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

Prakruthi Deepak Heragu
2018-07-31T18:22:56Z

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.

Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
Signed-off-by: Prakruthi Deepak Heragu <pheragu@codeaurora.org>
---
drivers/soc/qcom/Kconfig | 13 ++
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/eud.c | 340 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 354 insertions(+)
create mode 100644 drivers/soc/qcom/eud.c

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 5856e79..efd431f 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -136,4 +136,17 @@ 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
+ select SERIAL_CORE
+ 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 19dcf95..dd4701b 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_QCOM_SMP2P) += smp2p.o
obj-$(CONFIG_QCOM_SMSM) += smsm.o
obj-$(CONFIG_QCOM_WCNSS_CTRL) += wcnss_ctrl.o
obj-$(CONFIG_QCOM_APR) += apr.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..b4c4235
--- /dev/null
+++ b/drivers/soc/qcom/eud.c
@@ -0,0 +1,340 @@
+// 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/platform_device.h>
+#include <linux/extcon.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_NR 1
+
+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;
+ struct work_struct eud_work;
+};
+
+static const unsigned int eud_extcon_cable[] = {
+ EXTCON_USB,
+ EXTCON_CHG_USB_SDP,
+ EXTCON_NONE,
+};
+
+/*
+ * On the kernel command line specify eud.enable=1 to enable EUD.
+ * EUD is disabled by default.
+ */
+static int enable;
+static bool eud_ready;
+static struct eud_chip *eud_private;
+
+static void enable_eud(struct eud_chip *priv)
+{
+ struct power_supply *usb_psy = NULL;
+ union power_supply_propval pval = {0};
+ union power_supply_propval tval = {0};
+ int ret;
+
+ usb_psy = power_supply_get_by_name("usb");
+ if (!usb_psy)
+ return;
+
+ ret = power_supply_get_property(usb_psy,
+ POWER_SUPPLY_PROP_PRESENT, &pval);
+ if (ret)
+ return;
+
+ ret = power_supply_get_property(usb_psy,
+ POWER_SUPPLY_PROP_REAL_TYPE, &tval);
+ if (ret)
+ return;
+
+ if (pval.intval && (tval.intval == POWER_SUPPLY_TYPE_USB ||
+ tval.intval == POWER_SUPPLY_TYPE_USB_CDP)) {
+ /* 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 = extcon_set_state_sync(priv->extcon,
+ EXTCON_CHG_USB_SDP, true);
+ if (ret)
+ return;
+ } else {
+ return;
+ }
+
+}
+
+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 int param_eud_set(const char *val, const struct kernel_param *kp)
+{
+ int enable = 0;
+
+ if (sscanf(val, "%du", &enable) != 1)
+ return -EINVAL;
+
+ if (enable != EUD_ENABLE_CMD && enable != EUD_DISABLE_CMD)
+ return -EINVAL;
+
+ *((uint *)kp->arg) = enable;
+ if (!eud_ready)
+ return 0;
+
+ if (enable == EUD_ENABLE_CMD)
+ enable_eud(eud_private);
+ else if (enable == EUD_DISABLE_CMD)
+ disable_eud(eud_private);
+
+ return 0;
+}
+
+static const struct kernel_param_ops eud_param_ops = {
+ .set = param_eud_set,
+ .get = param_get_int,
+};
+
+module_param_cb(enable, &eud_param_ops, &enable, 0644);
+
+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);
+ if (reg & EUD_INT_VBUS) {
+ chip->int_status = EUD_INT_VBUS;
+ usb_attach_detach(chip);
+ } else if (reg & EUD_INT_CHGR) {
+ chip->int_status = EUD_INT_CHGR;
+ chgr_enable_disable(chip);
+ } else if (reg & EUD_INT_SAFE_MODE) {
+ pet_eud(chip);
+ } else {
+ 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) {
+ ret = -ENOMEM;
+ return ret;
+ }
+
+ 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) {
+ ret = -ENOMEM;
+ return ret;
+ }
+
+ 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);
+
+ eud_private = chip;
+ eud_ready = true;
+
+ /* Enable EUD */
+ if (enable)
+ enable_eud(eud_private);
+
+ return 0;
+}
+
+static int msm_eud_remove(struct platform_device *pdev)
+{
+ struct eud_chip *chip = platform_get_drvdata(pdev);
+
+ if (enable)
+ disable_eud(eud_private);
+ device_init_wakeup(&pdev->dev, false);
+ disable_irq_wake(chip->eud_irq);
+ platform_set_drvdata(pdev, NULL);
+
+ 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",
+ .of_match_table = msm_eud_dt_match,
+ },
+};
+module_platform_driver(msm_eud_driver);
+
+MODULE_DESCRIPTION("QTI EUD driver");
+MODULE_LICENSE("GPL v2");
--
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