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coresight: etm4x: Modify core-commit to avoid HiSilicon ETM overflow 

The ETM device can't keep up with the core pipeline when cpu core
is at full speed. This may cause overflow within core and its ETM.
This is a common phenomenon on ETM devices.

On HiSilicon Hip08 platform, a specific feature is added to set
core pipeline. So commit rate can be reduced manually to avoid ETM
overflow.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
[Modified changelog title and Kconfig description]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20201208182651.1597945-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Qi Liu 2020-12-08 11:26:51 -07:00 committed by Greg Kroah-Hartman
parent 45fe7befe0
commit e72550928f
3 changed files with 114 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/hwtracing/coresight/Kconfig
View File

@ -110,6 +110,14 @@ config CORESIGHT_SOURCE_ETM4X
To compile this driver as a module, choose M here: the
module will be called coresight-etm4x.
config ETM4X_IMPDEF_FEATURE
bool "Control implementation defined overflow support in ETM 4.x driver"
depends on CORESIGHT_SOURCE_ETM4X
help
This control provides implementation define control for CoreSight
ETM 4.x tracer module that can't reduce commit rate automatically.
This avoids overflow between the ETM tracer module and the cpu core.
config CORESIGHT_STM
tristate "CoreSight System Trace Macrocell driver"
depends on (ARM && !(CPU_32v3 || CPU_32v4 || CPU_32v4T)) || ARM64

98
drivers/hwtracing/coresight/coresight-etm4x-core.c
View File

@ -3,6 +3,7 @@
* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*/
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
@ -28,7 +29,9 @@
#include <linux/perf_event.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <asm/sections.h>
#include <asm/sysreg.h>
#include <asm/local.h>
#include <asm/virt.h>
@ -103,6 +106,97 @@ struct etm4_enable_arg {
int rc;
};
#ifdef CONFIG_ETM4X_IMPDEF_FEATURE
#define HISI_HIP08_AMBA_ID 0x000b6d01
#define ETM4_AMBA_MASK 0xfffff
#define HISI_HIP08_CORE_COMMIT_MASK 0x3000
#define HISI_HIP08_CORE_COMMIT_SHIFT 12
#define HISI_HIP08_CORE_COMMIT_FULL 0b00
#define HISI_HIP08_CORE_COMMIT_LVL_1 0b01
#define HISI_HIP08_CORE_COMMIT_REG sys_reg(3, 1, 15, 2, 5)
struct etm4_arch_features {
void (*arch_callback)(bool enable);
};
static bool etm4_hisi_match_pid(unsigned int id)
{
return (id & ETM4_AMBA_MASK) == HISI_HIP08_AMBA_ID;
}
static void etm4_hisi_config_core_commit(bool enable)
{
u8 commit = enable ? HISI_HIP08_CORE_COMMIT_LVL_1 :
HISI_HIP08_CORE_COMMIT_FULL;
u64 val;
/*
* bit 12 and 13 of HISI_HIP08_CORE_COMMIT_REG are used together
* to set core-commit, 2'b00 means cpu is at full speed, 2'b01,
* 2'b10, 2'b11 mean reduce pipeline speed, and 2'b01 means level-1
* speed(minimun value). So bit 12 and 13 should be cleared together.
*/
val = read_sysreg_s(HISI_HIP08_CORE_COMMIT_REG);
val &= ~HISI_HIP08_CORE_COMMIT_MASK;
val |= commit << HISI_HIP08_CORE_COMMIT_SHIFT;
write_sysreg_s(val, HISI_HIP08_CORE_COMMIT_REG);
}
static struct etm4_arch_features etm4_features[] = {
[ETM4_IMPDEF_HISI_CORE_COMMIT] = {
.arch_callback = etm4_hisi_config_core_commit,
},
{},
};
static void etm4_enable_arch_specific(struct etmv4_drvdata *drvdata)
{
struct etm4_arch_features *ftr;
int bit;
for_each_set_bit(bit, drvdata->arch_features, ETM4_IMPDEF_FEATURE_MAX) {
ftr = &etm4_features[bit];
if (ftr->arch_callback)
ftr->arch_callback(true);
}
}
static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
{
struct etm4_arch_features *ftr;
int bit;
for_each_set_bit(bit, drvdata->arch_features, ETM4_IMPDEF_FEATURE_MAX) {
ftr = &etm4_features[bit];
if (ftr->arch_callback)
ftr->arch_callback(false);
}
}
static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
unsigned int id)
{
if (etm4_hisi_match_pid(id))
set_bit(ETM4_IMPDEF_HISI_CORE_COMMIT, drvdata->arch_features);
}
#else
static void etm4_enable_arch_specific(struct etmv4_drvdata *drvdata)
{
}
static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
{
}
static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
unsigned int id)
{
}
#endif /* CONFIG_ETM4X_IMPDEF_FEATURE */
static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
{
int i, rc;
@ -110,6 +204,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
struct device *etm_dev = &drvdata->csdev->dev;
CS_UNLOCK(drvdata->base);
etm4_enable_arch_specific(drvdata);
etm4_os_unlock(drvdata);
@ -479,6 +574,7 @@ static void etm4_disable_hw(void *info)
int i;
CS_UNLOCK(drvdata->base);
etm4_disable_arch_specific(drvdata);
if (!drvdata->skip_power_up) {
/* power can be removed from the trace unit now */
@ -1563,6 +1659,8 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
drvdata->boot_enable = true;
}
etm4_check_arch_features(drvdata, id->id);
return 0;
}

8
drivers/hwtracing/coresight/coresight-etm4x.h
View File

@ -8,6 +8,7 @@
#include <asm/local.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include "coresight-priv.h"
/*
@ -203,6 +204,11 @@
/* Interpretation of resource numbers change at ETM v4.3 architecture */
#define ETM4X_ARCH_4V3 0x43
enum etm_impdef_type {
ETM4_IMPDEF_HISI_CORE_COMMIT,
ETM4_IMPDEF_FEATURE_MAX,
};
/**
* struct etmv4_config - configuration information related to an ETMv4
* @mode: Controls various modes supported by this ETM.
@ -415,6 +421,7 @@ struct etmv4_save_state {
* @state_needs_restore: True when there is context to restore after PM exit
* @skip_power_up: Indicates if an implementation can skip powering up
* the trace unit.
* @arch_features: Bitmap of arch features of etmv4 devices.
*/
struct etmv4_drvdata {
void __iomem *base;
@ -463,6 +470,7 @@ struct etmv4_drvdata {
struct etmv4_save_state *save_state;
bool state_needs_restore;
bool skip_power_up;
DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX);
};
/* Address comparator access types */