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

Dwivedi, Avaneesh Kumar (avani)
2020-02-16T16:22:44Z

On 2/7/2020 3:34 PM, Greg KH wrote:
> On Fri, Jan 31, 2020 at 10:13:31AM +0530, Avaneesh Kumar Dwivedi wrote:
>> 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.
> What are valid values to be used here?
it should be bool variable relying on 0 or 1.
>
>> +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
> Why not let everyone test build this?
EUD is Qualcomm IP, shall not it be associated with 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
> Don't need these.
OK
>
>> +
>> +#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;
> No, use the built-in kernel function to handle reading y/n/Y/N/0/1 from
> sysfs files, do not try to roll your own. As you have seen, you will
> get it wrong :)
ok
>
>
>
>> +
>> + 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
>> +};
> ATTRIBUTE_GROUPS()?
OK.
>
>> +
>> +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;
> No reference counting???
you mean get/put_device?
>
> thanks,
>
> greg k-h