Messages in this thread | | | Date | Sun, 8 Jan 2023 21:34:48 +0000 | From | Conor Dooley <> | Subject | Re: [PATCH v3] dt-bindings: riscv: add SBI PMU event mappings |
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Drew, Atish,
Mainly just a question about the OpenSBI doc at the end. Gonna fix up the rest of the wording and resend in a few.
On Tue, Jan 03, 2023 at 10:28:16AM +0100, Andrew Jones wrote: > On Mon, Jan 02, 2023 at 04:55:51PM +0000, Conor Dooley wrote: > > From: Conor Dooley <conor.dooley@microchip.com> > > > > 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@rivosinc.com> > > Signed-off-by: Atish Patra <atishp@rivosinc.com> > > Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> > + 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 platform expects to be written to the MHPMEVENTx CSR > ^ the
I think this one is arguable, it makes sense both ways IMO. I don't care since it's not my prose though ;)
> > + 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 > > > + * codes, U74 uses a bitfield for events encoding, so several U74 events > > + * can be bound to single perf id. > ^ a ID > > > + * See SBI PMU hardware id's in OpenSBI's include/sbi/sbi_ecall_interface.h > > IDs
Most of this stuff comes directly from the doc in OpenSBI that I copy-pasted. Atish, what do you wanna do once the binding is upstream about the original doc?
Thanks, Conor.
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