linux/drivers/usb/host/ehci-brcm.c

// 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
	 */
	ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);
	ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);

	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
	 */
	ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[1]);
	ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[3]);

	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");