From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 14 Nov 2013 15:07:03 -0800 From: Brian Norris To: Ezequiel Garcia Subject: Re: [PATCH v5 12/14] mtd: nand: pxa3xx: Introduce multiple page I/O support Message-ID: <20131114230703.GX9468@ld-irv-0074.broadcom.com> References: <1384464339-6817-1-git-send-email-ezequiel.garcia@free-electrons.com> <1384464339-6817-13-git-send-email-ezequiel.garcia@free-electrons.com> <20131114224056.GU9468@ld-irv-0074.broadcom.com> <20131114230249.GC24184@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131114230249.GC24184@localhost> Cc: Lior Amsalem , Thomas Petazzoni , Gregory Clement , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Nov 14, 2013 at 08:02:50PM -0300, Ezequiel Garcia wrote: > On Thu, Nov 14, 2013 at 02:40:56PM -0800, Brian Norris wrote: > > On Thu, Nov 14, 2013 at 06:25:37PM -0300, Ezequiel Garcia wrote: > > > --- a/drivers/mtd/nand/pxa3xx_nand.c > > > +++ b/drivers/mtd/nand/pxa3xx_nand.c > > > @@ -1151,7 +1288,28 @@ static int armada370_ecc_init(struct pxa3xx_nand_info *info, > > > struct nand_ecc_ctrl *ecc, > > > int strength, int page_size) > > > { > > > - /* Unimplemented yet */ > > > + if (strength == 4 && page_size == 4096) { > > > > I still think this sort of check can be improved just a bit. Can you > > comment on my additional diff, pasted below? (Not even compile-tested) > > > > > + info->ecc_bch = 1; > > > + info->chunk_size = 2048; > > > + info->spare_size = 32; > > > + info->ecc_size = 32; > > > + ecc->mode = NAND_ECC_HW; > > > + ecc->size = info->chunk_size; > > > + ecc->layout = &ecc_layout_4KB_bch4bit; > > > + ecc->strength = 16; > > > + return 1; > > > + > > > + } else if (strength == 8 && page_size == 4096) { > > > + info->ecc_bch = 1; > > > + info->chunk_size = 1024; > > > + info->spare_size = 0; > > > + info->ecc_size = 32; > > > + ecc->mode = NAND_ECC_HW; > > > + ecc->size = info->chunk_size; > > > + ecc->layout = &ecc_layout_4KB_bch8bit; > > > + ecc->strength = 16; > > > + return 1; > > > + } > > > return 0; > > > } > > > > > > > Brian > > > > diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c > > index 8cb6640..e219d75 100644 > > --- a/drivers/mtd/nand/pxa3xx_nand.c > > +++ b/drivers/mtd/nand/pxa3xx_nand.c > > @@ -1363,9 +1363,13 @@ static int pxa_ecc_init(struct pxa3xx_nand_info *info, > > > > static int armada370_ecc_init(struct pxa3xx_nand_info *info, > > struct nand_ecc_ctrl *ecc, > > - int strength, int page_size) > > + int strength, int ecc_stepsize, int page_size) > > { > > - if (strength == 4 && page_size == 4096) { > > + /* > > + * Required ECC: 4-bit correction per 512 bytes > > + * Select: 16-bit correction per 2048 bytes > > + */ > > + if (strength == 4 && ecc_stepsize == 512 && page_size == 4096) { > > info->ecc_bch = 1; > > info->chunk_size = 2048; > > info->spare_size = 32; > > @@ -1376,7 +1380,11 @@ static int armada370_ecc_init(struct pxa3xx_nand_info *info, > > ecc->strength = 16; > > return 1; > > > > - } else if (strength == 8 && page_size == 4096) { > > + /* > > + * Required ECC: 8-bit correction per 512 bytes > > + * Select: 16-bit correction per 1024 bytes > > + */ > > + } else if (strength == 8 && ecc_stepsize == 512 && page_size == 4096) { > > info->ecc_bch = 1; > > info->chunk_size = 1024; > > info->spare_size = 0; > > @@ -1484,6 +1492,7 @@ KEEP_CONFIG: > > if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370) > > ret = armada370_ecc_init(info, &chip->ecc, > > chip->ecc_strength_ds, > > + chip->ecc_step_ds, > > mtd->writesize); > > else > > ret = pxa_ecc_init(info, &chip->ecc, > > Looks good, but let me see if I'm getting this straight. > > Your point is that an ECC "strength" is meaningless without > the _step_ definition. > > So, I was assuming the step to be 512, and your diff is making such > assumption an explicit check. > > Correct me if I didn't understand. Exactly correct. I'll put a description on this and send it separately. Brian