Logo Search packages:      
Sourcecode: linux version File versions  Download package

etm.c

/*
 * linux/arch/arm/kernel/etm.c
 *
 * Driver for ARM's Embedded Trace Macrocell and Embedded Trace Buffer.
 *
 * Copyright (C) 2009 Nokia Corporation.
 * Alexander Shishkin
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/amba/bus.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <asm/hardware/coresight.h>
#include <asm/sections.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shishkin");

/*
 * ETM tracer state
 */
00036 struct tracectx {
      unsigned int      etb_bufsz;
      void __iomem      *etb_regs;
      void __iomem      *etm_regs;
      unsigned long     flags;
      int         ncmppairs;
      int         etm_portsz;
      struct device     *dev;
      struct clk  *emu_clk;
      struct mutex      mutex;
};

static struct tracectx tracer;

static inline bool trace_isrunning(struct tracectx *t)
{
      return !!(t->flags & TRACER_RUNNING);
}

static int etm_setup_address_range(struct tracectx *t, int n,
            unsigned long start, unsigned long end, int exclude, int data)
{
      u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
                ETMAAT_NOVALCMP;

      if (n < 1 || n > t->ncmppairs)
            return -EINVAL;

      /* comparators and ranges are numbered starting with 1 as opposed
       * to bits in a word */
      n--;

      if (data)
            flags |= ETMAAT_DLOADSTORE;
      else
            flags |= ETMAAT_IEXEC;

      /* first comparator for the range */
      etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2));
      etm_writel(t, start, ETMR_COMP_VAL(n * 2));

      /* second comparator is right next to it */
      etm_writel(t, flags, ETMR_COMP_ACC_TYPE(n * 2 + 1));
      etm_writel(t, end, ETMR_COMP_VAL(n * 2 + 1));

      flags = exclude ? ETMTE_INCLEXCL : 0;
      etm_writel(t, flags | (1 << n), ETMR_TRACEENCTRL);

      return 0;
}

static int trace_start(struct tracectx *t)
{
      u32 v;
      unsigned long timeout = TRACER_TIMEOUT;

      etb_unlock(t);

      etb_writel(t, 0, ETBR_FORMATTERCTRL);
      etb_writel(t, 1, ETBR_CTRL);

      etb_lock(t);

      /* configure etm */
      v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);

      if (t->flags & TRACER_CYCLE_ACC)
            v |= ETMCTRL_CYCLEACCURATE;

      etm_unlock(t);

      etm_writel(t, v, ETMR_CTRL);

      while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
            ;
      if (!timeout) {
            dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
            etm_lock(t);
            return -EFAULT;
      }

      etm_setup_address_range(t, 1, (unsigned long)_stext,
                  (unsigned long)_etext, 0, 0);
      etm_writel(t, 0, ETMR_TRACEENCTRL2);
      etm_writel(t, 0, ETMR_TRACESSCTRL);
      etm_writel(t, 0x6f, ETMR_TRACEENEVT);

      v &= ~ETMCTRL_PROGRAM;
      v |= ETMCTRL_PORTSEL;

      etm_writel(t, v, ETMR_CTRL);

      timeout = TRACER_TIMEOUT;
      while (etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM && --timeout)
            ;
      if (!timeout) {
            dev_dbg(t->dev, "Waiting for progbit to deassert timed out\n");
            etm_lock(t);
            return -EFAULT;
      }

      etm_lock(t);

      t->flags |= TRACER_RUNNING;

      return 0;
}

static int trace_stop(struct tracectx *t)
{
      unsigned long timeout = TRACER_TIMEOUT;

      etm_unlock(t);

      etm_writel(t, 0x440, ETMR_CTRL);
      while (!(etm_readl(t, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
            ;
      if (!timeout) {
            dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
            etm_lock(t);
            return -EFAULT;
      }

      etm_lock(t);

      etb_unlock(t);
      etb_writel(t, ETBFF_MANUAL_FLUSH, ETBR_FORMATTERCTRL);

      timeout = TRACER_TIMEOUT;
      while (etb_readl(t, ETBR_FORMATTERCTRL) &
                  ETBFF_MANUAL_FLUSH && --timeout)
            ;
      if (!timeout) {
            dev_dbg(t->dev, "Waiting for formatter flush to commence "
                        "timed out\n");
            etb_lock(t);
            return -EFAULT;
      }

      etb_writel(t, 0, ETBR_CTRL);

      etb_lock(t);

      t->flags &= ~TRACER_RUNNING;

      return 0;
}

static int etb_getdatalen(struct tracectx *t)
{
      u32 v;
      int rp, wp;

      v = etb_readl(t, ETBR_STATUS);

      if (v & 1)
            return t->etb_bufsz;

      rp = etb_readl(t, ETBR_READADDR);
      wp = etb_readl(t, ETBR_WRITEADDR);

      if (rp > wp) {
            etb_writel(t, 0, ETBR_READADDR);
            etb_writel(t, 0, ETBR_WRITEADDR);

            return 0;
      }

      return wp - rp;
}

/* sysrq+v will always stop the running trace and leave it at that */
static void etm_dump(void)
{
      struct tracectx *t = &tracer;
      u32 first = 0;
      int length;

      if (!t->etb_regs) {
            printk(KERN_INFO "No tracing hardware found\n");
            return;
      }

      if (trace_isrunning(t))
            trace_stop(t);

      etb_unlock(t);

      length = etb_getdatalen(t);

      if (length == t->etb_bufsz)
            first = etb_readl(t, ETBR_WRITEADDR);

      etb_writel(t, first, ETBR_READADDR);

      printk(KERN_INFO "Trace buffer contents length: %d\n", length);
      printk(KERN_INFO "--- ETB buffer begin ---\n");
      for (; length; length--)
            printk("%08x", cpu_to_be32(etb_readl(t, ETBR_READMEM)));
      printk(KERN_INFO "\n--- ETB buffer end ---\n");

      /* deassert the overflow bit */
      etb_writel(t, 1, ETBR_CTRL);
      etb_writel(t, 0, ETBR_CTRL);

      etb_writel(t, 0, ETBR_TRIGGERCOUNT);
      etb_writel(t, 0, ETBR_READADDR);
      etb_writel(t, 0, ETBR_WRITEADDR);

      etb_lock(t);
}

static void sysrq_etm_dump(int key)
{
      dev_dbg(tracer.dev, "Dumping ETB buffer\n");
      etm_dump();
}

static struct sysrq_key_op sysrq_etm_op = {
      .handler = sysrq_etm_dump,
      .help_msg = "ETM buffer dump",
      .action_msg = "etm",
};

static int etb_open(struct inode *inode, struct file *file)
{
      if (!tracer.etb_regs)
            return -ENODEV;

      file->private_data = &tracer;

      return nonseekable_open(inode, file);
}

static ssize_t etb_read(struct file *file, char __user *data,
            size_t len, loff_t *ppos)
{
      int total, i;
      long length;
      struct tracectx *t = file->private_data;
      u32 first = 0;
      u32 *buf;

      mutex_lock(&t->mutex);

      if (trace_isrunning(t)) {
            length = 0;
            goto out;
      }

      etb_unlock(t);

      total = etb_getdatalen(t);
      if (total == t->etb_bufsz)
            first = etb_readl(t, ETBR_WRITEADDR);

      etb_writel(t, first, ETBR_READADDR);

      length = min(total * 4, (int)len);
      buf = vmalloc(length);

      dev_dbg(t->dev, "ETB buffer length: %d\n", total);
      dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
      for (i = 0; i < length / 4; i++)
            buf[i] = etb_readl(t, ETBR_READMEM);

      /* the only way to deassert overflow bit in ETB status is this */
      etb_writel(t, 1, ETBR_CTRL);
      etb_writel(t, 0, ETBR_CTRL);

      etb_writel(t, 0, ETBR_WRITEADDR);
      etb_writel(t, 0, ETBR_READADDR);
      etb_writel(t, 0, ETBR_TRIGGERCOUNT);

      etb_lock(t);

      length -= copy_to_user(data, buf, length);
      vfree(buf);

out:
      mutex_unlock(&t->mutex);

      return length;
}

static int etb_release(struct inode *inode, struct file *file)
{
      /* there's nothing to do here, actually */
      return 0;
}

static const struct file_operations etb_fops = {
      .owner = THIS_MODULE,
      .read = etb_read,
      .open = etb_open,
      .release = etb_release,
      .llseek = no_llseek,
};

static struct miscdevice etb_miscdev = {
      .name = "tracebuf",
      .minor = 0,
      .fops = &etb_fops,
};

static int __init etb_probe(struct amba_device *dev, struct amba_id *id)
{
      struct tracectx *t = &tracer;
      int ret = 0;

      ret = amba_request_regions(dev, NULL);
      if (ret)
            goto out;

      t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
      if (!t->etb_regs) {
            ret = -ENOMEM;
            goto out_release;
      }

      amba_set_drvdata(dev, t);

      etb_miscdev.parent = &dev->dev;

      ret = misc_register(&etb_miscdev);
      if (ret)
            goto out_unmap;

      t->emu_clk = clk_get(&dev->dev, "emu_src_ck");
      if (IS_ERR(t->emu_clk)) {
            dev_dbg(&dev->dev, "Failed to obtain emu_src_ck.\n");
            return -EFAULT;
      }

      clk_enable(t->emu_clk);

      etb_unlock(t);
      t->etb_bufsz = etb_readl(t, ETBR_DEPTH);
      dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);

      /* make sure trace capture is disabled */
      etb_writel(t, 0, ETBR_CTRL);
      etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);
      etb_lock(t);

      dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");

out:
      return ret;

out_unmap:
      amba_set_drvdata(dev, NULL);
      iounmap(t->etb_regs);

out_release:
      amba_release_regions(dev);

      return ret;
}

static int etb_remove(struct amba_device *dev)
{
      struct tracectx *t = amba_get_drvdata(dev);

      amba_set_drvdata(dev, NULL);

      iounmap(t->etb_regs);
      t->etb_regs = NULL;

      clk_disable(t->emu_clk);
      clk_put(t->emu_clk);

      amba_release_regions(dev);

      return 0;
}

static struct amba_id etb_ids[] = {
      {
            .id   = 0x0003b907,
            .mask = 0x0007ffff,
      },
      { 0, 0 },
};

static struct amba_driver etb_driver = {
      .drv        = {
            .name = "etb",
            .owner      = THIS_MODULE,
      },
      .probe            = etb_probe,
      .remove           = etb_remove,
      .id_table   = etb_ids,
};

/* use a sysfs file "trace_running" to start/stop tracing */
static ssize_t trace_running_show(struct kobject *kobj,
                          struct kobj_attribute *attr,
                          char *buf)
{
      return sprintf(buf, "%x\n", trace_isrunning(&tracer));
}

static ssize_t trace_running_store(struct kobject *kobj,
                           struct kobj_attribute *attr,
                           const char *buf, size_t n)
{
      unsigned int value;
      int ret;

      if (sscanf(buf, "%u", &value) != 1)
            return -EINVAL;

      mutex_lock(&tracer.mutex);
      ret = value ? trace_start(&tracer) : trace_stop(&tracer);
      mutex_unlock(&tracer.mutex);

      return ret ? : n;
}

static struct kobj_attribute trace_running_attr =
      __ATTR(trace_running, 0644, trace_running_show, trace_running_store);

static ssize_t trace_info_show(struct kobject *kobj,
                          struct kobj_attribute *attr,
                          char *buf)
{
      u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;
      int datalen;

      etb_unlock(&tracer);
      datalen = etb_getdatalen(&tracer);
      etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
      etb_ra = etb_readl(&tracer, ETBR_READADDR);
      etb_st = etb_readl(&tracer, ETBR_STATUS);
      etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);
      etb_lock(&tracer);

      etm_unlock(&tracer);
      etm_ctrl = etm_readl(&tracer, ETMR_CTRL);
      etm_st = etm_readl(&tracer, ETMR_STATUS);
      etm_lock(&tracer);

      return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"
                  "ETBR_WRITEADDR:\t%08x\n"
                  "ETBR_READADDR:\t%08x\n"
                  "ETBR_STATUS:\t%08x\n"
                  "ETBR_FORMATTERCTRL:\t%08x\n"
                  "ETMR_CTRL:\t%08x\n"
                  "ETMR_STATUS:\t%08x\n",
                  datalen,
                  tracer.ncmppairs,
                  etb_wa,
                  etb_ra,
                  etb_st,
                  etb_fc,
                  etm_ctrl,
                  etm_st
                  );
}

static struct kobj_attribute trace_info_attr =
      __ATTR(trace_info, 0444, trace_info_show, NULL);

static ssize_t trace_mode_show(struct kobject *kobj,
                          struct kobj_attribute *attr,
                          char *buf)
{
      return sprintf(buf, "%d %d\n",
                  !!(tracer.flags & TRACER_CYCLE_ACC),
                  tracer.etm_portsz);
}

static ssize_t trace_mode_store(struct kobject *kobj,
                           struct kobj_attribute *attr,
                           const char *buf, size_t n)
{
      unsigned int cycacc, portsz;

      if (sscanf(buf, "%u %u", &cycacc, &portsz) != 2)
            return -EINVAL;

      mutex_lock(&tracer.mutex);
      if (cycacc)
            tracer.flags |= TRACER_CYCLE_ACC;
      else
            tracer.flags &= ~TRACER_CYCLE_ACC;

      tracer.etm_portsz = portsz & 0x0f;
      mutex_unlock(&tracer.mutex);

      return n;
}

static struct kobj_attribute trace_mode_attr =
      __ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);

static int __init etm_probe(struct amba_device *dev, struct amba_id *id)
{
      struct tracectx *t = &tracer;
      int ret = 0;

      if (t->etm_regs) {
            dev_dbg(&dev->dev, "ETM already initialized\n");
            ret = -EBUSY;
            goto out;
      }

      ret = amba_request_regions(dev, NULL);
      if (ret)
            goto out;

      t->etm_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));
      if (!t->etm_regs) {
            ret = -ENOMEM;
            goto out_release;
      }

      amba_set_drvdata(dev, t);

      mutex_init(&t->mutex);
      t->dev = &dev->dev;
      t->flags = TRACER_CYCLE_ACC;
      t->etm_portsz = 1;

      etm_unlock(t);
      (void)etm_readl(t, ETMMR_PDSR);
      /* dummy first read */
      (void)etm_readl(&tracer, ETMMR_OSSRR);

      t->ncmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
      etm_writel(t, 0x440, ETMR_CTRL);
      etm_lock(t);

      ret = sysfs_create_file(&dev->dev.kobj,
                  &trace_running_attr.attr);
      if (ret)
            goto out_unmap;

      /* failing to create any of these two is not fatal */
      ret = sysfs_create_file(&dev->dev.kobj, &trace_info_attr.attr);
      if (ret)
            dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");

      ret = sysfs_create_file(&dev->dev.kobj, &trace_mode_attr.attr);
      if (ret)
            dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");

      dev_dbg(t->dev, "ETM AMBA driver initialized.\n");

out:
      return ret;

out_unmap:
      amba_set_drvdata(dev, NULL);
      iounmap(t->etm_regs);

out_release:
      amba_release_regions(dev);

      return ret;
}

static int etm_remove(struct amba_device *dev)
{
      struct tracectx *t = amba_get_drvdata(dev);

      amba_set_drvdata(dev, NULL);

      iounmap(t->etm_regs);
      t->etm_regs = NULL;

      amba_release_regions(dev);

      sysfs_remove_file(&dev->dev.kobj, &trace_running_attr.attr);
      sysfs_remove_file(&dev->dev.kobj, &trace_info_attr.attr);
      sysfs_remove_file(&dev->dev.kobj, &trace_mode_attr.attr);

      return 0;
}

static struct amba_id etm_ids[] = {
      {
            .id   = 0x0003b921,
            .mask = 0x0007ffff,
      },
      { 0, 0 },
};

static struct amba_driver etm_driver = {
      .drv        = {
            .name   = "etm",
            .owner  = THIS_MODULE,
      },
      .probe            = etm_probe,
      .remove           = etm_remove,
      .id_table   = etm_ids,
};

static int __init etm_init(void)
{
      int retval;

      retval = amba_driver_register(&etb_driver);
      if (retval) {
            printk(KERN_ERR "Failed to register etb\n");
            return retval;
      }

      retval = amba_driver_register(&etm_driver);
      if (retval) {
            amba_driver_unregister(&etb_driver);
            printk(KERN_ERR "Failed to probe etm\n");
            return retval;
      }

      /* not being able to install this handler is not fatal */
      (void)register_sysrq_key('v', &sysrq_etm_op);

      return 0;
}

device_initcall(etm_init);


Generated by  Doxygen 1.6.0   Back to index