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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 4 Jan 2021 17:49:03 +0100
Message-ID: <CAMuHMdXG_B-3y1MWh64T6LU3Gmo6UQGGWU8EbLApjDeXVLL3GQ@mail.gmail.com>
Subject: Re: [PATCH v2] drivers/soc/litex: Add restart handler
To:     Karol Gugala <kgugala@antmicro.com>,
        Mateusz Holenko <mholenko@antmicro.com>
Cc:     Gabriel Somlo <gsomlo@gmail.com>,
        Stafford Horne <shorne@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-riscv <linux-riscv@lists.infradead.org>
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On Mon, Jan 4, 2021 at 5:45 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> Let the LiteX SoC Controller a register a restart handler, which resets
> the LiteX SoC by writing 1 to CSR_CTRL_RESET_ADDR.
>
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> Tested with linux-on-litex-vexriscv.
>
> This patch is based on upstream, i.e. not on top of Gabriel Somlo's
> "[PATCH v5 0/4] drivers/soc/litex: support 32-bit subregisters, 64-bit
> CPUs"
> (https://lore.kernel.org/lkml/20201227161320.2194830-1-gsomlo@gmail.com/)

Bummer, and that's why the RESET_REG_* definitions are no longer
next to the SCRATCH_REG_* definitions :-(

Well, I assume that will be fixed by evolution ;-)

> v2:
>   - Rebase on top of v5.11-rc1,
>   - Change reset handler priority to recommended default value of 128
>     (was 192).
>
> (v1 was not sent to a mailing list)
> ---
>  drivers/soc/litex/litex_soc_ctrl.c | 33 +++++++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/soc/litex/litex_soc_ctrl.c b/drivers/soc/litex/litex_soc_ctrl.c
> index 1217cafdfd4d1d2b..d729ad50d4ffca5e 100644
> --- a/drivers/soc/litex/litex_soc_ctrl.c
> +++ b/drivers/soc/litex/litex_soc_ctrl.c
> @@ -15,6 +15,11 @@
>  #include <linux/module.h>
>  #include <linux/errno.h>
>  #include <linux/io.h>
> +#include <linux/reboot.h>
> +
> +/* reset register located at the base address */
> +#define RESET_REG_OFF           0x00
> +#define RESET_REG_VALUE         0x00000001
>
>  /*
>   * LiteX SoC Generator, depending on the configuration, can split a single

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds