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path: root/drivers/usb/host/ehci-w90x900.c
blob: 63b9d0c67963094f15ba9950c9f85c1126f3a0db (plain)
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/*
 * linux/driver/usb/host/ehci-w90x900.c
 *
 * Copyright (c) 2008 Nuvoton technology corporation.
 *
 * Wan ZongShun <mcuos.com@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation;version 2 of the License.
 *
 */

#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>

#include "ehci.h"

/* enable phy0 and phy1 for w90p910 */
#define	ENPHY		(0x01<<8)
#define PHY0_CTR	(0xA4)
#define PHY1_CTR	(0xA8)

#define DRIVER_DESC "EHCI w90x900 driver"

static const char hcd_name[] = "ehci-w90x900 ";

static struct hc_driver __read_mostly ehci_w90x900_hc_driver;

static int ehci_w90x900_probe(struct platform_device *pdev)
{
	struct usb_hcd *hcd;
	struct ehci_hcd *ehci;
	struct resource *res;
	int retval = 0, irq;
	unsigned long val;

	hcd = usb_create_hcd(&ehci_w90x900_hc_driver,
			&pdev->dev, "w90x900 EHCI");
	if (!hcd) {
		retval = -ENOMEM;
		goto err1;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	hcd->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(hcd->regs)) {
		retval = PTR_ERR(hcd->regs);
		goto err2;
	}
	hcd->rsrc_start = res->start;
	hcd->rsrc_len = resource_size(res);

	ehci = hcd_to_ehci(hcd);
	ehci->caps = hcd->regs;
	ehci->regs = hcd->regs +
		HC_LENGTH(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));

	/* enable PHY 0,1,the regs only apply to w90p910
	 *  0xA4,0xA8 were offsets of PHY0 and PHY1 controller of
	 *  w90p910 IC relative to ehci->regs.
	 */
	val = __raw_readl(ehci->regs+PHY0_CTR);
	val |= ENPHY;
	__raw_writel(val, ehci->regs+PHY0_CTR);

	val = __raw_readl(ehci->regs+PHY1_CTR);
	val |= ENPHY;
	__raw_writel(val, ehci->regs+PHY1_CTR);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		retval = irq;
		goto err2;
	}

	retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
	if (retval != 0)
		goto err2;

	device_wakeup_enable(hcd->self.controller);
	return retval;
err2:
	usb_put_hcd(hcd);
err1:
	return retval;
}

static int ehci_w90x900_remove(struct platform_device *pdev)
{
	struct usb_hcd *hcd = platform_get_drvdata(pdev);

	usb_remove_hcd(hcd);
	usb_put_hcd(hcd);

	return 0;
}

static struct platform_driver ehci_hcd_w90x900_driver = {
	.probe  = ehci_w90x900_probe,
	.remove = ehci_w90x900_remove,
	.driver = {
		.name = "w90x900-ehci",
	},
};

static int __init ehci_w90X900_init(void)
{
	if (usb_disabled())
		return -ENODEV;

	pr_info("%s: " DRIVER_DESC "\n", hcd_name);

	ehci_init_driver(&ehci_w90x900_hc_driver, NULL);
	return platform_driver_register(&ehci_hcd_w90x900_driver);
}
module_init(ehci_w90X900_init);

static void __exit ehci_w90X900_cleanup(void)
{
	platform_driver_unregister(&ehci_hcd_w90x900_driver);
}
module_exit(ehci_w90X900_cleanup);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
MODULE_ALIAS("platform:w90p910-ehci");
MODULE_LICENSE("GPL v2");
end interrupt event. Now, consider that busy end completion is raised IN BETWEEN steps 3.a) and 3.c). In such a case, we may mistakenly clear busy end interrupt at step 3.c) while it has not yet been processed. This will result in mmc command to wait forever for a busy end completion that will never happen. To fix the problem, this patch implements the following changes: Considering that the mmci seems to be triggering the IRQ on both edges while monitoring DAT0 for busy completion and that same status bit is used to monitor start and end of busy detection, special care must be taken to make sure that both start and end interrupts are always cleared one after the other. 1) Clearing of card busy bit is moved in mmc_cmd_irq() function where unmasking of busy end bit is effectively handled. 2) Just before unmasking busy end event, busy start event is cleared by writing card busy bit in MMCICLEAR register. 3) Finally, once we are no more busy with a command, busy end event is cleared writing again card busy bit in MMCICLEAR register. This patch has been tested with the ST Accordo5 machine, not yet supported upstream but relies on the mmci driver. Signed-off-by: Sarang Mairal <sarang.mairal@garmin.com> Signed-off-by: Jean-Nicolas Graux <jean-nicolas.graux@st.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers')