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android_kernel_motorola_sm6225/drivers/usb/host/ohci-exynos.c
Vincent Palatin 57465109ce USB: ohci-exynos: initialize registers pointer earlier 
In the former code, we have a race condition between the first interrupt
and the regs field initilization in the usb_hcd structure.
If the OHCI irq fires before hcd->regs is set, we are getting a null
pointer dereference in ohci_irq.

When calling usb_add_hcd(), it first executes the reset() callback,
then enables the ohci interrupt, and finally executes the start()
callback. So moving the ohci_init() call which actually initializes the
reg field from start() to reset() should remove the race.

Tested by enabling the external HSIC hub in the bootloader on an exynos5
machine and booting. With the former code, this triggers an early interrupt
about 50% of the boots and a subsequent kernel panic in ohci_irq when trying
to access the registers.

Cc: Olof Johansson <olofj@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Arjun.K.V <arjun.kv@samsung.com>
Cc: Vikas Sajjan <vikas.sajjan@samsung.com>
Cc: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-02 09:25:20 -07:00

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6.8 KiB
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/*
* SAMSUNG EXYNOS USB HOST OHCI Controller
*
* Copyright (C) 2011 Samsung Electronics Co.Ltd
* Author: Jingoo Han <jg1.han@samsung.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; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/platform_data/usb-exynos.h>
#include <plat/usb-phy.h>
struct exynos_ohci_hcd {
struct device *dev;
struct usb_hcd *hcd;
struct clk *clk;
};
static int ohci_exynos_reset(struct usb_hcd *hcd)
{
return ohci_init(hcd_to_ohci(hcd));
}
static int ohci_exynos_start(struct usb_hcd *hcd)
{
struct ohci_hcd *ohci = hcd_to_ohci(hcd);
int ret;
ohci_dbg(ohci, "ohci_exynos_start, ohci:%p", ohci);
ret = ohci_run(ohci);
if (ret < 0) {
dev_err(hcd->self.controller, "can't start %s\n",
hcd->self.bus_name);
ohci_stop(hcd);
return ret;
}
return 0;
}
static const struct hc_driver exynos_ohci_hc_driver = {
.description = hcd_name,
.product_desc = "EXYNOS OHCI Host Controller",
.hcd_priv_size = sizeof(struct ohci_hcd),
.irq = ohci_irq,
.flags = HCD_MEMORY|HCD_USB11,
.reset = ohci_exynos_reset,
.start = ohci_exynos_start,
.stop = ohci_stop,
.shutdown = ohci_shutdown,
.get_frame_number = ohci_get_frame,
.urb_enqueue = ohci_urb_enqueue,
.urb_dequeue = ohci_urb_dequeue,
.endpoint_disable = ohci_endpoint_disable,
.hub_status_data = ohci_hub_status_data,
.hub_control = ohci_hub_control,
#ifdef CONFIG_PM
.bus_suspend = ohci_bus_suspend,
.bus_resume = ohci_bus_resume,
#endif
.start_port_reset = ohci_start_port_reset,
};
static u64 ohci_exynos_dma_mask = DMA_BIT_MASK(32);
static int __devinit exynos_ohci_probe(struct platform_device *pdev)
{
struct exynos4_ohci_platdata *pdata;
struct exynos_ohci_hcd *exynos_ohci;
struct usb_hcd *hcd;
struct ohci_hcd *ohci;
struct resource *res;
int irq;
int err;
pdata = pdev->dev.platform_data;
if (!pdata) {
dev_err(&pdev->dev, "No platform data defined\n");
return -EINVAL;
}
/*
* Right now device-tree probed devices don't get dma_mask set.
* Since shared usb code relies on it, set it here for now.
* Once we move to full device tree support this will vanish off.
*/
if (!pdev->dev.dma_mask)
pdev->dev.dma_mask = &ohci_exynos_dma_mask;
if (!pdev->dev.coherent_dma_mask)
pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
exynos_ohci = devm_kzalloc(&pdev->dev, sizeof(struct exynos_ohci_hcd),
GFP_KERNEL);
if (!exynos_ohci)
return -ENOMEM;
exynos_ohci->dev = &pdev->dev;
hcd = usb_create_hcd(&exynos_ohci_hc_driver, &pdev->dev,
dev_name(&pdev->dev));
if (!hcd) {
dev_err(&pdev->dev, "Unable to create HCD\n");
return -ENOMEM;
}
exynos_ohci->hcd = hcd;
exynos_ohci->clk = devm_clk_get(&pdev->dev, "usbhost");
if (IS_ERR(exynos_ohci->clk)) {
dev_err(&pdev->dev, "Failed to get usbhost clock\n");
err = PTR_ERR(exynos_ohci->clk);
goto fail_clk;
}
err = clk_prepare_enable(exynos_ohci->clk);
if (err)
goto fail_clk;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "Failed to get I/O memory\n");
err = -ENXIO;
goto fail_io;
}
hcd->rsrc_start = res->start;
hcd->rsrc_len = resource_size(res);
hcd->regs = devm_ioremap(&pdev->dev, res->start, hcd->rsrc_len);
if (!hcd->regs) {
dev_err(&pdev->dev, "Failed to remap I/O memory\n");
err = -ENOMEM;
goto fail_io;
}
irq = platform_get_irq(pdev, 0);
if (!irq) {
dev_err(&pdev->dev, "Failed to get IRQ\n");
err = -ENODEV;
goto fail_io;
}
if (pdata->phy_init)
pdata->phy_init(pdev, S5P_USB_PHY_HOST);
ohci = hcd_to_ohci(hcd);
ohci_hcd_init(ohci);
err = usb_add_hcd(hcd, irq, IRQF_SHARED);
if (err) {
dev_err(&pdev->dev, "Failed to add USB HCD\n");
goto fail_io;
}
platform_set_drvdata(pdev, exynos_ohci);
return 0;
fail_io:
clk_disable_unprepare(exynos_ohci->clk);
fail_clk:
usb_put_hcd(hcd);
return err;
}
static int __devexit exynos_ohci_remove(struct platform_device *pdev)
{
struct exynos4_ohci_platdata *pdata = pdev->dev.platform_data;
struct exynos_ohci_hcd *exynos_ohci = platform_get_drvdata(pdev);
struct usb_hcd *hcd = exynos_ohci->hcd;
usb_remove_hcd(hcd);
if (pdata && pdata->phy_exit)
pdata->phy_exit(pdev, S5P_USB_PHY_HOST);
clk_disable_unprepare(exynos_ohci->clk);
usb_put_hcd(hcd);
return 0;
}
static void exynos_ohci_shutdown(struct platform_device *pdev)
{
struct exynos_ohci_hcd *exynos_ohci = platform_get_drvdata(pdev);
struct usb_hcd *hcd = exynos_ohci->hcd;
if (hcd->driver->shutdown)
hcd->driver->shutdown(hcd);
}
#ifdef CONFIG_PM
static int exynos_ohci_suspend(struct device *dev)
{
struct exynos_ohci_hcd *exynos_ohci = dev_get_drvdata(dev);
struct usb_hcd *hcd = exynos_ohci->hcd;
struct ohci_hcd *ohci = hcd_to_ohci(hcd);
struct platform_device *pdev = to_platform_device(dev);
struct exynos4_ohci_platdata *pdata = pdev->dev.platform_data;
unsigned long flags;
int rc = 0;
/*
* Root hub was already suspended. Disable irq emission and
* mark HW unaccessible, bail out if RH has been resumed. Use
* the spinlock to properly synchronize with possible pending
* RH suspend or resume activity.
*/
spin_lock_irqsave(&ohci->lock, flags);
if (ohci->rh_state != OHCI_RH_SUSPENDED &&
ohci->rh_state != OHCI_RH_HALTED) {
rc = -EINVAL;
goto fail;
}
clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
if (pdata && pdata->phy_exit)
pdata->phy_exit(pdev, S5P_USB_PHY_HOST);
clk_disable_unprepare(exynos_ohci->clk);
fail:
spin_unlock_irqrestore(&ohci->lock, flags);
return rc;
}
static int exynos_ohci_resume(struct device *dev)
{
struct exynos_ohci_hcd *exynos_ohci = dev_get_drvdata(dev);
struct usb_hcd *hcd = exynos_ohci->hcd;
struct platform_device *pdev = to_platform_device(dev);
struct exynos4_ohci_platdata *pdata = pdev->dev.platform_data;
clk_prepare_enable(exynos_ohci->clk);
if (pdata && pdata->phy_init)
pdata->phy_init(pdev, S5P_USB_PHY_HOST);
ohci_resume(hcd, false);
return 0;
}
#else
#define exynos_ohci_suspend NULL
#define exynos_ohci_resume NULL
#endif
static const struct dev_pm_ops exynos_ohci_pm_ops = {
.suspend = exynos_ohci_suspend,
.resume = exynos_ohci_resume,
};
#ifdef CONFIG_OF
static const struct of_device_id exynos_ohci_match[] = {
{ .compatible = "samsung,exynos-ohci" },
{},
};
MODULE_DEVICE_TABLE(of, exynos_ohci_match);
#endif
static struct platform_driver exynos_ohci_driver = {
.probe = exynos_ohci_probe,
.remove = __devexit_p(exynos_ohci_remove),
.shutdown = exynos_ohci_shutdown,
.driver = {
.name = "exynos-ohci",
.owner = THIS_MODULE,
.pm = &exynos_ohci_pm_ops,
.of_match_table = of_match_ptr(exynos_ohci_match),
}
};
MODULE_ALIAS("platform:exynos-ohci");
MODULE_AUTHOR("Jingoo Han <jg1.han@samsung.com>");
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