usb: dwc3: add Keystone specific glue layer

Add Keystone platform specific glue layer to support
USB3 Host mode.

[ balbi@ti.com : fix order of clk_disable() and
	platform_device_unregister() ]

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

3 files changed, 210 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 70fc43027a5c..e2c730fc9a90 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -70,6 +70,13 @@ config USB_DWC3_PCI
           One such PCIe-based platform is Synopsys' PCIe HAPS model of
           this IP.
 
+config USB_DWC3_KEYSTONE
+        tristate "Texas Instruments Keystone2 Platforms"
+        default USB_DWC3
+        help
+          Support of USB2/3 functionality in TI Keystone2 platforms.
+          Say 'Y' or 'M' here if you have one such device
+
 comment "Debugging features"
 
 config USB_DWC3_DEBUG
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index dd1760145c46..10ac3e72482e 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -32,3 +32,4 @@ endif
 obj-$(CONFIG_USB_DWC3_OMAP)             += dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_EXYNOS)           += dwc3-exynos.o
 obj-$(CONFIG_USB_DWC3_PCI)              += dwc3-pci.o
+obj-$(CONFIG_USB_DWC3_KEYSTONE)         += dwc3-keystone.o
diff --git a/drivers/usb/dwc3/dwc3-keystone.c b/drivers/usb/dwc3/dwc3-keystone.c
new file mode 100644
index 000000000000..1fad1618df6e
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-keystone.c
@@ -0,0 +1,202 @@
+/**
+ * dwc3-keystone.c - Keystone Specific Glue layer
+ *
+ * Copyright (C) 2010-2013 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: WingMan Kwok <w-kwok2@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/of_platform.h>
+
+/* USBSS register offsets */
+#define USBSS_REVISION          0x0000
+#define USBSS_SYSCONFIG         0x0010
+#define USBSS_IRQ_EOI           0x0018
+#define USBSS_IRQSTATUS_RAW_0   0x0020
+#define USBSS_IRQSTATUS_0       0x0024
+#define USBSS_IRQENABLE_SET_0   0x0028
+#define USBSS_IRQENABLE_CLR_0   0x002c
+
+/* IRQ register bits */
+#define USBSS_IRQ_EOI_LINE(n)   BIT(n)
+#define USBSS_IRQ_EVENT_ST      BIT(0)
+#define USBSS_IRQ_COREIRQ_EN    BIT(0)
+#define USBSS_IRQ_COREIRQ_CLR   BIT(0)
+
+static u64 kdwc3_dma_mask;
+
+struct dwc3_keystone {
+        struct device                   *dev;
+        struct clk                      *clk;
+        void __iomem                    *usbss;
+};
+
+static inline u32 kdwc3_readl(void __iomem *base, u32 offset)
+{
+        return readl(base + offset);
+}
+
+static inline void kdwc3_writel(void __iomem *base, u32 offset, u32 value)
+{
+        writel(value, base + offset);
+}
+
+static void kdwc3_enable_irqs(struct dwc3_keystone *kdwc)
+{
+        u32 val;
+
+        val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
+        val |= USBSS_IRQ_COREIRQ_EN;
+        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
+}
+
+static void kdwc3_disable_irqs(struct dwc3_keystone *kdwc)
+{
+        u32 val;
+
+        val = kdwc3_readl(kdwc->usbss, USBSS_IRQENABLE_SET_0);
+        val &= ~USBSS_IRQ_COREIRQ_EN;
+        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, val);
+}
+
+static irqreturn_t dwc3_keystone_interrupt(int irq, void *_kdwc)
+{
+        struct dwc3_keystone    *kdwc = _kdwc;
+
+        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_CLR_0, USBSS_IRQ_COREIRQ_CLR);
+        kdwc3_writel(kdwc->usbss, USBSS_IRQSTATUS_0, USBSS_IRQ_EVENT_ST);
+        kdwc3_writel(kdwc->usbss, USBSS_IRQENABLE_SET_0, USBSS_IRQ_COREIRQ_EN);
+        kdwc3_writel(kdwc->usbss, USBSS_IRQ_EOI, USBSS_IRQ_EOI_LINE(0));
+
+        return IRQ_HANDLED;
+}
+
+static int kdwc3_probe(struct platform_device *pdev)
+{
+        struct device           *dev = &pdev->dev;
+        struct device_node      *node = pdev->dev.of_node;
+        struct dwc3_keystone    *kdwc;
+        struct resource         *res;
+        int                     error, irq;
+
+        kdwc = devm_kzalloc(dev, sizeof(*kdwc), GFP_KERNEL);
+        if (!kdwc)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, kdwc);
+
+        kdwc->dev = dev;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(dev, "missing usbss resource\n");
+                return -EINVAL;
+        }
+
+        kdwc->usbss = devm_ioremap_resource(dev, res);
+        if (IS_ERR(kdwc->usbss))
+                return PTR_ERR(kdwc->usbss);
+
+        kdwc3_dma_mask = dma_get_mask(dev);
+        dev->dma_mask = &kdwc3_dma_mask;
+
+        kdwc->clk = devm_clk_get(kdwc->dev, "usb");
+
+        error = clk_prepare_enable(kdwc->clk);
+        if (error < 0) {
+                dev_dbg(kdwc->dev, "unable to enable usb clock, err %d\n",
+                        error);
+                return error;
+        }
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(&pdev->dev, "missing irq\n");
+                goto err_irq;
+        }
+
+        error = devm_request_irq(dev, irq, dwc3_keystone_interrupt, IRQF_SHARED,
+                        dev_name(dev), kdwc);
+        if (error) {
+                dev_err(dev, "failed to request IRQ #%d --> %d\n",
+                                irq, error);
+                goto err_irq;
+        }
+
+        kdwc3_enable_irqs(kdwc);
+
+        error = of_platform_populate(node, NULL, NULL, dev);
+        if (error) {
+                dev_err(&pdev->dev, "failed to create dwc3 core\n");
+                goto err_core;
+        }
+
+        return 0;
+
+err_core:
+        kdwc3_disable_irqs(kdwc);
+err_irq:
+        clk_disable_unprepare(kdwc->clk);
+
+        return error;
+}
+
+static int kdwc3_remove_core(struct device *dev, void *c)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+
+        platform_device_unregister(pdev);
+
+        return 0;
+}
+
+static int kdwc3_remove(struct platform_device *pdev)
+{
+        struct dwc3_keystone *kdwc = platform_get_drvdata(pdev);
+
+        kdwc3_disable_irqs(kdwc);
+        device_for_each_child(&pdev->dev, NULL, kdwc3_remove_core);
+        clk_disable_unprepare(kdwc->clk);
+        platform_set_drvdata(pdev, NULL);
+
+        return 0;
+}
+
+static const struct of_device_id kdwc3_of_match[] = {
+        { .compatible = "ti,keystone-dwc3", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, kdwc3_of_match);
+
+static struct platform_driver kdwc3_driver = {
+        .probe          = kdwc3_probe,
+        .remove         = kdwc3_remove,
+        .driver         = {
+                .name   = "keystone-dwc3",
+                .owner          = THIS_MODULE,
+                .of_match_table = kdwc3_of_match,
+        },
+};
+
+module_platform_driver(kdwc3_driver);
+
+MODULE_ALIAS("platform:keystone-dwc3");
+MODULE_AUTHOR("WingMan Kwok <w-kwok2@ti.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DesignWare USB3 KEYSTONE Glue Layer");