CoreSight ETMv4.4 obsoletes memory mapped access to ETM and mandates the system instructions for registers. This also implies that they may not be on the amba bus. Right now all the CoreSight components are accessed via memory map. Also, we have some common routines in coresight generic code driver (e.g, CS_LOCK, claim/disclaim), which assume the mmio. In order to preserve the generic algorithms at a single place and to allow dynamic switch for ETMs, this series introduces an abstraction layer for accessing a coresight device. It is designed such that the mmio access are fast tracked (i.e, without an indirect function call).
This will also help us to get rid of the driver+attribute specific sysfs show/store routines and replace them with a single routine to access a given register offset (which can be embedded in the dev_ext_attribute). This is not currently implemented in the series, but can be achieved.
Further we switch the generic routines to work with the abstraction. With this in place, we refactor the etm4x code a bit to allow for supporting the system instructions with very little new code. The changes also switch to using the system instructions by default even when we may have an MMIO.
We use TRCDEVARCH for the detection of the ETM component, which is a standard register as per CoreSight architecture, rather than the etm specific id register TRCIDR1. This is for making sure that we are able to detect the ETM via system instructions accurately, when the the trace unit could be anything (etm or a custom trace unit). To keep the backward compatibility for any existing broken impelementation which may not implement TRCDEVARCH, we fall back to TRCIDR1. Also this covers us for the changes in the future architecture [0].
The series has been mildly tested on a model for system instructions. I would really appreciate any testing on real hardware.
Applies on coresight/next.
[0] https://developer.arm.com/docs/ddi0601/g/aarch64-system-registers/trcidr1
Known issues: Checkpatch failure for "coresight: etm4x: Add sysreg access helpers" :
ERROR: Macros with complex values should be enclosed in parentheses #121: FILE: drivers/hwtracing/coresight/coresight-etm4x.h:153: +#define CASE_READ(res, x) \ + case (x): { (res) = read_etm4x_sysreg_const_offset((x)); break; }
I don't know how to fix that without breaking the build ! Suggestions welcome.
Changes since V2: - Several fixes to the ETM register accesses. Access a register when it is present. - Add support for TRCIDR3.NUMPROCS for v4.2+ - Drop OS lock detection. Use software lock only in case of mmio. - Fix issues with the Exception level masks (Mike Leach) - Fall back to using TRCIDR1 when TRCDEVARCH is not "present" - Use a generic notion of ETM architecture (rather than using the encoding as in registers) - Fixed some checkpatch issues. - Add support for Self Hosted tracing Arm v8.4 extensions. (Mike Leach) Originally written by Jonathan, refactored and cleaned up. - Changed the dts compatible string to "arm,coresight-etm-sysreg" (Mike Leach)
Changes since V1: - Flip the switch for iomem from no_iomem to io_mem in csdev_access. - Split patches for claim/disclaim and CS_LOCK/UNLOCK conversions. - Move device access initialisation for etm4x to the target CPU - Cleanup secure exception level mask handling. - Switch to use TRCDEVARCH for ETM component discovery. This is for making - Check the availability of OS/Software Locks before using them.
Suzuki K Poulose (26): coresight: etm4x: Fix accesses to TRCVMIDCTLR1 coresight: etm4x: Fix accesses to TRCCIDCTLR1 coresight: etm4x: Update TRCIDR3.NUMPROCS handling to match v4.2 coresight: etm4x: Fix accesses to TRCPROCSELR coresight: etm4x: Handle TRCVIPCSSCTLR accesses coresight: etm4x: Handle access to TRCSSPCICRn coresight: Introduce device access abstraction coresight: tpiu: Prepare for using coresight device access abstraction coresight: Convert coresight_timeout to use access abstraction coresight: Convert claim/disclaim operations to use access wrappers coresight: etm4x: Always read the registers on the host CPU coresight: etm4x: Convert all register accesses coresight: etm4x: Add commentary on the registers coresight: etm4x: Add sysreg access helpers coresight: etm4x: Define DEVARCH register fields coresight: etm4x: Check for Software Lock coresight: etm4x: Cleanup secure exception level masks coresight: etm4x: Clean up exception level masks coresight: etm4x: Detect access early on the target CPU coresight: etm4x: Handle ETM architecture version coresight: etm4x: Use TRCDEVARCH for component discovery coresight: etm4x: Add necessary synchronization for sysreg access coresight: etm4x: Detect system instructions support coresight: etm4x: Refactor probing routine coresight: etm4x: Add support for sysreg only devices dts: bindings: coresight: ETM system register access only units
.../devicetree/bindings/arm/coresight.txt | 5 +- drivers/hwtracing/coresight/coresight-catu.c | 12 +- drivers/hwtracing/coresight/coresight-core.c | 130 ++- .../hwtracing/coresight/coresight-cti-core.c | 18 +- drivers/hwtracing/coresight/coresight-etb10.c | 10 +- .../coresight/coresight-etm3x-core.c | 9 +- .../coresight/coresight-etm4x-core.c | 758 +++++++++++------- .../coresight/coresight-etm4x-sysfs.c | 44 +- drivers/hwtracing/coresight/coresight-etm4x.h | 501 +++++++++++- .../hwtracing/coresight/coresight-funnel.c | 7 +- .../coresight/coresight-replicator.c | 17 +- drivers/hwtracing/coresight/coresight-stm.c | 4 +- .../hwtracing/coresight/coresight-tmc-core.c | 16 +- .../hwtracing/coresight/coresight-tmc-etf.c | 10 +- .../hwtracing/coresight/coresight-tmc-etr.c | 4 +- drivers/hwtracing/coresight/coresight-tpiu.c | 31 +- include/linux/coresight.h | 230 +++++- 17 files changed, 1376 insertions(+), 430 deletions(-)