intel_th: Add PTI output driver (14cdbf04) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/ABI/testing/sysfs-bus-intel_th-devices-pti

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		What: /sys/bus/intel_th/devices/<intel_th_id>-pti/mode
		Date: June 2015
		KernelVersion: 4.3
		Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
		Description: (RW) Configure PTI output width. Currently supported values
		are 4, 8, 12, 16.

		What: /sys/bus/intel_th/devices/<intel_th_id>-pti/freerunning_clock
		Date: June 2015
		KernelVersion: 4.3
		Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
		Description: (RW) 0: PTI trace clock acts as a strobe which only toggles
		when there is trace data to send. 1: PTI trace clock is a
		free-running clock.

		What: /sys/bus/intel_th/devices/<intel_th_id>-pti/clock_divider
		Date: June 2015
		KernelVersion: 4.3
		Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
		Description: (RW) Configure PTI port clock divider:
		- 0: Intel TH clock rate,
		- 1: 1/2 Intel TH clock rate,
		- 2: 1/4 Intel TH clock rate,
		- 3: 1/8 Intel TH clock rate.

drivers/hwtracing/intel_th/Kconfig

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		@@ -54,6 +54,15 @@ config INTEL_TH_MSU

		Say Y here to enable MSU output device for Intel TH.

		config INTEL_TH_PTI
		tristate "Intel(R) Trace Hub PTI output"
		help
		Parallel Trace Interface unit (PTI) is a trace output device
		of Intel TH architecture that facilitates STP trace output via
		a PTI port.

		Say Y to enable PTI output of Intel TH data.

		config INTEL_TH_DEBUG
		bool "Intel(R) Trace Hub debugging"
		depends on DEBUG_FS

drivers/hwtracing/intel_th/Makefile

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		@@ -13,3 +13,6 @@ intel_th_sth-y := sth.o

		obj-$(CONFIG_INTEL_TH_MSU) += intel_th_msu.o
		intel_th_msu-y := msu.o

		obj-$(CONFIG_INTEL_TH_PTI) += intel_th_pti.o
		intel_th_pti-y := pti.o

drivers/hwtracing/intel_th/pti.c

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		/*
		* Intel(R) Trace Hub PTI output driver
		*
		* Copyright (C) 2014-2015 Intel Corporation.
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms and conditions of the GNU General Public License,
		* version 2, as published by the Free Software Foundation.
		*
		* This program is distributed in the hope 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.
		*/

		#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

		#include <linux/types.h>
		#include <linux/module.h>
		#include <linux/device.h>
		#include <linux/sizes.h>
		#include <linux/printk.h>
		#include <linux/slab.h>
		#include <linux/mm.h>
		#include <linux/io.h>

		#include "intel_th.h"
		#include "pti.h"

		struct pti_device {
		void __iomem *base;
		struct intel_th_device *thdev;
		unsigned int mode;
		unsigned int freeclk;
		unsigned int clkdiv;
		unsigned int patgen;
		};

		/* map PTI widths to MODE settings of PTI_CTL register */
		static const unsigned int pti_mode[] = {
		0, 4, 8, 0, 12, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0,
		};

		static int pti_width_mode(unsigned int width)
		{
		int i;

		for (i = 0; i < ARRAY_SIZE(pti_mode); i++)
		if (pti_mode[i] == width)
		return i;

		return -EINVAL;
		}

		static ssize_t mode_show(struct device dev, struct device_attribute attr,
		char *buf)
		{
		struct pti_device *pti = dev_get_drvdata(dev);

		return scnprintf(buf, PAGE_SIZE, "%d\n", pti_mode[pti->mode]);
		}

		static ssize_t mode_store(struct device dev, struct device_attribute attr,
		const char *buf, size_t size)
		{
		struct pti_device *pti = dev_get_drvdata(dev);
		unsigned long val;
		int ret;

		ret = kstrtoul(buf, 10, &val);
		if (ret)
		return ret;

		ret = pti_width_mode(val);
		if (ret < 0)
		return ret;

		pti->mode = ret;

		return size;
		}

		static DEVICE_ATTR_RW(mode);

		static ssize_t
		freerunning_clock_show(struct device dev, struct device_attribute attr,
		char *buf)
		{
		struct pti_device *pti = dev_get_drvdata(dev);

		return scnprintf(buf, PAGE_SIZE, "%d\n", pti->freeclk);
		}

		static ssize_t
		freerunning_clock_store(struct device dev, struct device_attribute attr,
		const char *buf, size_t size)
		{
		struct pti_device *pti = dev_get_drvdata(dev);
		unsigned long val;
		int ret;

		ret = kstrtoul(buf, 10, &val);
		if (ret)
		return ret;

		pti->freeclk = !!val;

		return size;
		}

		static DEVICE_ATTR_RW(freerunning_clock);

		static ssize_t
		clock_divider_show(struct device dev, struct device_attribute attr,
		char *buf)
		{
		struct pti_device *pti = dev_get_drvdata(dev);

		return scnprintf(buf, PAGE_SIZE, "%d\n", 1u << pti->clkdiv);
		}

		static ssize_t
		clock_divider_store(struct device dev, struct device_attribute attr,
		const char *buf, size_t size)
		{
		struct pti_device *pti = dev_get_drvdata(dev);
		unsigned long val;
		int ret;

		ret = kstrtoul(buf, 10, &val);
		if (ret)
		return ret;

		if (!is_power_of_2(val) \|\| val > 8 \|\| !val)
		return -EINVAL;

		pti->clkdiv = val;

		return size;
		}

		static DEVICE_ATTR_RW(clock_divider);

		static struct attribute *pti_output_attrs[] = {
		&dev_attr_mode.attr,
		&dev_attr_freerunning_clock.attr,
		&dev_attr_clock_divider.attr,
		NULL,
		};

		static struct attribute_group pti_output_group = {
		.attrs = pti_output_attrs,
		};

		static int intel_th_pti_activate(struct intel_th_device *thdev)
		{
		struct pti_device *pti = dev_get_drvdata(&thdev->dev);
		u32 ctl = PTI_EN;

		if (pti->patgen)
		ctl \|= pti->patgen << __ffs(PTI_PATGENMODE);
		if (pti->freeclk)
		ctl \|= PTI_FCEN;
		ctl \|= pti->mode << __ffs(PTI_MODE);
		ctl \|= pti->clkdiv << __ffs(PTI_CLKDIV);

		iowrite32(ctl, pti->base + REG_PTI_CTL);

		intel_th_trace_enable(thdev);

		return 0;
		}

		static void intel_th_pti_deactivate(struct intel_th_device *thdev)
		{
		struct pti_device *pti = dev_get_drvdata(&thdev->dev);

		intel_th_trace_disable(thdev);

		iowrite32(0, pti->base + REG_PTI_CTL);
		}

		static void read_hw_config(struct pti_device *pti)
		{
		u32 ctl = ioread32(pti->base + REG_PTI_CTL);

		pti->mode = (ctl & PTI_MODE) >> __ffs(PTI_MODE);
		pti->clkdiv = (ctl & PTI_CLKDIV) >> __ffs(PTI_CLKDIV);
		pti->freeclk = !!(ctl & PTI_FCEN);

		if (!pti_mode[pti->mode])
		pti->mode = pti_width_mode(4);
		if (!pti->clkdiv)
		pti->clkdiv = 1;
		}

		static int intel_th_pti_probe(struct intel_th_device *thdev)
		{
		struct device *dev = &thdev->dev;
		struct resource *res;
		struct pti_device *pti;
		void __iomem *base;
		int ret;

		res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
		if (!res)
		return -ENODEV;

		base = devm_ioremap(dev, res->start, resource_size(res));
		if (IS_ERR(base))
		return PTR_ERR(base);

		pti = devm_kzalloc(dev, sizeof(*pti), GFP_KERNEL);
		if (!pti)
		return -ENOMEM;

		pti->thdev = thdev;
		pti->base = base;

		read_hw_config(pti);

		ret = sysfs_create_group(&dev->kobj, &pti_output_group);
		if (ret)
		return ret;

		dev_set_drvdata(dev, pti);

		return 0;
		}

		static void intel_th_pti_remove(struct intel_th_device *thdev)
		{
		}

		static struct intel_th_driver intel_th_pti_driver = {
		.probe = intel_th_pti_probe,
		.remove = intel_th_pti_remove,
		.activate = intel_th_pti_activate,
		.deactivate = intel_th_pti_deactivate,
		.driver = {
		.name = "pti",
		.owner = THIS_MODULE,
		},
		};

		module_driver(intel_th_pti_driver,
		intel_th_driver_register,
		intel_th_driver_unregister);

		MODULE_LICENSE("GPL v2");
		MODULE_DESCRIPTION("Intel(R) Trace Hub PTI output driver");
		MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");

drivers/hwtracing/intel_th/pti.h

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		/*
		* Intel(R) Trace Hub PTI output data structures
		*
		* Copyright (C) 2014-2015 Intel Corporation.
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms and conditions of the GNU General Public License,
		* version 2, as published by the Free Software Foundation.
		*
		* This program is distributed in the hope 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.
		*/

		#ifndef __INTEL_TH_STH_H__
		#define __INTEL_TH_STH_H__

		enum {
		REG_PTI_CTL = 0x1c00,
		};

		#define PTI_EN BIT(0)
		#define PTI_FCEN BIT(1)
		#define PTI_MODE 0xf0
		#define PTI_CLKDIV 0x000f0000
		#define PTI_PATGENMODE 0x00f00000

		#endif /* __INTEL_TH_STH_H__ */