Re: [PATCH v4 2/2] Embedded USB Debugger (EUD) driver
From: Dwivedi, Avaneesh Kumar (avani)
Date: Sun Feb 16 2020 - 09:14:51 EST
Thank you very much Bjorn for your comments, will address them and post
latest patchset soon.
On 2/4/2020 1:05 AM, Bjorn Andersson wrote:
On Thu 30 Jan 20:43 PST 2020, 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@xxxxxxxxxxxxxx>
Signed-off-by: Prakruthi Deepak Heragu <pheragu@xxxxxxxxxxxxxx>
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@xxxxxxxxxxxxxx>
Either ensure Satya is the author, or add some Co-developed-by to
indicate that all three of you have authored the patch.
Will add Co-developed-by.
---
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@xxxxxxxxxxxxxx>
+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
Please aim for keeping the sort order in this file (ignore QCOM_APR
which obviously is in the wrong place)
Please help to elaborate more, do you mean adding configs in
alphabetical order?
+ 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>
Please sort these.
OK
+
+#define EUD_ENABLE_CMD 1
+#define EUD_DISABLE_CMD 0
These defines doesn't add much value.
Will remove them.
+
+#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 */
Make up a define for BIT(0) and the next line is self explanatory - i.e.
drop the comment..
OK.
+ writel_relaxed(BIT(0), priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
Don't use _relaxed version of writel/readl unless you have a really good
reason - and if so provide a comment to why this is.
OK, will change to writel.
+ /* Enable vbus, chgr & safe mode warning interrupts */
This just repeats exactly what can be read from the next line.
Ok.
+ 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() ensures ordering, it deosn't wait for the operation to complete,
if you need that readl() the register.
Will fix.
+ 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);
Use writel() and drop the comment.
OK
+}
+
+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);
buf is not sizeof(int) big...Just do sprintf()...
OK
+}
+
+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;
You shouldn't need to initialize this as you're checking the return
value of sscanf().
OK
+ int ret = 0;
+
+ if (sscanf(buf, "%du", &enable) != 1)
+ return -EINVAL;
+
+ if (enable == EUD_ENABLE_CMD)
+ ret = enable_eud(chip);
If ret is !0 you should probably return that, rather than count...
ok
+ else if (enable == EUD_DISABLE_CMD)
+ disable_eud(chip);
+ if (!ret)
...and then you don't need this check, or initialize ret to 0 above.
ok
+ chip->enable = enable;
So if I write 42 to "enable" nothing will change in the hardware, but
chip->enable will be 42...
will change enable struct member to bool?
+ 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)
Why do you need a worker for this? Why not just use a threaded handler
and execute this directly in that context?
Will consider it.
+{
+ struct eud_chip *chip = container_of(eud_work, struct eud_chip,
+ eud_work);
+ int ret;
+
+ if (chip->int_status == EUD_INT_VBUS) {
And if you just call this function from the handler, you don't need
chip->int_status to pass parameters between the handler and the worker.
ok
+ 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))
Give this bit a define
ok
+ 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();
Use writel() and you probably don't need the wmb() here.
ok
+ 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))
Again, this deserves a define
ok
+ 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)) {
define
ok
+ /* Detach & Attach pet for EUD */
All comments in this driver relates to the very next line, but this
seems to document the next two writes - i.e. this seems to be a proper
comment.
ok
+ 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);
Better read back the value if you want to ensure the length of the delay
between the two writes.
ok
+ 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();
It will complete, if you need to wait for it to have completed read back
the value.
ok
+ }
+}
+
+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) {
What is the expected outcome if for some reason more than one of these
bits are set?
USB attach/detach events and Charger enable/disable events are
orthogonal and they both should be processed, will evaluate if break
statement should be removed.
+ 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);
Aren't we moving away from extcon in favor of the usb role switching
thing?
i could see that usb role switch has been implemented for c type
connector and that connector is modeled as child of usb controller, but
EUD is not a true connector, it intercepts PHY signals and reroute it to
USB controller as per EUD Command issued by debug appliaction
i am not sure if i need to implement EUD DT node as child of usb
controller, if i do so, as per my understanding EUD driver need to set
USB controller mode(host or device mode) by calling usb role switch
API's, please let me know if my understanding is correct?
+ 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);
Use devm_platform_ioremap_resource() instead
Ok.
+ 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);
Omit the irq trigger information here and let it come from devicetree.
Ok
+ 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)
Duplicate of the same check 8 lines up.
Ok
+ return ret;
+
+ /* Enable EUD */
+ if (chip->enable)
I'm not seeing where this would have been written during probe.
Will check and modify.
+ 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"},
Is this the one and only, past and future, version of the EUD hardware
block? Or do we need this compatible to be more specific?
EUD h/w IP is Qualcomm IP, As of now this is only hw IP available, if
future version of EUD IP comes, we can modify and add support then?
Nit. Please add a space after { and before }
Ok
Regards,
Bjorn
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