[PATCH] watchdog: add amlogic watchdog support

[Neil Armstrong]

On 07/06/2022 16:00, Neil Armstrong wrote:
> On 07/06/2022 15:28, Philippe Boos wrote:
>> Add support for hardware watchdog timer for Amlogic SoCs.
>> This driver has been heavily inspired by his Linux equivalent
>> (meson_gxbb_wdt.c).
>>
>> Reviewed-by: Jerome Brunet <jbrunet at baylibre.com>
>> Signed-off-by: Philippe Boos <pboos at baylibre.com>
>>
>> ---
>>
>> This watchdog driver has been tested on a GXL libretech-cc board and also on
>> a custom G12a board. I did the following test cases:
>>   * boot with a faulty boot command, then we reach watchdog reset successfully,
>>   * boot a Linux kernel with and without watchdog support, and check if it is
>>     working as expected.
>>
>>   drivers/watchdog/Kconfig          |   6 ++
>>   drivers/watchdog/Makefile         |   1 +
>>   drivers/watchdog/meson_gxbb_wdt.c | 126 ++++++++++++++++++++++++++++++
>>   3 files changed, 133 insertions(+)
>>   create mode 100644 drivers/watchdog/meson_gxbb_wdt.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index c3eb8a8aec..81b60482c9 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -175,6 +175,12 @@ config WDT_MAX6370
>>       help
>>         Select this to enable max6370 watchdog timer.
>> +config WDT_MESON_GXBB
>> +    bool "Amlogic watchdog timer support"
>> +    depends on WDT
>> +    help
>> +      Amlogic watchdog timer support.
>> +
>>   config WDT_MPC8xx
>>       bool "MPC8xx watchdog timer support"
>>       depends on WDT && MPC8xx
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 1f6199beca..0e2f582a5f 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -27,6 +27,7 @@ obj-$(CONFIG_WDT_ORION) += orion_wdt.o
>>   obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
>>   obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
>>   obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
>> +obj-$(CONFIG_WDT_MESON_GXBB) += meson_gxbb_wdt.o
>>   obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o
>>   obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o
>>   obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o
>> diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c
>> new file mode 100644
>> index 0000000000..56b8a8990c
>> --- /dev/null
>> +++ b/drivers/watchdog/meson_gxbb_wdt.c
>> @@ -0,0 +1,126 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright (c) 2022 BayLibre, SAS.
>> + */
>> +
>> +#include <clk.h>
>> +#include <common.h>
>> +#include <dm.h>
>> +#include <dm/device_compat.h>
>> +#include <reset.h>
>> +#include <wdt.h>
>> +#include <asm/io.h>
>> +#include <linux/bitops.h>
>> +
>> +#define GXBB_WDT_CTRL_REG            0x0
>> +#define GXBB_WDT_TCNT_REG            0x8
>> +#define GXBB_WDT_RSET_REG            0xc
>> +
>> +#define GXBB_WDT_CTRL_CLKDIV_EN            BIT(25)
>> +#define GXBB_WDT_CTRL_CLK_EN            BIT(24)
>> +#define GXBB_WDT_CTRL_EE_RESET            BIT(21)
>> +#define GXBB_WDT_CTRL_EN            BIT(18)
>> +
>> +#define GXBB_WDT_CTRL_DIV_MASK            GENMASK(17, 0)
>> +#define GXBB_WDT_TCNT_SETUP_MASK        GENMASK(15, 0)
>> +
>> +
>> +struct amlogic_wdt_priv {
>> +    void __iomem *reg_base;
>> +};
>> +
>> +static int amlogic_wdt_set_timeout(struct udevice *dev, u64 timeout_ms)
>> +{
>> +    struct amlogic_wdt_priv *data = dev_get_priv(dev);
>> +
>> +    if (timeout_ms > GXBB_WDT_TCNT_SETUP_MASK) {
>> +        dev_warn(dev, "%s: timeout_ms=%llu: maximum watchdog timeout "
>> +                 "exceeded\n", __func__, timeout_ms);
>> +        timeout_ms = GXBB_WDT_TCNT_SETUP_MASK;
>> +    }
>> +
>> +    writel(timeout_ms, data->reg_base + GXBB_WDT_TCNT_REG);
>> +
>> +    return 0;
>> +}
>> +
>> +static int amlogic_wdt_stop(struct udevice *dev)
>> +{
>> +    struct amlogic_wdt_priv *data = dev_get_priv(dev);
>> +
>> +    writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
>> +           data->reg_base + GXBB_WDT_CTRL_REG);
>> +
>> +    return 0;
>> +}
>> +
>> +static int amlogic_wdt_start(struct udevice *dev, u64 time_ms, ulong flags)
>> +{
>> +    struct amlogic_wdt_priv *data = dev_get_priv(dev);
>> +
>> +    writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
>> +           data->reg_base + GXBB_WDT_CTRL_REG);
>> +
>> +    return amlogic_wdt_set_timeout(dev, time_ms);
>> +}
>> +
>> +static int amlogic_wdt_reset(struct udevice *dev)
>> +{
>> +    struct amlogic_wdt_priv *data = dev_get_priv(dev);
>> +
>> +    writel(0, data->reg_base + GXBB_WDT_RSET_REG);
>> +
>> +    return 0;
>> +}
>> +
>> +static int amlogic_wdt_probe(struct udevice *dev)
>> +{
>> +    struct amlogic_wdt_priv *data = dev_get_priv(dev);
>> +    int ret;
>> +
>> +    data->reg_base = dev_remap_addr(dev);
>> +    if (!data->reg_base)
>> +        return -EINVAL;
>> +
>> +    struct clk clk;
>> +
>> +    ret = clk_get_by_index(dev, 0, &clk);
>> +    if (ret)
>> +        return ret;
>> +
>> +    ret = clk_enable(&clk);
>> +    if (ret) {
>> +        clk_free(&clk);
>> +        return ret;
>> +    }
>> +
>> +    /* Setup with 1ms timebase */
>> +    writel(((clk_get_rate(&clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
>> +           GXBB_WDT_CTRL_EE_RESET |
>> +           GXBB_WDT_CTRL_CLK_EN |
>> +           GXBB_WDT_CTRL_CLKDIV_EN,
>> +           data->reg_base + GXBB_WDT_CTRL_REG);
>> +
>> +    return 0;
>> +}
>> +
>> +static const struct wdt_ops amlogic_wdt_ops = {
>> +    .start = amlogic_wdt_start,
>> +    .reset = amlogic_wdt_reset,
>> +    .stop = amlogic_wdt_stop,
>> +};
>> +
>> +static const struct udevice_id amlogic_wdt_ids[] = {
>> +    { .compatible = "amlogic,meson-gxbb-wdt" },
>> +    {}
>> +};
>> +
>> +U_BOOT_DRIVER(amlogic_wdt) = {
>> +    .name = "amlogic_wdt",
>> +    .id = UCLASS_WDT,
>> +    .of_match = amlogic_wdt_ids,
>> +    .priv_auto = sizeof(struct amlogic_wdt_priv),
>> +    .probe = amlogic_wdt_probe,
>> +    .ops = &amlogic_wdt_ops,
>> +    .flags = DM_FLAG_PRE_RELOC,
>> +};
> 
> Can you update MAINTAINERS to include it in "ARM AMLOGIC SOC SUPPORT" entry ?
> 
> With this:
> Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>

Adding an entry in the support matrix would be also great !

(see doc/board/amlogic/index.rst)

Thanks,
Neil

> 
> Thanks,
> Neil