linux/arch/arm/kernel/etm.c

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/*
* 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 <linux/module.h>
#include <asm/hardware/coresight.h>
#include <asm/sections.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shishkin");
/*
* ETM tracer state
*/
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: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 18:52:59 +02:00
.llseek = no_llseek,
};
static struct miscdevice etb_miscdev = {
.name = "tracebuf",
.minor = 0,
.fops = &etb_fops,
};
static int __devinit etb_probe(struct amba_device *dev, const 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 __devinit etm_probe(struct amba_device *dev, const 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);