[PATCH 2/2] lib: utils/reset: Add a sunxi watchdog reset driver

[Anup Patel]

On Thu, Sep 9, 2021 at 7:40 AM Samuel Holland <samuel at sholland.org> wrote:
>
> One of the watchdogs in the D1 SoC provides a "soft reset" function,
> which allows software to immediately reset the entire SoC. Add a driver
> so it can implement the SBI system reset function.
>
> Signed-off-by: Samuel Holland <samuel at sholland.org>
> ---
>  lib/utils/reset/fdt_reset.c           |  2 +
>  lib/utils/reset/fdt_reset_sunxi_wdt.c | 77 +++++++++++++++++++++++++++
>  lib/utils/reset/objects.mk            |  1 +
>  3 files changed, 80 insertions(+)
>  create mode 100644 lib/utils/reset/fdt_reset_sunxi_wdt.c
>
> diff --git a/lib/utils/reset/fdt_reset.c b/lib/utils/reset/fdt_reset.c
> index 7f4b02a..168bb0c 100644
> --- a/lib/utils/reset/fdt_reset.c
> +++ b/lib/utils/reset/fdt_reset.c
> @@ -16,6 +16,7 @@ extern struct fdt_reset fdt_poweroff_gpio;
>  extern struct fdt_reset fdt_reset_gpio;
>  extern struct fdt_reset fdt_reset_htif;
>  extern struct fdt_reset fdt_reset_sifive_test;
> +extern struct fdt_reset fdt_reset_sunxi_wdt;
>  extern struct fdt_reset fdt_reset_thead;
>
>  static struct fdt_reset *reset_drivers[] = {
> @@ -23,6 +24,7 @@ static struct fdt_reset *reset_drivers[] = {
>         &fdt_reset_gpio,
>         &fdt_reset_htif,
>         &fdt_reset_sifive_test,
> +       &fdt_reset_sunxi_wdt,
>         &fdt_reset_thead,
>  };
>
> diff --git a/lib/utils/reset/fdt_reset_sunxi_wdt.c b/lib/utils/reset/fdt_reset_sunxi_wdt.c
> new file mode 100644
> index 0000000..d057c00
> --- /dev/null
> +++ b/lib/utils/reset/fdt_reset_sunxi_wdt.c
> @@ -0,0 +1,77 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2021 Samuel Holland <samuel at sholland.org>
> + */
> +
> +#include <libfdt.h>
> +#include <sbi/riscv_io.h>
> +#include <sbi/sbi_bitops.h>
> +#include <sbi/sbi_error.h>
> +#include <sbi/sbi_system.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/reset/fdt_reset.h>
> +
> +#define WDT_KEY_VAL                    0x16aa0000
> +
> +#define WDT_SOFT_RST_REG               0x08
> +#define WDT_SOFT_RST_EN                        BIT(0)
> +
> +#define WDT_MODE_REG                   0x18
> +
> +static volatile void *sunxi_wdt_base;
> +
> +static int sunxi_wdt_system_reset_check(u32 type, u32 reason)
> +{
> +       switch (type) {
> +       case SBI_SRST_RESET_TYPE_COLD_REBOOT:
> +       case SBI_SRST_RESET_TYPE_WARM_REBOOT:
> +               return 1;
> +       }
> +
> +       return 0;
> +}
> +
> +static void sunxi_wdt_system_reset(u32 type, u32 reason)
> +{
> +       /* Disable the watchdog. */
> +       writel_relaxed(WDT_KEY_VAL,
> +                      sunxi_wdt_base + WDT_MODE_REG);
> +
> +       /* Trigger soft reset. */
> +       writel_relaxed(WDT_KEY_VAL | WDT_SOFT_RST_EN,
> +                      sunxi_wdt_base + WDT_SOFT_RST_REG);
> +}
> +
> +static struct sbi_system_reset_device sunxi_wdt_reset = {
> +       .name = "sunxi-wdt-reset",
> +       .system_reset_check = sunxi_wdt_system_reset_check,
> +       .system_reset = sunxi_wdt_system_reset,
> +};
> +
> +static int sunxi_wdt_reset_init(void *fdt, int nodeoff,
> +                               const struct fdt_match *match)
> +{
> +       unsigned long reg_addr;
> +       int rc;
> +
> +       rc = fdt_get_node_addr_size(fdt, nodeoff, 0, &reg_addr, NULL);

The "reg_addr" should be uint64_t for the latest OpenSBI otherwise
it fails to compile.

> +       if (rc < 0 || !reg_addr)
> +               return SBI_ENODEV;
> +
> +       sunxi_wdt_base = (volatile void *)reg_addr;
> +
> +       sbi_system_reset_set_device(&sunxi_wdt_reset);
> +
> +       return 0;
> +}
> +
> +static const struct fdt_match sunxi_wdt_reset_match[] = {
> +       { .compatible = "allwinner,sun20i-d1-wdt-reset" },
> +       { },
> +};
> +
> +struct fdt_reset fdt_reset_sunxi_wdt = {
> +       .match_table = sunxi_wdt_reset_match,
> +       .init = sunxi_wdt_reset_init,
> +};
> diff --git a/lib/utils/reset/objects.mk b/lib/utils/reset/objects.mk
> index bb33179..6c95db3 100644
> --- a/lib/utils/reset/objects.mk
> +++ b/lib/utils/reset/objects.mk
> @@ -11,5 +11,6 @@ libsbiutils-objs-y += reset/fdt_reset.o
>  libsbiutils-objs-y += reset/fdt_reset_gpio.o
>  libsbiutils-objs-y += reset/fdt_reset_htif.o
>  libsbiutils-objs-y += reset/fdt_reset_sifive_test.o
> +libsbiutils-objs-y += reset/fdt_reset_sunxi_wdt.o
>  libsbiutils-objs-y += reset/fdt_reset_thead.o
>  libsbiutils-objs-y += reset/fdt_reset_thead_asm.o
> --
> 2.31.1
>
>
> --
> opensbi mailing list
> opensbi at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/opensbi

I have taken care of the minor comment above at the time of merging
this patch.

Reviewed-by: Anup Patel <anup.patel at wdc.com>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup