From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co202.xi-lite.net ([149.6.83.202]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1U9uIN-0004pa-8Q for linux-mtd@lists.infradead.org; Mon, 25 Feb 2013 09:24:29 +0000 Message-ID: <512B2DC6.8090104@parrot.com> Date: Mon, 25 Feb 2013 10:24:22 +0100 From: Matthieu CASTET MIME-Version: 1.0 To: "Gupta, Pekon" Subject: Re: [PATCH v2] mtd: nand: support BENAND (Built-in ECC NAND) References: <20980858CB6D3A4BAE95CA194937D5E73E99A025@DBDE01.ent.ti.com> In-Reply-To: <20980858CB6D3A4BAE95CA194937D5E73E99A025@DBDE01.ent.ti.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit Cc: "linux-mtd@lists.infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Gupta, Pekon a écrit : > Hi, > >> This enables support for BENAND, which is an SLC NAND flash solution >> with embedded error correction code (ECC), currently supports only >> 128bytes OOB type. >> >> In the read sequence, "status read command" is executed to check the >> ECC status after read data. If bitflips occur, these are >> automatically corrected by BENAND and the status indicates the result. >> >> The write sequence is the same as raw write and the ECC data are >> automatically written to OOB by BENAND. > > Just inquisitive, can anyone please share any throughput comparison between 'BENAND' & 'normal NAND' devices having same capacity and working on same clock-freq ? > > (a) Usually on-chip memory controllers work on faster clock frequencies, as compared to the NAND devices connected to them externally on board. > Thus I assume, ECC computation & correction can be done at faster rate. > > (b) However, on other hand BENAND(s) have luxury of accessing the Flash storage array locally, thus eliminating I/O delays | un-optimized IO signal timing from the access-path. > > So, if you can share the details throughput comparison between the two types of NAND devices, under various conditions it would be helpful. > You always have to transfer the data from/to the nand devices to/from the host. - Either the ecc internal controller is fast and the throughput are the same than 'normal nand' (assuming the ecc controller on the host is fast), - either it is slow and the throughput is limited by the internal ecc controller (throughput is slower than 'normal nand') Matthieu