[U-Boot] [PATCH v2] common: usb_storage : Implement logic to calculate optimal usb maximum trasfer blocks
Rajesh Bhagat
rajesh.bhagat at nxp.com
Mon Jun 6 06:19:11 CEST 2016
> -----Original Message-----
> From: Marek Vasut [mailto:marex at denx.de]
> Sent: Saturday, June 04, 2016 4:22 AM
> To: Rajesh Bhagat <rajesh.bhagat at nxp.com>; u-boot at lists.denx.de
> Cc: sjg at chromium.org; york sun <york.sun at nxp.com>; Sriram Dash
> <sriram.dash at nxp.com>
> Subject: Re: [PATCH v2] common: usb_storage : Implement logic to calculate optimal
> usb maximum trasfer blocks
>
> On 06/02/2016 06:56 AM, Rajesh Bhagat wrote:
> > Implements the logic to calculate the optimal usb maximum trasfer
> > blocks instead of sending USB_MAX_XFER_BLK blocks which is 65535 and
> > 20 in case of EHCI and other USB protocols respectively.
> >
> > It defines USB_MIN_XFER_BLK/USB_MAX_XFER_BLK trasfer blocks that
> > should be checked for success starting from minimum to maximum, and
> > rest of the read/write are performed with that optimal value. It tries
> > to increase/ decrease the blocks in follwing scenarios:
> >
> > 1.decrease blocks: when read/write for a particular number of blocks
> > fails.
> > 2. increase blocks: when read/write for a particular number of blocks
> > pass and amount left to trasfer is greater than current number of
> > blocks.
> >
> > Currently changes are done for EHCI where min = 4096 and max = 65535
> > is taken. And for other cases code is left unchanged by keeping min =
> > max = 20.
> >
> > Signed-off-by: Sriram Dash <sriram.dash at nxp.com>
> > Signed-off-by: Rajesh Bhagat <rajesh.bhagat at nxp.com>
> > ---
> > common/usb_storage.c | 71
> > +++++++++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 59 insertions(+), 12 deletions(-)
> >
> > diff --git a/common/usb_storage.c b/common/usb_storage.c index
> > 7e6e52d..eee8f4c 100644
> > --- a/common/usb_storage.c
> > +++ b/common/usb_storage.c
> > @@ -106,10 +106,13 @@ struct us_data {
> > * enough free heap space left, but the SCSI READ(10) and WRITE(10) commands
> are
> > * limited to 65535 blocks.
> > */
> > +#define USB_MIN_XFER_BLK 4095
> > #define USB_MAX_XFER_BLK 65535
> > #else
> > +#define USB_MIN_XFER_BLK 20
> > #define USB_MAX_XFER_BLK 20
> > #endif
> > +#define USB_CUR_XFER_BLK(n) (n >= 0 ? ((1 << (12 + (n))) - 1) : 0)
>
Hello Marek,
> Can this be ever called with n < 0 ? You should make this into a function to get
> typechecking on it too.
>
Yes. When transfer fails for the first time (pos - 1) is passed to this macro. Ok,
I will convert it to a function in v3.
> > #ifndef CONFIG_BLK
> > static struct us_data usb_stor[USB_MAX_STOR_DEV]; @@ -1117,11
> > +1120,13 @@ static unsigned long usb_stor_read(struct blk_desc *block_dev,
> lbaint_t blknr,
> > unsigned short smallblks;
> > struct usb_device *udev;
> > struct us_data *ss;
> > - int retry;
> > + int retry, pos = 0;
> > + bool retry_flag = false;
> > ccb *srb = &usb_ccb;
> > #ifdef CONFIG_BLK
> > struct blk_desc *block_dev;
> > #endif
> > + unsigned short usb_cur_xfer_blk = USB_CUR_XFER_BLK(pos);
>
> How will this behave if you keep alternating between two block_dev devices ? It will
> always start looking for the best possible transfer length from scratch, right ? That's
> not great ...
How about adding a field name "cur_xfer_blks" in struct usb_device and updating it
on device basis , it will help retain the value.
struct usb_device {
...
unsigned short cur_xfer_blks;
};
>
> > if (blkcnt == 0)
> > return 0;
> > @@ -1153,26 +1158,46 @@ static unsigned long usb_stor_read(struct blk_desc
> *block_dev, lbaint_t blknr,
> > /* XXX need some comment here */
> > retry = 2;
> > srb->pdata = (unsigned char *)buf_addr;
> > - if (blks > USB_MAX_XFER_BLK)
> > - smallblks = USB_MAX_XFER_BLK;
> > + if (blks > usb_cur_xfer_blk)
> > + smallblks = usb_cur_xfer_blk;
> > else
> > smallblks = (unsigned short) blks;
> > retry_it:
> > - if (smallblks == USB_MAX_XFER_BLK)
> > + debug("usb_read: retry #%d, usb_cur_xfer_blk %hu, smallblks %hu\n",
> > + retry, usb_cur_xfer_blk, smallblks);
> > + if (smallblks == usb_cur_xfer_blk)
> > usb_show_progress();
> > srb->datalen = block_dev->blksz * smallblks;
> > srb->pdata = (unsigned char *)buf_addr;
> > if (usb_read_10(srb, ss, start, smallblks)) {
> > debug("Read ERROR\n");
> > usb_request_sense(srb, ss);
> > - if (retry--)
> > + if (retry--) {
> > + /* decrease the usb_cur_xfer_blk */
> > + unsigned short size = USB_CUR_XFER_BLK(pos - 1);
> > + if (size >= USB_MIN_XFER_BLK) {
> > + smallblks = size;
> > + usb_cur_xfer_blk = smallblks;
> > + pos--;
> > + }
> > + retry_flag = true;
> > goto retry_it;
>
> What is the reason for having the same code twice in this patch ? Just pull the identical
> stuff into a function.
>
Ok, I will add above code in function namely dec_cur_xfer_blks/ inc_cur_xfer_blks in v3.
Best Regards,
Rajesh Bhagat
> > + }
> > blkcnt -= blks;
> > break;
> > }
> > start += smallblks;
> > blks -= smallblks;
> > buf_addr += srb->datalen;
> > +
> > + /* try to increase the usb_cur_xfer_blk */
> > + if (!retry_flag) {
> > + unsigned short size = USB_CUR_XFER_BLK(pos + 1);
> > + if (size <= blks && size <= USB_MAX_XFER_BLK) {
> > + usb_cur_xfer_blk = size;
> > + pos++;
> > + }
> > + }
> > } while (blks != 0);
> > ss->flags &= ~USB_READY;
> >
> > @@ -1181,7 +1206,7 @@ retry_it:
> > start, smallblks, buf_addr);
> >
> > usb_disable_asynch(0); /* asynch transfer allowed */
> > - if (blkcnt >= USB_MAX_XFER_BLK)
> > + if (blkcnt >= usb_cur_xfer_blk)
> > debug("\n");
> > return blkcnt;
> > }
> > @@ -1199,11 +1224,13 @@ static unsigned long usb_stor_write(struct blk_desc
> *block_dev, lbaint_t blknr,
> > unsigned short smallblks;
> > struct usb_device *udev;
> > struct us_data *ss;
> > - int retry;
> > + int retry, pos = 0;
> > + bool retry_flag = false;
> > ccb *srb = &usb_ccb;
> > #ifdef CONFIG_BLK
> > struct blk_desc *block_dev;
> > #endif
> > + unsigned short usb_cur_xfer_blk = USB_CUR_XFER_BLK(pos);
> >
> > if (blkcnt == 0)
> > return 0;
> > @@ -1239,26 +1266,46 @@ static unsigned long usb_stor_write(struct blk_desc
> *block_dev, lbaint_t blknr,
> > */
> > retry = 2;
> > srb->pdata = (unsigned char *)buf_addr;
> > - if (blks > USB_MAX_XFER_BLK)
> > - smallblks = USB_MAX_XFER_BLK;
> > + if (blks > usb_cur_xfer_blk)
> > + smallblks = usb_cur_xfer_blk;
> > else
> > smallblks = (unsigned short) blks;
> > retry_it:
> > - if (smallblks == USB_MAX_XFER_BLK)
> > + debug("usb_write: retry #%d, usb_cur_xfer_blk %hu, smallblks %hu\n",
> > + retry, usb_cur_xfer_blk, smallblks);
> > + if (smallblks == usb_cur_xfer_blk)
> > usb_show_progress();
> > srb->datalen = block_dev->blksz * smallblks;
> > srb->pdata = (unsigned char *)buf_addr;
> > if (usb_write_10(srb, ss, start, smallblks)) {
> > debug("Write ERROR\n");
> > usb_request_sense(srb, ss);
> > - if (retry--)
> > + if (retry--) {
> > + /* decrease the usb_cur_xfer_blk */
> > + unsigned short size = USB_CUR_XFER_BLK(pos - 1);
> > + if (size >= USB_MIN_XFER_BLK) {
> > + smallblks = size;
> > + usb_cur_xfer_blk = smallblks;
> > + pos--;
> > + }
> > + retry_flag = true;
> > goto retry_it;
> > + }
> > blkcnt -= blks;
> > break;
> > }
> > start += smallblks;
> > blks -= smallblks;
> > buf_addr += srb->datalen;
> > +
> > + /* try to increase the usb_cur_xfer_blk */
> > + if (!retry_flag) {
> > + unsigned short size = USB_CUR_XFER_BLK(pos + 1);
> > + if (size <= blks && size <= USB_MAX_XFER_BLK) {
> > + usb_cur_xfer_blk = size;
> > + pos++;
> > + }
> > + }
> > } while (blks != 0);
> > ss->flags &= ~USB_READY;
> >
> > @@ -1266,7 +1313,7 @@ retry_it:
> > PRIxPTR "\n", start, smallblks, buf_addr);
> >
> > usb_disable_asynch(0); /* asynch transfer allowed */
> > - if (blkcnt >= USB_MAX_XFER_BLK)
> > + if (blkcnt >= usb_cur_xfer_blk)
> > debug("\n");
> > return blkcnt;
> >
> >
>
>
> --
> Best regards,
> Marek Vasut
More information about the U-Boot
mailing list