val = header->mode; >> +            break; >> +        case 10: >> +            val = !!(header->ext_status & OCC_EXT_STAT_DVFS_VDD); >> +            break; >> +        case 11: >> +            val = header->ext_status & OCC_EXT_STAT_GPU_THROTTLE; >> +            break; >> +        default: >> +            return -EINVAL; >> +        } >> +    } else { >> +        if (sattr->index == 1) >> +            val = 0; >> +        else if (sattr->index <= 11) >> +            val = -ENODATA; >> +        else >> +            return -EINVAL; >>       } >>         return sysfs_emit(buf, "%d\n", val); >> @@ -95,7 +124,8 @@ static ssize_t occ_error_show(struct device *dev, >>   } >>     static SENSOR_DEVICE_ATTR(occ_master, 0444, occ_sysfs_show, NULL, >> 0); >> -static SENSOR_DEVICE_ATTR(occ_active, 0444, occ_sysfs_show, NULL, 1); >> +static SENSOR_DEVICE_ATTR(occ_active, 0644, occ_sysfs_show, >> occ_active_store, >> +              1); >>   static SENSOR_DEVICE_ATTR(occ_dvfs_overtemp, 0444, occ_sysfs_show, >> NULL, 2); >>   static SENSOR_DEVICE_ATTR(occ_dvfs_power, 0444, occ_sysfs_show, >> NULL, 3); >>   static SENSOR_DEVICE_ATTR(occ_mem_throttle, 0444, occ_sysfs_show, >> NULL, 4); >> @@ -139,7 +169,7 @@ void occ_sysfs_poll_done(struct occ *occ) >>        * On the first poll response, we haven't yet created the sysfs >>        * attributes, so don't make any notify calls. >>        */ >> -    if (!occ->hwmon) >> +    if (!occ->active) >>           goto done; >>         if ((header->status & OCC_STAT_MASTER) != >> @@ -148,12 +178,6 @@ void occ_sysfs_poll_done(struct occ *occ) >>           sysfs_notify(&occ->bus_dev->kobj, NULL, name); >>       } >>   -    if ((header->status & OCC_STAT_ACTIVE) != >> -        (occ->prev_stat & OCC_STAT_ACTIVE)) { >> -        name = sensor_dev_attr_occ_active.dev_attr.attr.name; >> -        sysfs_notify(&occ->bus_dev->kobj, NULL, name); >> -    } >> - >>       if ((header->ext_status & OCC_EXT_STAT_DVFS_OT) != >>           (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_OT)) { >>           name = sensor_dev_attr_occ_dvfs_overtemp.dev_attr.attr.name; >> @@ -227,8 +251,7 @@ int occ_setup_sysfs(struct occ *occ) >>       return sysfs_create_group(&occ->bus_dev->kobj, &occ_sysfs); >>   } >>   -void occ_shutdown(struct occ *occ) >> +void occ_shutdown_sysfs(struct occ *occ) >>   { >>       sysfs_remove_group(&occ->bus_dev->kobj, &occ_sysfs); >>   } >> -EXPORT_SYMBOL_GPL(occ_shutdown); >