Commit Graph

37 Commits

Author SHA1 Message Date
Suzuki K Poulose 0bbb194c0c coresight: Extend the PIDR mask to cover relevant bits in PIDR2
As per coresight standards, PIDR2 register has the following format :

 [2-0]	- JEP106_bits6to4
 [3]	- JEDEC, designer ID is specified by JEDEC.

However some of the drivers only use mask of 0x3 for the PIDR2 leaving
bits [3-2] unchecked, which could potentially match the component for
a different device altogether. This patch fixes the mask and the
corresponding id bits for the existing devices.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-20 15:03:06 +02:00
Arvind Yadav 6f964e7c17 coresight: tmc: constify amba_id
amba_id are not supposed to change at runtime. All functions
working with const amba_id. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:06:39 +02:00
Suzuki K Poulose 6495892c91 coresight tmc: Add support for Coresight SoC 600 TMC
The coresight SoC 600 supports ETR save-restore which allows us
to restore a trace session by retaining the RRP/RWP/STS.Full values
when the TMC leaves the Disabled state. However, the TMC doesn't
have a scatter-gather unit in built.

Also, TMCs have different PIDs in different configurations (ETF,
ETB & ETR), unlike the previous generation.

While the DEVID exposes some of the features/changes in the TMC,
it doesn't explicitly advertises the new save-restore feature
as described above.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:49 +02:00
Suzuki K Poulose ff11f5bc5a coresight tmc etr: Detect address width at runtime
TMC in Coresight SoC-600 advertises the AXI address width
in the device configuration register.

Bit 16 - AXIAW_VALID
 0 - AXI Address Width not valid
 1 - Valid AXI Address width in Bits[23-17]

Bits [23-17] - AXIAW. If AXIAW_VALID = b01 then
 0x20 - 32bit AXI address bus
 0x28 - 40bit AXI address bus
 0x2c - 44bit AXI address bus
 0x30 - 48bit AXI address bus
 0x34 - 52bit AXI address bus

Use the address bits from the device configuration register, if
available. Otherwise, default to 40bit.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:49 +02:00
Suzuki K Poulose 2e21934568 coresight tmc: Detect support for scatter gather
The SG unit in the TMC has been removed in Coresight SoC-600.
This is however advertised by DEVID:Bit 24 = 0b1. On the
previous generation, the bit is RES0, hence we can rely on the
DEVID to detect the support.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:49 +02:00
Suzuki K Poulose 2884132ae8 coresight tmc etr: Add capabilitiy information
With new version of TMC ETR, there are differing set of
features supported by the TMC. Add the capability of a
given TMC ETR for making safer decisions at runtime.

The device configuration register of the TMC (DEVID) lists
some of the capabilities. So, we can detect some of them at
probe. However, some of the features (or changes in behavior)
are not advertised and we have to depend on the PID to infer
the features. So we use a static description of the "unadvertised"
capabilities attached to the PID. Combining both, the static
and the dynamic capabilities, we maintain a bitmask of the
available features which can be later checked to take
appropriate actions.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:49 +02:00
Suzuki K Poulose 99ac6f1209 coresight tmc: Handle configuration types properly
Coresight SoC 600 defines a new configuration for TMC, Embedded Trace
Streamer (ETS), indicated by 0x3 in MODE:CONFIG_TYPE. This would break
the existing driver which will treat anything other than ETR/ETB as an
ETF. Fix the driver to check the configuration type properly and also
add a warning if we encounter an unsupported configuration (ETS).

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:49 +02:00
Suzuki K Poulose 2b4553399b coresight tmc: Expose DBA and AXICTL
Expose DBALO,DBAHI and AXICTL registers

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:48 +02:00
Suzuki K Poulose 47675f6a46 coresight: Use the new helper for defining registers
Use the new helpers for exposing coresight component registers,
choosing the 64bit variants for appropriate registers.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 16:05:48 +02:00
Robin Murphy a3959c50b0 coresight: tmc: Configure DMA mask appropriately
Before making any DMA API calls, the ETR driver should really be setting
its masks to ensure that DMA is possible. Especially since it can
address more than the 32-bit default mask set by the AMBA bus code.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:45:24 +02:00
Baoyou Xie 0ef7528d15 coresight: tmc: mark symbols static where possible
We get a few warnings when building kernel with W=1:
drivers/hwtracing/coresight/coresight-tmc-etr.c:23:6: warning: no previous prototype for 'tmc_etr_enable_hw' [-Wmissing-prototypes]
drivers/hwtracing/coresight/coresight-tmc-etf.c:25:6: warning: no previous prototype for 'tmc_etb_enable_hw' [-Wmissing-prototypes]
drivers/hwtracing/coresight/coresight-tmc.c:250:9: warning: no previous prototype for ‘trigger_cntr_show’ [-Wmissing-prototypes]
...

In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
so this patch marks these functions with 'static'.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-09 13:53:00 +02:00
Sudeep Holla 3224dcc5a6 coresight: fix handling of ETM trace register access via sysfs
The ETM registers are classified into 2 categories: trace and management.
The core power domain contains most of the trace unit logic including
all(except TRCOSLAR and TRCOSLSR) the trace registers. The debug power
domain contains the external debugger interface including all management
registers.

This patch adds coresight unit specific function coresight_simple_func
which can be used for ETM trace registers by providing a ETM specific
read function which does smp cross call to ensure the trace core is
powered up before the register is accessed.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:43 +02:00
Suzuki K Poulose 9486295ad1 coresight: Use local coresight_desc instances
Each coresight device prepares a description for coresight_register()
in struct coresight_desc. Once we register the device, the description is
useless and can be freed. The coresight_desc is small enough (48bytes on
64bit)i to be allocated on the stack. Hence use an automatic variable to
avoid a needless dynamic allocation and wasting the memory(which will only
be free'd when the device is destroyed).

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:43 +02:00
Suzuki K Poulose 67337e8d8d coresight: Add better messages for coresight_timeout
When we encounter a timeout waiting for a status change via
coresight_timeout, the caller always print the offset which
was tried. This is pretty much useless as it doesn't specify
the bit position we wait for. Also, one needs to lookup the
TRM to figure out, what was wrong. This patch changes all
such error messages to print something more meaningful.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:42 +02:00
Suzuki K Poulose 8505feaed9 coresight: tmc: Limit the trace to available data
At present the ETF or ETR gives out the entire device
buffer, even if there is less or even no trace data
available. This patch limits the trace data given out to
the actual trace data collected.

Cc: mathieu.poirier@linaro.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:42 +02:00
Suzuki K Poulose 3afd0634a2 coresight: Consolidate error handling path for tmc_probe
This patch cleans up the error handling path for tmc_probe
as a side effect of the removal of the spurious dma_free_coherent().

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:42 +02:00
Suzuki K Poulose 481e46fe7a coresight: Remove erroneous dma_free_coherent in tmc_probe
commit de5461970b ("coresight: tmc: allocating memory when needed")
removed the static allocation of buffer for the trace data in ETR mode in
tmc_probe. However it failed to remove the "devm_free_coherent" in
tmc_probe when the probe fails due to other reasons. This patch gets
rid of the incorrect dma_free_coherent() call.

Fixes: commit de5461970b ("coresight: tmc: allocating memory when needed")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-08-31 13:05:42 +02:00
Mathieu Poirier 4f1ff3de92 coresight: tmc: keep track of memory width
Accessing the HW configuration register each time the memory
width is needed simply doesn't make sense.  It is much more
efficient to read the value once and keep a reference for
later use.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier f74debbea0 coresight: tmc: getting rid of multiple read access
Allowing multiple readers to access the trace data simultaniously
via sysFS provides no shortage of opportunity for race condition,
mandates two variable to be maintained (drvdata::read_count and
drvdata::reading), makes the code complex and provide little
advantages, if any.

This patch streamlines the read process by restricting trace data
access to a single user.  That way drvdata::read_count can
be eliminated and race conditions (along with faulty error handling)
in function tmc_open() and tmc_release() eliminated.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier de5461970b coresight: tmc: allocating memory when needed
In it's current form the TMC probe() function allocates
trace buffer memory at boot time, event if coresight isn't
used.  This is highly inefficient since trace buffers can
occupy a lot of memory that could be used otherwised.

This patch allocates trace buffers on the fly, when the
coresight subsystem is solicited.  Allocated buffers are
released when traces are read using the device descriptors
under /dev.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 4525412a50 coresight: tmc: making prepare/unprepare functions generic
Dealing with HW related matters in tmc_read_prepare/unprepare
becomes convoluted when many cases need to be handled distinctively.

As such moving processing related to HW setup to individual driver
files and keep the core driver generic.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 6c6ed1e244 coresight: tmc: splitting driver in ETB/ETF and ETR components
The TMC block can operate in 3 modes (ETB, ETF and ETR) and accessed
via two interfaces (sysFS and Perf).  That makes 6 mode to cover, which
is way too much coupling for a single file.

This patch splits the original TMC driver in 2 halves, one for ETB/ETF
and another one for ETR mode.  A common core is kept for functionality
common to all 3 modes.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier a8ab4268e0 coresight: tmc: cleaning up header file
This patch first move the TMC_STS_TMCREADY_BIT and
TMC_FFCR_FLUSHMAN_BIT defines to their respective section.
It also removes TMC_FFCR_FLUSHMAN, since the same result
can easily be obtained using the BIT() macro.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 4c324b5f0e coresight: tmc: introducing new header file
The amount of #define, enumeration and structure definition
is big enough to justify moving them to a new header file.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier ebba56e7b2 coresight: tmc: clearly define number of transfers per burst
This patch makes the name of the define reflect the amount of
data tranfers per burst, in this case 16.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier b1789b793e coresight: tmc: re-implementing tmc_read_prepare/unprepare() functions
In their current implementation the tmc_read_prepare/unprepare()
are a lump of if/else that is difficult to read.  This patch is
alleviating that by using a switch statement.  The latter also
allows for a better control on the error path.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 358f42184e coresight: tmc: waiting for TMCReady bit before programming
According to the TRM before programming the TMC in circular
buffer mode (and that for any configuration, ETB, ETR, ETF),
the TMCReady bit in the status register has to be set.

This patch adds a check to make sure the state machine is in
a state where it can be configured, and complains otherwise.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 580ff804ec coresight: tmc: modifying naming convention
According to the TMC architectural state machine, the 'stopped'
state is reached when bit 2 (TMCReady) of the TMC Status register
turns to '1'.  The code is correct but the naming convention isn't.

The 'Triggered' bit occupies position '1' of the TMC Status register
and has nothing to do with the indication of the TMC entering the
stopped state. As such renaming function "tmc_wait_for_triggered()"
and changing the #define to reflect what the code is really doing.

This patch has no effect other than clarifying the semantic.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier 7d83d17795 coresight: tmc: adding sysFS management entries
Adding management registers that convey implementation
specific characteristics.  Those are useful for trace
configuration and collection along with general trouble
shooting.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-03 14:59:30 -07:00
Mathieu Poirier ef0fd640e3 coresight: removing gratuitous boot time log messages
Removing boot time log for drivers that don't report useful information
other than they came up properly.  The same information can be found in
sysFS once the system has booted and as such doesn't provide any value
in the boot log.

Reported-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-01 14:12:14 -07:00
Paul Gortmaker 941943cf51 drivers/hwtracing: make coresight-* explicitly non-modular
None of the Kconfig currently controlling compilation of any of
the files here are tristate, meaning that none of it currently
is being built as a module by anyone.

We need not be concerned about .remove functions and blocking the
unbind sysfs operations, since that was already done in a recent
commit.

Lets remove any remaining modular references, so that when reading the
drivers there is no doubt they are builtin-only.

All drivers get mostly the same changes, so they are handled in batch.
Changes are (1) convert to builtin_amba_driver, (2) delete module.h
include where unused, and (3) relocate the description into the
comments so we don't need MODULE_DESCRIPTION and associated tags.

The etm3x and etm4x use module_param_named, and have been adjusted
to just include moduleparam.h for that purpose.

In commit f309d44431 ("platform_device:
better support builtin boilerplate avoidance") we introduced the
builtin_driver macro.

Here we use that support and extend it to amba driver registration,
so where a driver is clearly non-modular and builtin-only, we can
update with the simple mapping of

     module_amba_driver(...)  ---> builtin_amba_driver(...)

Since module_amba_driver() uses the same init level priority as
builtin_amba_driver() the init ordering remains unchanged with
this commit.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier e827d4550a coresight: etb10: adding operation mode for sink->enable()
Adding an operation mode to the sink->enable() API in order
to prevent simultaneous access from different callers.

TPIU and TMC won't be supplemented with the AUX area
API immediately and as such ignore the new mode.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier 5da5325fa8 coresight: moving PM runtime operations to core framework
Moving PM runtime operations in Coresight devices enable() and
disable() API to the framework core when a path is setup.  That
way the runtime core doesn't have to be involved everytime a
path is enabled.  It also avoids calling runtime PM operations
in IRQ context.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Eric Long 61390593f7 coresight: etm4x: Check every parameter used by dma_xx_coherent.
The dma_alloc_coherent return an "void *" not an "void __iomen *".
It uses the wrong parameters when calls dma_free_coherent function.

The sparse tool output logs as the following:
coresight-tmc.c:199:23:    expected void *<noident>
coresight-tmc.c:199:23:    got void [noderef] <asn:2>*vaddr
coresight-tmc.c:336:30: warning: incorrect type in assignment
(different address spaces)
coresight-tmc.c:336:30:    expected char *buf
coresight-tmc.c:336:30:    got void [noderef] <asn:2>*
coresight-tmc.c:769:50: warning: incorrect type in argument 4
(different base types)
coresight-tmc.c:769:50:    expected unsigned long long
[unsigned] [usertype] dma_handle
coresight-tmc.c:769:50:    got restricted gfp_t

Signed-off-by: Eric Long <eric.long@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-20 14:11:01 -08:00
Mathieu Poirier b15f0fb657 coresight: removing bind/unbind options from sysfs
The coresight drivers have absolutely no control over bind and unbind
operations triggered from sysfs. The operations simply can't be
cancelled or denied event when one or several tracing sessions are
under way.  Since the memory associated to individual device is
invariably freed, the end result is a kernel crash when the path from
source to sink is travelled again as demonstrated here[1].

One solution could be to keep track of all the path (i.e tracing
session) that get created and iterate through the elements of those path
looking for the coresight device that is being removed.  This proposition
doesn't scale well since there is no upper bound on the amount of
concurrent trace session that can be created.

With the above in mind, this patch prevent devices from being unbounded
from their driver by using the driver->suppress_bind_attr option.  That way
trace sessions can be managed without fearing to loose devices.

Since device can't be removed anymore the xyz_remove() functions found in
each driver is also removed.

[1]. http://www.spinics.net/lists/arm-kernel/msg474952.html

Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07 22:12:18 -08:00
Linus Walleij 32398ef6f4 coresight: tmc: let runtime PM handle core clock
This uses runtime PM to manage the PCLK ("amba_pclk") instead
of screwing around with the framework by going in and taking
a copy from the amba device. The amba bus core will unprepare
and disable the clock when the device is unused when
CONFIG_PM is selected, else the clock will be always on.

Prior to this patch, as the AMBA primecell bus code enables
the PCLK, it would be left on after probe as
the clk_prepare_enable() and clk_disable_unprepare() was
called and thus just increase and decreas the refcount by
one, without it reaching zero and actually disabling the
clock. Now the runtime PM callbacks will make sure the PCLK
is properly disabled after probe.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24 11:12:08 -07:00
Mathieu Poirier 01081f5ab9 coresight: moving to new "hwtracing" directory
Keeping drivers related to HW tracing on ARM, i.e coresight,
under "drivers/coresight" doesn't make sense when other
architectures start rolling out technologies of the same
nature.

As such creating a new "drivers/hwtracing" directory where all
drivers of the same kind can reside, reducing namespace
pollution under "drivers/".

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-04-03 16:17:04 +02:00