6.6-stable review patch. If anyone has any objections, please let me know.
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From: Komal Bajaj komal.bajaj@oss.qualcomm.com
[ Upstream commit c0485e864a2eaa1d5a84c71e573dd236d0e885ae ]
EUD_MODE_MANAGER2 register is mapped to a memory region that is marked as read-only for operating system running at EL1, enforcing access restrictions that prohibit direct memory-mapped writes via writel().
Attempts to write to this region from HLOS can result in silent failures or memory access violations, particularly when toggling EUD (Embedded USB Debugger) state. To ensure secure register access, modify the driver to use qcom_scm_io_writel(), which routes the write operation to Qualcomm Secure Channel Monitor (SCM). SCM has the necessary permissions to access protected memory regions, enabling reliable control over EUD state.
SC7280, the only user of EUD is also affected, indicating that this could never have worked on a properly fused device.
Fixes: 9a1bf58ccd44 ("usb: misc: eud: Add driver support for Embedded USB Debugger(EUD)") Signed-off-by: Melody Olvera quic_molvera@quicinc.com Reviewed-by: Konrad Dybcio konrad.dybcio@oss.qualcomm.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com Reviewed-by: Souradeep Chowdhury quic_schowdhu@quicinc.com Signed-off-by: Komal Bajaj komal.bajaj@oss.qualcomm.com Link: https://lore.kernel.org/r/20250731-eud_mode_manager_secure_access-v8-1-4a5dc... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/misc/Kconfig | 1 + drivers/usb/misc/qcom_eud.c | 33 ++++++++++++++++++++++++--------- 2 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig index 99b15b77dfd57..fe1b5fec1dfca 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 7f371ea1248c3..cfb195a0f6ce2 100644 --- a/drivers/usb/misc/qcom_eud.c +++ b/drivers/usb/misc/qcom_eud.c @@ -15,6 +15,7 @@ #include <linux/slab.h> #include <linux/sysfs.h> #include <linux/usb/role.h> +#include <linux/firmware/qcom/qcom_scm.h>
#define EUD_REG_INT1_EN_MASK 0x0024 #define EUD_REG_INT_STATUS_1 0x0044 @@ -34,7 +35,7 @@ struct eud_chip { struct device *dev; struct usb_role_switch *role_sw; void __iomem *base; - void __iomem *mode_mgr; + phys_addr_t mode_mgr; unsigned int int_status; int irq; bool enabled; @@ -43,18 +44,29 @@ struct eud_chip {
static int enable_eud(struct eud_chip *priv) { + int ret; + + ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 1); + if (ret) + return ret; + 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);
return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE); }
-static void disable_eud(struct eud_chip *priv) +static int disable_eud(struct eud_chip *priv) { + int ret; + + ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 0); + if (ret) + return ret; + writel(0, priv->base + EUD_REG_CSR_EUD_EN); - writel(0, priv->mode_mgr + EUD_REG_EUD_EN2); + return 0; }
static ssize_t enable_show(struct device *dev, @@ -82,11 +94,12 @@ static ssize_t enable_store(struct device *dev, chip->enabled = enable; else disable_eud(chip); + } else { - disable_eud(chip); + ret = disable_eud(chip); }
- return count; + return ret < 0 ? ret : count; }
static DEVICE_ATTR_RW(enable); @@ -178,6 +191,7 @@ static void eud_role_switch_release(void *data) static int eud_probe(struct platform_device *pdev) { struct eud_chip *chip; + struct resource *res; int ret;
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); @@ -200,9 +214,10 @@ 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); + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (!res) + return -ENODEV; + chip->mode_mgr = res->start;
chip->irq = platform_get_irq(pdev, 0); ret = devm_request_threaded_irq(&pdev->dev, chip->irq, handle_eud_irq,