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sb_tbprof.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
 * Copyright (C) 2007 Ralf Baechle <ralf@linux-mips.org>
 * Copyright (C) 2007 MIPS Technologies, Inc.
 *    written by Ralf Baechle <ralf@linux-mips.org>
 */

#undef DEBUG

#include <linux/device.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <asm/io.h>
#include <asm/sibyte/sb1250.h>

#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
#include <asm/sibyte/bcm1480_regs.h>
#include <asm/sibyte/bcm1480_scd.h>
#include <asm/sibyte/bcm1480_int.h>
#elif defined(CONFIG_SIBYTE_SB1250) || defined(CONFIG_SIBYTE_BCM112X)
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_scd.h>
#include <asm/sibyte/sb1250_int.h>
#else
#error invalid SiByte UART configuation
#endif

#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
#undef K_INT_TRACE_FREEZE
#define K_INT_TRACE_FREEZE K_BCM1480_INT_TRACE_FREEZE
#undef K_INT_PERF_CNT
#define K_INT_PERF_CNT K_BCM1480_INT_PERF_CNT
#endif

#include <asm/system.h>
#include <asm/uaccess.h>

#define SBPROF_TB_MAJOR 240

typedef u64 tb_sample_t[6*256];

enum open_status {
      SB_CLOSED,
      SB_OPENING,
      SB_OPEN
};

struct sbprof_tb {
      wait_queue_head_t tb_sync;
      wait_queue_head_t tb_read;
      struct mutex            lock;
      enum open_status  open;
      tb_sample_t       *sbprof_tbbuf;
      int               next_tb_sample;

      volatile int            tb_enable;
      volatile int            tb_armed;

};

static struct sbprof_tb sbp;

#define MAX_SAMPLE_BYTES (24*1024*1024)
#define MAX_TBSAMPLE_BYTES (12*1024*1024)

#define MAX_SAMPLES (MAX_SAMPLE_BYTES/sizeof(u_int32_t))
#define TB_SAMPLE_SIZE (sizeof(tb_sample_t))
#define MAX_TB_SAMPLES (MAX_TBSAMPLE_BYTES/TB_SAMPLE_SIZE)

/* ioctls */
#define SBPROF_ZBSTART        _IOW('s', 0, int)
#define SBPROF_ZBSTOP         _IOW('s', 1, int)
#define SBPROF_ZBWAITFULL     _IOW('s', 2, int)

/*
 * Routines for using 40-bit SCD cycle counter
 *
 * Client responsible for either handling interrupts or making sure
 * the cycles counter never saturates, e.g., by doing
 * zclk_timer_init(0) at least every 2^40 - 1 ZCLKs.
 */

/*
 * Configures SCD counter 0 to count ZCLKs starting from val;
 * Configures SCD counters1,2,3 to count nothing.
 * Must not be called while gathering ZBbus profiles.
 */

#define zclk_timer_init(val) \
  __asm__ __volatile__ (".set push;" \
                  ".set mips64;" \
                  "la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
                  "sd   %0, 0x10($8);"   /* write val to counter0 */ \
                  "sd   %1, 0($8);"      /* config counter0 for zclks*/ \
                  ".set pop" \
                  : /* no outputs */ \
                                         /* enable, counter0 */ \
                  : /* inputs */ "r"(val), "r" ((1ULL << 33) | 1ULL) \
                  : /* modifies */ "$8" )


/* Reads SCD counter 0 and puts result in value
   unsigned long long val; */
#define zclk_get(val) \
  __asm__ __volatile__ (".set push;" \
                  ".set mips64;" \
                  "la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
                  "ld   %0, 0x10($8);"   /* write val to counter0 */ \
                  ".set pop" \
                  : /* outputs */ "=r"(val) \
                  : /* inputs */ \
                  : /* modifies */ "$8" )

#define DEVNAME "sb_tbprof"

#define TB_FULL (sbp.next_tb_sample == MAX_TB_SAMPLES)

/*
 * Support for ZBbus sampling using the trace buffer
 *
 * We use the SCD performance counter interrupt, caused by a Zclk counter
 * overflow, to trigger the start of tracing.
 *
 * We set the trace buffer to sample everything and freeze on
 * overflow.
 *
 * We map the interrupt for trace_buffer_freeze to handle it on CPU 0.
 *
 */

static u64 tb_period;

static void arm_tb(void)
{
        u64 scdperfcnt;
      u64 next = (1ULL << 40) - tb_period;
      u64 tb_options = M_SCD_TRACE_CFG_FREEZE_FULL;

      /*
       * Generate an SCD_PERFCNT interrupt in TB_PERIOD Zclks to
       * trigger start of trace.  XXX vary sampling period
       */
      __raw_writeq(0, IOADDR(A_SCD_PERF_CNT_1));
      scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));

      /*
       * Unfortunately, in Pass 2 we must clear all counters to knock down
       * a previous interrupt request.  This means that bus profiling
       * requires ALL of the SCD perf counters.
       */
#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
      __raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
                                    /* keep counters 0,2,3,4,5,6,7 as is */
                 V_SPC_CFG_SRC1(1),       /* counter 1 counts cycles */
                 IOADDR(A_BCM1480_SCD_PERF_CNT_CFG0));
      __raw_writeq(
                 M_SPC_CFG_ENABLE |       /* enable counting */
                 M_SPC_CFG_CLEAR |        /* clear all counters */
                 V_SPC_CFG_SRC1(1),       /* counter 1 counts cycles */
                 IOADDR(A_BCM1480_SCD_PERF_CNT_CFG1));
#else
      __raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
                                    /* keep counters 0,2,3 as is */
                 M_SPC_CFG_ENABLE |       /* enable counting */
                 M_SPC_CFG_CLEAR |        /* clear all counters */
                 V_SPC_CFG_SRC1(1),       /* counter 1 counts cycles */
                 IOADDR(A_SCD_PERF_CNT_CFG));
#endif
      __raw_writeq(next, IOADDR(A_SCD_PERF_CNT_1));
      /* Reset the trace buffer */
      __raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
#if 0 && defined(M_SCD_TRACE_CFG_FORCECNT)
      /* XXXKW may want to expose control to the data-collector */
      tb_options |= M_SCD_TRACE_CFG_FORCECNT;
#endif
      __raw_writeq(tb_options, IOADDR(A_SCD_TRACE_CFG));
      sbp.tb_armed = 1;
}

static irqreturn_t sbprof_tb_intr(int irq, void *dev_id)
{
      int i;

      pr_debug(DEVNAME ": tb_intr\n");

      if (sbp.next_tb_sample < MAX_TB_SAMPLES) {
            /* XXX should use XKPHYS to make writes bypass L2 */
            u64 *p = sbp.sbprof_tbbuf[sbp.next_tb_sample++];
            /* Read out trace */
            __raw_writeq(M_SCD_TRACE_CFG_START_READ,
                       IOADDR(A_SCD_TRACE_CFG));
            __asm__ __volatile__ ("sync" : : : "memory");
            /* Loop runs backwards because bundles are read out in reverse order */
            for (i = 256 * 6; i > 0; i -= 6) {
                  /* Subscripts decrease to put bundle in the order */
                  /*   t0 lo, t0 hi, t1 lo, t1 hi, t2 lo, t2 hi */
                  p[i - 1] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t2 hi */
                  p[i - 2] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t2 lo */
                  p[i - 3] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t1 hi */
                  p[i - 4] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t1 lo */
                  p[i - 5] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t0 hi */
                  p[i - 6] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
                  /* read t0 lo */
            }
            if (!sbp.tb_enable) {
                  pr_debug(DEVNAME ": tb_intr shutdown\n");
                  __raw_writeq(M_SCD_TRACE_CFG_RESET,
                             IOADDR(A_SCD_TRACE_CFG));
                  sbp.tb_armed = 0;
                  wake_up_interruptible(&sbp.tb_sync);
            } else {
                  /* knock down current interrupt and get another one later */
                  arm_tb();
            }
      } else {
            /* No more trace buffer samples */
            pr_debug(DEVNAME ": tb_intr full\n");
            __raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
            sbp.tb_armed = 0;
            if (!sbp.tb_enable)
                  wake_up_interruptible(&sbp.tb_sync);
            wake_up_interruptible(&sbp.tb_read);
      }
      return IRQ_HANDLED;
}

static irqreturn_t sbprof_pc_intr(int irq, void *dev_id)
{
      printk(DEVNAME ": unexpected pc_intr");
      return IRQ_NONE;
}

/*
 * Requires: Already called zclk_timer_init with a value that won't
 *           saturate 40 bits.  No subsequent use of SCD performance counters
 *           or trace buffer.
 */

static int sbprof_zbprof_start(struct file *filp)
{
      u64 scdperfcnt;
      int err;

      if (xchg(&sbp.tb_enable, 1))
            return -EBUSY;

      pr_debug(DEVNAME ": starting\n");

      sbp.next_tb_sample = 0;
      filp->f_pos = 0;

      err = request_irq(K_INT_TRACE_FREEZE, sbprof_tb_intr, 0,
                    DEVNAME " trace freeze", &sbp);
      if (err)
            return -EBUSY;

      /* Make sure there isn't a perf-cnt interrupt waiting */
      scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));
      /* Disable and clear counters, override SRC_1 */
      __raw_writeq((scdperfcnt & ~(M_SPC_CFG_SRC1 | M_SPC_CFG_ENABLE)) |
                 M_SPC_CFG_ENABLE | M_SPC_CFG_CLEAR | V_SPC_CFG_SRC1(1),
                 IOADDR(A_SCD_PERF_CNT_CFG));

      /*
       * We grab this interrupt to prevent others from trying to use
         * it, even though we don't want to service the interrupts
         * (they only feed into the trace-on-interrupt mechanism)
       */
      if (request_irq(K_INT_PERF_CNT, sbprof_pc_intr, 0, DEVNAME " scd perfcnt", &sbp)) {
            free_irq(K_INT_TRACE_FREEZE, &sbp);
            return -EBUSY;
      }

      /*
       * I need the core to mask these, but the interrupt mapper to
       *  pass them through.  I am exploiting my knowledge that
       *  cp0_status masks out IP[5]. krw
       */
#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
      __raw_writeq(K_BCM1480_INT_MAP_I3,
                 IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_MAP_BASE_L) +
                      ((K_BCM1480_INT_PERF_CNT & 0x3f) << 3)));
#else
      __raw_writeq(K_INT_MAP_I3,
                 IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
                      (K_INT_PERF_CNT << 3)));
#endif

      /* Initialize address traps */
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_0));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_1));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_2));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_3));

      __raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_0));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_1));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_2));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_3));

      __raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_0));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_1));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_2));
      __raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_3));

      /* Initialize Trace Event 0-7 */
      /*                      when interrupt  */
      __raw_writeq(M_SCD_TREVT_INTERRUPT, IOADDR(A_SCD_TRACE_EVENT_0));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_1));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_2));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_3));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_4));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_5));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_6));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_7));

      /* Initialize Trace Sequence 0-7 */
      /*                           Start on event 0 (interrupt) */
      __raw_writeq(V_SCD_TRSEQ_FUNC_START | 0x0fff,
                 IOADDR(A_SCD_TRACE_SEQUENCE_0));
      /*                  dsamp when d used | asamp when a used */
      __raw_writeq(M_SCD_TRSEQ_ASAMPLE | M_SCD_TRSEQ_DSAMPLE |
                 K_SCD_TRSEQ_TRIGGER_ALL,
                 IOADDR(A_SCD_TRACE_SEQUENCE_1));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_2));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_3));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_4));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_5));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_6));
      __raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_7));

      /* Now indicate the PERF_CNT interrupt as a trace-relevant interrupt */
#if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
      __raw_writeq(1ULL << (K_BCM1480_INT_PERF_CNT & 0x3f),
                 IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_TRACE_L)));
#else
      __raw_writeq(1ULL << K_INT_PERF_CNT,
                 IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_TRACE)));
#endif
      arm_tb();

      pr_debug(DEVNAME ": done starting\n");

      return 0;
}

static int sbprof_zbprof_stop(void)
{
      int err = 0;

      pr_debug(DEVNAME ": stopping\n");

      if (sbp.tb_enable) {
            /*
             * XXXKW there is a window here where the intr handler may run,
             * see the disable, and do the wake_up before this sleep
             * happens.
             */
            pr_debug(DEVNAME ": wait for disarm\n");
            err = wait_event_interruptible(sbp.tb_sync, !sbp.tb_armed);
            pr_debug(DEVNAME ": disarm complete, stat %d\n", err);

            if (err)
                  return err;

            sbp.tb_enable = 0;
            free_irq(K_INT_TRACE_FREEZE, &sbp);
            free_irq(K_INT_PERF_CNT, &sbp);
      }

      pr_debug(DEVNAME ": done stopping\n");

      return err;
}

static int sbprof_tb_open(struct inode *inode, struct file *filp)
{
      int minor;
      int err = 0;

      lock_kernel();
      minor = iminor(inode);
      if (minor != 0) {
            err = -ENODEV;
            goto out;
      }

      if (xchg(&sbp.open, SB_OPENING) != SB_CLOSED) {
            err = -EBUSY;
            goto out;
      }

      memset(&sbp, 0, sizeof(struct sbprof_tb));
      sbp.sbprof_tbbuf = vmalloc(MAX_TBSAMPLE_BYTES);
      if (!sbp.sbprof_tbbuf) {
            err = -ENOMEM;
            goto out;
      }
      memset(sbp.sbprof_tbbuf, 0, MAX_TBSAMPLE_BYTES);
      init_waitqueue_head(&sbp.tb_sync);
      init_waitqueue_head(&sbp.tb_read);
      mutex_init(&sbp.lock);

      sbp.open = SB_OPEN;

  out:
      unlock_kernel();
      return err;
}

static int sbprof_tb_release(struct inode *inode, struct file *filp)
{
      int minor;

      minor = iminor(inode);
      if (minor != 0 || !sbp.open)
            return -ENODEV;

      mutex_lock(&sbp.lock);

      if (sbp.tb_armed || sbp.tb_enable)
            sbprof_zbprof_stop();

      vfree(sbp.sbprof_tbbuf);
      sbp.open = 0;

      mutex_unlock(&sbp.lock);

      return 0;
}

static ssize_t sbprof_tb_read(struct file *filp, char *buf,
                        size_t size, loff_t *offp)
{
      int cur_sample, sample_off, cur_count, sample_left;
      char *src;
      int   count   =    0;
      char *dest    =    buf;
      long  cur_off = *offp;

      if (!access_ok(VERIFY_WRITE, buf, size))
            return -EFAULT;

      mutex_lock(&sbp.lock);

      count = 0;
      cur_sample = cur_off / TB_SAMPLE_SIZE;
      sample_off = cur_off % TB_SAMPLE_SIZE;
      sample_left = TB_SAMPLE_SIZE - sample_off;

      while (size && (cur_sample < sbp.next_tb_sample)) {
            int err;

            cur_count = size < sample_left ? size : sample_left;
            src = (char *)(((long)sbp.sbprof_tbbuf[cur_sample])+sample_off);
            err = __copy_to_user(dest, src, cur_count);
            if (err) {
                  *offp = cur_off + cur_count - err;
                  mutex_unlock(&sbp.lock);
                  return err;
            }
            pr_debug(DEVNAME ": read from sample %d, %d bytes\n",
                     cur_sample, cur_count);
            size -= cur_count;
            sample_left -= cur_count;
            if (!sample_left) {
                  cur_sample++;
                  sample_off = 0;
                  sample_left = TB_SAMPLE_SIZE;
            } else {
                  sample_off += cur_count;
            }
            cur_off += cur_count;
            dest += cur_count;
            count += cur_count;
      }
      *offp = cur_off;
      mutex_unlock(&sbp.lock);

      return count;
}

static long sbprof_tb_ioctl(struct file *filp,
                      unsigned int command,
                      unsigned long arg)
{
      int err = 0;

      switch (command) {
      case SBPROF_ZBSTART:
            mutex_lock(&sbp.lock);
            err = sbprof_zbprof_start(filp);
            mutex_unlock(&sbp.lock);
            break;

      case SBPROF_ZBSTOP:
            mutex_lock(&sbp.lock);
            err = sbprof_zbprof_stop();
            mutex_unlock(&sbp.lock);
            break;

      case SBPROF_ZBWAITFULL: {
            err = wait_event_interruptible(sbp.tb_read, TB_FULL);
            if (err)
                  break;

            err = put_user(TB_FULL, (int *) arg);
            break;
      }

      default:
            err = -EINVAL;
            break;
      }

      return err;
}

static const struct file_operations sbprof_tb_fops = {
      .owner            = THIS_MODULE,
      .open       = sbprof_tb_open,
      .release    = sbprof_tb_release,
      .read       = sbprof_tb_read,
      .unlocked_ioctl   = sbprof_tb_ioctl,
      .compat_ioctl     = sbprof_tb_ioctl,
      .mmap       = NULL,
};

static struct class *tb_class;
static struct device *tb_dev;

static int __init sbprof_tb_init(void)
{
      struct device *dev;
      struct class *tbc;
      int err;

      if (register_chrdev(SBPROF_TB_MAJOR, DEVNAME, &sbprof_tb_fops)) {
            printk(KERN_WARNING DEVNAME ": initialization failed (dev %d)\n",
                   SBPROF_TB_MAJOR);
            return -EIO;
      }

      tbc = class_create(THIS_MODULE, "sb_tracebuffer");
      if (IS_ERR(tbc)) {
            err = PTR_ERR(tbc);
            goto out_chrdev;
      }

      tb_class = tbc;

      dev = device_create_drvdata(tbc, NULL, MKDEV(SBPROF_TB_MAJOR, 0),
                            NULL, "tb");
      if (IS_ERR(dev)) {
            err = PTR_ERR(dev);
            goto out_class;
      }
      tb_dev = dev;

      sbp.open = 0;
      tb_period = zbbus_mhz * 10000LL;
      pr_info(DEVNAME ": initialized - tb_period = %lld\n",
            (long long) tb_period);
      return 0;

out_class:
      class_destroy(tb_class);
out_chrdev:
      unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);

      return err;
}

static void __exit sbprof_tb_cleanup(void)
{
      device_destroy(tb_class, MKDEV(SBPROF_TB_MAJOR, 0));
      unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
      class_destroy(tb_class);
}

module_init(sbprof_tb_init);
module_exit(sbprof_tb_cleanup);

MODULE_ALIAS_CHARDEV_MAJOR(SBPROF_TB_MAJOR);
MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
MODULE_LICENSE("GPL");

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