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SubjectRe: [PATCH 3/4] thermal: int340x: processor_thermal: Add RFIM driver
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Date
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?


> 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@linux.intel.com>
> ---
> .../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");
>


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