linux/drivers/usb/dwc3/dwc3-exynos.c
Stephen Warren 3b9561e9d9 USB: set device dma_mask without reference to global data
Many USB host drivers contain code such as:

if (!pdev->dev.dma_mask)
        pdev->dev.dma_mask = &tegra_ehci_dma_mask;

... where tegra_ehci_dma_mask is a global. I suspect this code originated
in commit 4a53f4e "USB: ehci-tegra: add probing through device tree" and
was simply copied everywhere else.

This works fine when the code is built-in, but can cause a crash when the
code is in a module. The first module load sets up the dma_mask pointer,
but if the module is removed and re-inserted, the value is now non-NULL,
and hence is not updated to point at the new location, and hence points
at a stale location within the previous module load address, which in
turn causes a crash if the pointer is de-referenced.

The simplest way of solving this seems to be to copy the code from
ehci-platform.c, which uses the coherent_dma_mask as the target for the
dma_mask pointer.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-16 17:30:52 -07:00

233 lines
5.0 KiB
C

/**
* dwc3-exynos.c - Samsung EXYNOS DWC3 Specific Glue layer
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com
*
* Author: Anton Tikhomirov <av.tikhomirov@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/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/platform_data/dwc3-exynos.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>
#include <linux/usb/otg.h>
#include <linux/usb/nop-usb-xceiv.h>
#include <linux/of.h>
#include <linux/of_platform.h>
struct dwc3_exynos {
struct platform_device *usb2_phy;
struct platform_device *usb3_phy;
struct device *dev;
struct clk *clk;
};
static int dwc3_exynos_register_phys(struct dwc3_exynos *exynos)
{
struct nop_usb_xceiv_platform_data pdata;
struct platform_device *pdev;
int ret;
memset(&pdata, 0x00, sizeof(pdata));
pdev = platform_device_alloc("nop_usb_xceiv", PLATFORM_DEVID_AUTO);
if (!pdev)
return -ENOMEM;
exynos->usb2_phy = pdev;
pdata.type = USB_PHY_TYPE_USB2;
ret = platform_device_add_data(exynos->usb2_phy, &pdata, sizeof(pdata));
if (ret)
goto err1;
pdev = platform_device_alloc("nop_usb_xceiv", PLATFORM_DEVID_AUTO);
if (!pdev) {
ret = -ENOMEM;
goto err1;
}
exynos->usb3_phy = pdev;
pdata.type = USB_PHY_TYPE_USB3;
ret = platform_device_add_data(exynos->usb3_phy, &pdata, sizeof(pdata));
if (ret)
goto err2;
ret = platform_device_add(exynos->usb2_phy);
if (ret)
goto err2;
ret = platform_device_add(exynos->usb3_phy);
if (ret)
goto err3;
return 0;
err3:
platform_device_del(exynos->usb2_phy);
err2:
platform_device_put(exynos->usb3_phy);
err1:
platform_device_put(exynos->usb2_phy);
return ret;
}
static int dwc3_exynos_remove_child(struct device *dev, void *unused)
{
struct platform_device *pdev = to_platform_device(dev);
platform_device_unregister(pdev);
return 0;
}
static int dwc3_exynos_probe(struct platform_device *pdev)
{
struct dwc3_exynos *exynos;
struct clk *clk;
struct device *dev = &pdev->dev;
struct device_node *node = dev->of_node;
int ret = -ENOMEM;
exynos = devm_kzalloc(dev, sizeof(*exynos), GFP_KERNEL);
if (!exynos) {
dev_err(dev, "not enough memory\n");
goto err1;
}
/*
* 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 (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
if (!dev->coherent_dma_mask)
dev->coherent_dma_mask = DMA_BIT_MASK(32);
platform_set_drvdata(pdev, exynos);
ret = dwc3_exynos_register_phys(exynos);
if (ret) {
dev_err(dev, "couldn't register PHYs\n");
goto err1;
}
clk = devm_clk_get(dev, "usbdrd30");
if (IS_ERR(clk)) {
dev_err(dev, "couldn't get clock\n");
ret = -EINVAL;
goto err1;
}
exynos->dev = dev;
exynos->clk = clk;
clk_prepare_enable(exynos->clk);
if (node) {
ret = of_platform_populate(node, NULL, NULL, dev);
if (ret) {
dev_err(dev, "failed to add dwc3 core\n");
goto err2;
}
} else {
dev_err(dev, "no device node, failed to add dwc3 core\n");
ret = -ENODEV;
goto err2;
}
return 0;
err2:
clk_disable_unprepare(clk);
err1:
return ret;
}
static int dwc3_exynos_remove(struct platform_device *pdev)
{
struct dwc3_exynos *exynos = platform_get_drvdata(pdev);
platform_device_unregister(exynos->usb2_phy);
platform_device_unregister(exynos->usb3_phy);
device_for_each_child(&pdev->dev, NULL, dwc3_exynos_remove_child);
clk_disable_unprepare(exynos->clk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id exynos_dwc3_match[] = {
{ .compatible = "samsung,exynos5250-dwusb3" },
{},
};
MODULE_DEVICE_TABLE(of, exynos_dwc3_match);
#endif
#ifdef CONFIG_PM_SLEEP
static int dwc3_exynos_suspend(struct device *dev)
{
struct dwc3_exynos *exynos = dev_get_drvdata(dev);
clk_disable(exynos->clk);
return 0;
}
static int dwc3_exynos_resume(struct device *dev)
{
struct dwc3_exynos *exynos = dev_get_drvdata(dev);
clk_enable(exynos->clk);
/* runtime set active to reflect active state. */
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
return 0;
}
static const struct dev_pm_ops dwc3_exynos_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(dwc3_exynos_suspend, dwc3_exynos_resume)
};
#define DEV_PM_OPS (&dwc3_exynos_dev_pm_ops)
#else
#define DEV_PM_OPS NULL
#endif /* CONFIG_PM_SLEEP */
static struct platform_driver dwc3_exynos_driver = {
.probe = dwc3_exynos_probe,
.remove = dwc3_exynos_remove,
.driver = {
.name = "exynos-dwc3",
.of_match_table = of_match_ptr(exynos_dwc3_match),
.pm = DEV_PM_OPS,
},
};
module_platform_driver(dwc3_exynos_driver);
MODULE_ALIAS("platform:exynos-dwc3");
MODULE_AUTHOR("Anton Tikhomirov <av.tikhomirov@samsung.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("DesignWare USB3 EXYNOS Glue Layer");