[U-Boot] [PATCH v3 1/2] usb: align buffers at cacheline

Marek Vasut
2012-03-02T10:43:31Z

> Hi,
>
> On Friday 02 March 2012 12:08 AM, Marek Vasut wrote:
> >> On Thursday 01 March 2012 03:05 AM, Marek Vasut wrote:
> >>>> As DMA expects the buffers to be equal and larger then
> >>>> cache lines, This aligns buffers at cacheline.
> >>>>
> >>>> Signed-off-by: Puneet Saxena<puneets@nvidia.com>
> >>>> ---
> >>>>
> >>>> Changes for V2:
> >>>> - Use "ARCH_DMA_MINALIGN" directly
> >>>> - Use "ALIGN" to align size as cacheline
> >>>> - Removed headers from usb.h
> >>>> - Send 8 bytes of device descriptor size to read
> >>>>
> >>>> Max packet size
> >>>>
> >>>> scsi.h header is needed to avoid extra memcpy from local buffer
> >>>> to global buffer.
> >>>>
> >>>> Changes for V3:
> >>>> - Removed local descriptor elements copy to global descriptor
> >>>> elements - Removed "Signed-off-by: Jim Lin<jilin@nvidia.com>"
> >>>> from commit
> >>>>
> >>>> message
> >>>>
> >>>> common/cmd_usb.c | 3 +-
> >>>> common/usb.c | 57
> >>>>
> >>>> ++++++++++++++++++++++------------------- common/usb_storage.c
> >>>> | 59 ++++++++++++++++++++---------------------- disk/part_dos.c
> >>>>
> >>>> | 2 +-
> >>>>
> >>>> drivers/usb/host/ehci-hcd.c | 8 ++++++
> >>>> include/scsi.h | 4 ++-
> >>>> 6 files changed, 73 insertions(+), 60 deletions(-)
> >>>>
> >>>> diff --git a/common/cmd_usb.c b/common/cmd_usb.c
> >>>> index 320667f..bca9d94 100644
> >>>> --- a/common/cmd_usb.c
> >>>> +++ b/common/cmd_usb.c
> >>>> @@ -150,7 +150,8 @@ void usb_display_class_sub(unsigned char dclass,
> >>>> unsigned char subclass,
> >>>>
> >>>> void usb_display_string(struct usb_device *dev, int index)
> >>>> {
> >>>>
> >>>> - char buffer[256];
> >>>> + ALLOC_CACHE_ALIGN_BUFFER(char, buffer, 256);
> >>>> +
> >>>>
> >>>> if (index != 0) {
> >>>>
> >>>> if (usb_string(dev, index,&buffer[0], 256)> 0)
> >>>>
> >>>> printf("String: \"%s\"", buffer);
> >>>>
> >>>> diff --git a/common/usb.c b/common/usb.c
> >>>> index 63a11c8..191bc5b 100644
> >>>> --- a/common/usb.c
> >>>> +++ b/common/usb.c
> >>>> @@ -73,7 +73,6 @@ static struct usb_device usb_dev[USB_MAX_DEVICE];
> >>>>
> >>>> static int dev_index;
> >>>> static int running;
> >>>> static int asynch_allowed;
> >>>>
> >>>> -static struct devrequest setup_packet;
> >>>>
> >>>> char usb_started; /* flag for the started/stopped USB status */
> >>>>
> >>>> @@ -185,23 +184,25 @@ int usb_control_msg(struct usb_device *dev,
> >>>> unsigned int pipe, unsigned short value, unsigned short index,
> >>>>
> >>>> void *data, unsigned short size, int timeout)
> >>>>
> >>>> {
> >>>>
> >>>> + ALLOC_CACHE_ALIGN_BUFFER(struct devrequest, setup_packet,
> >>>> + sizeof(struct devrequest));
> >>>>
> >>>> if ((timeout == 0)&& (!asynch_allowed)) {
> >>>>
> >>>> /* request for a asynch control pipe is not allowed */
> >>>> return -1;
> >>>>
> >>>> }
> >>>>
> >>>> /* set setup command */
> >>>>
> >>>> - setup_packet.requesttype = requesttype;
> >>>> - setup_packet.request = request;
> >>>> - setup_packet.value = cpu_to_le16(value);
> >>>> - setup_packet.index = cpu_to_le16(index);
> >>>> - setup_packet.length = cpu_to_le16(size);
> >>>> + setup_packet->requesttype = requesttype;
> >>>> + setup_packet->request = request;
> >>>> + setup_packet->value = cpu_to_le16(value);
> >>>> + setup_packet->index = cpu_to_le16(index);
> >>>> + setup_packet->length = cpu_to_le16(size);
> >>>>
> >>>> USB_PRINTF("usb_control_msg: request: 0x%X, requesttype: 0x%X, "
\
> >>>>
> >>>> "value 0x%X index 0x%X length 0x%X\n",
> >>>> request, requesttype, value, index, size);
> >>>>
> >>>> dev->status = USB_ST_NOT_PROC; /*not yet processed */
> >>>>
> >>>> - submit_control_msg(dev, pipe, data, size,&setup_packet);
> >>>> + submit_control_msg(dev, pipe, data, size, setup_packet);
> >>>>
> >>>> if (timeout == 0)
> >>>>
> >>>> return (int)size;
> >>>>
> >>>> @@ -694,7 +695,7 @@ static int usb_string_sub(struct usb_device *dev,
> >>>> unsigned int langid, */
> >>>>
> >>>> int usb_string(struct usb_device *dev, int index, char *buf, size_t
> >>>> size) {
> >>>>
> >>>> - unsigned char mybuf[USB_BUFSIZ];
> >>>> + ALLOC_CACHE_ALIGN_BUFFER(unsigned char, mybuf, USB_BUFSIZ);
> >>>>
> >>>> unsigned char *tbuf;
> >>>> int err;
> >>>> unsigned int u, idx;
> >>>>
> >>>> @@ -794,7 +795,7 @@ int usb_new_device(struct usb_device *dev)
> >>>>
> >>>> {
> >>>>
> >>>> int addr, err;
> >>>> int tmp;
> >>>>
> >>>> - unsigned char tmpbuf[USB_BUFSIZ];
> >>>> + ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, USB_BUFSIZ);
> >>>>
> >>>> /* We still haven't set the Address yet */
> >>>> addr = dev->devnum;
> >>>>
> >>>> @@ -842,7 +843,10 @@ int usb_new_device(struct usb_device *dev)
> >>>>
> >>>> dev->epmaxpacketin[0] = 64;
> >>>> dev->epmaxpacketout[0] = 64;
> >>>>
> >>>> - err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
> >>>> + desc->bMaxPacketSize0 = 0;
> >>>> + /*8 bytes of the descriptor to read Max packet size*/
> >>>> + err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc,
> >>>> + 8);
> >>>
> >>> Did some unrelated addition/change creep in here?
> >>
> >> No, This is the fix for the similar issue as is discussed for string
> >> fetch().
> >> When the device partially fills the passed buffer and we try to
> >> invalidate the partial buffer
> >> the cache alignment error crops up.
> >>
> >> The code in "ehci_submit_async() " invalidates *partially* the passed
> >> buffer though we pass aligned buffer after "STD_ASS"
> >> is received. Actually it should invalidate only the cached line which is
> >> equal(~32) to device desc length.
> >>
> >> If we pass actual device desc length the cache alignment error does not
> >> spew.
> >> Note that here we are aligning the buffer still the error comes.
> >
> > Then please send this fix as a separate patch. And I think ehci_hcd is
> > what should be fixed then as I said in the other email, or am I wrong?
>
> Yes, I will send this fix in separate patch. To address partial
> invalidate issue
> will send another patch in "ehci_hcd()".

Very good! I'm really glad we're working towards the proper solution, thanks for
all the effort you put into it!
>
> >>>> if (err< 0) {
> >>>>
> >>>> USB_PRINTF("usb_new_device: usb_get_descriptor()
failed\n");
> >>>> return 1;
> >>>>
> >>>> @@ -905,7 +909,7 @@ int usb_new_device(struct usb_device *dev)
> >>>>
> >>>> tmp = sizeof(dev->descriptor);
> >>>>
> >>>> err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
> >>>>
> >>>> - &dev->descriptor, sizeof(dev-
>descriptor));
> >>>> + desc, sizeof(dev->descriptor));
> >>>
> >>> Won't this change (desc) break anything?
> >>
> >> Its not breaking any thing. For safer side we could add memcpy to copy
> >> from local desc
> >> to global desc. What you say?
> >
> > What do you mean? So you changed the use from some global variable to
> > different (local) variable? This might break stuff I fear :-(
>
> Actually in previous comments it was said to not cache align "struct
> usb_device_descriptor descriptor; /* Device Descriptor */ Line:112
> usb.h, in header file. So another way is to define cache aligned local
> variable and pass it to "usb_get_descriptor". After returning from
> "usb_get_descriptor", memcpy this buffer to global variable
> "dev->descriptor".
> I verified the devices, usb mouse, mass-storage etc... that without this
> memcpy to global variable, its not breaking anything.
> That's why I avoided memcpy.

Oh ... maybe the global variable is unneeded at all and using the local only is
OK?

>
> >>>> if (err< tmp) {
> >>>>
> >>>> if (err< 0)
> >>>>
> >>>> printf("unable to get device descriptor
(error=%d)\n",
> >>>
> >>> The rest seems fine, from now on it seems to be only matter of trivial
> >>> fix. Thanks for your effort so far!
> >>>
> >>> M
> >>
> >> If rest of the code is fine in [Patch V3 1/2] except these two issue can
> >> it be acknowledged for up-streaming?
> >
> > Well, there are those two issues which I'd really prefer to be fixed
> > before accepting the code. I believe you can understand why.
> >
> > Thanks!
> >
> > M
>
> Thanx,
> Puneet

No, thank you !

M