@@ -91,6 +91,7 @@ static int trace_start(struct tracectx *t)
etb_unlock(t);
+ etb_writel(t, 0, ETBR_WRITEADDR);
etb_writel(t, 0, ETBR_FORMATTERCTRL);
etb_writel(t, 1, ETBR_CTRL);
@@ -184,24 +185,15 @@ static int trace_stop(struct tracectx *t)
static int etb_getdatalen(struct tracectx *t)
{
u32 v;
- int rp, wp;
+ int 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;
+ return wp;
}
/* sysrq+v will always stop the running trace and leave it at that */
@@ -234,14 +226,6 @@ static void etm_dump(void)
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);
}
@@ -275,6 +259,10 @@ static ssize_t etb_read(struct file *file, char __user *data,
struct tracectx *t = file->private_data;
u32 first = 0;
u32 *buf;
+ int wpos;
+ int skip;
+ long wlength;
+ loff_t pos = *ppos;
mutex_lock(&t->mutex);
@@ -289,28 +277,34 @@ static ssize_t etb_read(struct file *file, char __user *data,
if (total == t->etb_bufsz)
first = etb_readl(t, ETBR_WRITEADDR);
+ if (pos > total * 4) {
+ skip = 0;
+ wpos = total;
+ } else {
+ skip = (int)pos % 4;
+ wpos = (int)pos / 4;
+ }
+ total -= wpos;
+ first = (first + wpos) % t->etb_bufsz;
+
etb_writel(t, first, ETBR_READADDR);
- length = min(total * 4, (int)len);
- buf = vmalloc(length);
+ wlength = min(total, DIV_ROUND_UP(skip + (int)len, 4));
+ length = min(total * 4 - skip, (int)len);
+ buf = vmalloc(wlength * 4);
- dev_dbg(t->dev, "ETB buffer length: %d\n", total);
+ dev_dbg(t->dev, "ETB read %ld bytes to %lld from %ld words at %d\n",
+ length, pos, wlength, first);
+ dev_dbg(t->dev, "ETB buffer length: %d\n", total + wpos);
dev_dbg(t->dev, "ETB status reg: %x\n", etb_readl(t, ETBR_STATUS));
- for (i = 0; i < length / 4; i++)
+ for (i = 0; i < wlength; 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);
+ length -= copy_to_user(data, (u8 *)buf + skip, length);
vfree(buf);
+ *ppos = pos + length;
out:
mutex_unlock(&t->mutex);