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Date: Fri, 5 May 2023 13:05:34 +0200
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Bhupesh Sharma <bhupesh.sharma@...aro.org>,
linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
linux-usb@...r.kernel.org
Cc: agross@...nel.org, andersson@...nel.org,
linux-kernel@...r.kernel.org, bhupesh.linux@...il.com,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
krzysztof.kozlowski@...aro.org
Subject: Re: [PATCH v4 3/5] usb: misc: eud: Add driver support for SM6115 /
SM4250
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@...aro.org>
> ---
> 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);
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