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SubjectRe: [PATCH v4] hwmon: Add driver for AMD family 15h processor power information
Hi Andreas,

On Fri, 8 Apr 2011 15:54:07 +0200, Andreas Herrmann wrote:
> From: Andreas Herrmann <andreas.herrmann3@amd.com>
>
> This CPU family provides NB register values to gather following
> TDP information
>
> * ProcessorPwrWatts: Specifies in Watts the maximum amount of power
> the processor can support.
> * CurrPwrWatts: Specifies in Watts the current amount of power being
> consumed by the processor.
>
> This driver provides
>
> * power1_max (ProcessorPwrWatts)

Still questionable whether power1_crit would be more appropriate...

> * power1_input (CurrPwrWatts)
>
> Changes from v2:
> - fix format strings
> - removed paranoid checks for existense of functions 3 and 5
> - changed return type of function f15h_power_is_internal_node0
> - use power1_max instead of power1_cap
> - use dev_warn instead of WARN_ON
> - rebased against 2.6.39-rc2
> - added Documentation/hwmon/f15h_power
>
> Changes from v3:
> - read static power information only once (during driver initialization)
> - made use of attribute groups
> - renamed f15h_power to fam15h_power
>
> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
> ---
> Documentation/hwmon/fam15h_power | 37 ++++++
> drivers/hwmon/Kconfig | 10 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/fam15h_power.c | 229 ++++++++++++++++++++++++++++++++++++++
> 4 files changed, 277 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/hwmon/fam15h_power
> create mode 100644 drivers/hwmon/fam15h_power.c
>
> At this stage I consider the _max attribute as the right one for
> reporting ProcessorPwrWatts.
>
> Hopefully I've addressed all your coments.
> Please apply.

It seems I have some more comments, but these are very small things you
should have no problem addressing quickly:

> diff --git a/Documentation/hwmon/fam15h_power b/Documentation/hwmon/fam15h_power
> new file mode 100644
> index 0000000..2f4d291
> --- /dev/null
> +++ b/Documentation/hwmon/fam15h_power
> @@ -0,0 +1,37 @@
> +Kernel driver fam15h_power
> +==========================
> +
> +Supported chips:
> +* AMD Family 15h Processors
> +
> + Prefix: 'fam15h_power'
> + Addresses scanned: PCI space
> + Datasheets:
> + BIOS and Kernel Developer's Guide (BKDG) For AMD Family 15h Processors
> + (not yet published)
> +
> +Author: Andreas Herrmann <andreas.herrmann3@amd.com>
> +
> +Description
> +-----------
> +
> +This driver permits reading of registers providing power information
> +of AMD Family 15h processors.
> +
> +For AMD Family 15h processors the following power values can be
> +calculated using different processor northbridge function registers:
> +
> +* BasePwrWatts: Specifies in watts the maximum amount of power
> + consumed by the processor for NB and logic external to the core.
> +* ProcessorPwrWatts: Specifies in watts the maximum amount of power
> + the processor can support.
> +* CurrPwrWatts: Specifies in watts the current amount of power being
> + consumed by the processor.
> +
> +This driver provides ProcessorPwrWatts and CurrPwrWatts:
> +* power1_max (ProcessorPwrWatts)
> +* power1_input (CurrPwrWatts)
> +
> +On multi-node processors the calculated value is for the entire
> +package and not for a single node. Thus the driver creates sysfs
> +attributes only for internal node0 of a multi-node processor.
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 060ef63..fb3e334 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -249,6 +249,16 @@ config SENSORS_K10TEMP
> This driver can also be built as a module. If so, the module
> will be called k10temp.
>
> +config SENSORS_FAM15H_POWER
> + tristate "AMD Family 15h processor power"
> + depends on X86 && PCI
> + help
> + If you say yes here you get support for processor power
> + information of your AMD family 15h CPU.
> +
> + This driver can also be built as a module. If so, the module
> + will be called fam15h_power.
> +
> config SENSORS_ASB100
> tristate "Asus ASB100 Bach"
> depends on X86 && I2C && EXPERIMENTAL
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 967d0ea..236d3f9 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -49,6 +49,7 @@ obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o
> obj-$(CONFIG_SENSORS_F71805F) += f71805f.o
> obj-$(CONFIG_SENSORS_F71882FG) += f71882fg.o
> obj-$(CONFIG_SENSORS_F75375S) += f75375s.o
> +obj-$(CONFIG_SENSORS_FAM15H_POWER) += fam15h_power.o
> obj-$(CONFIG_SENSORS_FSCHMD) += fschmd.o
> obj-$(CONFIG_SENSORS_G760A) += g760a.o
> obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
> diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
> new file mode 100644
> index 0000000..cb6eb99
> --- /dev/null
> +++ b/drivers/hwmon/fam15h_power.c
> @@ -0,0 +1,229 @@
> +/*
> + * fam15h_power.c - AMD Family 15h processor power monitoring
> + *
> + * Copyright (c) 2011 Advanced Micro Devices, Inc.
> + * Author: Andreas Herrmann <andreas.herrmann3@amd.com>
> + *
> + *
> + * This driver is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License; either
> + * version 2 of the License, or (at your option) any later version.
> + *
> + * This driver 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 driver; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/bitops.h>
> +#include <asm/processor.h>
> +
> +MODULE_DESCRIPTION("AMD Family 15h CPU processor power monitor");
> +MODULE_AUTHOR("Andreas Herrmann <andreas.herrmann3@amd.com>");
> +MODULE_LICENSE("GPL");
> +
> +/* D18F3 */
> +#define REG_NORTHBRIDGE_CAP 0xe8
> +
> +/* D18F4 */
> +#define REG_PROCESSOR_TDP 0x1b8
> +
> +/* D18F5 */
> +#define REG_TDP_RUNNING_AVERAGE 0xe0
> +#define REG_TDP_LIMIT3 0xe8
> +
> +struct fam15h_power_data {
> + struct device *hwmon_dev;
> + unsigned int tdp_to_watt;
> + unsigned int base_tdp;
> + unsigned int processor_pwr_watts;

watt vs. watts is inconsistent, isn't it?

> +};
> +
> +static ssize_t show_power(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + u32 val, tdp_limit, running_avg_range;
> + s32 running_avg_capture;
> + u64 curr_pwr_watts;
> + struct pci_dev *f4 = to_pci_dev(dev);
> + struct fam15h_power_data *data = pci_get_drvdata(f4);

dev_get_drvdata(dev) would be more efficient.

> +
> + pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
> + REG_TDP_RUNNING_AVERAGE, &val);
> + running_avg_capture = (val >> 4) & 0x3fffff;
> + running_avg_capture = sign_extend32(running_avg_capture, 22);
> + running_avg_range = val & 0xf;
> +
> + pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
> + REG_TDP_LIMIT3, &val);
> +
> + tdp_limit = val >> 16;
> + curr_pwr_watts = tdp_limit + data->base_tdp -

Doubled space.

> + (s32)(running_avg_capture >> (running_avg_range + 1));
> + curr_pwr_watts *= data->tdp_to_watt;
> +
> + /*
> + * Convert to microWatt
> + *
> + * power is in Watt provided as fixed point integer with
> + * scaling factor 1/(2^16). For conversion we use
> + * (10^6)/(2^16) = 15625/(2^10)
> + */
> + curr_pwr_watts = (curr_pwr_watts * 15625) >> 10;
> + return sprintf(buf, "%u\n", (unsigned int) curr_pwr_watts);
> +}
> +static DEVICE_ATTR(power1_input, S_IRUGO, show_power, NULL);
> +
> +static ssize_t show_power_max(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct pci_dev *f4 = to_pci_dev(dev);
> + struct fam15h_power_data *data = pci_get_drvdata(f4);

dev_get_drvdata(dev) would be more efficient (you don't even need f4
then.)

> + return sprintf(buf, "%u\n", data->processor_pwr_watts);
> +}
> +static DEVICE_ATTR(power1_max, S_IRUGO, show_power_max, NULL);
> +
> +static ssize_t show_name(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "fam15h_power\n");
> +}
> +static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
> +
> +static struct attribute *fam15h_power_attrs[] = {
> + &dev_attr_power1_input.attr,
> + &dev_attr_power1_max.attr,
> + &dev_attr_name.attr,
> + NULL
> +};
> +
> +static struct attribute_group fam15h_power_attr_group = {

Can be made const.

> + .attrs = fam15h_power_attrs,
> +};
> +
> +static bool __devinit fam15h_power_is_internal_node0(struct pci_dev *f4)
> +{
> + u32 val;
> +
> + pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 3),
> + REG_NORTHBRIDGE_CAP, &val);
> + if ((val & BIT(29)) && ((val >> 30) & 3))
> + return false;
> +
> + return true;
> +}
> +
> +static void __devinit fam15h_power_init_data(struct pci_dev *f4,
> + struct fam15h_power_data *data)
> +{
> + u32 val;
> + u64 tmp;
> +
> + pci_read_config_dword(f4, REG_PROCESSOR_TDP, &val);
> + data->base_tdp = val >> 16;
> + tmp = val & 0xffff;
> +
> + pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
> + REG_TDP_LIMIT3, &val);
> +
> + data->tdp_to_watt = ((val & 0x3ff) << 6) | ((val >> 10) & 0x3f);
> + tmp *= data->tdp_to_watt;
> +
> + /* result not allowed to be >= 256W */
> + if ((tmp>>16) >= 256)

Please add spaces around ">>" for consistency.

> + dev_warn(&f4->dev, "Bogus value for ProcessorPwrWatts "
> + "(processor_pwr_watts>=%u)\n",
> + (unsigned int) (tmp >> 16));
> +
> + /* convert to microWatt */
> + data->processor_pwr_watts = (tmp * 15625) >> 10;
> +}
> +
> +static int __devinit fam15h_power_probe(struct pci_dev *pdev,
> + const struct pci_device_id *id)
> +{
> + struct fam15h_power_data *data;
> + struct device *dev;
> + int err;
> +
> + if (!fam15h_power_is_internal_node0(pdev)) {
> + err = -ENODEV;
> + goto exit;
> + }
> +
> + data = kzalloc(sizeof(struct fam15h_power_data), GFP_KERNEL);
> + if (!data) {
> + err = -ENOMEM;
> + goto exit;
> + }
> + fam15h_power_init_data(pdev, data);
> +
> + dev = &pdev->dev;
> + err = sysfs_create_group(&dev->kobj, &fam15h_power_attr_group);
> + if (err)
> + goto exit_free_data;
> +
> + data->hwmon_dev = hwmon_device_register(&pdev->dev);
> + if (IS_ERR(data->hwmon_dev)) {
> + err = PTR_ERR(data->hwmon_dev);
> + goto exit_remove_group;
> + }
> + pci_set_drvdata(pdev, data);

This is racy. pci_set_drvdata() should be called before creating the
sysfs attributes, because the sysfs callbacks need it.

> +
> + return 0;
> +
> +exit_remove_group:
> + sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
> +exit_free_data:
> + kfree(data);
> +exit:
> + return err;
> +}
> +
> +static void __devexit fam15h_power_remove(struct pci_dev *pdev)
> +{
> + struct device *dev;
> + struct fam15h_power_data *data = pci_get_drvdata(pdev);
> +
> + dev = &pdev->dev;
> + hwmon_device_unregister(data->hwmon_dev);
> + sysfs_remove_group(&dev->kobj, &fam15h_power_attr_group);
> + pci_set_drvdata(pdev, NULL);
> + kfree(data);
> +}
> +
> +static DEFINE_PCI_DEVICE_TABLE(fam15h_power_id_table) = {
> + { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
> + {}
> +};
> +MODULE_DEVICE_TABLE(pci, fam15h_power_id_table);
> +
> +static struct pci_driver fam15h_power_driver = {
> + .name = "fam15h_power",
> + .id_table = fam15h_power_id_table,
> + .probe = fam15h_power_probe,
> + .remove = __devexit_p(fam15h_power_remove),
> +};
> +
> +static int __init fam15h_power_init(void)
> +{
> + return pci_register_driver(&fam15h_power_driver);
> +}
> +
> +static void __exit fam15h_power_exit(void)
> +{
> + pci_unregister_driver(&fam15h_power_driver);
> +}
> +
> +module_init(fam15h_power_init)
> +module_exit(fam15h_power_exit)

Thanks,
--
Jean Delvare


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