Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
MIME-Version: 1.0
References: <20220511214132.2281431-1-heiko@sntech.de> <20220511214132.2281431-4-heiko@sntech.de>
 <CAAhSdy1riRoVKz=7N865ZJ6tsPO+diULZ8ctNrqVuXEmgtrqOA@mail.gmail.com>
In-Reply-To: <CAAhSdy1riRoVKz=7N865ZJ6tsPO+diULZ8ctNrqVuXEmgtrqOA@mail.gmail.com>
From:   Guo Ren <guoren@kernel.org>
Date:   Fri, 13 May 2022 21:37:59 +0800
Message-ID: <CAJF2gTRmt5rWHNdtC9mh6ODFTBTz3XZz9Gq=NfAdJJpxPO3tBQ@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] riscv: implement cache-management errata for
 T-Head SoCs
To:     Anup Patel <anup@brainfault.org>
Cc:     Heiko Stuebner <heiko@sntech.de>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Wei Fu <wefu@redhat.com>, Atish Patra <atishp@atishpatra.org>,
        Nick Kossifidis <mick@ics.forth.gr>,
        Samuel Holland <samuel@sholland.org>,
        Christoph Muellner <cmuellner@linux.com>,
        Philipp Tomsich <philipp.tomsich@vrull.eu>,
        Rob Herring <robh+dt@kernel.org>, krzk+dt@kernel.org,
        DTML <devicetree@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Reviewed-by: Guo Ren <guoren@kernel.org>

On Thu, May 12, 2022 at 12:41 PM Anup Patel <anup@brainfault.org> wrote:
>
> On Thu, May 12, 2022 at 3:11 AM Heiko Stuebner <heiko@sntech.de> wrote:
> >
> > The T-Head C906 and C910 implement a scheme for handling
> > cache operations different from the generic Zicbom extension.
> >
> > Add an errata for it next to the generic dma coherency ops.
> >
> > Tested-by: Samuel Holland <samuel@sholland.org>
> > Signed-off-by: Heiko Stuebner <heiko@sntech.de>
>
> Looks good to me.
>
> Reviewed-by: Anup Patel <anup@brainfault.org>
>
> Regards,
> Anup
>
> > ---
> >  arch/riscv/Kconfig.erratas           | 10 ++++++
> >  arch/riscv/errata/thead/errata.c     |  5 +++
> >  arch/riscv/include/asm/errata_list.h | 47 +++++++++++++++++++++++++---
> >  3 files changed, 58 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas
> > index ebfcd5cc6eaf..213629bac5d7 100644
> > --- a/arch/riscv/Kconfig.erratas
> > +++ b/arch/riscv/Kconfig.erratas
> > @@ -54,4 +54,14 @@ config ERRATA_THEAD_PBMT
> >
> >           If you don't know what to do here, say "Y".
> >
> > +config ERRATA_THEAD_CMO
> > +       bool "Apply T-Head cache management errata"
> > +       depends on ERRATA_THEAD && RISCV_ISA_ZICBOM
> > +       default y
> > +       help
> > +         This will apply the cache management errata to handle the
> > +         non-standard handling on non-coherent operations on T-Head SoCs.
> > +
> > +         If you don't know what to do here, say "Y".
> > +
> >  endmenu
> > diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
> > index e5d75270b99c..9545f43d3504 100644
> > --- a/arch/riscv/errata/thead/errata.c
> > +++ b/arch/riscv/errata/thead/errata.c
> > @@ -33,6 +33,11 @@ static const struct errata_info errata_list[ERRATA_THEAD_NUMBER] = {
> >                 .stage = RISCV_ALTERNATIVES_EARLY_BOOT,
> >                 .check_func = errata_mt_check_func
> >         },
> > +       {
> > +               .name = "cache-management",
> > +               .stage = RISCV_ALTERNATIVES_BOOT,
> > +               .check_func = errata_mt_check_func
> > +       },
> >  };
> >
> >  static u32 thead_errata_probe(unsigned int stage, unsigned long archid, unsigned long impid)
> > diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
> > index eebcd4415049..1da311fc5126 100644
> > --- a/arch/riscv/include/asm/errata_list.h
> > +++ b/arch/riscv/include/asm/errata_list.h
> > @@ -16,7 +16,8 @@
> >
> >  #ifdef CONFIG_ERRATA_THEAD
> >  #define        ERRATA_THEAD_PBMT 0
> > -#define        ERRATA_THEAD_NUMBER 1
> > +#define        ERRATA_THEAD_CMO 1
> > +#define        ERRATA_THEAD_NUMBER 2
> >  #endif
> >
> >  #define        CPUFEATURE_SVPBMT 0
> > @@ -111,8 +112,37 @@ asm volatile(ALTERNATIVE(                                          \
> >  #define CBO_CLEAN_A0   ".long 0x25200F"
> >  #define CBO_FLUSH_A0   ".long 0x05200F"
> >
> > +/*
> > + * dcache.ipa rs1 (invalidate, physical address)
> > + * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
> > + *   0000001    01010      rs1       000      00000  0001011
> > + * dache.iva rs1 (invalida, virtual address)
> > + *   0000001    00110      rs1       000      00000  0001011
> > + *
> > + * dcache.cpa rs1 (clean, physical address)
> > + * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
> > + *   0000001    01001      rs1       000      00000  0001011
> > + * dcache.cva rs1 (clean, virtual address)
> > + *   0000001    00100      rs1       000      00000  0001011
> > + *
> > + * dcache.cipa rs1 (clean then invalidate, physical address)
> > + * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
> > + *   0000001    01011      rs1       000      00000  0001011
> > + * dcache.civa rs1 (... virtual address)
> > + *   0000001    00111      rs1       000      00000  0001011
> > + *
> > + * sync.s (make sure all cache operations finished)
> > + * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
> > + *   0000000    11001     00000      000      00000  0001011
> > + */
> > +#define THEAD_INVAL_A0 ".long 0x0265000b"
> > +#define THEAD_CLEAN_A0 ".long 0x0245000b"
> > +#define THEAD_FLUSH_A0 ".long 0x0275000b"
> > +#define THEAD_SYNC_S   ".long 0x0190000b"
> > +
> >  #define ALT_CMO_OP(_op, _start, _size, _cachesize)                     \
> > -asm volatile(ALTERNATIVE(                                              \
> > +asm volatile(ALTERNATIVE_2(                                            \
> > +       "nop\n\t"                                                       \
> >         "nop\n\t"                                                       \
> >         "nop\n\t"                                                       \
> >         "nop\n\t"                                                       \
> > @@ -124,8 +154,17 @@ asm volatile(ALTERNATIVE(                                          \
> >         CBO_##_op##_A0 "\n\t"                                           \
> >         "add a0, a0, %0\n\t"                                            \
> >         "2:\n\t"                                                        \
> > -       "bltu a0, %2, 3b\n\t", 0,                                       \
> > -               CPUFEATURE_CMO, CONFIG_RISCV_ISA_ZICBOM)                \
> > +       "bltu a0, %2, 3b\n\t"                                           \
> > +       "nop", 0, CPUFEATURE_CMO, CONFIG_RISCV_ISA_ZICBOM,              \
> > +       "mv a0, %1\n\t"                                                 \
> > +       "j 2f\n\t"                                                      \
> > +       "3:\n\t"                                                        \
> > +       THEAD_##_op##_A0 "\n\t"                                         \
> > +       "add a0, a0, %0\n\t"                                            \
> > +       "2:\n\t"                                                        \
> > +       "bltu a0, %2, 3b\n\t"                                           \
> > +       THEAD_SYNC_S, THEAD_VENDOR_ID,                                  \
> > +                       ERRATA_THEAD_CMO, CONFIG_ERRATA_THEAD_CMO)      \
> >         : : "r"(_cachesize),                                            \
> >             "r"(ALIGN((_start), (_cachesize))),                         \
> >             "r"(ALIGN((_start) + (_size), (_cachesize))))
> > --
> > 2.35.1
> >


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/