Date:   Sun, 18 Nov 2018 10:09:00 +0000
From:   Pawel Laszczak <pawell@...ence.com>
To:     <devicetree@...r.kernel.org>
CC:     <gregkh@...uxfoundation.org>, <linux-usb@...r.kernel.org>,
        <rogerq@...com>, <linux-kernel@...r.kernel.org>,
        <adouglas@...ence.com>, <jbergsagel@...com>, <nsekhar@...com>,
        <nm@...com>, <sureshp@...ence.com>, <peter.chen@....com>,
        <pjez@...ence.com>, <kurahul@...ence.com>,
        "Pawel Laszczak" <pawell@...ence.com>
Subject: [RFC PATCH v2 04/15] usb:cdns3: Driver initialization code.

Patch adds core.c and core.h file that implements initialization
of platform driver and adds function responsible for selecting,
switching and running appropriate Device/Host mode.

Signed-off-by: Pawel Laszczak <pawell@...ence.com>
---
 drivers/usb/cdns3/Makefile |   2 +
 drivers/usb/cdns3/core.c   | 413 +++++++++++++++++++++++++++++++++++++
 drivers/usb/cdns3/core.h   | 100 +++++++++
 3 files changed, 515 insertions(+)
 create mode 100644 drivers/usb/cdns3/core.c
 create mode 100644 drivers/usb/cdns3/core.h

diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
index dcdd62003c6a..02d25b23c5d3 100644
--- a/drivers/usb/cdns3/Makefile
+++ b/drivers/usb/cdns3/Makefile
@@ -1,3 +1,5 @@
+obj-$(CONFIG_USB_CDNS3)			+= cdns3.o
 obj-$(CONFIG_USB_CDNS3_PCI_WRAP)	+= cdns3-pci.o
 
+cdns3-y					:= core.o
 cdns3-pci-y		 		:= cdns3-pci-wrap.o
diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
new file mode 100644
index 000000000000..f9055d4da67f
--- /dev/null
+++ b/drivers/usb/cdns3/core.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2018 Cadence.
+ *
+ * Author: Peter Chen <peter.chen@....com>
+ *         Pawel Laszczak <pawell@...ence.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+
+#include "gadget.h"
+#include "core.h"
+
+static inline struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
+{
+	WARN_ON(cdns->role >= CDNS3_ROLE_END || !cdns->roles[cdns->role]);
+	return cdns->roles[cdns->role];
+}
+
+static inline int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
+{
+	int ret;
+
+	if (role >= CDNS3_ROLE_END)
+		return 0;
+
+	if (!cdns->roles[role])
+		return -ENXIO;
+
+	mutex_lock(&cdns->mutex);
+	cdns->role = role;
+	ret = cdns->roles[role]->start(cdns);
+	mutex_unlock(&cdns->mutex);
+	return ret;
+}
+
+static inline void cdns3_role_stop(struct cdns3 *cdns)
+{
+	enum cdns3_roles role = cdns->role;
+
+	if (role == CDNS3_ROLE_END)
+		return;
+
+	mutex_lock(&cdns->mutex);
+	cdns->roles[role]->stop(cdns);
+	cdns->role = CDNS3_ROLE_END;
+	mutex_unlock(&cdns->mutex);
+}
+
+static enum cdns3_roles cdns3_get_role(struct cdns3 *cdns)
+{
+	if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) {
+		//TODO: implements selecting device/host mode
+		return CDNS3_ROLE_HOST;
+	}
+	return cdns->roles[CDNS3_ROLE_HOST]
+		? CDNS3_ROLE_HOST
+		: CDNS3_ROLE_GADGET;
+}
+
+/**
+ * cdns3_core_init_role - initialize role of operation
+ * @cdns: Pointer to cdns3 structure
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_core_init_role(struct cdns3 *cdns)
+{
+	struct device *dev = cdns->dev;
+	enum usb_dr_mode dr_mode;
+
+	dr_mode = usb_get_dr_mode(dev);
+	cdns->role = CDNS3_ROLE_END;
+
+	/*
+	 * If driver can't read mode by means of usb_get_dr_mdoe function then
+	 * chooses mode according with Kernel configuration. This setting
+	 * can be restricted later depending on strap pin configuration.
+	 */
+	if (dr_mode == USB_DR_MODE_UNKNOWN) {
+		if (IS_ENABLED(CONFIG_USB_CDNS3_HOST) &&
+		    IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
+			dr_mode = USB_DR_MODE_OTG;
+		else if (IS_ENABLED(CONFIG_USB_CDNS3_HOST))
+			dr_mode = USB_DR_MODE_HOST;
+		else if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
+			dr_mode = USB_DR_MODE_PERIPHERAL;
+	}
+
+	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
+		//TODO: implements host initialization
+	}
+
+	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
+		//TODO: implements device initialization
+	}
+
+	if (!cdns->roles[CDNS3_ROLE_HOST] && !cdns->roles[CDNS3_ROLE_GADGET]) {
+		dev_err(dev, "no supported roles\n");
+		return -ENODEV;
+	}
+
+	cdns->dr_mode = dr_mode;
+	return 0;
+}
+
+/**
+ * cdns3_irq - interrupt handler for cdns3 core device
+ *
+ * @irq: irq number for cdns3 core device
+ * @data: structure of cdns3
+ *
+ * Returns IRQ_HANDLED or IRQ_NONE
+ */
+static irqreturn_t cdns3_irq(int irq, void *data)
+{
+	struct cdns3 *cdns = data;
+	irqreturn_t ret = IRQ_NONE;
+
+	/* Handle device/host interrupt */
+	if (cdns->role != CDNS3_ROLE_END)
+		ret = cdns3_get_current_role_driver(cdns)->irq(cdns);
+
+	return ret;
+}
+
+static void cdns3_remove_roles(struct cdns3 *cdns)
+{
+	//TODO: implements this function
+}
+
+static int cdns3_do_role_switch(struct cdns3 *cdns, enum cdns3_roles role)
+{
+	enum cdns3_roles current_role;
+	int ret = 0;
+
+	current_role = cdns->role;
+
+	if (role == CDNS3_ROLE_END)
+		return 0;
+
+	dev_dbg(cdns->dev, "Switching role");
+
+	ret = cdns3_role_start(cdns, role);
+	if (ret) {
+		/* Back to current role */
+		dev_err(cdns->dev, "set %d has failed, back to %d\n",
+			role, current_role);
+		ret = cdns3_role_start(cdns, current_role);
+	}
+
+	return ret;
+}
+
+/**
+ * cdns3_role_switch - work queue handler for role switch
+ *
+ * @work: work queue item structure
+ *
+ * Handles below events:
+ * - Role switch for dual-role devices
+ * - CDNS3_ROLE_GADGET <--> CDNS3_ROLE_END for peripheral-only devices
+ */
+static void cdns3_role_switch(struct work_struct *work)
+{
+	enum cdns3_roles role = CDNS3_ROLE_END;
+	struct cdns3 *cdns;
+	bool device, host;
+
+	cdns = container_of(work, struct cdns3, role_switch_wq);
+
+	//TODO: implements this functions.
+	//host = cdns3_is_host(cdns);
+	//device = cdns3_is_device(cdns);
+	host = 1;
+	device = 0;
+
+	if (host)
+		role = CDNS3_ROLE_HOST;
+	else if (device)
+		role = CDNS3_ROLE_GADGET;
+
+	if (cdns->desired_dr_mode == cdns->current_dr_mode &&
+	    cdns->role == role)
+		return;
+
+	pm_runtime_get_sync(cdns->dev);
+	cdns3_role_stop(cdns);
+
+	if (host) {
+		if (cdns->roles[CDNS3_ROLE_HOST])
+			cdns3_do_role_switch(cdns, CDNS3_ROLE_HOST);
+		pm_runtime_put_sync(cdns->dev);
+		return;
+	}
+
+	if (device)
+		cdns3_do_role_switch(cdns, CDNS3_ROLE_GADGET);
+	else
+		cdns3_do_role_switch(cdns, CDNS3_ROLE_END);
+
+	pm_runtime_put_sync(cdns->dev);
+}
+
+/**
+ * cdns3_probe - probe for cdns3 core device
+ * @pdev: Pointer to cdns3 core platform device
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource	*res;
+	struct cdns3 *cdns;
+	void __iomem *regs;
+	int ret;
+
+	cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
+	if (!cdns)
+		return -ENOMEM;
+
+	cdns->dev = dev;
+
+	platform_set_drvdata(pdev, cdns);
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		dev_err(dev, "missing IRQ\n");
+		return -ENODEV;
+	}
+	cdns->irq = res->start;
+
+	/*
+	 * Request memory region
+	 * region-0: xHCI
+	 * region-1: Peripheral
+	 * region-2: OTG registers
+	 */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(dev, res);
+
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+	cdns->xhci_regs = regs;
+	cdns->xhci_res = res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+	cdns->dev_regs	= regs;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+	cdns->otg_regs = regs;
+
+	mutex_init(&cdns->mutex);
+
+	cdns->phy = devm_phy_get(dev, "cdns3,usbphy");
+	if (IS_ERR(cdns->phy)) {
+		dev_info(dev, "no generic phy found\n");
+		cdns->phy = NULL;
+		/*
+		 * fall through here!
+		 * if no generic phy found, phy init
+		 * should be done under boot!
+		 */
+	} else {
+		phy_init(cdns->phy);
+	}
+
+	ret = cdns3_core_init_role(cdns);
+	if (ret)
+		goto err1;
+
+	INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
+	if (ret)
+		goto err2;
+
+	if (ret)
+		goto err2;
+
+	cdns->role = cdns3_get_role(cdns);
+
+	ret = devm_request_irq(dev, cdns->irq, cdns3_irq, IRQF_SHARED,
+			       dev_name(dev), cdns);
+
+	if (ret)
+		goto err2;
+
+	ret = cdns3_role_start(cdns, cdns->role);
+	if (ret) {
+		dev_err(dev, "can't start %s role\n",
+			cdns3_get_current_role_driver(cdns)->name);
+		goto err2;
+	}
+
+	device_set_wakeup_capable(dev, true);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	/*
+	 * The controller needs less time between bus and controller suspend,
+	 * and we also needs a small delay to avoid frequently entering low
+	 * power mode.
+	 */
+	pm_runtime_set_autosuspend_delay(dev, 20);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_use_autosuspend(dev);
+	dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
+
+	return 0;
+
+err2:
+	cdns3_remove_roles(cdns);
+err1:
+	return ret;
+}
+
+/**
+ * cdns3_remove - unbind drd driver and clean up
+ * @pdev: Pointer to Linux platform device
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_remove(struct platform_device *pdev)
+{
+	struct cdns3 *cdns = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	cdns3_remove_roles(cdns);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_cdns3_match[] = {
+	{ .compatible = "cdns,usb3" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, of_cdns3_match);
+#endif
+
+#ifdef CONFIG_PM
+
+#ifdef CONFIG_PM_SLEEP
+static int cdns3_suspend(struct device *dev)
+{
+	//TODO: implements this function
+	return 0;
+}
+
+static int cdns3_resume(struct device *dev)
+{
+	//TODO: implements this function
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+static int cdns3_runtime_suspend(struct device *dev)
+{	//TODO: implements this function
+	return 0;
+}
+
+static int cdns3_runtime_resume(struct device *dev)
+{
+	//TODO: implements this function
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops cdns3_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(cdns3_suspend, cdns3_resume)
+	SET_RUNTIME_PM_OPS(cdns3_runtime_suspend, cdns3_runtime_resume, NULL)
+};
+
+static struct platform_driver cdns3_driver = {
+	.probe		= cdns3_probe,
+	.remove		= cdns3_remove,
+	.driver		= {
+		.name	= "cdns-usb3",
+		.of_match_table	= of_match_ptr(of_cdns3_match),
+		.pm	= &cdns3_pm_ops,
+	},
+};
+
+static int __init cdns3_driver_platform_register(void)
+{
+	return platform_driver_register(&cdns3_driver);
+}
+module_init(cdns3_driver_platform_register);
+
+static void __exit cdns3_driver_platform_unregister(void)
+{
+	platform_driver_unregister(&cdns3_driver);
+}
+module_exit(cdns3_driver_platform_unregister);
+
+MODULE_ALIAS("platform:cdns3");
+MODULE_AUTHOR("Pawel Laszczak <pawell@...ence.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");
diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
new file mode 100644
index 000000000000..7c8204fe4d3d
--- /dev/null
+++ b/drivers/usb/cdns3/core.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2017 NXP
+ * Copyright (C) 2018 Cadence.
+ *
+ * Authors: Peter Chen <peter.chen@....com>
+ *          Pawel Laszczak <pawell@...ence.com>
+ */
+#include <linux/usb/otg.h>
+
+#ifndef __LINUX_CDNS3_CORE_H
+#define __LINUX_CDNS3_CORE_H
+
+struct cdns3;
+enum cdns3_roles {
+	CDNS3_ROLE_HOST = 0,
+	CDNS3_ROLE_GADGET,
+	CDNS3_ROLE_END,
+};
+
+/**
+ * struct cdns3_role_driver - host/gadget role driver
+ * @start: start this role
+ * @stop: stop this role
+ * @suspend: suspend callback for this role
+ * @resume: resume callback for this role
+ * @irq: irq handler for this role
+ * @name: role name string (host/gadget)
+ */
+struct cdns3_role_driver {
+	int (*start)(struct cdns3 *cdns);
+	void (*stop)(struct cdns3 *cdns);
+	int (*suspend)(struct cdns3 *cdns, bool do_wakeup);
+	int (*resume)(struct cdns3 *cdns, bool hibernated);
+	irqreturn_t (*irq)(struct cdns3 *cdns);
+	const char *name;
+};
+
+#define CDNS3_NUM_OF_CLKS	5
+/**
+ * struct cdns3 - Representation of Cadence USB3 DRD controller.
+ * @dev: pointer to Cadence device struct
+ * @xhci_regs: pointer to base of xhci registers
+ * @xhci_res: the resource for xhci
+ * @dev_regs: pointer to base of dev registers
+ * @otg_regs: pointer to base of otg registers
+ * @irq: irq number for controller
+ * @roles: array of supported roles for this controller
+ * @role: current role
+ * @host_dev: the child host device pointer for cdns3 core
+ * @gadget_dev: the child gadget device pointer for cdns3 core
+ * @usb: phy for this controller
+ * @role_switch_wq: work queue item for role switch
+ * @in_lpm: the controller in low power mode
+ * @wakeup_int: the wakeup interrupt
+ * @mutex: the mutex for concurrent code at driver
+ * @dr_mode: supported mode of operation it can be only Host, only Device
+ *           or OTG mode that allow to switch between Device and Host mode.
+ *           This field based on hardware configuration and cant't be changed.
+ * @current_dr_role: current mode of operation when in dual-role mode
+ * @desired_dr_role: desired mode of operation when in dual-role mode.
+ *           This value can be changed during runtime.
+ *           Available options depends on  dr_mode:
+ *           dr_mode                 |  desired_dr_role and current_dr_role
+ *           ----------------------------------------------------------------
+ *           USB_DR_MODE_HOST        | only USB_DR_MODE_HOST
+ *           USB_DR_MODE_PERIPHERAL  | only USB_DR_MODE_PERIPHERAL
+ *           USB_DR_MODE_OTG         | only USB_DR_MODE_HOST
+ *           USB_DR_MODE_OTG         | only USB_DR_MODE_PERIPHERAL
+ *           USB_DR_MODE_OTG         | USB_DR_MODE_OTG
+ *
+ *           Desired_dr_role can be changed by means of debugfs.
+ * @root: debugfs root folder pointer
+ */
+struct cdns3 {
+	struct device			*dev;
+	void __iomem			*xhci_regs;
+	struct resource			*xhci_res;
+	struct cdns3_usb_regs __iomem	*dev_regs;
+	struct cdns3_otg_regs		*otg_regs;
+	int irq;
+	struct cdns3_role_driver	*roles[CDNS3_ROLE_END];
+	enum cdns3_roles		role;
+	struct device			*host_dev;
+	struct device			*gadget_dev;
+	struct phy			*phy;
+	struct work_struct		role_switch_wq;
+	int				in_lpm:1;
+	int				wakeup_int:1;
+	/* mutext used in workqueue*/
+	struct mutex			mutex;
+	enum usb_dr_mode		dr_mode;
+	enum usb_dr_mode		current_dr_mode;
+	enum usb_dr_mode		desired_dr_mode;
+	struct dentry			*root;
+};
+
+#endif /* __LINUX_CDNS3_CORE_H */
-- 
2.17.1

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