From: Lukasz Majewski <l.majewski@majess.pl>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 4/6] usb:udc:samsung: Zero copy approach for data passed to Samsung's UDC driver
Date: Sat, 1 Feb 2014 12:05:29 +0100 [thread overview]
Message-ID: <20140201120529.5a494cf0@jawa> (raw)
In-Reply-To: <201402010355.20302.marex@denx.de>
On Sat, 1 Feb 2014 03:55:20 +0100
Marek Vasut <marex@denx.de> wrote:
> On Friday, January 31, 2014 at 01:16:27 PM, Lukasz Majewski wrote:
> > The Samsung's UDC driver is not anymore copying data from USB
> > requests to data aligned internal buffers. Now it works directly in
> > data allocated in the upper layers like UMS, DFU, THOR.
> >
> > This change is possible since those gadgets now take care to
> > allocate buffers aligned to cache line (CONFIG_SYS_CACHELINE_SIZE ).
> >
> > Previously the UDC needed to copy this data to internal aligned
> > buffer to prevent from unaligned access exceptions.
> >
> > Test condition
> > - test HW + measurement: Trats - Exynos4210 rev.1
> > - test HW Trats2 - Exynos4412 rev.1
> > 400 MiB compressed rootfs image download with `thor 0 mmc 0`
> >
> > Measurement:
> > Transmission speed: 27.04 MiB/s
> >
> > Change-Id: I1df1fbafc72ec703f0367ddee3fedf3a3f5523ed
> > Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
> > Cc: Marek Vasut <marex@denx.de>
>
> You should use ROUND_UP(), not ROUND() throughout the patch.
> Otherwise you might fail to flush/invalidate the last little bit of
> data in some cacheline.
I might overlooked something, so please correct me if needed.
I allocate buffers in gadgets which are aligned to cache line with
starting address and its size is a multiplication of cache line size
(so I will not trash data allocated next to it when I invalidate cache).
In the code I'm using ROUND to invalidate/flush more data than needed
(ROUND(176, 32) = 192). I'm prepared for this since buffer in gadget is
properly allocated (with DEFINE_CACHE_ALIGN_BUFFER() which uses
roundup() internally).
Best regards,
Lukasz Majewski
>
> Best regards,
> Marek Vasut
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: not available
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20140201/b6505cbd/attachment.pgp>
next prev parent reply other threads:[~2014-02-01 11:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-31 12:16 [U-Boot] [PATCH 0/6] usb:samsung: Exynos4 SoC USB code improvements Lukasz Majewski
2014-01-31 12:16 ` [U-Boot] [PATCH 1/6] usb:gadget:ums: Replace malloc calls with memalign to fix cache buffer alignment Lukasz Majewski
2014-02-01 2:48 ` Marek Vasut
2014-02-01 9:10 ` Lukasz Majewski
2014-01-31 12:16 ` [U-Boot] [PATCH 2/6] usb:udc:samsung: Remove redundant cache operation from Samsung UDC driver Lukasz Majewski
2014-02-01 2:50 ` Marek Vasut
2014-02-01 9:56 ` Lukasz Majewski
2014-02-01 22:49 ` Marek Vasut
2014-02-03 8:05 ` Lukasz Majewski
2014-02-03 18:06 ` Marek Vasut
2014-02-04 6:23 ` Lukasz Majewski
2014-01-31 12:16 ` [U-Boot] [PATCH 3/6] usb:udc:samsung: Allow burst transfers for non EP0 endpints Lukasz Majewski
2014-01-31 12:16 ` [U-Boot] [PATCH 4/6] usb:udc:samsung: Zero copy approach for data passed to Samsung's UDC driver Lukasz Majewski
2014-02-01 2:55 ` Marek Vasut
2014-02-01 11:05 ` Lukasz Majewski [this message]
2014-02-01 22:55 ` Marek Vasut
2014-02-03 11:06 ` Lukasz Majewski
2014-02-03 18:11 ` Marek Vasut
2014-02-04 7:29 ` Lukasz Majewski
2014-02-04 20:21 ` Marek Vasut
2014-02-04 21:49 ` Lukasz Majewski
2014-02-05 2:35 ` Marek Vasut
2014-01-31 12:16 ` [U-Boot] [PATCH 5/6] usb:gadget:f_thor: Allocate request up to THOR_PACKET_SIZE not ep->maxpacket Lukasz Majewski
2014-01-31 12:16 ` [U-Boot] [PATCH 6/6] usb:gadget:f_thor: cosmetic: Remove debug memset Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 0/6] usb:samsung: Exynos4 SoC USB code improvements Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 1/6] usb:gadget:ums: Replace malloc calls with memalign to fix cache buffer alignment Lukasz Majewski
2014-02-06 1:20 ` Marek Vasut
2014-02-06 6:33 ` Lukasz Majewski
2014-02-06 6:41 ` Marek Vasut
2014-02-06 8:16 ` Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 2/6] usb:udc:samsung: Remove redundant cache operation from Samsung UDC driver Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 3/6] usb:udc:samsung: Allow burst transfers for non EP0 endpints Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 4/6] usb:udc:samsung: Zero copy approach for data passed to Samsung's UDC driver Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 5/6] usb:gadget:f_thor: Allocate request up to THOR_PACKET_SIZE not ep->maxpacket Lukasz Majewski
2014-02-05 9:10 ` [U-Boot] [PATCH v2 6/6] usb:gadget:f_thor: cosmetic: Remove debug memset Lukasz Majewski
2014-02-06 1:24 ` [U-Boot] [PATCH v2 0/6] usb:samsung: Exynos4 SoC USB code improvements Marek Vasut
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140201120529.5a494cf0@jawa \
--to=l.majewski@majess.pl \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.