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a9c174302b
The udc uses an shared dma memory space between hard and software. This memory layout is described in ci13xxx_qh and ci13xxx_td which are marked with the attribute ((packed)). The compiler currently does not know about the alignment of the memory layout, and will create strb and ldrb operations. The Datasheet of the synopsys core describes, that some operations on the mapped memory need to be atomic double word operations. I.e. the next pointer addressing in the qhead, as otherwise the hardware will read wrong data and totally stuck. This is also possible while working with the current active td queue, and preparing the td->ptr.next in software while the hardware is still working with the current active td which is supposed to be changed: writeb(0xde, &td->ptr.next + 0x0); /* strb */ writeb(0xad, &td->ptr.next + 0x1); /* strb */ <----- hardware reads value of td->ptr.next and get stuck! writeb(0xbe, &td->ptr.next + 0x2); /* strb */ writeb(0xef, &td->ptr.next + 0x3); /* strb */ This appeares on armv5 machines where the hardware does not support unaligned 32bit operations. This patch adds the attribute ((aligned(4))) to the structures to tell the compiler to use 32bit operations. It also adds an wmb() for the prepared TD data before it gets enqueued into the qhead. Cc: stable <stable@vger.kernel.org> # v3.5 Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> Reviewed-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
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| phy | ||
| renesas_usbhs | ||
| serial | ||
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| Makefile | ||
| README | ||
| usb-common.c | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.