[PATCH v4 2/2] Embedded USB Debugger (EUD) driver

Avaneesh Kumar Dwivedi
2020-01-31T04:44:13Z

Add support for control peripheral of EUD (Embedded USB Debugger) to
listen to events such as USB attach/detach, charger enable/disable, pet
EUD to indicate software is functional. Reusing the platform device kobj,
sysfs entry 'enable' is created to enable or disable EUD.

Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
Signed-off-by: Prakruthi Deepak Heragu <pheragu@codeaurora.org>
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>
---
Documentation/ABI/stable/sysfs-driver-msm-eud | 5 +
drivers/soc/qcom/Kconfig | 12 +
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/eud.c | 329 ++++++++++++++++++++++++++
4 files changed, 347 insertions(+)
create mode 100644 Documentation/ABI/stable/sysfs-driver-msm-eud
create mode 100644 drivers/soc/qcom/eud.c

diff --git a/Documentation/ABI/stable/sysfs-driver-msm-eud b/Documentation/ABI/stable/sysfs-driver-msm-eud
new file mode 100644
index 0000000..d96ae05
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-driver-msm-eud
@@ -0,0 +1,5 @@
+What: /sys/bus/platform/drivers/msm-eud/enable
+Date: Jan 2020
+Contact: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>
+Description: Enable/Disable use of eud device.
+Users: User space debug application which intend to use EUD h/w block.
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index d0a73e7..6b7c9d0 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -202,4 +202,16 @@ config QCOM_APR
application processor and QDSP6. APR is
used by audio driver to configure QDSP6
ASM, ADM and AFE modules.
+
+config QCOM_EUD
+ tristate "QTI Embedded USB Debugger (EUD)"
+ depends on ARCH_QCOM
+ help
+ The Embedded USB Debugger (EUD) driver is a driver for the
+ control peripheral which waits on events like USB attach/detach
+ and charger enable/disable. The control peripheral further helps
+ support the USB-based debug and trace capabilities.
+ This module enables support for Qualcomm Technologies, Inc.
+ Embedded USB Debugger (EUD).
+ If unsure, say N.
endmenu
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 9fb35c8..c15be68 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_QCOM_APR) += apr.o
obj-$(CONFIG_QCOM_LLCC) += llcc-qcom.o
obj-$(CONFIG_QCOM_RPMHPD) += rpmhpd.o
obj-$(CONFIG_QCOM_RPMPD) += rpmpd.o
+obj-$(CONFIG_QCOM_EUD) += eud.o
diff --git a/drivers/soc/qcom/eud.c b/drivers/soc/qcom/eud.c
new file mode 100644
index 0000000..e6c3604
--- /dev/null
+++ b/drivers/soc/qcom/eud.c
@@ -0,0 +1,329 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/extcon.h>
+#include <linux/extcon-provider.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/workqueue.h>
+#include <linux/power_supply.h>
+
+#define EUD_ENABLE_CMD 1
+#define EUD_DISABLE_CMD 0
+
+#define EUD_REG_INT1_EN_MASK 0x0024
+#define EUD_REG_INT_STATUS_1 0x0044
+#define EUD_REG_CTL_OUT_1 0x0074
+#define EUD_REG_VBUS_INT_CLR 0x0080
+#define EUD_REG_CHGR_INT_CLR 0x0084
+#define EUD_REG_CSR_EUD_EN 0x1014
+#define EUD_REG_SW_ATTACH_DET 0x1018
+
+#define EUD_INT_VBUS BIT(2)
+#define EUD_INT_CHGR BIT(3)
+#define EUD_INT_SAFE_MODE BIT(4)
+#define EUD_INT_ALL (EUD_INT_VBUS|EUD_INT_CHGR|\
+ EUD_INT_SAFE_MODE)
+
+struct eud_chip {
+ struct device *dev;
+ int eud_irq;
+ unsigned int extcon_id;
+ unsigned int int_status;
+ bool usb_attach;
+ bool chgr_enable;
+ void __iomem *eud_reg_base;
+ struct extcon_dev *extcon;
+ int enable;
+ struct work_struct eud_work;
+};
+
+static const unsigned int eud_extcon_cable[] = {
+ EXTCON_USB,
+ EXTCON_CHG_USB_SDP,
+ EXTCON_NONE,
+};
+
+static int enable_eud(struct eud_chip *priv)
+{
+ int ret;
+
+ /* write into CSR to enable EUD */
+ writel_relaxed(BIT(0), priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+ /* Enable vbus, chgr & safe mode warning interrupts */
+ writel_relaxed(EUD_INT_VBUS | EUD_INT_CHGR | EUD_INT_SAFE_MODE,
+ priv->eud_reg_base + EUD_REG_INT1_EN_MASK);
+
+ /* Ensure Register Writes Complete */
+ wmb();
+
+ /*
+ * Set the default cable state to usb connect and charger
+ * enable
+ */
+ ret = extcon_set_state_sync(priv->extcon, EXTCON_USB, true);
+ if (ret)
+ return ret;
+ ret = extcon_set_state_sync(priv->extcon,
+ EXTCON_CHG_USB_SDP, true);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void disable_eud(struct eud_chip *priv)
+{
+ /* write into CSR to disable EUD */
+ writel_relaxed(0, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+}
+
+static ssize_t enable_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct eud_chip *chip = dev_get_drvdata(dev);
+
+ return snprintf(buf, sizeof(int), "%d", chip->enable);
+}
+
+static ssize_t enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct eud_chip *chip = dev_get_drvdata(dev);
+ int enable = 0;
+ int ret = 0;
+
+ if (sscanf(buf, "%du", &enable) != 1)
+ return -EINVAL;
+
+ if (enable == EUD_ENABLE_CMD)
+ ret = enable_eud(chip);
+ else if (enable == EUD_DISABLE_CMD)
+ disable_eud(chip);
+ if (!ret)
+ chip->enable = enable;
+ return count;
+}
+
+static DEVICE_ATTR_RW(enable);
+
+static struct attribute *attrs[] = {
+ &dev_attr_enable.attr,
+ NULL
+};
+
+static struct attribute_group attr_group = {
+ .attrs = attrs,
+};
+
+static const struct attribute_group *attr_groups[] = {
+ &attr_group,
+ NULL
+};
+
+static void eud_event_notifier(struct work_struct *eud_work)
+{
+ struct eud_chip *chip = container_of(eud_work, struct eud_chip,
+ eud_work);
+ int ret;
+
+ if (chip->int_status == EUD_INT_VBUS) {
+ ret = extcon_set_state_sync(chip->extcon, chip->extcon_id,
+ chip->usb_attach);
+ if (ret)
+ return;
+ } else if (chip->int_status == EUD_INT_CHGR) {
+ ret = extcon_set_state_sync(chip->extcon, chip->extcon_id,
+ chip->chgr_enable);
+ if (ret)
+ return;
+ }
+}
+
+static void usb_attach_detach(struct eud_chip *chip)
+{
+ u32 reg;
+
+ chip->extcon_id = EXTCON_USB;
+ /* read ctl_out_1[4] to find USB attach or detach event */
+ reg = readl_relaxed(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+ if (reg & BIT(4))
+ chip->usb_attach = true;
+ else
+ chip->usb_attach = false;
+
+ schedule_work(&chip->eud_work);
+
+ /* set and clear vbus_int_clr[0] to clear interrupt */
+ writel_relaxed(BIT(0), chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+ /* Ensure Register Writes Complete */
+ wmb();
+ writel_relaxed(0, chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+}
+
+static void chgr_enable_disable(struct eud_chip *chip)
+{
+ u32 reg;
+
+ chip->extcon_id = EXTCON_CHG_USB_SDP;
+ /* read ctl_out_1[6] to find charger enable or disable event */
+ reg = readl_relaxed(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+ if (reg & BIT(6))
+ chip->chgr_enable = true;
+ else
+ chip->chgr_enable = false;
+
+ schedule_work(&chip->eud_work);
+
+ /* set and clear chgr_int_clr[0] to clear interrupt */
+ writel_relaxed(BIT(0), chip->eud_reg_base + EUD_REG_CHGR_INT_CLR);
+ /* Ensure Register Writes Complete */
+ wmb();
+ writel_relaxed(0, chip->eud_reg_base + EUD_REG_CHGR_INT_CLR);
+}
+
+static void pet_eud(struct eud_chip *chip)
+{
+ u32 reg;
+
+ /* read sw_attach_det[0] to find attach/detach event */
+ reg = readl_relaxed(chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+ if (reg & BIT(0)) {
+ /* Detach & Attach pet for EUD */
+ writel_relaxed(0, chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+ /* Ensure Register Writes Complete */
+ wmb();
+ /* Delay to make sure detach pet is done before attach pet */
+ udelay(100);
+ writel_relaxed(BIT(0), chip->eud_reg_base +
+ EUD_REG_SW_ATTACH_DET);
+ /* Ensure Register Writes Complete */
+ wmb();
+ } else {
+ /* Attach pet for EUD */
+ writel_relaxed(BIT(0), chip->eud_reg_base +
+ EUD_REG_SW_ATTACH_DET);
+ /* Ensure Register Writes Complete */
+ wmb();
+ }
+}
+
+static irqreturn_t handle_eud_irq(int irq, void *data)
+{
+ struct eud_chip *chip = data;
+ u32 reg;
+
+ /* read status register and find out which interrupt triggered */
+ reg = readl_relaxed(chip->eud_reg_base + EUD_REG_INT_STATUS_1);
+ switch (reg & EUD_INT_ALL) {
+ case EUD_INT_VBUS:
+ chip->int_status = EUD_INT_VBUS;
+ usb_attach_detach(chip);
+ break;
+ case EUD_INT_CHGR:
+ chip->int_status = EUD_INT_CHGR;
+ chgr_enable_disable(chip);
+ break;
+ case EUD_INT_SAFE_MODE:
+ pet_eud(chip);
+ break;
+ default:
+ return IRQ_NONE;
+ }
+ return IRQ_HANDLED;
+}
+
+static int msm_eud_probe(struct platform_device *pdev)
+{
+ struct eud_chip *chip;
+ struct resource *res;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->dev = &pdev->dev;
+ platform_set_drvdata(pdev, chip);
+
+ chip->extcon = devm_extcon_dev_allocate(&pdev->dev, eud_extcon_cable);
+ if (IS_ERR(chip->extcon))
+ return PTR_ERR(chip->extcon);
+
+ ret = devm_extcon_dev_register(&pdev->dev, chip->extcon);
+ if (ret)
+ return ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENOMEM;
+
+ chip->eud_reg_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(chip->eud_reg_base))
+ return PTR_ERR(chip->eud_reg_base);
+
+ chip->eud_irq = platform_get_irq(pdev, 0);
+
+ ret = devm_request_irq(&pdev->dev, chip->eud_irq, handle_eud_irq,
+ IRQF_TRIGGER_HIGH, NULL, chip);
+ if (ret)
+ return ret;
+
+ device_init_wakeup(&pdev->dev, true);
+ enable_irq_wake(chip->eud_irq);
+
+ INIT_WORK(&chip->eud_work, eud_event_notifier);
+
+ if (ret)
+ return ret;
+
+ /* Enable EUD */
+ if (chip->enable)
+ enable_eud(chip);
+
+ return 0;
+}
+
+static int msm_eud_remove(struct platform_device *pdev)
+{
+ struct eud_chip *chip = platform_get_drvdata(pdev);
+
+ if (chip->enable)
+ disable_eud(chip);
+ device_init_wakeup(&pdev->dev, false);
+ disable_irq_wake(chip->eud_irq);
+
+ return 0;
+}
+
+static const struct of_device_id msm_eud_dt_match[] = {
+ {.compatible = "qcom,msm-eud"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, msm_eud_dt_match);
+
+static struct platform_driver msm_eud_driver = {
+ .probe = msm_eud_probe,
+ .remove = msm_eud_remove,
+ .driver = {
+ .name = "msm-eud",
+ .groups = attr_groups,
+ .of_match_table = msm_eud_dt_match,
+ },
+};
+module_platform_driver(msm_eud_driver);
+
+MODULE_DESCRIPTION("QTI EUD driver");
+MODULE_LICENSE("GPL v2");