From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LC3FY-0001jl-6Y for qemu-devel@nongnu.org; Sun, 14 Dec 2008 21:32:00 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LC3FW-0001i0-Ms for qemu-devel@nongnu.org; Sun, 14 Dec 2008 21:31:59 -0500 Received: from [199.232.76.173] (port=37694 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LC3FW-0001hx-Cm for qemu-devel@nongnu.org; Sun, 14 Dec 2008 21:31:58 -0500 Received: from rv-out-0708.google.com ([209.85.198.248]:42474) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LC3FV-0001to-SE for qemu-devel@nongnu.org; Sun, 14 Dec 2008 21:31:58 -0500 Received: by rv-out-0708.google.com with SMTP id f25so2300680rvb.22 for ; Sun, 14 Dec 2008 18:31:55 -0800 (PST) Message-ID: Date: Mon, 15 Dec 2008 03:31:55 +0100 From: "andrzej zaborowski" Subject: Re: [Qemu-devel] [PATCH] NAND: Correct random data reads. In-Reply-To: <20081212121030.GC27147@edgar.se.axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081212121030.GC27147@edgar.se.axis.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org 2008/12/12 Edgar E. Iglesias : > I'm having problems with machine that uses a NAND_MFR_STMICRO 0xf1, > recent Linux versions cannot properly read from the flash. > > Turns out that Linux MTD recently learned howto do randomly accessed reads > from NAND flashes. QEMU has problemns emulating these. > > This patch fixes the problem for me but I've only tested on one flash > model and only with Linux. I'd appreciate help with testing more machines > with NANDs and ofcourse any comments people may have on the patch. > > Thanks > > commit 68a19f4348b12f85bd5fbfd8cf7b19033e1fd784 > Author: Edgar E. Iglesias > Date: Fri Dec 12 12:48:58 2008 +0100 > > NAND: Correct random data reads. > > Random reading depends on having the last row/page latched and not beeing > clobbered between read and any following random reads. > > Also, s->iolen must be updated when loading the io/data register with randomly > accessed flash data. > > Signed-off-by: Edgar E. Iglesias > > diff --git a/hw/nand.c b/hw/nand.c > index 7c9f0aa..a6f67c6 100644 > --- a/hw/nand.c > +++ b/hw/nand.c > @@ -212,6 +212,7 @@ void nand_reset(struct nand_flash_s *s) > > static void nand_command(struct nand_flash_s *s) > { > + unsigned int offset; > switch (s->cmd) { > case NAND_CMD_READ0: > s->iolen = 0; > @@ -233,8 +234,12 @@ static void nand_command(struct nand_flash_s *s) > case NAND_CMD_NOSERIALREAD2: > if (!(nand_flash_ids[s->chip_id].options & NAND_SAMSUNG_LP)) > break; > - > - s->blk_load(s, s->addr, s->addr & ((1 << s->addr_shift) - 1)); > + offset = s->addr & ((1 << s->addr_shift) - 1); > + s->blk_load(s, s->addr, offset); > + if (s->gnd) > + s->iolen = (1 << s->page_shift) - offset; > + else > + s->iolen = (1 << s->page_shift) + (1 << s->oob_shift) - offset; > break; > > case NAND_CMD_RESET: > @@ -380,12 +385,15 @@ void nand_setio(struct nand_flash_s *s, uint8_t value) > > if (s->cmd != NAND_CMD_RANDOMREAD2) { > s->addrlen = 0; > - s->addr = 0; > } > } > > if (s->ale) { > - s->addr |= value << (s->addrlen * 8); > + unsigned int shift = s->addrlen * 8; > + unsigned int mask = ~(0xff << shift); > + unsigned int v = value << shift; > + > + s->addr = (s->addr & mask) | v; > s->addrlen ++; > > if (s->addrlen == 1 && s->cmd == NAND_CMD_READID) > @@ -680,9 +688,6 @@ static void glue(nand_blk_load_, PAGE_SIZE)(struct nand_flash_s *s, > offset, PAGE_SIZE + OOB_SIZE - offset); > s->ioaddr = s->io; > } > - > - s->addr &= PAGE_SIZE - 1; > - s->addr += PAGE_SIZE; Won't that break sequential reading? I think the other modifications should also be conditional on the command being RANDOMREAD. BTW, do you happen to know what the difference is between RANDOMREAD2 and NOSERIALREAD2? I basically added those commands because various drivers I found had them declared or some specs had them but there seems to be no standard or any place where they would be defined. Cheers