[PATCH] coresight-stm: adding driver for CoreSight STM component
From: Paul Bolle <hidden>
Date: 2015-02-05 11:27:46
Also in:
linux-api, lkml
On Wed, 2015-02-04 at 15:22 -0700, mathieu.poirier at linaro.org wrote:
From: Pratik Patel <redacted> This driver adds support for the STM CoreSight IP block, allowing any system compoment (HW or SW) to log and aggregate messages via a single entity. The STM exposes an application defined number of channels called stimulus port. Configuration is done using entries in sysfs and channels made available to userspace via devfs. Signed-off-by: Pratik Patel <redacted> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
This needs "coresight: Adding coresight support for arm64 architecture" (https://lkml.org/lkml/2015/2/3/677 ) in order to get applied. Perhaps that's obvious to the people working on this. A few comments follow.
quoted hunk ↗ jump to hunk
--- .../ABI/testing/sysfs-bus-coresight-devices-stm | 62 ++ Documentation/trace/coresight.txt | 88 +- drivers/coresight/Kconfig | 10 + drivers/coresight/Makefile | 1 + drivers/coresight/coresight-stm.c | 1090 ++++++++++++++++++++ include/linux/coresight-stm.h | 35 + include/uapi/linux/coresight-stm.h | 23 + 7 files changed, 1307 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-bus-coresight-devices-stm create mode 100644 drivers/coresight/coresight-stm.c create mode 100644 include/linux/coresight-stm.h create mode 100644 include/uapi/linux/coresight-stm.h [...]diff --git a/drivers/coresight/Kconfig b/drivers/coresight/Kconfig index fc1f1ae7a49d..08806cc7d737 100644 --- a/drivers/coresight/Kconfig +++ b/drivers/coresight/Kconfig@@ -58,4 +58,14 @@ config CORESIGHT_SOURCE_ETM3X which allows tracing the instructions that a processor is executing This is primarily useful for instruction level tracing. Depending the ETM version data tracing may also be available. + +config CORESIGHT_STM + bool "CoreSight System Trace Macrocell driver" + depends on (ARM && !(CPU_32v4 || CPU_32v4T)) || ARM64 || (64BIT && COMPILE_TEST)
I'm _guessing_ that CPU_32v4 and CPU_32v4T are needed for the ldrd and
strd assembler instructions. If that's right a next _guess_ would be
that you also need to mention CPU_32v3 here.
Furthermore, this file is only sourced by arch/arm/Kconfig.debug and
arch/arm64/Kconfig.debug. So 64BIT should always be equal to ARM64 and
the
|| (64BIT && COMPILE_TEST)
part shouldn't be needed, isn't it?
quoted hunk ↗ jump to hunk
+ select CORESIGHT_LINKS_AND_SINKS + help + This driver provides support for hardware assisted software + instrumentation based tracing. This is primarily used for + logging useful software events or data coming from various entities + in the system, possibly running different OSs endif [...]diff --git a/drivers/coresight/coresight-stm.c b/drivers/coresight/coresight-stm.c new file mode 100644 index 000000000000..e59b0fe01d87 --- /dev/null +++ b/drivers/coresight/coresight-stm.c@@ -0,0 +1,1090 @@[...] +#ifndef CONFIG_64BIT +static inline void __raw_writeq(u64 val, volatile void __iomem *addr) +{ + asm volatile("strd %1, %0" + : "+Qo" (*(volatile u64 __force *)addr) + : "r" (val)); +} + +static inline u64 __raw_readq(const volatile void __iomem *addr) +{ + u64 val; + + asm volatile("ldrd %1, %0" + : "+Qo" (*(volatile u64 __force *)addr), + "=r" (val)); + return val; +} + +#undef readq_relaxed +#define readq_relaxed(c) ({ u64 __r = le64_to_cpu((__force __le64) \ + __raw_readq(c)); __r; })
I spotted no users of readq_relaxed. Is it needed?
+#undef writeq_relaxed +#define writeq_relaxed(v, c) __raw_writeq((__force u64) cpu_to_le64(v), c) +#endif + [...]
+static ssize_t entities_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+ ssize_t len;
+
+ len = bitmap_scnprintf(buf, PAGE_SIZE, drvdata->entities,
+ STM_ENTITY_MAX);
+bitmap_scnprintf is gone in current linux-next. I changed it to len = scnprintf(buf, PAGE_SIZE, "%*pb", STM_ENTITY_MAX, drvdata->entities); to get this file to compile. (On x86_64, that is, but please don't tell anybody!) Paul Bolle