[U-Boot] [PATCH v2] common: usb_storage : Implement logic to calculate optimal usb maximum trasfer blocks
Marek Vasut
marex at denx.de
Mon Jun 6 15:19:01 CEST 2016
On 06/06/2016 06:19 AM, Rajesh Bhagat wrote:
>
>
>> -----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.
This should be handled outside of the macro then.
>>> #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.
That might work, yes.
> 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
--
Best regards,
Marek Vasut
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