[U-Boot] [PATCH 2/2] drivers: watchdog: Add brcm iproc sp805 watchdog driver

[Stefan Roese <sr@denx.de>]

On 23.11.19 00:23, Vladimir Olovyannikov wrote:
> From: Pramod Kumar <pramod.kumar@broadcom.com>
> 
> Add sp805 watchdog driver for Broadcom iproc socs (DM).
> 
> Signed-off-by: Pramod Kumar <pramod.kumar@broadcom.com>
> Signed-off-by: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
> ---
>   drivers/watchdog/Kconfig        |  10 ++
>   drivers/watchdog/Makefile       |   1 +
>   drivers/watchdog/sp805_wdt_dm.c | 181 ++++++++++++++++++++++++++++++++
>   3 files changed, 192 insertions(+)
>   create mode 100644 drivers/watchdog/sp805_wdt_dm.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 8c16d69d33..74a5319467 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -40,6 +40,16 @@ config OMAP_WATCHDOG
>   	help
>   	  Say Y here to enable the OMAP3+ watchdog driver.
>   
> +config SP805_WATCHDOG
> +	bool "Enable ARM SP805 watchdog driver (DM)"
> +	depends on WDT
> +	imply WATCHDOG
> +	help
> +	  Say Y here to enable the sp805 watchdog (DM)
> +
> +	  This provides basic infrastructure to support sp805 watchdog
> +	  hardware; driver model.
> +
>   config ULP_WATCHDOG
>   	bool "i.MX7ULP watchdog"
>   	help
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 955caef815..aacabf1f2e 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_S5P)               += s5p_wdt.o
>   obj-$(CONFIG_XILINX_TB_WATCHDOG) += xilinx_tb_wdt.o
>   obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
>   obj-$(CONFIG_DESIGNWARE_WATCHDOG) += designware_wdt.o
> +obj-$(CONFIG_SP805_WATCHDOG) += sp805_iproc_dm.o
>   obj-$(CONFIG_ULP_WATCHDOG) += ulp_wdog.o
>   obj-$(CONFIG_$(SPL_TPL_)WDT) += wdt-uclass.o
>   obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
> diff --git a/drivers/watchdog/sp805_wdt_dm.c b/drivers/watchdog/sp805_wdt_dm.c
> new file mode 100644
> index 0000000000..56d0e77080
> --- /dev/null
> +++ b/drivers/watchdog/sp805_wdt_dm.c
> @@ -0,0 +1,181 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018 Broadcom.
> + */
> +
> +#include <common.h>
> +#include <command.h>
> +#include <dm/device.h>
> +#include <dm/read.h>
> +#include <log.h>
> +#include <wdt.h>
> +#include <asm/io.h>
> +#include <linux/bitops.h>
> +
> +/* SP805 register offset */
> +#define SP805_WDOG_LOAD_OFF		0x000
> +#define SP805_WDOG_CTR_OFF		0x008
> +#define SP805_WDOG_CLR_OFF		0x00c
> +#define SP805_WDOG_LOCK_OFF		0xc00
> +
> +/* Magic word to unlock the wd registers */
> +#define WDOG_UNLOCK_KEY			0x1ACCE551
> +
> +/* Register field definitions */
> +#define SP805_CTR_RESEN			BIT(1)
> +#define SP805_CTR_INTEN			BIT(0)
> +
> +struct sp805_wdt_platdata {
> +	void __iomem *regs;
> +	u32 timeout_msec;
> +	u32 clk_mhz;
> +};
> +
> +/* Inline register access functions */
> +
> +static inline void sp805_write_wdog_load(void __iomem *base, u32 value)
> +{
> +	writel(value, base + SP805_WDOG_LOAD_OFF);
> +}
> +
> +static inline void sp805_write_wdog_ctrl(void __iomem *base, u32 value)
> +{
> +	writel(value, base + SP805_WDOG_CTR_OFF);
> +}
> +
> +static inline void sp805_write_wdog_lock(void __iomem *base, u32 value)
> +{
> +	writel(value, base + SP805_WDOG_LOCK_OFF);
> +}
> +
> +static inline void sp805_write_wdog_kick(void __iomem *base, u32 value)
> +{
> +	writel(value, base + SP805_WDOG_CLR_OFF);
> +}
> +
> +static u32 msec_to_ticks(struct udevice *dev)
> +{
> +	u32 timeout_msec;
> +	u32 msec;
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +
> +	timeout_msec = env_get_ulong("wdt_timeout_msec", 16, 0);
> +	if (timeout_msec) {
> +		dev_dbg(dev, "Overriding timeout :%u\n", timeout_msec);
> +		msec = timeout_msec;
> +	} else {
> +		msec = pd->timeout_msec;
> +	}
> +
> +	timeout_msec = (msec / 2) * (pd->clk_mhz / 1000);
> +
> +	dev_dbg(dev, "ticks :%u\n", timeout_msec);
> +
> +	return timeout_msec;
> +}
> +
> +static int sp805_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +
> +	sp805_write_wdog_lock(pd->regs, WDOG_UNLOCK_KEY);
> +	sp805_write_wdog_load(pd->regs, 0);
> +	sp805_write_wdog_lock(pd->regs, 0);
> +
> +	return 0;
> +}
> +
> +static int sp805_wdt_reset(struct udevice *dev)
> +{
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +	u32 ticks;
> +
> +	ticks = msec_to_ticks(dev);
> +
> +	sp805_write_wdog_lock(pd->regs, WDOG_UNLOCK_KEY);
> +	sp805_write_wdog_load(pd->regs, ticks);
> +	sp805_write_wdog_lock(pd->regs, 0);
> +
> +	dev_dbg(dev, "%s ", __func__);
> +
> +	return 0;
> +}
> +
> +static int sp805_wdt_stop(struct udevice *dev)
> +{
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +
> +	sp805_write_wdog_lock(pd->regs, WDOG_UNLOCK_KEY);
> +	sp805_write_wdog_ctrl(pd->regs, 0);
> +
> +	dev_dbg(dev, "Watchdog disabled!\n");
> +
> +	return 0;
> +}
> +
> +static int sp805_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
> +{
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +	u32 ticks;
> +
> +	ticks = msec_to_ticks(dev);
> +
> +	dev_dbg(dev, "%s:\n", __func__);
> +
> +	sp805_write_wdog_load(pd->regs, ticks);
> +	sp805_write_wdog_ctrl(pd->regs, SP805_CTR_RESEN | SP805_CTR_INTEN);
> +	/* Lock registers access */
> +	sp805_write_wdog_lock(pd->regs, 0);
> +
> +	return 0;
> +}
> +
> +static int sp805_wdt_probe(struct udevice *dev)
> +{
> +	dev_dbg(dev, "%s: Probing wdt%u\n", __func__, dev->seq);
> +
> +	return 0;
> +}
> +
> +static int sp805_wdt_ofdata_to_platdata(struct udevice *dev)
> +{
> +	struct sp805_wdt_platdata *pd = dev_get_platdata(dev);
> +
> +	dev_dbg(dev, "%s->\n", __func__);
> +	pd->regs = dev_read_addr_ptr(dev);
> +	if (!pd->regs)
> +		return -ENODEV;
> +
> +	if (dev_read_u32(dev, "timeout-msec", &pd->timeout_msec))
> +		return -ENODATA;

Why are you not using the already supported "timeout-sec" DT property
instead? This one is also supported in Linux, so please move to this
one. This DT values is already read in initr_watchdog() and provided to
your DM enabled driver.

Thanks,
Stefan