[PATCH v2 5/6] lib: utils/reset: Add generic GPIO reset driver
Atish Patra
atishp at atishpatra.org
Fri Jul 9 12:30:51 PDT 2021
On Fri, Jul 9, 2021 at 6:11 AM Anup Patel <anup.patel at wdc.com> wrote:
>
> From: Green Wan <green.wan at sifive.com>
>
> We add generic GPIO reset driver inspired from gpio-restart
> and gpio-poweroff drivers of Linux kernel.
>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> ---
> lib/utils/reset/fdt_reset.c | 2 +
> lib/utils/reset/fdt_reset_gpio.c | 146 +++++++++++++++++++++++++++++++
> lib/utils/reset/objects.mk | 1 +
> 3 files changed, 149 insertions(+)
> create mode 100644 lib/utils/reset/fdt_reset_gpio.c
>
> diff --git a/lib/utils/reset/fdt_reset.c b/lib/utils/reset/fdt_reset.c
> index 48a49fb..aa5f59f 100644
> --- a/lib/utils/reset/fdt_reset.c
> +++ b/lib/utils/reset/fdt_reset.c
> @@ -12,11 +12,13 @@
> #include <sbi_utils/fdt/fdt_helper.h>
> #include <sbi_utils/reset/fdt_reset.h>
>
> +extern struct fdt_reset fdt_reset_gpio;
> extern struct fdt_reset fdt_reset_sifive_test;
> extern struct fdt_reset fdt_reset_htif;
> extern struct fdt_reset fdt_reset_thead;
>
> static struct fdt_reset *reset_drivers[] = {
> + &fdt_reset_gpio,
> &fdt_reset_sifive_test,
> &fdt_reset_htif,
> &fdt_reset_thead,
> diff --git a/lib/utils/reset/fdt_reset_gpio.c b/lib/utils/reset/fdt_reset_gpio.c
> new file mode 100644
> index 0000000..a315ec9
> --- /dev/null
> +++ b/lib/utils/reset/fdt_reset_gpio.c
> @@ -0,0 +1,146 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2021 SiFive
> + * Copyright (c) 2021 Western Digital Corporation or its affiliates.
> + *
> + * Authors:
> + * Green Wan <green.wan at sifive.com>
> + * Anup Patel <anup.patel at wdc.com>
> + */
> +
> +#include <libfdt.h>
> +#include <sbi/sbi_ecall_interface.h>
> +#include <sbi/sbi_hart.h>
> +#include <sbi/sbi_system.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/gpio/fdt_gpio.h>
> +#include <sbi_utils/reset/fdt_reset.h>
> +
> +static u32 poweroff_active_delay = 100;
> +static u32 poweroff_inactive_delay = 100;
> +static struct gpio_pin poweroff_pin;
> +
> +static u32 restart_active_delay = 100;
> +static u32 restart_inactive_delay = 100;
> +static struct gpio_pin restart_pin;
> +
> +/* Custom mdelay function until we have a generic mdelay() API */
> +static void gpio_mdelay(unsigned long msecs)
> +{
> + volatile int i;
> + while (msecs--)
> + for (i = 0; i < 10000; i++) ;
> +}
> +
> +static int gpio_system_reset_check(u32 type, u32 reason)
> +{
> + switch (type) {
> + case SBI_SRST_RESET_TYPE_SHUTDOWN:
> + case SBI_SRST_RESET_TYPE_COLD_REBOOT:
> + case SBI_SRST_RESET_TYPE_WARM_REBOOT:
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static void gpio_system_reset(u32 type, u32 reason)
> +{
> + struct gpio_pin *pin = NULL;
> + u32 active_delay = 0, inactive_delay = 0;
> +
> + switch (type) {
> + case SBI_SRST_RESET_TYPE_SHUTDOWN:
> + pin = &poweroff_pin;
> + active_delay = poweroff_active_delay;
> + inactive_delay = poweroff_inactive_delay;
> + break;
> + case SBI_SRST_RESET_TYPE_COLD_REBOOT:
> + case SBI_SRST_RESET_TYPE_WARM_REBOOT:
> + pin = &restart_pin;
> + active_delay = restart_active_delay;
> + inactive_delay = restart_inactive_delay;
> + break;
> + }
> +
> + if (pin) {
> + /* drive it active, also inactive->active edge */
> + gpio_direction_output(pin, 1);
> + gpio_mdelay(active_delay);
> +
> + /* drive inactive, also active->inactive edge */
> + gpio_set(pin, 0);
> + gpio_mdelay(inactive_delay);
> +
> + /* drive it active, also inactive->active edge */
> + gpio_set(pin, 1);
> +
> + /* hang !!! */
> + sbi_hart_hang();
> + }
> +}
> +
> +static struct sbi_system_reset_device gpio_reset = {
> + .name = "gpio",
> + .system_reset_check = gpio_system_reset_check,
> + .system_reset = gpio_system_reset
> +};
> +
> +static int gpio_reset_init(void *fdt, int nodeoff,
> + const struct fdt_match *match)
> +{
> + int rc, len;
> + const fdt32_t *val;
> + bool is_restart = (ulong)match->data;
> +
> + rc = fdt_gpio_pin_get(fdt, nodeoff, 0,
> + (is_restart) ? &restart_pin : &poweroff_pin);
> + if (rc)
> + return rc;
> +
> + if (is_restart) {
> + if (fdt_getprop(fdt, nodeoff, "open-source", &len)) {
> + rc = gpio_direction_input(&restart_pin);
> + if (rc)
> + return rc;
> + }
> +
> + val = fdt_getprop(fdt, nodeoff, "active-delay-ms", &len);
> + if (len > 0)
> + restart_active_delay = fdt32_to_cpu(*val);
> +
> + val = fdt_getprop(fdt, nodeoff, "inactive-delay-ms", &len);
> + if (len > 0)
> + restart_inactive_delay = fdt32_to_cpu(*val);
> + } else {
> + if (fdt_getprop(fdt, nodeoff, "input", &len)) {
> + rc = gpio_direction_input(&poweroff_pin);
> + if (rc)
> + return rc;
> + }
> +
> + val = fdt_getprop(fdt, nodeoff, "active-delay-ms", &len);
> + if (len > 0)
> + poweroff_active_delay = fdt32_to_cpu(*val);
> +
> + val = fdt_getprop(fdt, nodeoff, "inactive-delay-ms", &len);
> + if (len > 0)
> + poweroff_inactive_delay = fdt32_to_cpu(*val);
Just a personal preference:
These two fdt_getprop can be done outside of the if else block and
assignment inside it.
> + }
> +
> + sbi_system_reset_set_device(&gpio_reset);
> +
> + return 0;
> +}
> +
> +static const struct fdt_match gpio_reset_match[] = {
> + { .compatible = "gpio-poweroff", .data = (void *)FALSE },
> + { .compatible = "gpio-restart", .data = (void *)TRUE },
> + { },
> +};
> +
> +struct fdt_reset fdt_reset_gpio = {
> + .match_table = gpio_reset_match,
> + .init = gpio_reset_init,
> +};
> diff --git a/lib/utils/reset/objects.mk b/lib/utils/reset/objects.mk
> index 672aad9..4215396 100644
> --- a/lib/utils/reset/objects.mk
> +++ b/lib/utils/reset/objects.mk
> @@ -8,6 +8,7 @@
> #
>
> 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_thead.o
> libsbiutils-objs-y += reset/fdt_reset_thead_asm.o
> --
> 2.25.1
>
>
> --
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Otherwise, it looks
Reviewed-by: Atish Patra <atish.patra at wdc.com> good to me.
--
Regards,
Atish
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