> -----Original Message-----
> From: Marek Vasut [mailto:ma...@denx.de]
> Sent: Wednesday, June 08, 2016 8:38 AM
> To: Rajesh Bhagat <rajesh.bha...@nxp.com>; u-boot@lists.denx.de
> Cc: s...@chromium.org; york sun <york....@nxp.com>; Sriram Dash
> <sriram.d...@nxp.com>
> Subject: Re: [PATCH v3] common: usb_storage : Implement logic to calculate
> optimal
> usb maximum trasfer blocks
>
> On 06/07/2016 11:29 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.d...@nxp.com>
> > Signed-off-by: Rajesh Bhagat <rajesh.bha...@nxp.com>
> > ---
> > 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 | 78
> ++++++++++++++++++++++++++++++++++++++++++++--------
> > include/usb.h | 1 +
> > 2 files changed, 67 insertions(+), 12 deletions(-)
> >
> > diff --git a/common/usb_storage.c b/common/usb_storage.c index
> > 7e6e52d..e08dcd4 100644
> > --- a/common/usb_storage.c
> > +++ b/common/usb_storage.c
> > @@ -106,11 +106,40 @@ 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 / (USB_MIN_XFER_BLK +
> 1)))
> > +#define CALC_CUR_XFER_BLKS(pos) ((1 << (12 + pos)) - 1)
> > +
> > +static int dec_cur_xfer_blks(int *pos, unsigned short *smallblks) {
> > + /* decrease the cur_xfer_blks */
> > + unsigned short size = (*pos > 0) ? CALC_CUR_XFER_BLKS(*pos - 1) : 0;
>
Hello Marek,
> If someone passes null pointer into the function, it will fail.
> Also, you can refactor it to make it more readable:
>
> if (!pos)
> return -EINVAL;
> if (size < USB_MIN_XFER_BLK)
> return -EINVAL;
> ... do stuff ...
>
Refactoring the code to return early in case of error conditions is fine. But
pos and smallblks can never be passed as NULL in these functions.
> I still don't understand why $pos isn't unsigned int, it should be.
>
I believe keeping a variable as "int" provides a natural way of checking for
overflow conditions. We check can check if number has become negative and take
actions, which is not possible when number is taken as "unsigned int".
> > + if (size >= USB_MIN_XFER_BLK) {
> > + *smallblks = size;
> > + (*pos)--;
> > + return 0;
> > + }
> > + return -EINVAL;
> > +}
> > +
> > +static int inc_cur_xfer_blks(int *pos, unsigned short *smallblks,
> > +lbaint_t blks) {
> > + /* try to increase the cur_xfer_blks */
> > + unsigned short size = (*pos >= 0) ? CALC_CUR_XFER_BLKS(*pos + 1) : 0;
> > + if (size <= blks && size <= USB_MAX_XFER_BLK) {
> > + *smallblks = size;
> > + (*pos)++;
> > + return 0;
> > + }
> > + return -EINVAL;
> > +}
> > +
> > #ifndef CONFIG_BLK
> > static struct us_data usb_stor[USB_MAX_STOR_DEV]; #endif @@ -1117,7
> > +1146,8 @@ 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;
> > + bool retry_flag = false;
> > ccb *srb = &usb_ccb;
> > #ifdef CONFIG_BLK
> > struct blk_desc *block_dev;
> > @@ -1145,6 +1175,7 @@ static unsigned long usb_stor_read(struct blk_desc
> *block_dev, lbaint_t blknr,
> > buf_addr = (uintptr_t)buffer;
> > start = blknr;
> > blks = blkcnt;
> > + pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
>
> Is this $pos even needed ? Why ?
$pos variable is updated in dec/inc_cur_xfer_blks functions which calculates
the
next transfer blocks, and finally when all conditions are met is stored in
udev->cur_xfer_blks.
>
> > debug("\nusb_read: dev %d startblk " LBAF ", blccnt " LBAF " buffer %"
> > PRIxPTR "\n", block_dev->devnum, start, blks, buf_addr); @@
> > -1153,26 +1184,35 @@ 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 > udev->cur_xfer_blks)
> > + smallblks = udev->cur_xfer_blks;
> > else
> > smallblks = (unsigned short) blks;
> > retry_it:
> > - if (smallblks == USB_MAX_XFER_BLK)
> > + debug("usb_read: retry #%d, cur_xfer_blks %hu, smallblks %hu\n",
> > + 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_read_10(srb, ss, start, smallblks)) {
> > debug("Read ERROR\n");
> > usb_request_sense(srb, ss);
> > - if (retry--)
> > + if (retry--) {
> > + if (!dec_cur_xfer_blks(&pos, &smallblks))
> > + udev->cur_xfer_blks = smallblks;
> > + retry_flag = true;
> > goto retry_it;
> > + }
> > blkcnt -= blks;
>
> The same piece of code is below. I would rather see you factor out the common
> code
> and then make any changes.
>
IMHO, All the common code is moved in functions dec/inc_cur_xfer_blks as
pointed earlier.
Are you are referring to other common code of usb_stor_read/write functions
which is not
part of this patchset. If yes, I would prefer to take it as a next patch set.
Best Regards,
Rajesh Bhagat
> > break;
> > }
> > start += smallblks;
> > blks -= smallblks;
> > buf_addr += srb->datalen;
> > +
> > + if (!retry_flag && !inc_cur_xfer_blks(&pos, &smallblks, blks))
> > + udev->cur_xfer_blks = smallblks;
> > } while (blks != 0);
> > ss->flags &= ~USB_READY;
> >
> > @@ -1181,7 +1221,7 @@ retry_it:
> > 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;
> > }
> > @@ -1199,7 +1239,8 @@ 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;
> > + bool retry_flag = false;
> > ccb *srb = &usb_ccb;
> > #ifdef CONFIG_BLK
> > struct blk_desc *block_dev;
> > @@ -1222,6 +1263,7 @@ static unsigned long usb_stor_write(struct blk_desc
> *block_dev, lbaint_t blknr,
> > }
> > #endif
> > ss = (struct us_data *)udev->privptr;
> > + pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
> >
> > usb_disable_asynch(1); /* asynch transfer not allowed */
> >
> > @@ -1239,26 +1281,35 @@ 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 > udev->cur_xfer_blks)
> > + smallblks = udev->cur_xfer_blks;
> > else
> > smallblks = (unsigned short) blks;
> > retry_it:
> > - if (smallblks == USB_MAX_XFER_BLK)
> > + debug("usb_write: retry #%d, cur_xfer_blks %hu, smallblks
> > %hu\n",
> > + 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_write_10(srb, ss, start, smallblks)) {
> > debug("Write ERROR\n");
> > usb_request_sense(srb, ss);
> > - if (retry--)
> > + if (retry--) {
> > + if (!dec_cur_xfer_blks(&pos, &smallblks))
> > + udev->cur_xfer_blks = smallblks;
> > + retry_flag = true;
> > goto retry_it;
> > + }
> > blkcnt -= blks;
> > break;
> > }
> > start += smallblks;
> > blks -= smallblks;
> > buf_addr += srb->datalen;
> > +
> > + if (!retry_flag && !inc_cur_xfer_blks(&pos, &smallblks, blks))
> > + udev->cur_xfer_blks = smallblks;
> > } while (blks != 0);
> > ss->flags &= ~USB_READY;
> >
> > @@ -1266,7 +1317,7 @@ retry_it:
> > PRIxPTR "\n", 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;
> >
> > @@ -1331,6 +1382,9 @@ 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..bd49014
> > 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,
> Marek Vasut
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