perf: CXL: fix CPMU filter value mask length

CPMU filter value is described as 4B length in CXL r3.0 8.2.7.2.2.
However, it is used as 2B length in code and comments.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Hojin Nam <hj96.nam@samsung.com>
Link: https://lore.kernel.org/r/20240216014522.32321-1-hj96.nam@samsung.com
Signed-off-by: Will Deacon <will@kernel.org>

perf: CXL: fix mismatched cpmu event opcode

S2M NDR BI-ConflictAck opcode is described as 4 in the CXL
r3.0 3.3.9 Table 3.43. However, it is defined as 3 in macro definition.

Fixes: 5d7107c72796 ("perf: CXL Performance Monitoring Unit driver")
Signed-off-by: Hojin Nam <hj96.nam@samsung.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240208013415epcms2p2904187c8a863f4d0d2adc980fb91a2dc@epcms2p2
Signed-off-by: Will Deacon <will@kernel.org>

perf: CXL: fix mismatched number of counters mask

The number of Count Units field is described as 6 bits long
in the CXL 3.0 specification. However, its mask value was
only declared as 5 bits long.

Signed-off-by: Jeongtae Park <jtp.park@samsung.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230905123309.775854-1-jtp.park@samsung.com
Signed-off-by: Will Deacon <will@kernel.org>

perf: CXL Performance Monitoring Unit driver

CXL rev 3.0 introduces a standard performance monitoring hardware
block to CXL. Instances are discovered using CXL Register Locator DVSEC
entries. Each CXL component may have multiple PMUs.

This initial driver supports a subset of types of counter.
It supports counters that are either fixed or configurable, but requires
that they support the ability to freeze and write value whilst frozen.

Development done with QEMU model which will be posted shortly.

Example:

$ perf stat -a -e cxl_pmu_mem0.0/h2d_req_snpcur/ -e cxl_pmu_mem0.0/h2d_req_snpdata/ -e cxl_pmu_mem0.0/clock_ticks/ sleep 1

Performance counter stats for 'system wide':

96,757,023,244,321 cxl_pmu_mem0.0/h2d_req_snpcur/
96,757,023,244,365 cxl_pmu_mem0.0/h2d_req_snpdata/
193,514,046,488,653 cxl_pmu_mem0.0/clock_ticks/

1.090539600 seconds time elapsed

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230526095824.16336-5-Jonathan.Cameron@huawei.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>