[PATCH v6 0/2] riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores

[Palmer Dabbelt]

On Tue, 11 Oct 2022 16:18:39 PDT (-0700), heiko at sntech.de wrote:
> The PMU on T-Head C9xx cores is quite similar to the SSCOFPMF extension
> but not completely identical, so this series

The rest of that sentance got dropped, so I put in

    The PMU on T-Head C9xx cores is quite similar to the SSCOFPMF extension
    but not completely identical, so this series adds a T-Head PMU errata
    that handlen the differences.

but LMK if you had a better version, it's still early so I don't mind 
swapping it around.

b4 also got kind of confused here so I had to merge suff manually.

> changes in v6:
> - follow Anup's suggestion and hook into the (pending) cpuinfo patch [2]
>   instead of modifying the core sbi_get_* functions
>
> changes in v5:
> - add received Reviews
> - fix sbi caching wrt. negative values (Drew)
> - add comment about specific c9xx arch- and imp-ids (Conor)
>
> changes in v4:
> - add new patch to cache sbi mvendor, march and mimp-ids (Atish)
> - errata dependencies in one line (Conor)
> - make driver detection conditional on CONFIG_ERRATA_THEAD_PMU too (Atish)
>
> changes in v3:
> - improve commit message (Atish, Conor)
> - IS_ENABLED and BIT() in errata probe (Conor)
>
> The change depends on my cpufeature/t-head errata probe cleanup series [1].
>
>
> changes in v2:
> - use alternatives for the CSR access
> - make the irq num selection a bit nicer
>
> There is of course a matching opensbi-part whose most recent implementation
> can be found on [0].
>
>
> [0] https://patchwork.ozlabs.org/project/opensbi/cover/20221004164227.1381825-1-heiko@sntech.de
> [1] https://lore.kernel.org/all/20220905111027.2463297-1-heiko@sntech.de/
> [2] https://lore.kernel.org/r/20220727043829.151794-1-apatel@ventanamicro.com
>
> Heiko Stuebner (2):
>   RISC-V: Cache SBI vendor values
>   drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head
>     C9xx cores
>
>  arch/riscv/Kconfig.erratas           | 13 +++++++++++
>  arch/riscv/errata/thead/errata.c     | 19 ++++++++++++++++
>  arch/riscv/include/asm/errata_list.h | 16 ++++++++++++-
>  arch/riscv/include/asm/sbi.h         |  5 ++++
>  arch/riscv/kernel/cpu.c              | 30 +++++++++++++++++++++---
>  drivers/perf/riscv_pmu_sbi.c         | 34 ++++++++++++++++++++--------
>  6 files changed, 103 insertions(+), 14 deletions(-)