Messages in this thread | | | From | Andy Duan <> | Subject | RE: [EXT] Re: [PATCH nvmem 1/1] nvmem: imx: correct the fuse word index | Date | Fri, 5 Jul 2019 02:46:32 +0000 |
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From: Andy Duan Sent: Friday, July 5, 2019 12:08 AM > From: Lothar Waßmann <LW@KARO-electronics.de> Sent: Thursday, July 4, > 2019 11:46 PM > > Hi, > > > > On Thu, 4 Jul 2019 22:20:15 +0800 fugang.duan@nxp.com wrote: > > > From: Fugang Duan <fugang.duan@nxp.com> > > > > > > iMX8 fuse word index represent as one 4-bytes word, it should not be > > > divided by 4. > > > > > > Exp: > > > - MAC0 address layout in fuse: > > > offset 708: MAC[3] MAC[2] MAC[1] MAC[0] > > > offset 709: XX xx MAC[5] MAC[4] > > > > > > Signed-off-by: Fugang Duan <fugang.duan@nxp.com> > > > --- > > > drivers/nvmem/imx-ocotp-scu.c | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/nvmem/imx-ocotp-scu.c > > > b/drivers/nvmem/imx-ocotp-scu.c index d9dc482..be2f5f0 100644 > > > --- a/drivers/nvmem/imx-ocotp-scu.c > > > +++ b/drivers/nvmem/imx-ocotp-scu.c > > > @@ -71,8 +71,8 @@ static int imx_scu_ocotp_read(void *context, > > > unsigned > > int offset, > > > void *p; > > > int i, ret; > > > > > > - index = offset >> 2; > > > - num_bytes = round_up((offset % 4) + bytes, 4); > > > + index = offset; > > > + num_bytes = round_up(bytes, 4); > > > count = num_bytes >> 2; > > > > > > if (count > (priv->data->nregs - index)) @@ -100,7 +100,7 @@ > > > static int imx_scu_ocotp_read(void *context, unsigned int offset, > > > buf++; > > > } > > > > > > - memcpy(val, (u8 *)p + offset % 4, bytes); > > > + memcpy(val, (u8 *)p, bytes); > > > > > > kfree(p); > > > > > With these changes you could use the 'val' pointer directly as the > > destination for ocotp_read() without need for an intermediate buffer. > > > > > > Lothar Waßmann > > You are right, in fact, we can remove "p" and "buf" pointer. > Thanks for your review, I will send out the V2.
Hi Lothar,
It still need intermediate buffer to read out n words (n * 4 bytes) from eFuse. Because 'val' buffer size is real count parsed from DT, which is not an integer multiple of 4.
For example, cell->bytes is parsed from "reg" property and it is real count like 6. fec_mac0: mac@2c4 { reg = <0x2c4 6>; };
So we have to use intermediate buffer here.
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