[PATCH v3 1/2] arm: a driver for on-chip ETM and ETB
Alexander Shishkin
virtuoso at slind.org
Thu Oct 22 12:51:54 EDT 2009
This driver implements support for on-chip Embedded Tracing Macrocell and
Embedded Trace Buffer. It allows to trigger tracing of kernel execution flow
and exporting trace output to userspace via character device and a sysrq
combo.
Trace output can then be decoded by a fairly simple open source tool [1]
which is already sufficient to get the idea of what the kernel is doing.
[1]: http://github.com/virtuoso/etm2human
Signed-off-by: Alexander Shishkin <virtuoso at slind.org>
---
Changes:
v3 -- major update:
* switched from platform device to AMBA device
* started using clk API in a more proper way
* changed omap3 Kconfig part to select the driver instead of depending
on it
v2 -- major update:
* fixes according to comments from Linus Walleij and Anand Gadiyar
* omap3 clock-related stuff moved to platform device
v1 -- fixed comments from Juha Leppanen
v0 -- initial implementation, has been sent to linux-omap only
arch/arm/Kconfig.debug | 8 +
arch/arm/include/asm/hardware/coresight.h | 165 ++++++++
arch/arm/kernel/Makefile | 2 +
arch/arm/kernel/etm.c | 641 +++++++++++++++++++++++++++++
4 files changed, 816 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/include/asm/hardware/coresight.h
create mode 100644 arch/arm/kernel/etm.c
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 1a6f70e..ff54c23 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -83,6 +83,14 @@ config DEBUG_ICEDCC
It does include a timeout to ensure that the system does not
totally freeze when there is nothing connected to read.
+config OC_ETM
+ bool "On-chip ETM and ETB"
+ select ARM_AMBA
+ help
+ Enables the on-chip embedded trace macrocell and embedded trace
+ buffer driver that will allow you to collect traces of the
+ kernel code.
+
config DEBUG_DC21285_PORT
bool "Kernel low-level debugging messages via footbridge serial port"
depends on DEBUG_LL && FOOTBRIDGE
diff --git a/arch/arm/include/asm/hardware/coresight.h b/arch/arm/include/asm/hardware/coresight.h
new file mode 100644
index 0000000..f82b25d
--- /dev/null
+++ b/arch/arm/include/asm/hardware/coresight.h
@@ -0,0 +1,165 @@
+/*
+ * linux/arch/arm/include/asm/hardware/coresight.h
+ *
+ * CoreSight components' registers
+ *
+ * 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.
+ */
+
+#ifndef __ASM_HARDWARE_CORESIGHT_H
+#define __ASM_HARDWARE_CORESIGHT_H
+
+#define TRACER_ACCESSED_BIT 0
+#define TRACER_RUNNING_BIT 1
+#define TRACER_CYCLE_ACC_BIT 2
+#define TRACER_ACCESSED BIT(TRACER_ACCESSED_BIT)
+#define TRACER_RUNNING BIT(TRACER_RUNNING_BIT)
+#define TRACER_CYCLE_ACC BIT(TRACER_CYCLE_ACC_BIT)
+
+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;
+};
+
+#define TRACER_TIMEOUT 10000
+
+#define etm_writel(t, v, x) \
+ (__raw_writel((v), (t)->etm_regs + (x)))
+#define etm_readl(t, x) (__raw_readl((t)->etm_regs + (x)))
+
+/* CoreSight Management Registers */
+#define CSMR_LOCKACCESS 0xfb0
+#define CSMR_LOCKSTATUS 0xfb4
+#define CSMR_AUTHSTATUS 0xfb8
+#define CSMR_DEVID 0xfc8
+#define CSMR_DEVTYPE 0xfcc
+/* CoreSight Component Registers */
+#define CSCR_CLASS 0xff4
+
+#define CSCR_PRSR 0x314
+
+#define UNLOCK_MAGIC 0xc5acce55
+
+/* ETM control register, "ETM Architecture", 3.3.1 */
+#define ETMR_CTRL 0
+#define ETMCTRL_POWERDOWN 1
+#define ETMCTRL_PROGRAM (1 << 10)
+#define ETMCTRL_PORTSEL (1 << 11)
+#define ETMCTRL_DO_CONTEXTID (3 << 14)
+#define ETMCTRL_PORTMASK1 (7 << 4)
+#define ETMCTRL_PORTMASK2 (1 << 21)
+#define ETMCTRL_PORTMASK (ETMCTRL_PORTMASK1 | ETMCTRL_PORTMASK2)
+#define ETMCTRL_PORTSIZE(x) ((((x) & 7) << 4) | (!!((x) & 8)) << 21)
+#define ETMCTRL_DO_CPRT (1 << 1)
+#define ETMCTRL_DATAMASK (3 << 2)
+#define ETMCTRL_DATA_DO_DATA (1 << 2)
+#define ETMCTRL_DATA_DO_ADDR (1 << 3)
+#define ETMCTRL_DATA_DO_BOTH (ETMCTRL_DATA_DO_DATA | ETMCTRL_DATA_DO_ADDR)
+#define ETMCTRL_BRANCH_OUTPUT (1 << 8)
+#define ETMCTRL_CYCLEACCURATE (1 << 12)
+
+/* ETM configuration code register */
+#define ETMR_CONFCODE (0x04)
+
+/* ETM trace start/stop resource control register */
+#define ETMR_TRACESSCTRL (0x18)
+
+/* ETM trigger event register */
+#define ETMR_TRIGEVT (0x08)
+
+/* address access type register bits, "ETM architecture",
+ * table 3-27 */
+/* - access type */
+#define ETMAAT_IFETCH 0
+#define ETMAAT_IEXEC 1
+#define ETMAAT_IEXECPASS 2
+#define ETMAAT_IEXECFAIL 3
+#define ETMAAT_DLOADSTORE 4
+#define ETMAAT_DLOAD 5
+#define ETMAAT_DSTORE 6
+/* - comparison access size */
+#define ETMAAT_JAVA (0 << 3)
+#define ETMAAT_THUMB (1 << 3)
+#define ETMAAT_ARM (3 << 3)
+/* - data value comparison control */
+#define ETMAAT_NOVALCMP (0 << 5)
+#define ETMAAT_VALMATCH (1 << 5)
+#define ETMAAT_VALNOMATCH (3 << 5)
+/* - exact match */
+#define ETMAAT_EXACTMATCH (1 << 7)
+/* - context id comparator control */
+#define ETMAAT_IGNCONTEXTID (0 << 8)
+#define ETMAAT_VALUE1 (1 << 8)
+#define ETMAAT_VALUE2 (2 << 8)
+#define ETMAAT_VALUE3 (3 << 8)
+/* - security level control */
+#define ETMAAT_IGNSECURITY (0 << 10)
+#define ETMAAT_NSONLY (1 << 10)
+#define ETMAAT_SONLY (2 << 10)
+
+#define ETMR_COMP_VAL(x) (0x40 + (x) * 4)
+#define ETMR_COMP_ACC_TYPE(x) (0x80 + (x) * 4)
+
+/* ETM status register, "ETM Architecture", 3.3.2 */
+#define ETMR_STATUS (0x10)
+#define ETMST_OVERFLOW (1 << 0)
+#define ETMST_PROGBIT (1 << 1)
+#define ETMST_STARTSTOP (1 << 2)
+#define ETMST_TRIGGER (1 << 3)
+
+#define etm_progbit(t) (etm_readl((t), ETMR_STATUS) & ETMST_PROGBIT)
+#define etm_started(t) (etm_readl((t), ETMR_STATUS) & ETMST_STARTSTOP)
+#define etm_triggered(t) (etm_readl((t), ETMR_STATUS) & ETMST_TRIGGER)
+
+#define ETMR_TRACEENCTRL2 0x1c
+#define ETMR_TRACEENCTRL 0x24
+#define ETMTE_INCLEXCL (1 << 24)
+#define ETMR_TRACEENEVT 0x20
+#define ETMCTRL_OPTS (ETMCTRL_DO_CPRT | \
+ ETMCTRL_DATA_DO_ADDR | \
+ ETMCTRL_BRANCH_OUTPUT | \
+ ETMCTRL_DO_CONTEXTID)
+
+/* ETB registers, "CoreSight Components TRM", 9.3 */
+#define ETBR_DEPTH 0x04
+#define ETBR_STATUS 0x0c
+#define ETBR_READMEM 0x10
+#define ETBR_READADDR 0x14
+#define ETBR_WRITEADDR 0x18
+#define ETBR_TRIGGERCOUNT 0x1c
+#define ETBR_CTRL 0x20
+#define ETBR_FORMATTERCTRL 0x304
+#define ETBFF_ENFTC 1
+#define ETBFF_ENFCONT (1 << 1)
+#define ETBFF_FONFLIN (1 << 4)
+#define ETBFF_MANUAL_FLUSH (1 << 6)
+#define ETBFF_TRIGIN (1 << 8)
+#define ETBFF_TRIGEVT (1 << 9)
+#define ETBFF_TRIGFL (1 << 10)
+
+#define etb_writel(t, v, x) \
+ (__raw_writel((v), (t)->etb_regs + (x)))
+#define etb_readl(t, x) (__raw_readl((t)->etb_regs + (x)))
+
+#define etm_lock(t) do { etm_writel((t), 0, CSMR_LOCKACCESS); } while (0)
+#define etm_unlock(t) \
+ do { etm_writel((t), UNLOCK_MAGIC, CSMR_LOCKACCESS); } while (0)
+
+#define etb_lock(t) do { etb_writel((t), 0, CSMR_LOCKACCESS); } while (0)
+#define etb_unlock(t) \
+ do { etb_writel((t), UNLOCK_MAGIC, CSMR_LOCKACCESS); } while (0)
+
+#endif /* __ASM_HARDWARE_CORESIGHT_H */
+
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 79087dd..e7ccf7e 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -17,6 +17,8 @@ obj-y := compat.o elf.o entry-armv.o entry-common.o irq.o \
process.o ptrace.o return_address.o setup.o signal.o \
sys_arm.o stacktrace.o time.o traps.o
+obj-$(CONFIG_OC_ETM) += etm.o
+
obj-$(CONFIG_ISA_DMA_API) += dma.o
obj-$(CONFIG_ARCH_ACORN) += ecard.o
obj-$(CONFIG_FIQ) += fiq.o
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
new file mode 100644
index 0000000..8277539
--- /dev/null
+++ b/arch/arm/kernel/etm.c
@@ -0,0 +1,641 @@
+/*
+ * 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");
+
+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, struct tty_struct *tty)
+{
+ 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,
+};
+
+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);
+ ret = etm_readl(t, CSCR_PRSR);
+
+ 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);
+
--
1.6.3.3
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