Re: [PATCH] v3 of IBM power meter driver

Mark M. Hoffman
2007-09-11T13:28:27Z

Hi Darrick:

* Darrick J. Wong <djwong@us.ibm.com> [2007-08-28 16:25:05 -0700]:
> Dave Hansen complained about the magic numbers, repetitive code, and
> various other minor problems with the driver code, so here's a v3 with
> the magic numbers migrated to the top of the file and #define'd,
> helper macros taking place of the bit shifting/masking activities, and
> the compression of the value/min/max sysfs code into parameterized
> functions.
> --
> ibm_pex: Driver to export IBM PowerExecutive power meter sensors.
>
> Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>

I am not an IPMI expert, so I would appreciate getting an Acked-by from
someone who knows more about that subsystem.

Anyway, some comments are below. This is nowhere near a complete review yet.

> ---
>
> drivers/hwmon/Kconfig | 12 +
> drivers/hwmon/Makefile | 1
> drivers/hwmon/ibmpex.c | 564 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 577 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 555f470..41ffa2e 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -275,6 +275,18 @@ config SENSORS_CORETEMP
> sensor inside your CPU. Supported all are all known variants
> of Intel Core family.
>
> +config SENSORS_IBMPEX
> + tristate "IBM PowerExecutive temperature/power sensors"
> + depends on IPMI_SI

Open question: can we use "select" here? As written, it took some hunting to
even get this driver to show up as an option in menuconfig.

> + help
> + If you say yes here you get support for the temperature and
> + power sensors in various IBM System X servers that support
> + PowerExecutive. So far this includes the x3550, x3650, x3655,
> + x3755, and certain HS20 blades.
> +
> + This driver can also be built as a module. If so, the module
> + will be called ibmpex.
> +
> config SENSORS_IT87
> tristate "ITE IT87xx and compatibles"
> select HWMON_VID
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index a133981..31da6fe 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_FSCPOS) += fscpos.o
> obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
> obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
> obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o
> +obj-$(CONFIG_SENSORS_IBMPEX) += ibmpex.o
> obj-$(CONFIG_SENSORS_IT87) += it87.o
> obj-$(CONFIG_SENSORS_K8TEMP) += k8temp.o
> obj-$(CONFIG_SENSORS_LM63) += lm63.o
> diff --git a/drivers/hwmon/ibmpex.c b/drivers/hwmon/ibmpex.c
> new file mode 100644
> index 0000000..632f897
> --- /dev/null
> +++ b/drivers/hwmon/ibmpex.c
> @@ -0,0 +1,564 @@
> +/*
> + * A hwmon driver for the IBM PowerExecutive temperature/power sensors
> + * Copyright (C) 2007 IBM
> + *
> + * Author: Darrick J. Wong <djwong@us.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +
> +#include <linux/ipmi.h>
> +#include <linux/module.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>

#include <linux/jiffies.h>

> +#include <linux/mutex.h>
> +
> +#define REFRESH_INTERVAL (5 * HZ)
> +#define DRVNAME "ibmpex"
> +
> +#define PEX_GET_VERSION 1
> +#define PEX_GET_SENSOR_COUNT 2
> +#define PEX_GET_SENSOR_NAME 3
> +#define PEX_GET_SENSOR_DATA 6
> +
> +#define PEX_NET_FUNCTION 0x3A
> +#define PEX_COMMAND 0x3C
> +
> +static inline u16 extract_value(const char *data, int offset)
> +{
> + u16 val = *(u16*)&data[offset];
> + return be16_to_cpu(val);

return be16_to_cpup((u16*)&data[offset]);

> +}
> +
> +#define PEX_INTERFACE(idx) ((idx) >> 16)
> +#define PEX_SENSOR(idx) (((idx) >> 8) & 0xFF)
> +#define PEX_FUNC(idx) ((idx) & 0xFF)
> +#define PEX_INDEX(iface, num, fn) (((iface) << 16) | ((num) << 8) | (fn))
> +
> +#define PEX_SENSOR_TYPE_LEN 3
> +static char power_sensor_sig[] = {0x70, 0x77, 0x72};
> +static char temp_sensor_sig[] = {0x74, 0x65, 0x6D};
> +
> +#define PEX_MULT_LEN 2
> +static char watt_sensor_sig[] = {0x41, 0x43};
> +

All three above should be "static u8 const"

> +#define PEX_NUM_SENSOR_FUNCS 3
> +static char *sensor_name_templates[] = {
> + "%s%d_input",
> + "%s%d_min_input",
> + "%s%d_max_input"
> +};
> +

static char const * const sensor_name_templates[] = {

> +static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
> +static void ibmpex_register_bmc(int iface, struct device *dev);
> +static void ibmpex_bmc_gone(int iface);
> +
> +struct ibmpex_sensor_data {
> + int in_use;
> + s16 values[PEX_NUM_SENSOR_FUNCS];
> + int multiplier;
> +
> + struct sensor_device_attribute attr[PEX_NUM_SENSOR_FUNCS];
> +};
> +
> +struct ibmpex_bmc_data {
> + struct list_head list;
> + struct class_device *class_dev;

My current stack of patches includes one which requires that this be changed
to 'struct device *hwmon_dev', as 'struct class_device' is going away soon.
You may rebase on my testing tree[1], or else I will just follow up with a
patch to fix this up after I eventually merge yours.

[1] http://lm-sensors.org/kernel?p=kernel/mhoffman/hwmon-2.6.git;a=shortlog;h=testing

> + struct device *bmc_device;
> + struct mutex lock;
> + char valid;
> + unsigned long last_updated; /* In jiffies */
> +
> + struct ipmi_addr address;
> + struct completion read_complete;
> + ipmi_user_t user;
> + int interface;
> +
> + struct kernel_ipmi_msg tx_message;
> + unsigned char tx_msg_data[IPMI_MAX_MSG_LENGTH];
> + long tx_msgid;
> +
> + unsigned char rx_msg_data[IPMI_MAX_MSG_LENGTH];
> + unsigned long rx_msg_len;
> + unsigned char rx_result;
> + int rx_recv_type;
> +
> + unsigned char sensor_major;
> + unsigned char sensor_minor;
> +
> + unsigned char num_sensors;
> + struct ibmpex_sensor_data *sensors;
> +};
> +
> +struct ibmpex_driver_data {
> + struct list_head bmc_data;
> + struct ipmi_smi_watcher bmc_events;
> + struct ipmi_user_hndl ipmi_hndlrs;
> +};
> +
> +static struct ibmpex_driver_data driver_data = {
> + .bmc_data = LIST_HEAD_INIT(driver_data.bmc_data),
> + .bmc_events = {
> + .owner = THIS_MODULE,
> + .new_smi = ibmpex_register_bmc,
> + .smi_gone = ibmpex_bmc_gone,
> + },
> + .ipmi_hndlrs = {
> + .ipmi_recv_hndl = ibmpex_msg_handler,
> + },
> +};
> +
> +static int ibmpex_send_message(struct ibmpex_bmc_data *data)
> +{
> + int err;
> +
> + err = ipmi_validate_addr(&data->address, sizeof(data->address));
> + if (err)
> + goto out;
> +
> + data->tx_msgid++;
> + err = ipmi_request_settime(data->user, &data->address, data->tx_msgid,
> + &data->tx_message, data, 0, 0, 0);
> + if (err)
> + goto out1;
> +
> + return 0;
> +out1:
> + printk(KERN_ERR "%s: request_settime=%x\n", __FUNCTION__, err);
> + return err;
> +out:
> + printk(KERN_ERR "%s: validate_addr=%x\n", __FUNCTION__, err);
> + return err;
> +}
> +
> +static int ibmpex_ver_check(struct ibmpex_bmc_data *data)
> +{
> + data->tx_msg_data[0] = PEX_GET_VERSION;
> + data->tx_message.data_len = 1;
> + ibmpex_send_message(data);
> +
> + wait_for_completion(&data->read_complete);
> +
> + if (data->rx_result || data->rx_msg_len != 6)
> + return -ENOENT;
> +
> + data->sensor_major = data->rx_msg_data[0];
> + data->sensor_minor = data->rx_msg_data[1];
> +
> + printk(KERN_INFO DRVNAME ": Found BMC with sensor interface "
> + "v%d.%d %d-%02d-%02d on interface %d\n",
> + data->sensor_major,
> + data->sensor_minor,
> + extract_value(data->rx_msg_data, 2),
> + data->rx_msg_data[4],
> + data->rx_msg_data[5],
> + data->interface);
> +
> + return 0;
> +}
> +
> +static int ibmpex_query_sensor_count(struct ibmpex_bmc_data *data)
> +{
> + data->tx_msg_data[0] = PEX_GET_SENSOR_COUNT;
> + data->tx_message.data_len = 1;
> + ibmpex_send_message(data);
> +
> + wait_for_completion(&data->read_complete);
> +
> + if (data->rx_result || data->rx_msg_len != 1)
> + return -ENOENT;
> +
> + return data->rx_msg_data[0];
> +}
> +
> +static int ibmpex_query_sensor_name(struct ibmpex_bmc_data *data, int sensor)
> +{
> + data->tx_msg_data[0] = PEX_GET_SENSOR_NAME;
> + data->tx_msg_data[1] = sensor;
> + data->tx_message.data_len = 2;
> + ibmpex_send_message(data);
> +
> + wait_for_completion(&data->read_complete);
> +
> + if (data->rx_result || data->rx_msg_len < 1)
> + return -ENOENT;
> +
> + return 0;
> +}
> +
> +static int ibmpex_query_sensor_data(struct ibmpex_bmc_data *data, int sensor)
> +{
> + data->tx_msg_data[0] = PEX_GET_SENSOR_DATA;
> + data->tx_msg_data[1] = sensor;
> + data->tx_message.data_len = 2;
> + ibmpex_send_message(data);
> +
> + wait_for_completion(&data->read_complete);
> +
> + if (data->rx_result || data->rx_msg_len < 26) {
> + printk(KERN_ERR "Error reading sensor %d, please check.\n",
> + sensor);
> + return -ENOENT;
> + }
> +
> + return 0;
> +}
> +
> +static void ibmpex_update_device(struct ibmpex_bmc_data *data)
> +{
> + int i, err;
> +
> + mutex_lock(&data->lock);
> + if (time_before(jiffies, data->last_updated + REFRESH_INTERVAL) &&
> + data->valid)
> + goto out;
> +
> + for (i = 0; i < data->num_sensors; i++) {
> + if (!data->sensors[i].in_use)
> + continue;
> + err = ibmpex_query_sensor_data(data, i);
> + if (err)
> + continue;
> + data->sensors[i].values[0] =
> + extract_value(data->rx_msg_data, 16);
> + data->sensors[i].values[1] =
> + extract_value(data->rx_msg_data, 18);
> + data->sensors[i].values[2] =
> + extract_value(data->rx_msg_data, 20);
> + }
> +
> + data->last_updated = jiffies;
> + data->valid = 1;
> +
> +out:
> + mutex_unlock(&data->lock);
> +}
> +
> +static struct ibmpex_bmc_data *get_bmc_data(int iface)
> +{
> + struct ibmpex_bmc_data *p, *next;
> +
> + list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
> + if (p->interface == iface)
> + return p;
> +
> + return NULL;
> +}
> +

That function is yucky...

> +static ssize_t show_name(struct device *dev, struct device_attribute *devattr,
> + char *buf)
> +{
> + return sprintf(buf, "%s\n", DRVNAME);
> +}
> +static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, 0);
> +
> +static ssize_t ibmpex_show_sensor(struct device *dev,
> + struct device_attribute *devattr,
> + char *buf)
> +{
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + int iface = PEX_INTERFACE(attr->index);
> + int sensor = PEX_SENSOR(attr->index);
> + int func = PEX_FUNC(attr->index);
> + struct ibmpex_bmc_data *data = get_bmc_data(iface);

... especially given how many times you're going to call it. Is there any
reason you can't use the driver_data field of struct device *dev for that?

E.g. i2c based hwmon drivers do this at some point during the probe:

i2c_set_clientdata(new_client, data);

(which becomes)

dev_set_drvdata(&new_client->dev, data);

If you could do that, then you no longer need 'iface' at all in the function
above... *that* may allow you to use the SENSOR_ATTR_2 mechanism from
hwmon-sysfs.h - much easier to read than the manual number packing for 'sensor'
and 'func'.

> + int multiplier = data->sensors[sensor].multiplier;
> + ibmpex_update_device(data);
> +
> + return sprintf(buf, "%d\n",
> + data->sensors[sensor].values[func] * multiplier);
> +}
> +
> +static int is_power_sensor(const char *sensor_id, int len)
> +{
> + if (len < PEX_SENSOR_TYPE_LEN)
> + return 0;
> +
> + if (!memcmp(sensor_id, power_sensor_sig, PEX_SENSOR_TYPE_LEN))
> + return 1;
> + return 0;
> +}
> +
> +static int is_temp_sensor(const char *sensor_id, int len)
> +{
> + if (len < PEX_SENSOR_TYPE_LEN)
> + return 0;
> +
> + if (!memcmp(sensor_id, temp_sensor_sig, PEX_SENSOR_TYPE_LEN))
> + return 1;
> + return 0;
> +}
> +
> +static int power_sensor_multiplier(const char *sensor_id, int len)
> +{
> + int i;
> +
> + for (i = PEX_SENSOR_TYPE_LEN; i < len - 1; i++)
> + if (!memcmp(&sensor_id[i], watt_sensor_sig, PEX_MULT_LEN))
> + return 1000;
> +
> + return 100;
> +}
> +
> +static int create_sensor(struct ibmpex_bmc_data *data, const char *type,
> + int counter, int sensor, int func)
> +{
> + int err;
> + char *n;
> +
> + n = kmalloc(32, GFP_KERNEL);
> + if (!n)
> + return -ENOMEM;
> +
> + sprintf(n, sensor_name_templates[func], type, counter);
> + data->sensors[sensor].attr[func].dev_attr.attr.name = n;
> + data->sensors[sensor].attr[func].dev_attr.attr.mode = S_IRUGO;
> + data->sensors[sensor].attr[func].dev_attr.show = ibmpex_show_sensor;
> + data->sensors[sensor].attr[func].index =
> + PEX_INDEX(data->interface, sensor, func);
> +
> + err = device_create_file(data->bmc_device,
> + &data->sensors[sensor].attr[func].dev_attr);
> + if (err) {
> + data->sensors[sensor].attr[func].dev_attr.attr.name = NULL;
> + kfree(n);
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
> +{
> + int i, j, err;
> + char *sensor_type;
> + int sensor_counter;
> + int num_power = 0;
> + int num_temp = 0;
> +
> + err = ibmpex_query_sensor_count(data);
> + if (err < 0)
> + return -ENOENT;
> + data->num_sensors = err;
> +

Did you mean 'if (err <= 0)' ?

> + data->sensors = kzalloc(data->num_sensors * sizeof(*data->sensors),
> + GFP_KERNEL);
> + if (!data->sensors)
> + return -ENOMEM;
> +
> + for (i = 0; i < data->num_sensors; i++) {
> + err = ibmpex_query_sensor_name(data, i);
> + if (err)
> + continue;
> +
> + if (is_power_sensor(data->rx_msg_data, data->rx_msg_len)) {
> + sensor_type = "power";
> + num_power++;
> + sensor_counter = num_power;
> + data->sensors[i].multiplier =
> + power_sensor_multiplier(data->rx_msg_data,
> + data->rx_msg_len);
> + } else if (is_temp_sensor(data->rx_msg_data,
> + data->rx_msg_len)) {
> + sensor_type = "temp";
> + num_temp++;
> + sensor_counter = num_temp;
> + data->sensors[i].multiplier = 1;
> + } else
> + continue;
> +
> + data->sensors[i].in_use = 1;
> +
> + /* Create attributes */
> + for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++)
> + if (create_sensor(data, sensor_type, sensor_counter,
> + i, j))

Why not 'err = create_sensor(...)' and propagate the actual error here?

> + goto exit_remove;
> + }
> +
> + err = device_create_file(data->bmc_device,
> + &sensor_dev_attr_name.dev_attr);
> + if (err)
> + goto exit_remove;
> +
> + return 0;
> +
> +exit_remove:
> + for (i = 0; i < data->num_sensors; i++)
> + for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
> + if (!data->sensors[i].attr[j].dev_attr.attr.name)
> + continue;
> + device_remove_file(data->bmc_device,
> + &data->sensors[i].attr[j].dev_attr);
> + kfree(data->sensors[i].attr[j].dev_attr.attr.name);
> + }
> +
> + kfree(data->sensors);
> + return -ENOENT;

... and 'return err' here instead.

> +}
> +
> +static void ibmpex_register_bmc(int iface, struct device *dev)
> +{
> + struct ibmpex_bmc_data *data;
> + int err;
> +
> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> + if (!data) {
> + printk(KERN_ERR DRVNAME ": Insufficient memory for BMC "
> + "interface %d.\n", data->interface);
> + return;
> + }
> +
> + data->address.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
> + data->address.channel = IPMI_BMC_CHANNEL;
> + data->address.data[0] = 0;
> + data->interface = iface;
> + data->bmc_device = dev;
> +
> + /* Create IPMI messaging interface user */
> + err = ipmi_create_user(data->interface, &driver_data.ipmi_hndlrs,
> + data, &data->user);
> + if (err < 0) {
> + printk(KERN_ERR DRVNAME ": Error, unable to register user with "
> + "ipmi interface %d\n",
> + data->interface);
> + goto out;
> + }
> +
> + mutex_init(&data->lock);
> +
> + /* Initialize message */
> + data->tx_msgid = 0;
> + init_completion(&data->read_complete);
> + data->tx_message.netfn = PEX_NET_FUNCTION;
> + data->tx_message.cmd = PEX_COMMAND;
> + data->tx_message.data = data->tx_msg_data;
> +
> + /* Does this BMC support PowerExecutive? */
> + err = ibmpex_ver_check(data);
> + if (err)
> + goto out_user;
> +
> + /* Register the BMC as a HWMON class device */
> + data->class_dev = hwmon_device_register(data->bmc_device);
> +
> + if (IS_ERR(data->class_dev)) {
> + printk(KERN_ERR DRVNAME ": Error, unable to register hwmon "
> + "class device for interface %d\n",
> + data->interface);
> + kfree(data);
> + return;
> + }
> +
> + /* finally add the new bmc data to the bmc data list */
> + list_add_tail(&data->list, &driver_data.bmc_data);
> +
> + /* Now go find all the sensors */
> + err = ibmpex_find_sensors(data);
> + if (err) {
> + printk(KERN_ERR "Error %d allocating memory\n", err);
> + goto out_register;
> + }
> +
> + return;
> +
> +out_register:
> + hwmon_device_unregister(data->class_dev);
> +out_user:
> + ipmi_destroy_user(data->user);
> +out:
> + kfree(data);
> +}
> +
> +static void ibmpex_bmc_delete(struct ibmpex_bmc_data *data)
> +{
> + int i, j;
> +
> + device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
> + for (i = 0; i < data->num_sensors; i++)
> + for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
> + if (!data->sensors[i].attr[j].dev_attr.attr.name)
> + continue;
> + device_remove_file(data->bmc_device,
> + &data->sensors[i].attr[j].dev_attr);
> + kfree(data->sensors[i].attr[j].dev_attr.attr.name);
> + }
> +
> + list_del(&data->list);
> + hwmon_device_unregister(data->class_dev);
> + ipmi_destroy_user(data->user);
> + if (data->sensors)
> + kfree(data->sensors);
> + kfree(data);
> +}
> +
> +static void ibmpex_bmc_gone(int iface)
> +{
> + struct ibmpex_bmc_data *data = get_bmc_data(iface);
> +
> + if (!data)
> + return;
> +
> + ibmpex_bmc_delete(data);
> +}
> +
> +static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
> +{
> + struct ibmpex_bmc_data *data = (struct ibmpex_bmc_data *)user_msg_data;
> +
> + if (msg->msgid != data->tx_msgid) {
> + printk(KERN_ERR "Received msgid (%02x) and transmitted "
> + "msgid (%02x) mismatch!\n",
> + (int)msg->msgid,
> + (int)data->tx_msgid);
> + ipmi_free_recv_msg(msg);
> + return;
> + }
> +
> + data->rx_recv_type = msg->recv_type;
> + if (msg->msg.data_len > 0)
> + data->rx_result = msg->msg.data[0];
> + else
> + data->rx_result = IPMI_UNKNOWN_ERR_COMPLETION_CODE;
> +
> + if (msg->msg.data_len > 1) {
> + data->rx_msg_len = msg->msg.data_len - 1;
> + memcpy(data->rx_msg_data, msg->msg.data + 1, data->rx_msg_len);
> + } else
> + data->rx_msg_len = 0;
> +
> + ipmi_free_recv_msg(msg);
> + complete(&data->read_complete);
> +}
> +
> +static int __init ibmpex_init(void)
> +{
> + return ipmi_smi_watcher_register(&driver_data.bmc_events);
> +}
> +
> +static void __exit ibmpex_exit(void)
> +{
> + struct ibmpex_bmc_data *p, *next;
> +
> + ipmi_smi_watcher_unregister(&driver_data.bmc_events);
> + list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
> + ibmpex_bmc_delete(p);
> +}
> +
> +MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
> +MODULE_DESCRIPTION("IBM PowerExecutive power/temperature sensor driver");
> +MODULE_LICENSE("GPL");
> +
> +module_init(ibmpex_init);
> +module_exit(ibmpex_exit);

Regards,

--
Mark M. Hoffman
mhoffman@lightlink.com