On Sun, Jan 08, 2023 at 09:50:48PM +0000, Conor Dooley wrote: > From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > > The SBI PMU extension requires a firmware to be aware of the event to > counter/mhpmevent mappings supported by the hardware. OpenSBI may use > DeviceTree to describe the PMU mappings. This binding is currently > described in markdown in OpenSBI (since v1.0 in Dec 2021) & used by QEMU > since v7.2.0. > > Import the binding for use while validating dtb dumps from QEMU and > upcoming hardware (eg JH7110 SoC) that will make use of the event > mapping. > > Link: https://github.com/riscv-software-src/opensbi/blob/master/docs/pmu_support.md > Link: https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc # Performance Monitoring Unit Extension > Co-developed-by: Atish Patra <atishp@xxxxxxxxxxxx> > Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx> > Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > --- > Changes in v4: > - A bunch of minor description/comment changes suggested by Drew > > Changes in v3: > - align descriptions to SBI spec (and fix a misinterpretation of mine) > - switch to a nested items description, since the descriptions are for > the elements of each entry, not the entries themselves > > Changes in v2: > - use the schema mechanism for dependancies between properties > - +CC perf maintainers... > - move the matrix element descriptions into regular item descriptions > rather than doing so freeform in the property description > - drop some description text that no longer applies since changes were > made to the SBI spec > - drop mention of the "generic platform" which is OpenSBI specific > - drop the min/max items from the matrices, they don't appear to be > needed? > > Note: > OpenSBI is BSD-2-Clause licensed so I am unsure as to whether I can > submit it with a dual license. > --- > .../devicetree/bindings/perf/riscv,pmu.yaml | 160 ++++++++++++++++++ > 1 file changed, 160 insertions(+) > create mode 100644 Documentation/devicetree/bindings/perf/riscv,pmu.yaml > > diff --git a/Documentation/devicetree/bindings/perf/riscv,pmu.yaml b/Documentation/devicetree/bindings/perf/riscv,pmu.yaml > new file mode 100644 > index 000000000000..5e7a54e3d91b > --- /dev/null > +++ b/Documentation/devicetree/bindings/perf/riscv,pmu.yaml > @@ -0,0 +1,160 @@ > +# SPDX-License-Identifier: BSD-2-Clause > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/perf/riscv,pmu.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: RISC-V SBI PMU events > + > +maintainers: > + - Atish Patra <atishp@xxxxxxxxxxxx> > + > +description: | > + The SBI PMU extension allows supervisor software to configure, start and > + stop any performance counter at anytime. Thus, a user can leverage all > + capabilities of performance analysis tools, such as perf, if the SBI PMU > + extension is enabled. The following constraints apply: > + > + The platform must provide information about PMU event to counter mappings > + via device tree or platform specific hooks. Otherwise, the SBI PMU > + extension will not be enabled. > + > + Platforms should provide information about the PMU event selector values > + that should be encoded in the expected value of MHPMEVENTx while configuring > + MHPMCOUNTERx for that specific event. This can be done via a device tree or > + platform specific hooks. The exact value to be written to MHPMEVENTx is > + completely dependent on the platform. The previous two paragraphs reference 'platform specific hooks'. I don't think this DT-specific description, as opposed to the more general OpenSBI description it's derived from, should reference the hooks, as "hooks" aren't defined in this context. > + > + For information on the SBI specification see the section "Performance > + Monitoring Unit Extension" of: > + https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc > + > +properties: > + compatible: > + const: riscv,pmu > + > + riscv,event-to-mhpmevent: > + $ref: /schemas/types.yaml#/definitions/uint32-matrix > + description: > + Represents an ONE-to-ONE mapping between a PMU event and the event > + selector value that the platform expects to be written to the MHPMEVENTx > + CSR for that event. > + The mapping is encoded in an matrix format where each element represents > + an event. > + This property shouldn't encode any raw hardware event. > + items: > + items: > + - description: event_idx, a 20-bit wide encoding of the event type and > + code. Refer to the SBI specification for a complete description of > + the event types and codes. > + - description: upper 32 bits of the event selector value for MHPMEVENTx > + - description: lower 32 bits of the event selector value for MHPMEVENTx > + > + riscv,event-to-mhpmcounters: > + $ref: /schemas/types.yaml#/definitions/uint32-matrix > + description: > + Represents a MANY-to-MANY mapping between a range of events and all the > + MHPMCOUNTERx in a bitmap format that can be used to monitor these range > + of events. The information is encoded in an matrix format where each > + element represents a certain range of events and corresponding counters. > + This property shouldn't encode any raw event. > + items: > + items: > + - description: first event_idx of the range of events > + - description: last event_idx of the range of events > + - description: bitmap of MHPMCOUNTERx for this event > + > + riscv,raw-event-to-mhpmcounters: > + $ref: /schemas/types.yaml#/definitions/uint32-matrix > + description: > + Represents an ONE-to-MANY or MANY-to-MANY mapping between the rawevent(s) > + and all the MHPMCOUNTERx in a bitmap format that can be used to monitor > + that raw event. > + The encoding of the raw events are platform specific. The information is > + encoded in a matrix format where each element represents the specific raw > + event(s). > + If a platform directly encodes each raw PMU event as a unique ID, the > + value of variant must be 0xffffffff_ffffffff. > + items: > + items: > + - description: > + upper 32 invariant bits for the range of events > + - description: > + lower 32 invariant bits for the range of events > + - description: > + upper 32 bits of the variant bit mask for the range of events > + - description: > + lower 32 bits of the variant bit mask for the range of events > + - description: > + bitmap of all MHPMCOUNTERx that can monitor the range of events > + > +dependencies: > + "riscv,event-to-mhpmevent": [ "riscv,event-to-mhpmcounters" ] > + "riscv,event-to-mhpmcounters": [ "riscv,event-to-mhpmevent" ] > + > +required: > + - compatible > + > +additionalProperties: false > + > +examples: > + - | > + pmu { > + compatible = "riscv,pmu"; > + riscv,event-to-mhpmevent = <0x0000B 0x0000 0x0001>; > + riscv,event-to-mhpmcounters = <0x00001 0x00001 0x00000001>, > + <0x00002 0x00002 0x00000004>, > + <0x00003 0x0000A 0x00000ff8>, > + <0x10000 0x10033 0x000ff000>; > + riscv,raw-event-to-mhpmcounters = > + /* For event ID 0x0002 */ > + <0x0000 0x0002 0xffffffff 0xffffffff 0x00000f8>, > + /* For event ID 0-4 */ > + <0x0 0x0 0xffffffff 0xfffffff0 0x00000ff0>, > + /* For event ID 0xffffffff0000000f - 0xffffffff000000ff */ > + <0xffffffff 0x0 0xffffffff 0xffffff0f 0x00000ff0>; > + }; > + > + - | > + /* > + * For HiFive Unmatched board the encodings can be found here > + * https://sifive.cdn.prismic.io/sifive/1a82e600-1f93-4f41-b2d8-86ed8b16acba_fu740-c000-manual-v1p6.pdf > + * > + * This example also binds standard SBI PMU hardware IDs to U74 PMU event > + * codes, U74 uses a bitfield for events encoding, so several U74 events > + * can be bound to a single perf ID. > + * See SBI PMU hardware IDs in arch/riscv/include/asm/sbi.h > + */ > + pmu { > + compatible = "riscv,pmu"; > + riscv,event-to-mhpmevent = > + /* SBI_PMU_HW_CACHE_REFERENCES -> Instruction or Data cache/ITIM busy */ > + <0x00003 0x00000000 0x1801>, > + /* SBI_PMU_HW_CACHE_MISSES -> Instruction or Data cache miss or MMIO access */ > + <0x00004 0x00000000 0x0302>, > + /* SBI_PMU_HW_BRANCH_INSTRUCTIONS -> Conditional branch retired */ > + <0x00005 0x00000000 0x4000>, > + /* SBI_PMU_HW_BRANCH_MISSES -> Branch or jump misprediction */ > + <0x00006 0x00000000 0x6001>, > + /* L1D_READ_MISS -> Data cache miss or MMIO access */ > + <0x10001 0x00000000 0x0202>, > + /* L1D_WRITE_ACCESS -> Data cache write-back */ > + <0x10002 0x00000000 0x0402>, > + /* L1I_READ_ACCESS -> Instruction cache miss */ > + <0x10009 0x00000000 0x0102>, > + /* LL_READ_MISS -> UTLB miss */ > + <0x10011 0x00000000 0x2002>, > + /* DTLB_READ_MISS -> Data TLB miss */ > + <0x10019 0x00000000 0x1002>, > + /* ITLB_READ_MISS-> Instruction TLB miss */ > + <0x10021 0x00000000 0x0802>; > + riscv,event-to-mhpmcounters = <0x00003 0x00006 0x18>, > + <0x10001 0x10002 0x18>, > + <0x10009 0x10009 0x18>, > + <0x10011 0x10011 0x18>, > + <0x10019 0x10019 0x18>, > + <0x10021 0x10021 0x18>; > + riscv,raw-event-to-mhpmcounters = <0x0 0x0 0xffffffff 0xfc0000ff 0x18>, > + <0x0 0x1 0xffffffff 0xfff800ff 0x18>, > + <0x0 0x2 0xffffffff 0xffffe0ff 0x18>; > + }; > -- > 2.39.0 > Besides the comment above, Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx> Thanks, drew
