[PATCH] usb: fix unaligned access

Fabian van der Werf fvanderwerf at gmail.com
Sun Oct 23 05:29:58 EDT 2011


>
> Looks like a valid patch, I wonder that this never was a problem before.
> ARM should break here aswell I think. What architecture are you using?
>

I am working with a pandaboard (arm cortex a9). The pandaboard has a
usb ethernet controller, so I need usb to boot over tftp. I guess that
most arm configurations don't need usb for booting, and in that case
you won't run into this problem.

Regards,
Fabian

> Sascha
>
>>
>> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
>> index 7039a2c..369a393 100644
>> --- a/drivers/usb/core/usb.c
>> +++ b/drivers/usb/core/usb.c
>> @@ -50,6 +50,7 @@
>>  #include <driver.h>
>>  #include <linux/ctype.h>
>>  #include <asm/byteorder.h>
>> +#include <asm/unaligned.h>
>>  #include <xfuncs.h>
>>  #include <init.h>
>>
>> @@ -1071,6 +1072,7 @@ static int usb_hub_configure(struct usb_device *dev)
>>       struct usb_hub_status *hubsts;
>>       int i;
>>       struct usb_hub_device *hub;
>> +     unsigned short hub_chars;
>>
>>       hub = xzalloc(sizeof (*hub));
>>       dev->hub = hub;
>> @@ -1100,8 +1102,8 @@ static int usb_hub_configure(struct usb_device *dev)
>>       }
>>       memcpy((unsigned char *)&hub->desc, buffer, descriptor->bLength);
>>       /* adjust 16bit values */
>> -     hub->desc.wHubCharacteristics =
>> -                             le16_to_cpu(descriptor->wHubCharacteristics);
>> +     hub_chars = le16_to_cpu(get_unaligned(&descriptor->wHubCharacteristics));
>> +     put_unaligned(hub_chars, &hub->desc.wHubCharacteristics);
>>       /* set the bitmap */
>>       bitmap = (unsigned char *)&hub->desc.DeviceRemovable[0];
>>       /* devices not removable by default */
>> @@ -1118,7 +1120,7 @@ static int usb_hub_configure(struct usb_device *dev)
>>       dev->maxchild = descriptor->bNbrPorts;
>>       USB_HUB_PRINTF("%d ports detected\n", dev->maxchild);
>>
>> -     switch (hub->desc.wHubCharacteristics & HUB_CHAR_LPSM) {
>> +     switch (hub_chars & HUB_CHAR_LPSM) {
>>       case 0x00:
>>               USB_HUB_PRINTF("ganged power switching\n");
>>               break;
>> @@ -1131,12 +1133,12 @@ static int usb_hub_configure(struct usb_device *dev)
>>               break;
>>       }
>>
>> -     if (hub->desc.wHubCharacteristics & HUB_CHAR_COMPOUND)
>> +     if (hub_chars & HUB_CHAR_COMPOUND)
>>               USB_HUB_PRINTF("part of a compound device\n");
>>       else
>>               USB_HUB_PRINTF("standalone hub\n");
>>
>> -     switch (hub->desc.wHubCharacteristics & HUB_CHAR_OCPM) {
>> +     switch (hub_chars & HUB_CHAR_OCPM) {
>>       case 0x00:
>>               USB_HUB_PRINTF("global over-current protection\n");
>>               break;
>> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
>> index 72f1c14..20c518a 100644
>> --- a/drivers/usb/host/ehci-hcd.c
>> +++ b/drivers/usb/host/ehci-hcd.c
>> @@ -33,6 +33,7 @@
>>  #include <errno.h>
>>  #include <usb/ehci.h>
>>  #include <asm/mmu.h>
>> +#include <asm/unaligned.h>
>>
>>  #include "ehci.h"
>>
>> @@ -795,6 +796,7 @@ static int ehci_init(struct usb_host *host)
>>       struct ehci_priv *ehci = to_ehci(host);
>>       uint32_t reg;
>>       uint32_t cmd;
>> +     unsigned short hub_chars;
>>
>>       ehci_halt(ehci);
>>
>> @@ -819,12 +821,15 @@ static int ehci_init(struct usb_host *host)
>>       reg = ehci_readl(&ehci->hccr->cr_hcsparams);
>>       descriptor.hub.bNbrPorts = HCS_N_PORTS(reg);
>>
>> +     hub_chars = get_unaligned(&descriptor.hub.wHubCharacteristics);
>>       /* Port Indicators */
>>       if (HCS_INDICATOR(reg))
>> -             descriptor.hub.wHubCharacteristics |= 0x80;
>> +             hub_chars |= 0x80;
>>       /* Port Power Control */
>>       if (HCS_PPC(reg))
>> -             descriptor.hub.wHubCharacteristics |= 0x01;
>> +             hub_chars |= 0x01;
>> +
>> +     put_unaligned(hub_chars, &descriptor.hub.wHubCharacteristics);
>>
>>       /* Start the host controller. */
>>       cmd = ehci_readl(&ehci->hcor->or_usbcmd);
>> --
>> 1.7.0.4
>>
>>
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>
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