[U-Boot] [PATCH v4] usb: align buffers at cacheline

[Marek Vasut <marex@denx.de>]

> On Friday 02 March 2012 08:11 PM, Marek Vasut wrote:
> >> On Friday 02 March 2012 07:16 PM, 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 V3:
> >>>>       - Removed local descriptor elements copy to global descriptor
> >>>>       elements - Removed "Signed-off-by: Jim Lin<jilin@nvidia.com>"
> >>>>       from commit
> >>>> 
> >>>> message
> >>>> 
> >>>> Changes for V4:
> >>>>       - Added memcpy to copy local descriptor to global descriptor.
> >>>>       
> >>>>         Without that, USB version, class, vendor, product Id...etc is
> >>>>         not
> >>>> 
> >>>> configured. This information is useful for loading correct device
> >>>> driver and possible configuration.
> >>>> 
> >>>>    common/cmd_usb.c            |    3 +-
> >>>>    common/usb.c                |   56
> >>>> 
> >>>> ++++++++++++++++++++++------------------ 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(+), 59 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 6e21ae2..42a44e2 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;
> >>>> 
> >>>> @@ -698,7 +699,7 @@ 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;
> >>>> 
> >>>> @@ -798,7 +799,7 @@ 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;
> >>>> 
> >>>> @@ -909,7 +910,7 @@ 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));
> >>>> 
> >>>>    	if (err<   tmp) {
> >>>>    	
> >>>>    		if (err<   0)
> >>>>    		
> >>>>    			printf("unable to get device descriptor 
(error=%d)\n",
> >>>> 
> >>>> @@ -919,14 +920,18 @@ int usb_new_device(struct usb_device *dev)
> >>>> 
> >>>>    				"(expected %i, got %i)\n", tmp, err);
> >>>>    		
> >>>>    		return 1;
> >>>>    	
> >>>>    	}
> >>>> 
> >>>> +
> >>>> +	/* Now copy the local device descriptor to global device
> >>>> descriptor*/ +	memcpy(&dev->descriptor, desc,
> >>>> sizeof(dev->descriptor));
> >>> 
> >>> Hey, it's almost perfect!
> >>> 
> >>> Just one last question -- why do you need to copy this stuff?
> >> 
> >> We need to copy this stuff as I spoke in previous reply  -
> >> "memcpy" is needed to configure Usb version, vendor id, prod Id ..etc
> >> 
> >>>   of the device. Its also useful to hook actual device driver and
> >>>   detect no. of configuration supported. The effect can be verified
> >> 
> >> with/without using memcpy
> >> in "usb tree" and "usb info" commands.
> >> 
> >>> It's because dev-
> >>> 
> >>>> descriptor is unaligned?
> >> 
> >> No, As global dev - descriptor is unaligned we are passing aligned local
> >> dev-desc and memcpy in global.
> > 
> > Can't we just align the global one?
> 
> That's what I did in original patch where I am aligning it by adding the
> line
> 
> +        /* Device Descriptor */
> +#ifdef ARCH_DMA_MINALIGN
> +       struct usb_device_descriptor descriptor
> +               __attribute__((aligned(ARCH_DMA_MINALIGN)));
> +#else
> +       struct usb_device_descriptor descriptor;
> +#endif
> 
> in usb.h Line:112
> 
> > M
> 
I see ...and I told you it's wrong? I must have misunderstood, I'm sorry about 
that. But if you actually do this, you can avoid memcpy, right?

M