intel_th: Add PTI output driver

Parallel Trace Interface (PTI) unit is a trace output device that sends
data over a PTI port.

The driver provides interfaces to configure bus width, bus clock divider
and mode. Tracing is enabled via output device's "active" attribute.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 293 insertions, 0 deletions

diff --git a/drivers/hwtracing/intel_th/Kconfig b/drivers/hwtracing/intel_th/Kconfig
index d9a1217e27bf..b7a9073d968b 100644
--- a/drivers/hwtracing/intel_th/Kconfig
+++ b/drivers/hwtracing/intel_th/Kconfig
@@ -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
diff --git a/drivers/hwtracing/intel_th/Makefile b/drivers/hwtracing/intel_th/Makefile
index 4636757df2a1..81d42fe918f7 100644
--- a/drivers/hwtracing/intel_th/Makefile
+++ b/drivers/hwtracing/intel_th/Makefile
@@ -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
diff --git a/drivers/hwtracing/intel_th/pti.c b/drivers/hwtracing/intel_th/pti.c
new file mode 100644
index 000000000000..1e3bbc89825c
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.c
@@ -0,0 +1,252 @@
+/*
+ * 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>");
diff --git a/drivers/hwtracing/intel_th/pti.h b/drivers/hwtracing/intel_th/pti.h
new file mode 100644
index 000000000000..20883f5628cf
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.h
@@ -0,0 +1,29 @@
+/*
+ * 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__ */