| Message ID | ce9ab5790912230133wae2c4dcw73051221b66cb40f@mail.gmail.com |
|---|---|
| State | New, archived |
| Headers | show |
* Vimal Singh <vimal.newwork@gmail.com> [091223 01:32]: > In omap nand driver we used to do 32-bit reads (in function > omap_read_buf_pref, using 'ioread32_rep' i.e.: __raw_readsl), and it > was working fine till some time back. But now, somehow, this has got > some problem. Reads are not being done successfully, and driver gives > lots for error reprot like below: > > td->read(0x604 bytes from 0x1fc) returned ECC error > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > uncorrectable error : > mtd->read(0x520 bytes from 0x2e0) returned ECC error > > While if we change 32-bit reads to 16-bit reads (using 'ioread16_rep' > i.e.: __raw_readwl) makes it working fine. (A patch to do this is > listed below at the bottom of this mail.) > > I have not seen any change in routine '__raw_readsl'. > So, could someone help me find out the root cause the issue? > > Thanks for any input. Maybe an issue with the GPMC timings? Regards, Tony > > -- > Regards, > Vimal Singh > > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > index aaef170..dc493f5 100644 > --- a/drivers/mtd/nand/omap2.c > +++ b/drivers/mtd/nand/omap2.c > @@ -288,14 +288,14 @@ static void omap_read_buf_pref(struct mtd_info > struct omap_nand_info, mtd); > uint32_t pfpw_status = 0, r_count = 0; > int ret = 0; > - u32 *p = (u32 *)buf; > + u16 *p = (u16 *)buf; > > /* take care of subpage reads */ > - for (; len % 4 != 0; ) { > + for (; len % 2 != 0; ) { > *buf++ = __raw_readb(info->nand.IO_ADDR_R); > len--; > } > - p = (u32 *) buf; > + p = (u16 *) buf; > > /* configure and start prefetch transfer */ > ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0); > @@ -308,10 +308,10 @@ static void omap_read_buf_pref(struct mtd_info > *mtd, u_char *buf, int len) > } else { > do { > pfpw_status = gpmc_prefetch_status(); > - r_count = ((pfpw_status >> 24) & 0x7F) >> 2; > - ioread32_rep(info->nand_pref_fifo_add, p, r_count); > + r_count = ((pfpw_status >> 24) & 0x7F) >> 1; > + ioread16_rep(info->nand_pref_fifo_add, p, r_count); > p += r_count; > - len -= r_count << 2; > + len -= r_count << 1; > } while (len); > > /* disable and stop the PFPW engine */ > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Dec 23, 2009 at 9:44 AM, Tony Lindgren <tony@atomide.com> wrote: > * Vimal Singh <vimal.newwork@gmail.com> [091223 01:32]: >> In omap nand driver we used to do 32-bit reads (in function >> omap_read_buf_pref, using 'ioread32_rep' i.e.: __raw_readsl), and it >> was working fine till some time back. But now, somehow, this has got >> some problem. Reads are not being done successfully, and driver gives >> lots for error reprot like below: >> >> td->read(0x604 bytes from 0x1fc) returned ECC error >> uncorrectable error : >> uncorrectable error : >> uncorrectable error : >> uncorrectable error : >> uncorrectable error : >> uncorrectable error : >> mtd->read(0x520 bytes from 0x2e0) returned ECC error >> >> While if we change 32-bit reads to 16-bit reads (using 'ioread16_rep' >> i.e.: __raw_readwl) makes it working fine. (A patch to do this is >> listed below at the bottom of this mail.) >> >> I have not seen any change in routine '__raw_readsl'. >> So, could someone help me find out the root cause the issue? >> >> Thanks for any input. > > Maybe an issue with the GPMC timings? I can confirm that this issue exists on Overo too. Sadly, switching to 16 bit reads does not fix the issue for me. I'll start digging to see if I can find what's broken. Steve > Regards, > > Tony > >> >> -- >> Regards, >> Vimal Singh >> >> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c >> index aaef170..dc493f5 100644 >> --- a/drivers/mtd/nand/omap2.c >> +++ b/drivers/mtd/nand/omap2.c >> @@ -288,14 +288,14 @@ static void omap_read_buf_pref(struct mtd_info >> struct omap_nand_info, mtd); >> uint32_t pfpw_status = 0, r_count = 0; >> int ret = 0; >> - u32 *p = (u32 *)buf; >> + u16 *p = (u16 *)buf; >> >> /* take care of subpage reads */ >> - for (; len % 4 != 0; ) { >> + for (; len % 2 != 0; ) { >> *buf++ = __raw_readb(info->nand.IO_ADDR_R); >> len--; >> } >> - p = (u32 *) buf; >> + p = (u16 *) buf; >> >> /* configure and start prefetch transfer */ >> ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0); >> @@ -308,10 +308,10 @@ static void omap_read_buf_pref(struct mtd_info >> *mtd, u_char *buf, int len) >> } else { >> do { >> pfpw_status = gpmc_prefetch_status(); >> - r_count = ((pfpw_status >> 24) & 0x7F) >> 2; >> - ioread32_rep(info->nand_pref_fifo_add, p, r_count); >> + r_count = ((pfpw_status >> 24) & 0x7F) >> 1; >> + ioread16_rep(info->nand_pref_fifo_add, p, r_count); >> p += r_count; >> - len -= r_count << 2; >> + len -= r_count << 1; >> } while (len); >> >> /* disable and stop the PFPW engine */ >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-omap" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
On Tue, Dec 29, 2009 at 12:38 PM, Steve Sakoman <sakoman@gmail.com> wrote: > I can confirm that this issue exists on Overo too. Sadly, switching > to 16 bit reads does not fix the issue for me. I'll start digging to > see if I can find what's broken. I can also confirm that there are days when I am not even capable of applying a patch properly :-( Switching to 16 bit read accesses does indeed fix the ECC issue on Overo too. Which still leaves us needing to find the root cause of the breakage . . . Steve
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index aaef170..dc493f5 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -288,14 +288,14 @@ static void omap_read_buf_pref(struct mtd_info struct omap_nand_info, mtd); uint32_t pfpw_status = 0, r_count = 0; int ret = 0; - u32 *p = (u32 *)buf; + u16 *p = (u16 *)buf; /* take care of subpage reads */ - for (; len % 4 != 0; ) { + for (; len % 2 != 0; ) { *buf++ = __raw_readb(info->nand.IO_ADDR_R); len--; } - p = (u32 *) buf; + p = (u16 *) buf; /* configure and start prefetch transfer */ ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0); @@ -308,10 +308,10 @@ static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len) } else { do { pfpw_status = gpmc_prefetch_status(); - r_count = ((pfpw_status >> 24) & 0x7F) >> 2; - ioread32_rep(info->nand_pref_fifo_add, p, r_count); + r_count = ((pfpw_status >> 24) & 0x7F) >> 1; + ioread16_rep(info->nand_pref_fifo_add, p, r_count); p += r_count; - len -= r_count << 2; + len -= r_count << 1; } while (len);