usb: dwc3: dwc3-octeon: Convert to glue driver

DWC3 as implemented in Cavium SoC is using UCTL bridge unit
between I/O interconnect and USB controller.

Currently there is no bond with dwc3 core code, so if anything goes
wrong in UCTL setup dwc3 is left in reset, which leads to bus error
while trying to read any device register. Thus any failure in UCTL
initialization ends with kernel panic.

To avoid this move Octeon DWC3 glue code from arch/mips and make it
proper glue driver which is used instead of dwc3-of-simple.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/ZMd/ReyiY7wS6DvN@lenoch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/mips/cavium-octeon/Makefile

@@ -18,4 +18,3 @@ obj-y += crypto/
 obj-$(CONFIG_MTD)		      += flash_setup.o
 obj-$(CONFIG_SMP)		      += smp.o
 obj-$(CONFIG_OCTEON_ILM)	      += oct_ilm.o
-obj-$(CONFIG_USB)		      += octeon-usb.o

arch/mips/cavium-octeon/octeon-platform.c

@@ -450,7 +450,6 @@ static const struct of_device_id octeon_ids[] __initconst = {
 	{ .compatible = "cavium,octeon-3860-bootbus", },
 	{ .compatible = "cavium,mdio-mux", },
 	{ .compatible = "gpio-leds", },
-	{ .compatible = "cavium,octeon-7130-usb-uctl", },
 	{},
 };
 

drivers/usb/dwc3/Kconfig

@@ -168,4 +168,14 @@ config USB_DWC3_AM62
 	  The Designware Core USB3 IP is programmed to operate in
 	  in USB 2.0 mode only.
 	  Say 'Y' or 'M' here if you have one such device
+
+config USB_DWC3_OCTEON
+	tristate "Cavium Octeon Platforms"
+	depends on CAVIUM_OCTEON_SOC || COMPILE_TEST
+	default USB_DWC3
+	help
+	  Support Cavium Octeon platforms with DesignWare Core USB3 IP.
+	  Only the host mode is currently supported.
+	  Say 'Y' or 'M' here if you have one such device.
+
 endif

drivers/usb/dwc3/Makefile

@@ -54,3 +54,4 @@ obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
 obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom.o
 obj-$(CONFIG_USB_DWC3_IMX8MP)		+= dwc3-imx8mp.o
 obj-$(CONFIG_USB_DWC3_XILINX)		+= dwc3-xilinx.o
+obj-$(CONFIG_USB_DWC3_OCTEON)		+= dwc3-octeon.o

drivers/usb/dwc3/dwc3-octeon.c

@@ -187,7 +187,10 @@
 #define USBDRD_UCTL_ECC				0xf0
 #define USBDRD_UCTL_SPARE1			0xf8
 
-static DEFINE_MUTEX(dwc3_octeon_clocks_mutex);
+struct dwc3_octeon {
+	struct device *dev;
+	void __iomem *base;
+};
 
 #ifdef CONFIG_CAVIUM_OCTEON_SOC
 #include <asm/octeon/octeon.h>
@@ -233,6 +236,11 @@ static inline uint64_t dwc3_octeon_readq(void __iomem *addr)
 static inline void dwc3_octeon_writeq(void __iomem *base, uint64_t val) { }
 
 static inline void dwc3_octeon_config_gpio(int index, int gpio) { }
+
+static uint64_t octeon_get_io_clock_rate(void)
+{
+	return 150000000;
+}
 #endif
 
 static int dwc3_octeon_get_divider(void)
@@ -494,58 +502,59 @@ static void __init dwc3_octeon_phy_reset(void __iomem *base)
 	dwc3_octeon_writeq(uctl_ctl_reg, val);
 }
 
-static int __init dwc3_octeon_device_init(void)
+static int dwc3_octeon_probe(struct platform_device *pdev)
 {
-	const char compat_node_name[] = "cavium,octeon-7130-usb-uctl";
-	struct platform_device *pdev;
-	struct device_node *node;
-	struct resource *res;
-	void __iomem *base;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct dwc3_octeon *octeon;
+	int err;
 
-	/*
-	 * There should only be three universal controllers, "uctl"
-	 * in the device tree. Two USB and a SATA, which we ignore.
-	 */
-	node = NULL;
-	do {
-		node = of_find_node_by_name(node, "uctl");
-		if (!node)
-			return -ENODEV;
+	octeon = devm_kzalloc(dev, sizeof(*octeon), GFP_KERNEL);
+	if (!octeon)
+		return -ENOMEM;
 
-		if (of_device_is_compatible(node, compat_node_name)) {
-			pdev = of_find_device_by_node(node);
-			if (!pdev)
-				return -ENODEV;
+	octeon->dev = dev;
+	octeon->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(octeon->base))
+		return PTR_ERR(octeon->base);
 
-			/*
-			 * The code below maps in the registers necessary for
-			 * setting up the clocks and reseting PHYs. We must
-			 * release the resources so the dwc3 subsystem doesn't
-			 * know the difference.
-			 */
-			base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
-			if (IS_ERR(base)) {
-				put_device(&pdev->dev);
-				return PTR_ERR(base);
+	err = dwc3_octeon_clocks_start(dev, octeon->base);
+	if (err)
+		return err;
+
+	dwc3_octeon_set_endian_mode(octeon->base);
+	dwc3_octeon_phy_reset(octeon->base);
+
+	platform_set_drvdata(pdev, octeon);
+
+	return of_platform_populate(node, NULL, NULL, dev);
 }
 
-			mutex_lock(&dwc3_octeon_clocks_mutex);
-			if (dwc3_octeon_clocks_start(&pdev->dev, base) == 0)
-				dev_info(&pdev->dev, "clocks initialized.\n");
-			dwc3_octeon_set_endian_mode(base);
-			dwc3_octeon_phy_reset(base);
-			mutex_unlock(&dwc3_octeon_clocks_mutex);
-			devm_iounmap(&pdev->dev, base);
-			devm_release_mem_region(&pdev->dev, res->start,
-						resource_size(res));
-			put_device(&pdev->dev);
-		}
-	} while (node != NULL);
+static void dwc3_octeon_remove(struct platform_device *pdev)
+{
+	struct dwc3_octeon *octeon = platform_get_drvdata(pdev);
 
-	return 0;
+	of_platform_depopulate(octeon->dev);
+	platform_set_drvdata(pdev, NULL);
 }
-device_initcall(dwc3_octeon_device_init);
 
+static const struct of_device_id dwc3_octeon_of_match[] = {
+	{ .compatible = "cavium,octeon-7130-usb-uctl" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, dwc3_octeon_of_match);
+
+static struct platform_driver dwc3_octeon_driver = {
+	.probe		= dwc3_octeon_probe,
+	.remove_new	= dwc3_octeon_remove,
+	.driver		= {
+		.name	= "dwc3-octeon",
+		.of_match_table = dwc3_octeon_of_match,
+	},
+};
+module_platform_driver(dwc3_octeon_driver);
+
+MODULE_ALIAS("platform:dwc3-octeon");
 MODULE_AUTHOR("David Daney <david.daney@cavium.com>");
 MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("USB driver for OCTEON III SoC");
+MODULE_DESCRIPTION("DesignWare USB3 OCTEON III Glue Layer");

drivers/usb/dwc3/dwc3-of-simple.c

@@ -170,7 +170,6 @@ static const struct dev_pm_ops dwc3_of_simple_dev_pm_ops = {
 
 static const struct of_device_id of_dwc3_simple_match[] = {
 	{ .compatible = "rockchip,rk3399-dwc3" },
-	{ .compatible = "cavium,octeon-7130-usb-uctl" },
 	{ .compatible = "sprd,sc9860-dwc3" },
 	{ .compatible = "allwinner,sun50i-h6-dwc3" },
 	{ .compatible = "hisilicon,hi3670-dwc3" },