Re: [PATCH v4 3/5] usb: misc: eud: Add driver support for SM6115 / SM4250

[Konrad Dybcio]

On 5.05.2023 08:40, Bhupesh Sharma wrote:
> Add SM6115 / SM4250 SoC EUD support in qcom_eud driver.
> 
> On some SoCs (like the SM6115 / SM4250 SoC), the mode manager
> needs to be accessed only via the secure world (through 'scm'
> calls).
> 
> Also, the enable bit inside 'tcsr_check_reg' needs to be set
> first to set the eud in 'enable' mode on these SoCs.
> 
> Since this difference comes from how the firmware is configured, so
> the driver now relies on the presence of an extra boolean DT property
> to identify if secure access is needed.
> 
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxx>
> ---
>  drivers/usb/misc/Kconfig    |  1 +
>  drivers/usb/misc/qcom_eud.c | 74 +++++++++++++++++++++++++++++++++----
>  2 files changed, 68 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> index 99b15b77dfd5..fe1b5fec1dfc 100644
> --- a/drivers/usb/misc/Kconfig
> +++ b/drivers/usb/misc/Kconfig
> @@ -147,6 +147,7 @@ config USB_APPLEDISPLAY
>  config USB_QCOM_EUD
>  	tristate "QCOM Embedded USB Debugger(EUD) Driver"
>  	depends on ARCH_QCOM || COMPILE_TEST
> +	select QCOM_SCM
>  	select USB_ROLE_SWITCH
>  	help
>  	  This module enables support for Qualcomm Technologies, Inc.
> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
> index b7f13df00764..18a2dee3b4b9 100644
> --- a/drivers/usb/misc/qcom_eud.c
> +++ b/drivers/usb/misc/qcom_eud.c
> @@ -5,12 +5,14 @@
>  
>  #include <linux/bitops.h>
>  #include <linux/err.h>
> +#include <linux/firmware/qcom/qcom_scm.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/iopoll.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/sysfs.h>
> @@ -22,23 +24,35 @@
>  #define EUD_REG_VBUS_INT_CLR	0x0080
>  #define EUD_REG_CSR_EUD_EN	0x1014
>  #define EUD_REG_SW_ATTACH_DET	0x1018
> -#define EUD_REG_EUD_EN2        0x0000
> +#define EUD_REG_EUD_EN2		0x0000
>  
>  #define EUD_ENABLE		BIT(0)
> -#define EUD_INT_PET_EUD	BIT(0)
> +#define EUD_INT_PET_EUD		BIT(0)
>  #define EUD_INT_VBUS		BIT(2)
>  #define EUD_INT_SAFE_MODE	BIT(4)
>  #define EUD_INT_ALL		(EUD_INT_VBUS | EUD_INT_SAFE_MODE)
>  
> +#define EUD_EN2_SECURE_EN	BIT(0)
> +#define EUD_EN2_NONSECURE_EN	(1)
BIT(0) == 1, is that actually a separate register or does it just
reflect whether scm_writel is used?

If the latter, perhaps it'd be okay to just call it EUD_EN2_EN or
something along those lines? Isn't that perhaps what the docs call it?


> +#define EUD_EN2_DISABLE		(0)
> +#define TCSR_CHECK_EN		BIT(0)
> +
> +struct eud_soc_cfg {
> +	u32 tcsr_check_offset;
> +};
> +
>  struct eud_chip {
>  	struct device			*dev;
>  	struct usb_role_switch		*role_sw;
> +	const struct eud_soc_cfg	*eud_cfg;
>  	void __iomem			*base;
>  	void __iomem			*mode_mgr;
>  	unsigned int			int_status;
>  	int				irq;
>  	bool				enabled;
>  	bool				usb_attached;
> +	bool				secure_mode_enable;
Since it's only used in the probe function now, we can get rid
of it!

> +	phys_addr_t			secure_mode_mgr;
>  };
>  
>  static int enable_eud(struct eud_chip *priv)
> @@ -46,7 +60,11 @@ static int enable_eud(struct eud_chip *priv)
>  	writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN);
>  	writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
>  			priv->base + EUD_REG_INT1_EN_MASK);
> -	writel(1, priv->mode_mgr + EUD_REG_EUD_EN2);
> +
> +	if (priv->secure_mode_mgr)
> +		qcom_scm_io_writel(priv->secure_mode_mgr + EUD_REG_EUD_EN2, EUD_EN2_SECURE_EN);
> +	else
> +		writel(EUD_EN2_NONSECURE_EN, priv->mode_mgr + EUD_REG_EUD_EN2);
>  
>  	return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
>  }
> @@ -54,7 +72,11 @@ static int enable_eud(struct eud_chip *priv)
>  static void disable_eud(struct eud_chip *priv)
>  {
>  	writel(0, priv->base + EUD_REG_CSR_EUD_EN);
> -	writel(0, priv->mode_mgr + EUD_REG_EUD_EN2);
> +
> +	if (priv->secure_mode_mgr)
> +		qcom_scm_io_writel(priv->secure_mode_mgr + EUD_REG_EUD_EN2, EUD_EN2_DISABLE);
> +	else
> +		writel(EUD_EN2_DISABLE, priv->mode_mgr + EUD_REG_EUD_EN2);
>  }
>  
>  static ssize_t enable_show(struct device *dev,
> @@ -178,6 +200,8 @@ static void eud_role_switch_release(void *data)
>  static int eud_probe(struct platform_device *pdev)
>  {
>  	struct eud_chip *chip;
> +	struct resource *res;
> +	phys_addr_t tcsr_base, tcsr_check;
>  	int ret;
>  
>  	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
> @@ -200,9 +224,40 @@ static int eud_probe(struct platform_device *pdev)
>  	if (IS_ERR(chip->base))
>  		return PTR_ERR(chip->base);
>  
> -	chip->mode_mgr = devm_platform_ioremap_resource(pdev, 1);
> -	if (IS_ERR(chip->mode_mgr))
> -		return PTR_ERR(chip->mode_mgr);
> +	chip->secure_mode_enable = of_property_read_bool(chip->dev->of_node,
> +						"qcom,secure-mode-enable");
> +	/*
> +	 * EUD block on a few Qualcomm SoCs need secure register access.
> +	 * Check for the same.
> +	 */
> +	if (chip->secure_mode_enable) {
if (of_property_read_bool...)

> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +		if (!res)
> +			return dev_err_probe(chip->dev, -ENODEV,
> +					     "failed to get secure_mode_mgr reg base\n");
> +
> +		chip->secure_mode_mgr = res->start;
> +	} else {
> +		chip->mode_mgr = devm_platform_ioremap_resource(pdev, 1);
> +		if (IS_ERR(chip->mode_mgr))
> +			return PTR_ERR(chip->mode_mgr);
> +	}
> +
> +	/* Check for any SoC specific config data */
> +	chip->eud_cfg = of_device_get_match_data(&pdev->dev);
> +	if (chip->eud_cfg) {
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tcsr-base");
> +		if (!res)
> +			return dev_err_probe(chip->dev, -ENODEV,
> +					     "failed to get tcsr reg base\n");
> +
> +		tcsr_base = res->start;
This variable does not seem very useful, we can get rid of it.

> +		tcsr_check = tcsr_base + chip->eud_cfg->tcsr_check_offset;
> +
> +		ret = qcom_scm_io_writel(tcsr_check, TCSR_CHECK_EN);
> +		if (ret)
> +			return dev_err_probe(chip->dev, ret, "failed to write tcsr check reg\n");
> +	}
>  
>  	chip->irq = platform_get_irq(pdev, 0);
>  	ret = devm_request_threaded_irq(&pdev->dev, chip->irq, handle_eud_irq,
> @@ -230,8 +285,13 @@ static int eud_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct eud_soc_cfg sm6115_eud_cfg = {
This could be marked __initconst, but I'm not sure if future
additions won't need to be accessed after the driver has already
gone through its probe function.. Your call!


Konrad
> +	.tcsr_check_offset = 0x25018,
> +};
> +
>  static const struct of_device_id eud_dt_match[] = {
>  	{ .compatible = "qcom,sc7280-eud" },
> +	{ .compatible = "qcom,sm6115-eud", .data = &sm6115_eud_cfg },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(of, eud_dt_match);