From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wy0-f177.google.com ([74.125.82.177]) by canuck.infradead.org with esmtps (Exim 4.72 #1 (Red Hat Linux)) id 1Q4B2A-0002pS-Pa for barebox@lists.infradead.org; Mon, 28 Mar 2011 11:54:59 +0000 Received: by wyb28 with SMTP id 28so3225435wyb.36 for ; Mon, 28 Mar 2011 04:54:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110328084642.GG7285@pengutronix.de> References: <20110328084642.GG7285@pengutronix.de> Date: Mon, 28 Mar 2011 21:54:56 +1000 Message-ID: From: Geoff Smith List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============0907804677==" Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: Just how fast is barebox? To: Sascha Hauer Cc: barebox@lists.infradead.org --===============0907804677== Content-Type: multipart/alternative; boundary=0016e64c3efac41adf049f899ca0 --0016e64c3efac41adf049f899ca0 Content-Type: text/plain; charset=ISO-8859-1 Thanks, very helpful info. Looks like I may have to do something light weight like ecos. I believe redboot is based on ecos so there may be a starting point there for the i.mx27. Regards Geoff On Mon, Mar 28, 2011 at 6:46 PM, Sascha Hauer wrote: > Hi Geoff, > > On Mon, Mar 28, 2011 at 01:25:18PM +1000, Geoff Smith wrote: > > Apologies for the newbie question. I am looking for a fastboot option for > > the i.MX27 > > > > I want to be capturing video data from a cold start within 300ms > (preferably > > 200ms). > > The best I could get out of an i.MX27 was about 700ms. The main limiting > factor is how fast you can load an image from the boot medium (Nand > flash in my case). Given that I can read from Nand with 16MB/s a 5MB > image takes about 300ms to load. I think you'll need many dirty tricks > doing this with Linux, like a massively stripped down kernel and perhaps > starting the capture in the kernel (not in the application). > > I wouldn't say it's not possible, but it's definitely a hard task. > > Sascha > > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > -- *Geoff Smith * *Founder and CTO* *gjsmith@vardr.com * *+61 4 1200 7354 * --0016e64c3efac41adf049f899ca0 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Thanks, very helpful info.

Looks like I may have to do s= omething light weight like ecos.
I believe redboot is based on ec= os so there may be a starting point there for the i.mx27.

Regards
Geoff


On Mon, Mar 28, 2011 at 6:46 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
Hi Geoff,

On Mon, Mar 28, 2011 at 01:25:18PM +1000, Geoff Smith wrote:
> Apologies for the newbie question. I am looking for a fastboot option = for
> =A0the i.MX27
>
> I want to be capturing video data from a cold start within 300ms (pref= erably
> 200ms).

The best I could get out of an i.MX27 was about 700ms. The main limit= ing
factor is how fast you can load an image from the boot medium (Nand
flash in my case). Given that I can read from Nand with 16MB/s a 5MB
image takes about 300ms to load. I think you'll need many dirty tricks<= br> doing this with Linux, like a massively stripped down kernel and perhaps starting the capture in the kernel (not in the application).

I wouldn't say it's not possible, but it's definitely a hard ta= sk.

Sascha


--
Pengutronix e.K. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 |
Industrial Linux Solutions =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | http://www.pengutronix.de/ = =A0|
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 =A0 = =A0|
Amtsgericht Hildesheim, HRA 2686 =A0 =A0 =A0 =A0 =A0 | Fax: =A0 +49-5121-20= 6917-5555 |



--
Geoff Smith
Founder and CTO
+61 4 = 1200 7354


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