Re: [PATCH 3/3] watchdog: sbsa_gwdt: add support for Marvell ac5

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 14/12/2023 16:04, Elad Nachman wrote:
> From: Elad Nachman <enachman@marvell.com>
> 
> Add support for Marvell ac5/x variant of the ARM
> sbsa global watchdog. This watchdog deviates from
> the standard driver by the following items:
> 
> 1. Registers reside in secure register section.
>    hence access is only possible via SMC calls to ATF.
> 
> 2. There are couple more registers which reside in
>    other register areas, which needs to be configured
>    in order for the watchdog to properly generate
>    reset through the SOC.
> 
> The new Marvell compatibility string differentiates between
> the original sbsa mode of operation and the Marvell mode of
> operation.
> 
> Signed-off-by: Elad Nachman <enachman@marvell.com>
> ---

...

>  	gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
>  	if (!gwdt)
>  		return -ENOMEM;
>  	platform_set_drvdata(pdev, gwdt);
>  
> -	cf_base = devm_platform_ioremap_resource(pdev, 0);
> -	if (IS_ERR(cf_base))
> -		return PTR_ERR(cf_base);
> -
> -	rf_base = devm_platform_ioremap_resource(pdev, 1);
> -	if (IS_ERR(rf_base))
> -		return PTR_ERR(rf_base);
> +	if (of_device_is_compatible(np, "marvell,ac5-wd")) {

No, use match data. That's its purpose, don't put comaptibles inside code.

> +		marvell = true;
> +		gwdt->soc_reg_ops = &smc_reg_ops;
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +		if (IS_ERR(res))
> +			return PTR_ERR(res);
> +		cf_base = res->start;

Why do you use entirely different code?

> +
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +		if (IS_ERR(res))
> +			return PTR_ERR(res);
> +		rf_base = res->start;
> +
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
> +		if (IS_ERR(res))
> +			return PTR_ERR(res);
> +		cpu_ctrl_base = res->start;
> +		mng_base = devm_platform_ioremap_resource(pdev, 3);
> +		if (IS_ERR(mng_base))
> +			return PTR_ERR(mng_base);
> +		rst_ctrl_base = devm_platform_ioremap_resource(pdev, 4);
> +		if (IS_ERR(rst_ctrl_base))
> +			return PTR_ERR(rst_ctrl_base);
> +	} else {
> +		gwdt->soc_reg_ops = &direct_reg_ops;
> +		cf_base = devm_platform_ioremap_resource(pdev, 0);
> +		if (IS_ERR(cf_base))
> +			return PTR_ERR(cf_base);

Why? This is shared.

> +
> +		rf_base = devm_platform_ioremap_resource(pdev, 1);
> +		if (IS_ERR(rf_base))
> +			return PTR_ERR(rf_base);

Ditto

> +	}
>  
>  	/*
>  	 * Get the frequency of system counter from the cp15 interface of ARM
> @@ -299,7 +482,7 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>  	else
>  		wdd->max_hw_heartbeat_ms = GENMASK_ULL(47, 0) / gwdt->clk * 1000;
>  
> -	status = readl(cf_base + SBSA_GWDT_WCS);
> +	status = gwdt->soc_reg_ops->reg_read32(cf_base + SBSA_GWDT_WCS);
>  	if (status & SBSA_GWDT_WCS_WS1) {
>  		dev_warn(dev, "System reset by WDT.\n");
>  		wdd->bootstatus |= WDIOF_CARDRESET;
> @@ -317,7 +500,7 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>  			 * In case there is a pending ws0 interrupt, just ping
>  			 * the watchdog before registering the interrupt routine
>  			 */
> -			writel(0, rf_base + SBSA_GWDT_WRR);
> +			gwdt->soc_reg_ops->reg_write32(0, rf_base + SBSA_GWDT_WRR);
>  			if (devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
>  					     pdev->name, gwdt)) {
>  				action = 0;
> @@ -347,7 +530,28 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>  	ret = devm_watchdog_register_device(dev, wdd);
>  	if (ret)
>  		return ret;
> -
> +	/*
> +	 * Marvell AC5/X/IM: need to configure the watchdog
> +	 * HW to trigger reset on WS1 (Watchdog Signal 1):
> +	 *
> +	 * 1. Configure the watchdog signal enable (routing)
> +	 *    according to configuration
> +	 * 2. Unmask the wd_rst input signal to the reset unit
> +	 */
> +	if (marvell) {
> +		gwdt->soc_reg_ops->reg_write32(reset, cpu_ctrl_base +
> +					       SBSA_GWDT_MARVELL_CPU_WD_RST_EN_REG);
> +		id = readl(mng_base + SBSA_GWDT_MARVELL_MNG_ID_REG) &
> +			   SBSA_GWDT_MARVELL_ID_MASK;
> +
> +		if (id == SBSA_GWDT_MARVELL_AC5_ID)
> +			val = SBSA_GWDT_MARVELL_AC5_RST_UNIT_WD_BIT;
> +		else
> +			val = SBSA_GWDT_MARVELL_IRONMAN_RST_UNIT_WD_BIT;
> +
> +		writel(readl(rst_ctrl_base + SBSA_GWDT_MARVELL_RST_CTRL_REG) & ~val,
> +		       rst_ctrl_base + SBSA_GWDT_MARVELL_RST_CTRL_REG);
> +	}
>  	dev_info(dev, "Initialized with %ds timeout @ %u Hz, action=%d.%s\n",
>  		 wdd->timeout, gwdt->clk, action,
>  		 status & SBSA_GWDT_WCS_EN ? " [enabled]" : "");
> @@ -383,6 +587,7 @@ static const struct dev_pm_ops sbsa_gwdt_pm_ops = {
>  
>  static const struct of_device_id sbsa_gwdt_of_match[] = {
>  	{ .compatible = "arm,sbsa-gwdt", },
> +	{ .compatible = "marvell,ac5-wd", },
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match);

Best regards,
Krzysztof