[PATCH v1 10/11] intel_th: Add PTI output driver

From: Alexander Shishkin
Date: Fri Mar 20 2015 - 13:33:37 EST


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@xxxxxxxxxxxxxxx>
---
.../ABI/testing/sysfs-bus-intel_th-devices-pti | 24 ++
drivers/hwtracing/intel_th/Kconfig | 9 +
drivers/hwtracing/intel_th/Makefile | 3 +
drivers/hwtracing/intel_th/pti.c | 252 +++++++++++++++++++++
drivers/hwtracing/intel_th/pti.h | 29 +++
5 files changed, 317 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-intel_th-devices-pti
create mode 100644 drivers/hwtracing/intel_th/pti.c
create mode 100644 drivers/hwtracing/intel_th/pti.h

diff --git a/Documentation/ABI/testing/sysfs-bus-intel_th-devices-pti b/Documentation/ABI/testing/sysfs-bus-intel_th-devices-pti
new file mode 100644
index 0000000000..c179f41878
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-intel_th-devices-pti
@@ -0,0 +1,24 @@
+What: /sys/bus/intel_th/devices/<intel_th_id>-pti/mode
+Date: February 2015
+KernelVersion: 4.1
+Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
+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: February 2015
+KernelVersion: 4.1
+Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
+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: February 2015
+KernelVersion: 4.1
+Contact: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
+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.
diff --git a/drivers/hwtracing/intel_th/Kconfig b/drivers/hwtracing/intel_th/Kconfig
index cfb68c3f58..29287c6b18 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 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 Trace Hub debugging"
depends on DEBUG_FS
diff --git a/drivers/hwtracing/intel_th/Makefile b/drivers/hwtracing/intel_th/Makefile
index 4636757df2..81d42fe918 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 0000000000..599689fe69
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.c
@@ -0,0 +1,252 @@
+/*
+ * Intel 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 Trace Hub PTI output driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>");
diff --git a/drivers/hwtracing/intel_th/pti.h b/drivers/hwtracing/intel_th/pti.h
new file mode 100644
index 0000000000..3084064731
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.h
@@ -0,0 +1,29 @@
+/*
+ * Intel 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__ */
--
2.1.4

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