[U-Boot] [PATCH v5 2/2] common: usb_storage : Implement logic to calculate optimal usb maximum trasfer blocks
Rajesh Bhagat
rajesh.bhagat at nxp.com
Tue Jun 14 05:41:05 CEST 2016
> -----Original Message-----
> From: Marek Vasut [mailto:marex at denx.de]
> Sent: Monday, June 13, 2016 7:07 PM
> 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>; Rajesh Bhagat <rajesh.bhagat at freescale.com>
> Subject: Re: [PATCH v5 2/2] common: usb_storage : Implement logic to calculate
> optimal usb maximum trasfer blocks
>
> On 06/13/2016 06:03 AM, Rajesh Bhagat wrote:
> > From: Rajesh Bhagat <rajesh.bhagat at freescale.com>
> >
> > 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>
> > ---
> > Changes in v5:
> > - None
> >
> > Changes in v4:
> > - Adds udev paramater in dec/inc_cur_xfer_blks function and adds
> > sanity check on it.
> > - Changes type of pos varible to unsigned int in
> > dec/inc_cur_xfer_blks
> > - Removes usage of pos varible from usb_stor_read/write
> >
> > Changes in v3:
> > - Adds cur_xfer_blks in struct usb_device to retain values
> > - Adds functions dec/inc_cur_xfer_blks to remove code duplication
> > - Moves check from macro to calling functions
> >
> > Changes in v2:
> > - Removes table to store blocks and use formula (1 << (12 + n)) - 1
> > - Adds logic to start from minimum, go to maximum in each read/write
> >
> > common/usb_storage.c | 67
> ++++++++++++++++++++++++++++++++++++++++++++++---
> > include/usb.h | 1 +
> > 2 files changed, 63 insertions(+), 5 deletions(-)
> >
> > diff --git a/common/usb_storage.c b/common/usb_storage.c index
> > f060637..9b09412 100644
> > --- a/common/usb_storage.c
> > +++ b/common/usb_storage.c
> > @@ -106,11 +106,16 @@ 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 GET_CUR_XFER_BLKS(blks) (LOG2((blks + 1) /
> (USB_MIN_XFER_BLK + 1)))
> > +#define CALC_CUR_XFER_BLKS(pos) ((1 << (12 + pos)) - 1)
Hello Marek,
>
> Parenthesis around variables are missing.
>
Will take care in v6.
> > #ifndef CONFIG_BLK
> > static struct us_data usb_stor[USB_MAX_STOR_DEV]; #endif @@ -141,6
> > +146,44 @@ static void usb_show_progress(void)
> > debug(".");
> > }
> >
> > +static int dec_cur_xfer_blks(struct usb_device *udev) {
> > + /* decrease the cur_xfer_blks */
> > + unsigned int pos;
> > + unsigned short size;
> > +
> > + if (!udev)
> > + return -EINVAL;
> > +
> > + pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
> > + size = pos ? CALC_CUR_XFER_BLKS(pos - 1) : 0;
>
> If pos == 0 , the condition below will be true (size will be 2047), so this extra ternary
> is unnecessary.
>
Will take care in v6. Will remove the extra ternary operator used, as 2047 will follow the
below check (size < USB_MIN_XFER_BLK) and code will work fine.
> > + if (size < USB_MIN_XFER_BLK)
> > + return -EINVAL;
> > +
> > + udev->cur_xfer_blks = size;
> > + return 0;
> > +}
> > +
> > +static int inc_cur_xfer_blks(struct usb_device *udev, lbaint_t blks)
> > +{
> > + /* try to increase the cur_xfer_blks */
> > + unsigned int pos;
> > + unsigned short size;
> > +
> > + if (!udev)
> > + return -EINVAL;
> > +
> > + pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
> > + size = CALC_CUR_XFER_BLKS(pos + 1);
> > +
> > + if (size > blks || size > USB_MAX_XFER_BLK)
> > + return -EINVAL;
>
> Why don't you clamp the size to min(blks, USB_MAX_XFER_BLK) instead ?
>
Do you mean below statement?
if (size > min(blks, USB_MAX_XFER_BLK))
return -EINVAL;
> > + udev->cur_xfer_blks = size;
> > + return 0;
> > +}
> > +
> >
> /**********************************************************************
> *********
> > * show info on storage devices; 'usb start/init' must be invoked earlier
> > * as we only retrieve structures populated during devices
> > initialization @@ -1128,6 +1171,7 @@ static unsigned long
> usb_stor_read_write(struct blk_desc *block_dev,
> > struct usb_device *udev;
> > struct us_data *ss;
> > int retry;
> > + bool retry_flag = false;
> > ccb *srb = &usb_ccb;
> > #ifdef CONFIG_BLK
> > struct blk_desc *block_dev;
> > @@ -1167,26 +1211,36 @@ static unsigned long usb_stor_read_write(struct
> blk_desc *block_dev,
> > */
> > retry = 2;
> > srb->pdata = (unsigned char *)buf_addr;
> > - if (blks > USB_MAX_XFER_BLK)
> > - smallblks = USB_MAX_XFER_BLK;
> > + if (blks > udev->cur_xfer_blks)
> > + smallblks = udev->cur_xfer_blks;
> > else
> > smallblks = (unsigned short) blks;
> > retry_it:
> > - if (smallblks == USB_MAX_XFER_BLK)
> > + debug("usb_%s: retry #%d, cur_xfer_blks %hu, smallblks %hu\n",
> > + USB_STOR_OP_TYPE, retry, udev->cur_xfer_blks,
> > + smallblks);
> > + if (smallblks == udev->cur_xfer_blks)
> > usb_show_progress();
> > srb->datalen = block_dev->blksz * smallblks;
> > srb->pdata = (unsigned char *)buf_addr;
> > if (usb_stor_operation(srb, ss, start, smallblks, is_write)) {
> > debug("%s ERROR\n", USB_STOR_OP_TYPE);
> > usb_request_sense(srb, ss);
> > - if (retry--)
> > + if (retry--) {
> > + if (!dec_cur_xfer_blks(udev))
> > + smallblks = udev->cur_xfer_blks;
> > + retry_flag = true;
> > goto retry_it;
> > + }
> > blkcnt -= blks;
> > break;
> > }
> > start += smallblks;
> > blks -= smallblks;
> > buf_addr += srb->datalen;
> > +
> > + if (!retry_flag && !inc_cur_xfer_blks(udev, blks))
> > + smallblks = udev->cur_xfer_blks;
> > } while (blks != 0);
> > ss->flags &= ~USB_READY;
> >
> > @@ -1195,7 +1249,7 @@ retry_it:
> > USB_STOR_OP_TYPE, start, smallblks, buf_addr);
> >
> > usb_disable_asynch(0); /* asynch transfer allowed */
> > - if (blkcnt >= USB_MAX_XFER_BLK)
> > + if (blkcnt >= udev->cur_xfer_blks)
> > debug("\n");
> > return blkcnt;
> > }
> > @@ -1282,6 +1336,9 @@ int usb_storage_probe(struct usb_device *dev, unsigned
> int ifnum,
> > break;
> > }
> >
> > + /* Initialize the current transfer blocks to minimum value */
> > + dev->cur_xfer_blks = USB_MIN_XFER_BLK;
> > +
> > /*
> > * We are expecting a minimum of 2 endpoints - in and out (bulk).
> > * An optional interrupt is OK (necessary for CBI protocol).
> > diff --git a/include/usb.h b/include/usb.h index 02a0ccd..b815816
> > 100644
> > --- a/include/usb.h
> > +++ b/include/usb.h
> > @@ -153,6 +153,7 @@ struct usb_device {
> > struct udevice *dev; /* Pointer to associated device */
> > struct udevice *controller_dev; /* Pointer to associated controller */
> > #endif
> > + unsigned short cur_xfer_blks; /* Current maximum transfer blocks */
> > };
> >
> > struct int_queue;
> >
>
Best Regards,
Rajesh Bhagat
>
> --
> Best regards,
> Marek Vasut
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