[PATCH] generic: fu740: add workaround for CIP-1200 errata

[Atish Patra]

On Tue, Jul 20, 2021 at 10:03 AM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> From: David Abdurachmanov <david.abdurachmanov at sifive.com>
>
> Instruction TLB can fail to respect a non-global SFENCE thus we need to
> flush the TLB using SFENCE.VMA x0, x0
>
> See full description of CIP-1200 in Errata_FU740-C000_20210205 from
> https://www.sifive.com/boards/hifive-unmatched
>
> Signed-off-by: David Abdurachmanov <david.abdurachmanov at sifive.com>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  platform/generic/objects.mk     |  1 +
>  platform/generic/platform.c     |  2 ++
>  platform/generic/sifive_fu740.c | 36 +++++++++++++++++++++++++++++++++
>  3 files changed, 39 insertions(+)
>  create mode 100644 platform/generic/sifive_fu740.c
>
> diff --git a/platform/generic/objects.mk b/platform/generic/objects.mk
> index d6c8a42..cb15a18 100644
> --- a/platform/generic/objects.mk
> +++ b/platform/generic/objects.mk
> @@ -9,3 +9,4 @@
>
>  platform-objs-y += platform.o
>  platform-objs-y += sifive_fu540.o
> +platform-objs-y += sifive_fu740.o
> diff --git a/platform/generic/platform.c b/platform/generic/platform.c
> index 8c1e06f..2d5e930 100644
> --- a/platform/generic/platform.c
> +++ b/platform/generic/platform.c
> @@ -23,9 +23,11 @@
>  #include <sbi_utils/reset/fdt_reset.h>
>
>  extern const struct platform_override sifive_fu540;
> +extern const struct platform_override sifive_fu740;
>
>  static const struct platform_override *special_platforms[] = {
>         &sifive_fu540,
> +       &sifive_fu740,
>  };
>
>  static const struct platform_override *generic_plat = NULL;
> diff --git a/platform/generic/sifive_fu740.c b/platform/generic/sifive_fu740.c
> new file mode 100644
> index 0000000..c8325d3
> --- /dev/null
> +++ b/platform/generic/sifive_fu740.c
> @@ -0,0 +1,36 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2021 SiFive
> + *
> + * Authors:
> + *   David Abdurachmanov <david.abdurachmanov at sifive.com>
> + */
> +
> +#include <platform_override.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/fdt/fdt_fixup.h>
> +
> +static u64 sifive_fu740_tlbr_flush_limit(const struct fdt_match *match)
> +{
> +       /*
> +        * Needed to address CIP-1200 errata on SiFive FU740
> +        * Title: Instruction TLB can fail to respect a non-global SFENCE
> +        * Workaround: Flush the TLB using SFENCE.VMA x0, x0
> +        * See Errata_FU740-C000_20210205 from
> +        * https://www.sifive.com/boards/hifive-unmatched
> +        */
> +       return 0;
> +}
> +
> +static const struct fdt_match sifive_fu740_match[] = {
> +       { .compatible = "sifive,fu740" },
> +       { .compatible = "sifive,fu740-c000" },
> +       { .compatible = "sifive,hifive-unmatched-a00" },
> +       { },
> +};
> +
> +const struct platform_override sifive_fu740 = {
> +       .match_table = sifive_fu740_match,
> +       .tlbr_flush_limit = sifive_fu740_tlbr_flush_limit,
> +};
> --
> 2.29.2
>
>
> --
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Reviewed-by: Atish Patra <atish.patra at wdc.com>

-- 
Regards,
Atish