usb: ehci: Add new EHCI driver for Broadcom STB SoC's

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020, Broadcom */

#include <linux/clk.h>

#include <linux/dma-mapping.h>

#include <linux/err.h>

#include <linux/kernel.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/usb.h>

#include <linux/usb/hcd.h>

#include <linux/iopoll.h>

#include "ehci.h"

#define hcd_to_ehci_priv(h) ((struct brcm_priv *)hcd_to_ehci(h)->priv)

struct brcm_priv {

	struct clk *clk;

};

/*

 * ehci_brcm_wait_for_sof

 * Wait for start of next microframe, then wait extra delay microseconds

 */

static inline void ehci_brcm_wait_for_sof(struct ehci_hcd *ehci, u32 delay)

{

	u32 frame_idx = ehci_readl(ehci, &ehci->regs->frame_index);

	u32 val;

	int res;

	/* Wait for next microframe (every 125 usecs) */

	res = readl_relaxed_poll_timeout(&ehci->regs->frame_index, val,

					 val != frame_idx, 1, 130);

	if (res)

		ehci_err(ehci, "Error waiting for SOF\n");

	udelay(delay);

}

/*

 * ehci_brcm_hub_control

 * The EHCI controller has a bug where it can violate the SOF

 * interval between the first two SOF's transmitted after resume

 * if the resume occurs near the end of the microframe. This causees

 * the controller to detect babble on the suspended port and

 * will eventually cause the controller to reset the port.

 * The fix is to Intercept the echi-hcd request to complete RESUME and

 * align it to the start of the next microframe.

 * See SWLINUX-1909 for more details

 */

static int ehci_brcm_hub_control(

	struct usb_hcd	*hcd,

	u16		typeReq,

	u16		wValue,

	u16		wIndex,

	char		*buf,

	u16		wLength)

{

	struct ehci_hcd	*ehci = hcd_to_ehci(hcd);

	int		ports = HCS_N_PORTS(ehci->hcs_params);

	u32 __iomem	*status_reg;

	unsigned long flags;

	int retval, irq_disabled = 0;

	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];

	/*

	 * RESUME is cleared when GetPortStatus() is called 20ms after start

	 * of RESUME

	 */

	if ((typeReq == GetPortStatus) &&

	    (wIndex && wIndex <= ports) &&

	    ehci->reset_done[wIndex-1] &&

	    time_after_eq(jiffies, ehci->reset_done[wIndex-1]) &&

	    (ehci_readl(ehci, status_reg) & PORT_RESUME)) {

		/*

		 * to make sure we are not interrupted until RESUME bit

		 * is cleared, disable interrupts on current CPU

		 */

		ehci_dbg(ehci, "SOF alignment workaround\n");

		irq_disabled = 1;

		local_irq_save(flags);

		ehci_brcm_wait_for_sof(ehci, 5);

	}

	retval = ehci_hub_control(hcd, typeReq, wValue, wIndex, buf, wLength);

	if (irq_disabled)

		local_irq_restore(flags);

	return retval;

}

static int ehci_brcm_reset(struct usb_hcd *hcd)

{

	struct ehci_hcd *ehci = hcd_to_ehci(hcd);

	int len;

	ehci->big_endian_mmio = 1;

	ehci->caps = (void __iomem *)hcd->regs;

	len = HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));

	ehci->regs = (void __iomem *)(hcd->regs + len);

	/* This fixes the lockup during reboot due to prior interrupts */

	ehci_writel(ehci, CMD_RESET, &ehci->regs->command);

	mdelay(10);

	/*

	 * SWLINUX-1705: Avoid OUT packet underflows during high memory

	 *   bus usage

	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90

	 */

	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);

	return ehci_setup(hcd);

}

static struct hc_driver __read_mostly ehci_brcm_hc_driver;

static const struct ehci_driver_overrides brcm_overrides __initconst = {

	.reset = ehci_brcm_reset,

	.extra_priv_size = sizeof(struct brcm_priv),

};

static int ehci_brcm_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct resource *res_mem;

	struct brcm_priv *priv;

	struct usb_hcd *hcd;

	int irq;

	int err;

	err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));

	if (err)

		return err;

	irq = platform_get_irq(pdev, 0);

	if (irq <= 0)

		return irq ? irq : -EINVAL;

	/* Hook the hub control routine to work around a bug */

	ehci_brcm_hc_driver.hub_control = ehci_brcm_hub_control;

	/* initialize hcd */

	hcd = usb_create_hcd(&ehci_brcm_hc_driver, dev, dev_name(dev));

	if (!hcd)

		return -ENOMEM;

	platform_set_drvdata(pdev, hcd);

	priv = hcd_to_ehci_priv(hcd);

	priv->clk = devm_clk_get_optional(dev, NULL);

	if (IS_ERR(priv->clk)) {

		err = PTR_ERR(priv->clk);

		goto err_hcd;

	}

	err = clk_prepare_enable(priv->clk);

	if (err)

		goto err_hcd;

	hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res_mem);

	if (IS_ERR(hcd->regs)) {

		err = PTR_ERR(hcd->regs);

		goto err_clk;

	}

	hcd->rsrc_start = res_mem->start;

	hcd->rsrc_len = resource_size(res_mem);

	err = usb_add_hcd(hcd, irq, IRQF_SHARED);

	if (err)

		goto err_clk;

	device_wakeup_enable(hcd->self.controller);

	device_enable_async_suspend(hcd->self.controller);

	return 0;

err_clk:

	clk_disable_unprepare(priv->clk);

err_hcd:

	usb_put_hcd(hcd);

	return err;

}

static int ehci_brcm_remove(struct platform_device *dev)

{

	struct usb_hcd *hcd = platform_get_drvdata(dev);

	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);

	usb_remove_hcd(hcd);

	clk_disable_unprepare(priv->clk);

	usb_put_hcd(hcd);

	return 0;

}

static int __maybe_unused ehci_brcm_suspend(struct device *dev)

{

	int ret;

	struct usb_hcd *hcd = dev_get_drvdata(dev);

	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);

	bool do_wakeup = device_may_wakeup(dev);

	ret = ehci_suspend(hcd, do_wakeup);

	if (ret)

		return ret;

	clk_disable_unprepare(priv->clk);

	return 0;

}

static int __maybe_unused ehci_brcm_resume(struct device *dev)

{

	struct usb_hcd *hcd = dev_get_drvdata(dev);

	struct ehci_hcd *ehci = hcd_to_ehci(hcd);

	struct brcm_priv *priv = hcd_to_ehci_priv(hcd);

	int err;

	err = clk_prepare_enable(priv->clk);

	if (err)

		return err;

	/*

	 * SWLINUX-1705: Avoid OUT packet underflows during high memory

	 *   bus usage

	 * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00

	 * @ 0x90

	 */

	ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]);

	ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]);

	ehci_resume(hcd, false);

	pm_runtime_disable(dev);

	pm_runtime_set_active(dev);

	pm_runtime_enable(dev);

	return 0;

}

static SIMPLE_DEV_PM_OPS(ehci_brcm_pm_ops, ehci_brcm_suspend,

		ehci_brcm_resume);

static const struct of_device_id brcm_ehci_of_match[] = {

	{ .compatible = "brcm,ehci-brcm-v2", },

	{ .compatible = "brcm,bcm7445-ehci", },

	{}

};

static struct platform_driver ehci_brcm_driver = {

	.probe		= ehci_brcm_probe,

	.remove		= ehci_brcm_remove,

	.shutdown	= usb_hcd_platform_shutdown,

	.driver		= {

		.name	= "ehci-brcm",

		.pm	= &ehci_brcm_pm_ops,

		.of_match_table = brcm_ehci_of_match,

	}

};

static int __init ehci_brcm_init(void)

{

	if (usb_disabled())

		return -ENODEV;

	ehci_init_driver(&ehci_brcm_hc_driver, &brcm_overrides);

	return platform_driver_register(&ehci_brcm_driver);

}

module_init(ehci_brcm_init);

static void __exit ehci_brcm_exit(void)

{

	platform_driver_unregister(&ehci_brcm_driver);

}

module_exit(ehci_brcm_exit);

MODULE_ALIAS("platform:ehci-brcm");

MODULE_DESCRIPTION("EHCI Broadcom STB driver");

MODULE_AUTHOR("Al Cooper");

MODULE_LICENSE("GPL");