[PATCH v4 1/2] mtd: nand: fix generating over-boundary ECC data when writing

[Boris Brezillon]

On Wed, 31 Aug 2016 16:19:09 +0800
RogerCC.Lin <rogercc.lin at mediatek.com> wrote:

> On Wed, 2016-08-31 at 10:09 +0200, Boris Brezillon wrote:
> > On Tue, 30 Aug 2016 20:35:47 +0800
> > RogerCC Lin <rogercc.lin at mediatek.com> wrote:
> >   
> > > From: RogerCC Lin <rogercc.lin at mediatek.com>
> > > 
> > > When mtk_ecc_encode() is writing the ECC parity data to the OOB
> > > region,because each register is 4 bytes in length,but the len's unit is
> > > in bytes,the operation in the for loop will cross the ECC's boundary.
> > > 
> > > Signed-off-by: RogerCC Lin <rogercc.lin at mediatek.com>
> > > ---
> > >  drivers/mtd/nand/mtk_ecc.c |   12 ++++++++----
> > >  1 files changed, 8 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/mtd/nand/mtk_ecc.c b/drivers/mtd/nand/mtk_ecc.c
> > > index 25a4fbd..495538e 100644
> > > --- a/drivers/mtd/nand/mtk_ecc.c
> > > +++ b/drivers/mtd/nand/mtk_ecc.c
> > > @@ -366,7 +366,8 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config,
> > >  		   u8 *data, u32 bytes)
> > >  {
> > >  	dma_addr_t addr;
> > > -	u32 *p, len, i;
> > > +	u8 *p;
> > > +	u32 len, i, val;
> > >  	int ret = 0;
> > >  
> > >  	addr = dma_map_single(ecc->dev, data, bytes, DMA_TO_DEVICE);
> > > @@ -392,11 +393,14 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config,
> > >  
> > >  	/* Program ECC bytes to OOB: per sector oob = FDM + ECC + SPARE */
> > >  	len = (config->strength * ECC_PARITY_BITS + 7) >> 3;
> > > -	p = (u32 *)(data + bytes);
> > > +	p = data + bytes;
> > >  
> > >  	/* write the parity bytes generated by the ECC back to the OOB region */
> > > -	for (i = 0; i < len; i++)
> > > -		p[i] = readl(ecc->regs + ECC_ENCPAR(i));
> > > +	for (i = 0; i < len; i++) {
> > > +		if ((i % 4) == 0)
> > > +			val = readl(ecc->regs + ECC_ENCPAR(i >> 2));  
> > 
> > I'm nitpicking, but I'd prefer to have 'i / 4' instead of 'i >> 2' to
> > be consistent with the 'i % 4' operation, and I also find it clearer.
> > 
> > If you agree, I can do this change while applying the patch, no need to
> > resend.  
> 
> Of course, please apply the patch with 'i / 4', 
> thank you.

Sorry, but I'd prefer to have this patch in -rc7 or -rc8, and I'm not
taking the fixes in my tree (it goes through the MTD tree).

Can you resend a version?

You can add

Acked-by: Boris Brezillon <boris.brezillon at free-electrons.com>

> 
> > > +		p[i] = (val >> ((i % 4) * 8)) & 0xff;
> > > +	}
> > >  timeout:
> > >  
> > >  	dma_unmap_single(ecc->dev, addr, bytes, DMA_TO_DEVICE);  
> >   
> 
>