Re: [PATCH 3/4] thermal: int340x: processor_thermal: Add RFIM driver

[Srinivas Pandruvada]

On Wed, 2020-12-09 at 21:48 +0100, Daniel Lezcano wrote:
> On 26/11/2020 18:18, Srinivas Pandruvada wrote:
> > Add support for RFIM (Radio Frequency Interference Mitigation)
> > support
> > via processor thermal PCI device. This drivers allows adjustment of
> > FIVR (Fully Integrated Voltage Regulator) and DDR (Double Data
> > Rate)
> > frequencies to avoid RF interference with WiFi and 5G.
> > 
> > Switching voltage regulators (VR) generate radiated EMI or RFI at
> > the
> > fundamental frequency and its harmonics. Some harmonics may
> > interfere
> > with very sensitive wireless receivers such as Wi-Fi and cellular
> > that
> > are integrated into host systems like notebook PCs.  One of
> > mitigation
> > methods is requesting SOC integrated VR (IVR) switching frequency
> > to a
> > small % and shift away the switching noise harmonic interference
> > from
> > radio channels.  OEM or ODMs can use the driver to control SOC IVR
> > operation within the range where it does not impact IVR
> > performance.
> > 
> > DRAM devices of DDR IO interface and their power plane can generate
> > EMI
> > at the data rates. Similar to IVR control mechanism, Intel offers a
> > mechanism by which DDR data rates can be changed if several
> > conditions
> > are met: there is strong RFI interference because of DDR; CPU power
> > management has no other restriction in changing DDR data rates;
> > PC ODMs enable this feature (real time DDR RFI Mitigation referred
> > to as
> > DDR-RFIM) for Wi-Fi from BIOS.
> 
> Thanks for the technical details, it is interesting.
> 
> May be I missed something but how this is related to thermal

Not directly offering thermal control but uses the thermal PCI device
(via MMIO) as this allows optimal RF frequencies which will result in
optimal TX power. Higher TX power consumption can result in non optimal
die temperature. Idea is manage power before this cause issue.

Thanks,
Srinivas

> 
> 
> > This change exports two folders under
> > /sys/bus/pci/devices/0000:00:04.0.
> > One folder "fivr" contains all attributes exposed for controling
> > FIVR
> > features. The other folder "dvfs" contains all attributes for DDR
> > features.
> > 
> > Changes done to implement:
> > - New module for rfim interfaces
> > - Two new per processor features for DDR and FIVR
> > - Enable feature for Tiger Lake (FIVR only) and Alder Lake
> > 
> > The attributes exposed and explanation:
> > 
> > FIVR attributes
> > 
> > vco_ref_code_lo (RW): The VCO reference code is an 11-bit field and
> > controls the FIVR switching frequency. This is the 3-bit LSB field.
> > 
> > vco_ref_code_hi (RW): The VCO reference code is an 11-bit field and
> > controls the FIVR switching frequency. This is the 8-bit MSB field.
> > 
> > spread_spectrum_pct (RW): Set the FIVR spread spectrum clocking
> > percentage
> > 
> > spread_spectrum_clk_enable (RW): Enable/disable of the FIVR spread
> > spectrum clocking feature
> > 
> > rfi_vco_ref_code (RW): This field is a read only status register
> > which
> > reflects the current FIVR switching frequency
> > 
> > fivr_fffc_rev (RW): This field indicated the revision of the FIVR
> > HW.
> > 
> > DVFS attributes
> > 
> > rfi_restriction_run_busy (RW): Request the restriction of specific
> > DDR
> > data rate and set this value 1. Self reset to 0 after operation.
> > 
> > rfi_restriction_err_code (RW): Values:  0 :Request is accepted,
> > 1:Feature
> > disabled, 2: the request restricts more points than it is allowed
> > 
> > rfi_restriction_data_rate_Delta (RW): Restricted DDR data rate for
> > RFI
> > protection: Lower Limit
> > 
> > rfi_restriction_data_rate_Base (RW): Restricted DDR data rate for
> > RFI
> > protection: Upper Limit
> > 
> > ddr_data_rate_point_0 (RO): DDR data rate selection 1st point
> > 
> > ddr_data_rate_point_1 (RO): DDR data rate selection 2nd point
> > 
> > ddr_data_rate_point_2 (RO): DDR data rate selection 3rd point
> > 
> > ddr_data_rate_point_3 (RO): DDR data rate selection 4th point
> > 
> > rfi_disable (RW): Disable DDR rate change feature
> > 
> > Signed-off-by: Srinivas Pandruvada <
> > srinivas.pandruvada@xxxxxxxxxxxxxxx>
> > ---
> >  .../thermal/intel/int340x_thermal/Makefile    |   1 +
> >  .../processor_thermal_device.c                |  23 +-
> >  .../processor_thermal_device.h                |   5 +
> >  .../int340x_thermal/processor_thermal_rfim.c  | 244
> > ++++++++++++++++++
> >  4 files changed, 270 insertions(+), 3 deletions(-)
> >  create mode 100644
> > drivers/thermal/intel/int340x_thermal/processor_thermal_rfim.c
> > 
> > diff --git a/drivers/thermal/intel/int340x_thermal/Makefile
> > b/drivers/thermal/intel/int340x_thermal/Makefile
> > index 86e8d3c87df7..f4e2eb7d9606 100644
> > --- a/drivers/thermal/intel/int340x_thermal/Makefile
> > +++ b/drivers/thermal/intel/int340x_thermal/Makefile
> > @@ -5,5 +5,6 @@ obj-$(CONFIG_INT340X_THERMAL)	+=
> > int3402_thermal.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= int3403_thermal.o
> >  obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_device.o
> >  obj-$(CONFIG_PROC_THERMAL_MMIO_RAPL) += processor_thermal_rapl.o
> > +obj-$(CONFIG_INT340X_THERMAL)	+= processor_thermal_rfim.o
> >  obj-$(CONFIG_INT3406_THERMAL)	+= int3406_thermal.o
> >  obj-$(CONFIG_ACPI_THERMAL_REL)	+= acpi_thermal_rel.o
> > diff --git
> > a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
> > index 589ac7deec02..b6a7358b989d 100644
> > ---
> > a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
> > +++
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.c
> > @@ -429,6 +429,8 @@ static int proc_thermal_mmio_add(struct pci_dev
> > *pdev,
> >  {
> >  	int ret;
> >  
> > +	proc_priv->mmio_feature_mask = feature_mask;
> > +
> >  	if (feature_mask) {
> >  		ret = proc_thermal_set_mmio_base(pdev, proc_priv);
> >  		if (ret)
> > @@ -443,9 +445,21 @@ static int proc_thermal_mmio_add(struct
> > pci_dev *pdev,
> >  		}
> >  	}
> >  
> > -	proc_priv->mmio_feature_mask = feature_mask;
> > +	if (feature_mask & PROC_THERMAL_FEATURE_FIVR ||
> > +	    feature_mask & PROC_THERMAL_FEATURE_DVFS) {
> > +		ret = proc_thermal_rfim_add(pdev, proc_priv);
> > +		if (ret) {
> > +			dev_err(&pdev->dev, "failed to add RFIM
> > interface\n");
> > +			goto err_rem_rapl;
> > +		}
> > +	}
> >  
> >  	return 0;
> > +
> > +err_rem_rapl:
> > +	proc_thermal_rapl_remove();
> > +
> > +	return ret;
> >  }
> >  
> >  static void proc_thermal_mmio_remove(struct pci_dev *pdev)
> > @@ -455,6 +469,9 @@ static void proc_thermal_mmio_remove(struct
> > pci_dev *pdev)
> >  	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_RAPL)
> >  		proc_thermal_rapl_remove();
> >  
> > +	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_FIVR ||
> > +	    proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_DVFS)
> > +		proc_thermal_rfim_remove(pdev);
> >  }
> >  
> >  static int  proc_thermal_pci_probe(struct pci_dev *pdev,
> > @@ -566,7 +583,7 @@ static int proc_thermal_resume(struct device
> > *dev)
> >  static SIMPLE_DEV_PM_OPS(proc_thermal_pm, NULL,
> > proc_thermal_resume);
> >  
> >  static const struct pci_device_id proc_thermal_pci_ids[] = {
> > -	{ PCI_DEVICE_DATA(INTEL, ADL_THERMAL,
> > PROC_THERMAL_FEATURE_RAPL) },
> > +	{ PCI_DEVICE_DATA(INTEL, ADL_THERMAL, PROC_THERMAL_FEATURE_RAPL
> > | PROC_THERMAL_FEATURE_FIVR | PROC_THERMAL_FEATURE_DVFS) },
> >  	{ PCI_DEVICE_DATA(INTEL, BDW_THERMAL, 0) },
> >  	{ PCI_DEVICE_DATA(INTEL, BSW_THERMAL, 0) },
> >  	{ PCI_DEVICE_DATA(INTEL, BXT0_THERMAL, 0) },
> > @@ -580,7 +597,7 @@ static const struct pci_device_id
> > proc_thermal_pci_ids[] = {
> >  	{ PCI_DEVICE_DATA(INTEL, ICL_THERMAL,
> > PROC_THERMAL_FEATURE_RAPL) },
> >  	{ PCI_DEVICE_DATA(INTEL, JSL_THERMAL, 0) },
> >  	{ PCI_DEVICE_DATA(INTEL, SKL_THERMAL,
> > PROC_THERMAL_FEATURE_RAPL) },
> > -	{ PCI_DEVICE_DATA(INTEL, TGL_THERMAL,
> > PROC_THERMAL_FEATURE_RAPL) },
> > +	{ PCI_DEVICE_DATA(INTEL, TGL_THERMAL, PROC_THERMAL_FEATURE_RAPL
> > | PROC_THERMAL_FEATURE_FIVR) },
> >  	{ },
> >  };
> >  
> > diff --git
> > a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
> > index 45214571e00d..4bbb88f6b4a7 100644
> > ---
> > a/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
> > +++
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_device.h
> > @@ -54,6 +54,8 @@ struct rapl_mmio_regs {
> >  
> >  #define PROC_THERMAL_FEATURE_NONE	0x00
> >  #define PROC_THERMAL_FEATURE_RAPL	0x01
> > +#define PROC_THERMAL_FEATURE_FIVR	0x02
> > +#define PROC_THERMAL_FEATURE_DVFS	0x04
> >  
> >  #if IS_ENABLED(CONFIG_PROC_THERMAL_MMIO_RAPL)
> >  int proc_thermal_rapl_add(struct pci_dev *pdev, struct
> > proc_thermal_device *proc_priv);
> > @@ -70,4 +72,7 @@ static void __maybe_unused
> > proc_thermal_rapl_remove(void)
> >  }
> >  #endif
> >  
> > +int proc_thermal_rfim_add(struct pci_dev *pdev, struct
> > proc_thermal_device *proc_priv);
> > +void proc_thermal_rfim_remove(struct pci_dev *pdev);
> > +
> >  #endif
> > diff --git
> > a/drivers/thermal/intel/int340x_thermal/processor_thermal_rfim.c
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_rfim.c
> > new file mode 100644
> > index 000000000000..aef993a813e2
> > --- /dev/null
> > +++
> > b/drivers/thermal/intel/int340x_thermal/processor_thermal_rfim.c
> > @@ -0,0 +1,244 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * processor thermal device RFIM control
> > + * Copyright (c) 2020, Intel Corporation.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include "processor_thermal_device.h"
> > +
> > +struct mmio_reg {
> > +	int read_only;
> > +	u32 offset;
> > +	int bits;
> > +	u16 mask;
> > +	u16 shift;
> > +};
> > +
> > +/* These will represent sysfs attribute names */
> > +static const char * const fivr_strings[] = {
> > +	"vco_ref_code_lo",
> > +	"vco_ref_code_hi",
> > +	"spread_spectrum_pct",
> > +	"spread_spectrum_clk_enable",
> > +	"rfi_vco_ref_code",
> > +	"fivr_fffc_rev",
> > +	NULL
> > +};
> > +
> > +static const struct mmio_reg tgl_fivr_mmio_regs[] = {
> > +	{ 0, 0x5A18, 3, 0x7, 12}, /* vco_ref_code_lo */
> > +	{ 0, 0x5A18, 8, 0xFF, 16}, /* vco_ref_code_hi */
> > +	{ 0, 0x5A08, 8, 0xFF, 0}, /* spread_spectrum_pct */
> > +	{ 0, 0x5A08, 1, 0x1, 8}, /* spread_spectrum_clk_enable */
> > +	{ 1, 0x5A10, 12, 0xFFF, 0}, /* rfi_vco_ref_code */
> > +	{ 1, 0x5A14, 2, 0x3, 1}, /* fivr_fffc_rev */
> > +};
> > +
> > +/* These will represent sysfs attribute names */
> > +static const char * const dvfs_strings[] = {
> > +	"rfi_restriction_run_busy",
> > +	"rfi_restriction_err_code",
> > +	"rfi_restriction_data_rate",
> > +	"rfi_restriction_data_rate_base",
> > +	"ddr_data_rate_point_0",
> > +	"ddr_data_rate_point_1",
> > +	"ddr_data_rate_point_2",
> > +	"ddr_data_rate_point_3",
> > +	"rfi_disable",
> > +	NULL
> > +};
> > +
> > +static const struct mmio_reg adl_dvfs_mmio_regs[] = {
> > +	{ 0, 0x5A38, 1, 0x1, 31}, /* rfi_restriction_run_busy */
> > +	{ 0, 0x5A38, 7, 0x7F, 24}, /* rfi_restriction_err_code */
> > +	{ 0, 0x5A38, 8, 0xFF, 16}, /* rfi_restriction_data_rate */
> > +	{ 0, 0x5A38, 16, 0xFFFF, 0}, /* rfi_restriction_data_rate_base
> > */
> > +	{ 0, 0x5A30, 10, 0x3FF, 0}, /* ddr_data_rate_point_0 */
> > +	{ 0, 0x5A30, 10, 0x3FF, 10}, /* ddr_data_rate_point_1 */
> > +	{ 0, 0x5A30, 10, 0x3FF, 20}, /* ddr_data_rate_point_2 */
> > +	{ 0, 0x5A30, 10, 0x3FF, 30}, /* ddr_data_rate_point_3 */
> > +	{ 0, 0x5A40, 1, 0x1, 0}, /* rfi_disable */
> > +};
> > +
> > +#define RFIM_SHOW(suffix, table)\
> > +static ssize_t suffix##_show(struct device *dev,\
> > +			      struct device_attribute *attr,\
> > +			      char *buf)\
> > +{\
> > +	struct proc_thermal_device *proc_priv;\
> > +	struct pci_dev *pdev = to_pci_dev(dev);\
> > +	const struct mmio_reg *mmio_regs;\
> > +	const char **match_strs;\
> > +	u32 reg_val;\
> > +	int ret;\
> > +\
> > +	proc_priv = pci_get_drvdata(pdev);\
> > +	if (table) {\
> > +		match_strs = (const char **)dvfs_strings;\
> > +		mmio_regs = adl_dvfs_mmio_regs;\
> > +	} else { \
> > +		match_strs = (const char **)fivr_strings;\
> > +		mmio_regs = tgl_fivr_mmio_regs;\
> > +	} \
> > +	\
> > +	ret = match_string(match_strs, -1, attr->attr.name);\
> > +	if (ret < 0)\
> > +		return ret;\
> > +	reg_val = readl((void __iomem *) (proc_priv->mmio_base +
> > mmio_regs[ret].offset));\
> > +	ret = (reg_val >> mmio_regs[ret].shift) & mmio_regs[ret].mask;\
> > +	return sprintf(buf, "%u\n", ret);\
> > +}
> > +
> > +#define RFIM_STORE(suffix, table)\
> > +static ssize_t suffix##_store(struct device *dev,\
> > +			       struct device_attribute *attr,\
> > +			       const char *buf, size_t count)\
> > +{\
> > +	struct proc_thermal_device *proc_priv;\
> > +	struct pci_dev *pdev = to_pci_dev(dev);\
> > +	unsigned int input;\
> > +	const char **match_strs;\
> > +	const struct mmio_reg *mmio_regs;\
> > +	int ret, err;\
> > +	u32 reg_val;\
> > +	u32 mask;\
> > +\
> > +	proc_priv = pci_get_drvdata(pdev);\
> > +	if (table) {\
> > +		match_strs = (const char **)dvfs_strings;\
> > +		mmio_regs = adl_dvfs_mmio_regs;\
> > +	} else { \
> > +		match_strs = (const char **)fivr_strings;\
> > +		mmio_regs = tgl_fivr_mmio_regs;\
> > +	} \
> > +	\
> > +	ret = match_string(match_strs, -1, attr->attr.name);\
> > +	if (ret < 0)\
> > +		return ret;\
> > +	if (mmio_regs[ret].read_only)\
> > +		return -EPERM;\
> > +	err = kstrtouint(buf, 10, &input);\
> > +	if (err)\
> > +		return err;\
> > +	mask = GENMASK(mmio_regs[ret].shift + mmio_regs[ret].bits - 1,
> > mmio_regs[ret].shift);\
> > +	reg_val = readl((void __iomem *) (proc_priv->mmio_base +
> > mmio_regs[ret].offset));\
> > +	reg_val &= ~mask;\
> > +	reg_val |= (input << mmio_regs[ret].shift);\
> > +	writel(reg_val, (void __iomem *) (proc_priv->mmio_base +
> > mmio_regs[ret].offset));\
> > +	return count;\
> > +}
> > +
> > +RFIM_SHOW(vco_ref_code_lo, 0)
> > +RFIM_SHOW(vco_ref_code_hi, 0)
> > +RFIM_SHOW(spread_spectrum_pct, 0)
> > +RFIM_SHOW(spread_spectrum_clk_enable, 0)
> > +RFIM_SHOW(rfi_vco_ref_code, 0)
> > +RFIM_SHOW(fivr_fffc_rev, 0)
> > +
> > +RFIM_STORE(vco_ref_code_lo, 0)
> > +RFIM_STORE(vco_ref_code_hi, 0)
> > +RFIM_STORE(spread_spectrum_pct, 0)
> > +RFIM_STORE(spread_spectrum_clk_enable, 0)
> > +RFIM_STORE(rfi_vco_ref_code, 0)
> > +RFIM_STORE(fivr_fffc_rev, 0)
> > +
> > +static DEVICE_ATTR_RW(vco_ref_code_lo);
> > +static DEVICE_ATTR_RW(vco_ref_code_hi);
> > +static DEVICE_ATTR_RW(spread_spectrum_pct);
> > +static DEVICE_ATTR_RW(spread_spectrum_clk_enable);
> > +static DEVICE_ATTR_RW(rfi_vco_ref_code);
> > +static DEVICE_ATTR_RW(fivr_fffc_rev);
> > +
> > +static struct attribute *fivr_attrs[] = {
> > +	&dev_attr_vco_ref_code_lo.attr,
> > +	&dev_attr_vco_ref_code_hi.attr,
> > +	&dev_attr_spread_spectrum_pct.attr,
> > +	&dev_attr_spread_spectrum_clk_enable.attr,
> > +	&dev_attr_rfi_vco_ref_code.attr,
> > +	&dev_attr_fivr_fffc_rev.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group fivr_attribute_group = {
> > +	.attrs = fivr_attrs,
> > +	.name = "fivr"
> > +};
> > +
> > +RFIM_SHOW(rfi_restriction_run_busy, 1)
> > +RFIM_SHOW(rfi_restriction_err_code, 1)
> > +RFIM_SHOW(rfi_restriction_data_rate, 1)
> > +RFIM_SHOW(ddr_data_rate_point_0, 1)
> > +RFIM_SHOW(ddr_data_rate_point_1, 1)
> > +RFIM_SHOW(ddr_data_rate_point_2, 1)
> > +RFIM_SHOW(ddr_data_rate_point_3, 1)
> > +RFIM_SHOW(rfi_disable, 1)
> > +
> > +RFIM_STORE(rfi_restriction_run_busy, 1)
> > +RFIM_STORE(rfi_restriction_err_code, 1)
> > +RFIM_STORE(rfi_restriction_data_rate, 1)
> > +RFIM_STORE(rfi_disable, 1)
> > +
> > +static DEVICE_ATTR_RW(rfi_restriction_run_busy);
> > +static DEVICE_ATTR_RW(rfi_restriction_err_code);
> > +static DEVICE_ATTR_RW(rfi_restriction_data_rate);
> > +static DEVICE_ATTR_RO(ddr_data_rate_point_0);
> > +static DEVICE_ATTR_RO(ddr_data_rate_point_1);
> > +static DEVICE_ATTR_RO(ddr_data_rate_point_2);
> > +static DEVICE_ATTR_RO(ddr_data_rate_point_3);
> > +static DEVICE_ATTR_RW(rfi_disable);
> > +
> > +static struct attribute *dvfs_attrs[] = {
> > +	&dev_attr_rfi_restriction_run_busy.attr,
> > +	&dev_attr_rfi_restriction_err_code.attr,
> > +	&dev_attr_rfi_restriction_data_rate.attr,
> > +	&dev_attr_ddr_data_rate_point_0.attr,
> > +	&dev_attr_ddr_data_rate_point_1.attr,
> > +	&dev_attr_ddr_data_rate_point_2.attr,
> > +	&dev_attr_ddr_data_rate_point_3.attr,
> > +	&dev_attr_rfi_disable.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group dvfs_attribute_group = {
> > +	.attrs = dvfs_attrs,
> > +	.name = "dvfs"
> > +};
> > +
> > +int proc_thermal_rfim_add(struct pci_dev *pdev, struct
> > proc_thermal_device *proc_priv)
> > +{
> > +	int ret;
> > +
> > +	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_FIVR) {
> > +		ret = sysfs_create_group(&pdev->dev.kobj,
> > &fivr_attribute_group);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_DVFS) {
> > +		ret = sysfs_create_group(&pdev->dev.kobj,
> > &dvfs_attribute_group);
> > +		if (ret && proc_priv->mmio_feature_mask &
> > PROC_THERMAL_FEATURE_FIVR) {
> > +			sysfs_remove_group(&pdev->dev.kobj,
> > &fivr_attribute_group);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(proc_thermal_rfim_add);
> > +
> > +void proc_thermal_rfim_remove(struct pci_dev *pdev)
> > +{
> > +	struct proc_thermal_device *proc_priv = pci_get_drvdata(pdev);
> > +
> > +	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_FIVR)
> > +		sysfs_remove_group(&pdev->dev.kobj,
> > &fivr_attribute_group);
> > +
> > +	if (proc_priv->mmio_feature_mask & PROC_THERMAL_FEATURE_DVFS)
> > +		sysfs_remove_group(&pdev->dev.kobj,
> > &dvfs_attribute_group);
> > +}
> > +EXPORT_SYMBOL_GPL(proc_thermal_rfim_remove);
> > +
> > +MODULE_LICENSE("GPL v2");
> > 
> 
>