/*
   * Memory mapped I/O tracing
   *
   * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   */
  
  #define DEBUG 1
  
  #include <linux/kernel.h>
  #include <linux/mmiotrace.h>

  #include <linux/pci.h>

  #include <linux/slab.h>

  #include <linux/time.h>

  #include <linux/atomic.h>

  
  #include "trace.h"

  #include "trace_output.h"

  struct header_iter {
  	struct pci_dev *dev;
  };

  static struct trace_array *mmio_trace_array;

  static bool overrun_detected;

  static unsigned long prev_overruns;

  static atomic_t dropped_count;

  static void mmio_reset_data(struct trace_array *tr)
  {

  	overrun_detected = false;

  	prev_overruns = 0;

  	tracing_reset_online_cpus(tr);

  }

  static int mmio_trace_init(struct trace_array *tr)

  {
  	pr_debug("in %s
  ", __func__);
  	mmio_trace_array = tr;

  
  	mmio_reset_data(tr);
  	enable_mmiotrace();

  	return 0;

  }
  
  static void mmio_trace_reset(struct trace_array *tr)
  {
  	pr_debug("in %s
  ", __func__);

  
  	disable_mmiotrace();

  	mmio_reset_data(tr);
  	mmio_trace_array = NULL;

  }

  static void mmio_trace_start(struct trace_array *tr)

  {
  	pr_debug("in %s
  ", __func__);

  	mmio_reset_data(tr);

  }

  static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  {
  	int ret = 0;
  	int i;
  	resource_size_t start, end;
  	const struct pci_driver *drv = pci_dev_driver(dev);
  
  	/* XXX: incomplete checks for trace_seq_printf() return value */
  	ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  				dev->bus->number, dev->devfn,
  				dev->vendor, dev->device, dev->irq);
  	/*
  	 * XXX: is pci_resource_to_user() appropriate, since we are
  	 * supposed to interpret the __ioremap() phys_addr argument based on
  	 * these printed values?
  	 */
  	for (i = 0; i < 7; i++) {
  		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  		ret += trace_seq_printf(s, " %llx",
  			(unsigned long long)(start |
  			(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  	}
  	for (i = 0; i < 7; i++) {
  		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  		ret += trace_seq_printf(s, " %llx",
  			dev->resource[i].start < dev->resource[i].end ?
  			(unsigned long long)(end - start) + 1 : 0);
  	}
  	if (drv)
  		ret += trace_seq_printf(s, " %s
  ", drv->name);
  	else
  		ret += trace_seq_printf(s, " 
  ");
  	return ret;
  }

  static void destroy_header_iter(struct header_iter *hiter)
  {
  	if (!hiter)
  		return;
  	pci_dev_put(hiter->dev);
  	kfree(hiter);
  }
  
  static void mmio_pipe_open(struct trace_iterator *iter)

  {

  	struct header_iter *hiter;

  	struct trace_seq *s = &iter->seq;

  
  	trace_seq_printf(s, "VERSION 20070824
  ");

  	hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
  	if (!hiter)
  		return;
  
  	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
  	iter->private = hiter;
  }
  
  /* XXX: This is not called when the pipe is closed! */
  static void mmio_close(struct trace_iterator *iter)
  {
  	struct header_iter *hiter = iter->private;
  	destroy_header_iter(hiter);
  	iter->private = NULL;
  }

  static unsigned long count_overruns(struct trace_iterator *iter)
  {

  	unsigned long cnt = atomic_xchg(&dropped_count, 0);

  	unsigned long over = ring_buffer_overruns(iter->tr->buffer);
  
  	if (over > prev_overruns)

  		cnt += over - prev_overruns;

  	prev_overruns = over;

  	return cnt;
  }

  static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
  				char __user *ubuf, size_t cnt, loff_t *ppos)
  {
  	ssize_t ret;
  	struct header_iter *hiter = iter->private;
  	struct trace_seq *s = &iter->seq;

  	unsigned long n;
  
  	n = count_overruns(iter);
  	if (n) {
  		/* XXX: This is later than where events were lost. */
  		trace_seq_printf(s, "MARK 0.000000 Lost %lu events.
  ", n);
  		if (!overrun_detected)
  			pr_warning("mmiotrace has lost events.
  ");
  		overrun_detected = true;
  		goto print_out;
  	}

  
  	if (!hiter)
  		return 0;
  
  	mmio_print_pcidev(s, hiter->dev);
  	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
  
  	if (!hiter->dev) {
  		destroy_header_iter(hiter);
  		iter->private = NULL;
  	}

  print_out:

  	ret = trace_seq_to_user(s, ubuf, cnt);
  	return (ret == -EBUSY) ? 0 : ret;

  }

  static enum print_line_t mmio_print_rw(struct trace_iterator *iter)

  {
  	struct trace_entry *entry = iter->ent;

  	struct trace_mmiotrace_rw *field;
  	struct mmiotrace_rw *rw;

  	struct trace_seq *s	= &iter->seq;

  	unsigned long long t	= ns2usecs(iter->ts);

  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);

  	unsigned secs		= (unsigned long)t;
  	int ret = 1;

  	trace_assign_type(field, entry);
  	rw = &field->rw;

  	switch (rw->opcode) {

  	case MMIO_READ:
  		ret = trace_seq_printf(s,

  			"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d
  ",

  			rw->width, secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,

  			rw->value, rw->pc, 0);

  		break;
  	case MMIO_WRITE:
  		ret = trace_seq_printf(s,

  			"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d
  ",

  			rw->width, secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,

  			rw->value, rw->pc, 0);

  		break;
  	case MMIO_UNKNOWN_OP:
  		ret = trace_seq_printf(s,

  			"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
  			"%02lx 0x%lx %d
  ",

  			secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,

  			(rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,

  			(rw->value >> 0) & 0xff, rw->pc, 0);

  		break;
  	default:
  		ret = trace_seq_printf(s, "rw what?
  ");
  		break;
  	}
  	if (ret)

  		return TRACE_TYPE_HANDLED;
  	return TRACE_TYPE_PARTIAL_LINE;

  }

  static enum print_line_t mmio_print_map(struct trace_iterator *iter)

  {
  	struct trace_entry *entry = iter->ent;

  	struct trace_mmiotrace_map *field;
  	struct mmiotrace_map *m;

  	struct trace_seq *s	= &iter->seq;

  	unsigned long long t	= ns2usecs(iter->ts);

  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);

  	unsigned secs		= (unsigned long)t;

  	int ret;

  	trace_assign_type(field, entry);
  	m = &field->map;

  	switch (m->opcode) {

  	case MMIO_PROBE:
  		ret = trace_seq_printf(s,

  			"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d
  ",

  			secs, usec_rem, m->map_id,
  			(unsigned long long)m->phys, m->virt, m->len,

  			0UL, 0);

  		break;
  	case MMIO_UNPROBE:
  		ret = trace_seq_printf(s,

  			"UNMAP %u.%06lu %d 0x%lx %d
  ",

  			secs, usec_rem, m->map_id, 0UL, 0);

  		break;
  	default:
  		ret = trace_seq_printf(s, "map what?
  ");
  		break;
  	}
  	if (ret)

  		return TRACE_TYPE_HANDLED;
  	return TRACE_TYPE_PARTIAL_LINE;

  }

  static enum print_line_t mmio_print_mark(struct trace_iterator *iter)

  {
  	struct trace_entry *entry = iter->ent;

  	struct print_entry *print = (struct print_entry *)entry;

  	const char *msg		= print->buf;

  	struct trace_seq *s	= &iter->seq;

  	unsigned long long t	= ns2usecs(iter->ts);

  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);

  	unsigned secs		= (unsigned long)t;
  	int ret;
  
  	/* The trailing newline must be in the message. */

  	ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);

  	if (!ret)

  		return TRACE_TYPE_PARTIAL_LINE;

  	return TRACE_TYPE_HANDLED;

  }

  static enum print_line_t mmio_print_line(struct trace_iterator *iter)

  {
  	switch (iter->ent->type) {
  	case TRACE_MMIO_RW:
  		return mmio_print_rw(iter);
  	case TRACE_MMIO_MAP:
  		return mmio_print_map(iter);

  	case TRACE_PRINT:
  		return mmio_print_mark(iter);

  	default:

  		return TRACE_TYPE_HANDLED; /* ignore unknown entries */

  	}

  }
  
  static struct tracer mmio_tracer __read_mostly =
  {
  	.name		= "mmiotrace",
  	.init		= mmio_trace_init,
  	.reset		= mmio_trace_reset,

  	.start		= mmio_trace_start,

  	.pipe_open	= mmio_pipe_open,
  	.close		= mmio_close,
  	.read		= mmio_read,

  	.print_line	= mmio_print_line,

  };
  
  __init static int init_mmio_trace(void)
  {

  	return register_tracer(&mmio_tracer);
  }
  device_initcall(init_mmio_trace);

  static void __trace_mmiotrace_rw(struct trace_array *tr,
  				struct trace_array_cpu *data,
  				struct mmiotrace_rw *rw)
  {

  	struct ftrace_event_call *call = &event_mmiotrace_rw;

  	struct ring_buffer *buffer = tr->buffer;

  	struct ring_buffer_event *event;

  	struct trace_mmiotrace_rw *entry;

  	int pc = preempt_count();

  	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,

  					  sizeof(*entry), 0, pc);

  	if (!event) {
  		atomic_inc(&dropped_count);

  		return;

  	}

  	entry	= ring_buffer_event_data(event);

  	entry->rw			= *rw;

  
  	if (!filter_check_discard(call, entry, buffer, event))
  		trace_buffer_unlock_commit(buffer, event, 0, pc);

  }

  void mmio_trace_rw(struct mmiotrace_rw *rw)

  {
  	struct trace_array *tr = mmio_trace_array;
  	struct trace_array_cpu *data = tr->data[smp_processor_id()];

  	__trace_mmiotrace_rw(tr, data, rw);
  }

  static void __trace_mmiotrace_map(struct trace_array *tr,
  				struct trace_array_cpu *data,
  				struct mmiotrace_map *map)
  {

  	struct ftrace_event_call *call = &event_mmiotrace_map;

  	struct ring_buffer *buffer = tr->buffer;

  	struct ring_buffer_event *event;

  	struct trace_mmiotrace_map *entry;

  	int pc = preempt_count();

  	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,

  					  sizeof(*entry), 0, pc);

  	if (!event) {
  		atomic_inc(&dropped_count);

  		return;

  	}

  	entry	= ring_buffer_event_data(event);

  	entry->map			= *map;

  
  	if (!filter_check_discard(call, entry, buffer, event))
  		trace_buffer_unlock_commit(buffer, event, 0, pc);

  }

  void mmio_trace_mapping(struct mmiotrace_map *map)
  {
  	struct trace_array *tr = mmio_trace_array;
  	struct trace_array_cpu *data;
  
  	preempt_disable();
  	data = tr->data[smp_processor_id()];
  	__trace_mmiotrace_map(tr, data, map);
  	preempt_enable();

  }

  
  int mmio_trace_printk(const char *fmt, va_list args)
  {

  	return trace_vprintk(0, fmt, args);

  }