From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f179.google.com (mail-yx0-f179.google.com [209.85.213.179]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id AFFE31007DB for ; Thu, 24 Nov 2011 22:06:39 +1100 (EST) Received: by yenm6 with SMTP id m6so224576yen.38 for ; Thu, 24 Nov 2011 03:06:32 -0800 (PST) Subject: Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip From: Artem Bityutskiy To: LiuShuo Date: Thu, 24 Nov 2011 13:07:13 +0200 In-Reply-To: <4ECE162D.7080408@freescale.com> References: <1322095306-13156-1-git-send-email-b35362@freescale.com> <1322095306-13156-3-git-send-email-b35362@freescale.com> <1322120515.24797.296.camel@sauron.fi.intel.com> <3F607A5180246847A760FD34122A1E052DC61F@039-SN1MPN1-003.039d.mgd.msft.net> <1322122592.24797.299.camel@sauron.fi.intel.com> <4ECE162D.7080408@freescale.com> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-QMGEMjzdNHkByEM8QSYD" Message-ID: <1322132839.24797.301.camel@sauron.fi.intel.com> Mime-Version: 1.0 Cc: "Artem.Bityutskiy@nokia.com" , Li Yang-R58472 , Wood Scott-B07421 , "dwmw2@infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "akpm@linux-foundation.org" , "linuxppc-dev@lists.ozlabs.org" Reply-To: dedekind1@gmail.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-QMGEMjzdNHkByEM8QSYD Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2011-11-24 at 18:02 +0800, LiuShuo wrote: > =E4=BA=8E 2011=E5=B9=B411=E6=9C=8824=E6=97=A5 16:16, Artem Bityutskiy =E5= =86=99=E9=81=93: > > On Thu, 2011-11-24 at 07:49 +0000, Li Yang-R58472 wrote: > >>> Subject: Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to s= upport > >>> large-page Nand chip > >>> > >>> On Thu, 2011-11-24 at 08:41 +0800, b35362@freescale.com wrote: > >>>> + /* > >>>> + * Freescale FCM controller has a 2K size limitation= of buffer > >>>> + * RAM, so elbc_fcm_ctrl->buffer have to be used if = writesize > >>>> + * of chip is greater than 2048. > >>>> + * We malloc a large enough buffer (maximum page siz= e is > >>> 16K). > >>>> + */ > >>>> + elbc_fcm_ctrl->buffer =3D kmalloc(1024 * 16 + 1024, > >>> GFP_KERNEL); > >>> > >>> Are there NANDs with 16KiB page size? > >> We are not sure, but are there possibility that chip with 16K page wil= l appear? Or maybe we can add a MACRO for the maximum page size? > > I do not know, but I know that allocating 32KiB of contiguous physical > > RAM may cause unneeded memory pressure and even fail if the memory is > > too fragmented. So I would not go for this unless this is necessary. > What is your suggestion ? 8k is enough ? Up to you, I do not have suggestions, just expressed a concern. I'd keep the buffer smaller if possible. By the time 16KiB pages appear, your HW may retire already :-) --=20 Best Regards, Artem Bityutskiy --=-QMGEMjzdNHkByEM8QSYD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJOziVhAAoJECmIfjd9wqK0dUUQAJXvsAdOTgo3ewdN8MExeQ6q P6E8WMMcX+8RgPCAbnQjeGPYvKCdNq3bG0bWANrxBjOk5DoTePz+4C1DriIVFT3X WjL64fULmfDRAk/4yNx/J1+J8X3fEdI4GwSWnWeOCzZpm+9SWJaePj/2e5RpAbET AYRX22G/2Eh8kd89Vje3KYOtTBdaNgnQiOss1Tudr6qRaDrJENXlixSnqjnaInB/ zEIDKc/tzgra/suVC8vIFhaoikYHycL0MSa59sXHU8hGcDz6j5iCjbiJC0jgMb7V 4FOg4CxmpD9RonX2qydUQzfJXTHAC04zfOpkbv62Gc0fCYpcfhoqfrTaulL0+Rx+ mlMqob7Dz2v24yul7muE9AL+WcwVTAf6Anx/RwIPGGN6I9NipfeCLQhs0BkUE8U/ OylPpQ98BB5hmXzksSsG6PA7DGlF0xkUEZn5qCCDrFPUy5vhWeVS6suat6lyqG6Z WbNxUtBrExvlNh/5fWV3av0oz53wt+MQlqw4mJEopQTS0An+Dvw+Zc5y2dizl41M sJy1k5KE6g/F6zijsnzJLxRThOXsrl0AtviiZx7jirrbTW2US0Vw5L6goDxFbBUf 1LmuslsdbMA2IqGiig52MGjGzoo7bks23Z+XwwyhagwleEHvSvo/2h5n4SJUWhN7 eymrbGr9JfHjj5cM45Hs =+v3x -----END PGP SIGNATURE----- --=-QMGEMjzdNHkByEM8QSYD--