[U-Boot] [PATCH v3] common: usb_storage : Implement logic to calculate optimal usb maximum trasfer blocks
Marek Vasut
marex at denx.de
Wed Jun 8 05:08:24 CEST 2016
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.dash at nxp.com>
> Signed-off-by: Rajesh Bhagat <rajesh.bhagat at 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;
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 ...
I still don't understand why $pos isn't unsigned int, it should be.
> + 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 ?
> 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.
> 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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