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* Re: [PATCH] mtd: nand: Add support for reading ooblayout from device tree
@ 2018-05-12 11:55 Paul Cercueil
  0 siblings, 0 replies; 9+ messages in thread
From: Paul Cercueil @ 2018-05-12 11:55 UTC (permalink / raw)
  To: Boris Brezillon
  Cc: Mark Rutland, David Woodhouse, linux-mtd, Rob Herring,
	linux-kernel, devicetree, Brian Norris, Richard Weinberger,
	Boris Brezillon, Marek Vasut

Hi Boris,

Le 12 mai 2018 02:55, Boris Brezillon <boris.brezillon@bootlin.com> a écrit :
>
> Hi Paul, 
>
> On Fri, 11 May 2018 23:29:12 +0200 
> Paul Cercueil <paul@crapouillou.net> wrote: 
>
> > By specifying the properties "mtd-oob-ecc" and "mtd-oob-free", it is 
> > now possible to specify from devicetree where the ECC data is located 
> > inside the OOB region. 
>
> Why would we want to do that? I mean, ECC/free regions are ECC 
> controller dependent (and NAND chip dependent for the OOB size part), 
> so there's no reason to describe it in the DT. And more importantly, 
> people are likely to get it wrong. 
>
> I'm curious, why do you need that? 

Good question.

The reason is that some SoCs have no ECC controller.
The various boards for these SoCs then all use a different layout.

My motivation is to get rid of this (move it to devicetree):
https://elixir.bootlin.com/linux/latest/source/arch/mips/jz4740/board-qi_lb60.c#L93
And enable the support of other boards with custom OOB layouts.

> Regards, 
>
> Boris 

Thanks,
-Paul

> > 
> > Signed-off-by: Paul Cercueil <paul@crapouillou.net> 
> > --- 
> >  Documentation/devicetree/bindings/mtd/nand.txt |  7 +++++ 
> >  drivers/mtd/nand/raw/nand_base.c               | 42 ++++++++++++++++++++++++++ 
> >  2 files changed, 49 insertions(+) 
> > 
> > diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt 
> > index 8bb11d809429..118ea92787cb 100644 
> > --- a/Documentation/devicetree/bindings/mtd/nand.txt 
> > +++ b/Documentation/devicetree/bindings/mtd/nand.txt 
> > @@ -45,6 +45,13 @@ Optional NAND chip properties: 
> >       as reliable as possible. 
> >  - nand-rb: shall contain the native Ready/Busy ids. 
> >  
> > +- nand-oob-ecc: <offset, length> couples of integers, specifying the offset 
> > +      and length of the ECC data in the OOB region. There can be more 
> > +      than one couple. 
> > +- nand-oob-free: <offset, length> couples of integers, specifying the offset 
> > +      and length of a free-to-use area in the OOB region. There can be 
> > +      more than one couple. 
> > + 
> >  The ECC strength and ECC step size properties define the correction capability 
> >  of a controller. Together, they say a controller can correct "{strength} bit 
> >  errors per {size} bytes". 
> > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c 
> > index 72f3a89da513..c905531effb0 100644 
> > --- a/drivers/mtd/nand/raw/nand_base.c 
> > +++ b/drivers/mtd/nand/raw/nand_base.c 
> > @@ -213,6 +213,43 @@ static const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = { 
> >  .free = nand_ooblayout_free_lp_hamming, 
> >  }; 
> >  
> > +static int nand_oob_of(struct device_node *np, int section, 
> > +        struct mtd_oob_region *oobregion, const char *prop) 
> > +{ 
> > + int ret = of_property_read_u32_index(np, prop, 
> > + section * 2, &oobregion->offset); 
> > + if (ret == -EOVERFLOW) 
> > + return -ERANGE; /* We're done */ 
> > + if (ret) 
> > + return ret; 
> > + 
> > + ret = of_property_read_u32_index(np, prop, 
> > + section * 2 + 1, &oobregion->length); 
> > + if (ret == -EOVERFLOW) 
> > + return -EINVAL; /* We must have an even number of integers */ 
> > + 
> > + return ret; 
> > +} 
> > + 
> > +static int nand_ooblayout_ecc_of(struct mtd_info *mtd, int section, 
> > + struct mtd_oob_region *oobregion) 
> > +{ 
> > + return nand_oob_of(mtd->dev.of_node, section, 
> > + oobregion, "nand-oob-ecc"); 
> > +} 
> > + 
> > +static int nand_ooblayout_free_of(struct mtd_info *mtd, int section, 
> > + struct mtd_oob_region *oobregion) 
> > +{ 
> > + return nand_oob_of(mtd->dev.of_node, section, 
> > + oobregion, "nand-oob-free"); 
> > +} 
> > + 
> > +static const struct mtd_ooblayout_ops nand_ooblayout_of_ops = { 
> > + .ecc = nand_ooblayout_ecc_of, 
> > + .free = nand_ooblayout_free_of, 
> > +}; 
> > + 
> >  static int check_offs_len(struct mtd_info *mtd, 
> >  loff_t ofs, uint64_t len) 
> >  { 
> > @@ -5843,6 +5880,11 @@ static int nand_dt_init(struct nand_chip *chip) 
> >  if (of_property_read_bool(dn, "nand-ecc-maximize")) 
> >  chip->ecc.options |= NAND_ECC_MAXIMIZE; 
> >  
> > + if (!chip->mtd.ooblayout && 
> > + of_property_read_bool(dn, "nand-oob-ecc") && 
> > + of_property_read_bool(dn, "nand-oob-free")) 
> > + chip->mtd.ooblayout = &nand_ooblayout_of_ops; 
> > + 
> >  return 0; 
> >  } 
> >  
>

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH] mtd: nand: Add support for reading ooblayout from device tree
@ 2018-05-11 21:29 Paul Cercueil
  2018-05-12  5:55 ` Boris Brezillon
  0 siblings, 1 reply; 9+ messages in thread
From: Paul Cercueil @ 2018-05-11 21:29 UTC (permalink / raw)
  To: David Woodhouse, Brian Norris, Boris Brezillon, Marek Vasut,
	Richard Weinberger, Rob Herring, Mark Rutland
  Cc: linux-mtd, devicetree, linux-kernel, Paul Cercueil

By specifying the properties "mtd-oob-ecc" and "mtd-oob-free", it is
now possible to specify from devicetree where the ECC data is located
inside the OOB region.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 Documentation/devicetree/bindings/mtd/nand.txt |  7 +++++
 drivers/mtd/nand/raw/nand_base.c               | 42 ++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
index 8bb11d809429..118ea92787cb 100644
--- a/Documentation/devicetree/bindings/mtd/nand.txt
+++ b/Documentation/devicetree/bindings/mtd/nand.txt
@@ -45,6 +45,13 @@ Optional NAND chip properties:
 		     as reliable as possible.
 - nand-rb: shall contain the native Ready/Busy ids.
 
+- nand-oob-ecc: <offset, length> couples of integers, specifying the offset
+		     and length of the ECC data in the OOB region. There can be more
+		     than one couple.
+- nand-oob-free: <offset, length> couples of integers, specifying the offset
+		     and length of a free-to-use area in the OOB region. There can be
+		     more than one couple.
+
 The ECC strength and ECC step size properties define the correction capability
 of a controller. Together, they say a controller can correct "{strength} bit
 errors per {size} bytes".
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 72f3a89da513..c905531effb0 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -213,6 +213,43 @@ static const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = {
 	.free = nand_ooblayout_free_lp_hamming,
 };
 
+static int nand_oob_of(struct device_node *np, int section,
+		       struct mtd_oob_region *oobregion, const char *prop)
+{
+	int ret = of_property_read_u32_index(np, prop,
+			section * 2, &oobregion->offset);
+	if (ret == -EOVERFLOW)
+		return -ERANGE; /* We're done */
+	if (ret)
+		return ret;
+
+	ret = of_property_read_u32_index(np, prop,
+			section * 2 + 1, &oobregion->length);
+	if (ret == -EOVERFLOW)
+		return -EINVAL; /* We must have an even number of integers */
+
+	return ret;
+}
+
+static int nand_ooblayout_ecc_of(struct mtd_info *mtd, int section,
+				 struct mtd_oob_region *oobregion)
+{
+	return nand_oob_of(mtd->dev.of_node, section,
+			oobregion, "nand-oob-ecc");
+}
+
+static int nand_ooblayout_free_of(struct mtd_info *mtd, int section,
+				 struct mtd_oob_region *oobregion)
+{
+	return nand_oob_of(mtd->dev.of_node, section,
+			oobregion, "nand-oob-free");
+}
+
+static const struct mtd_ooblayout_ops nand_ooblayout_of_ops = {
+	.ecc = nand_ooblayout_ecc_of,
+	.free = nand_ooblayout_free_of,
+};
+
 static int check_offs_len(struct mtd_info *mtd,
 					loff_t ofs, uint64_t len)
 {
@@ -5843,6 +5880,11 @@ static int nand_dt_init(struct nand_chip *chip)
 	if (of_property_read_bool(dn, "nand-ecc-maximize"))
 		chip->ecc.options |= NAND_ECC_MAXIMIZE;
 
+	if (!chip->mtd.ooblayout &&
+				of_property_read_bool(dn, "nand-oob-ecc") &&
+				of_property_read_bool(dn, "nand-oob-free"))
+		chip->mtd.ooblayout = &nand_ooblayout_of_ops;
+
 	return 0;
 }
 
-- 
2.11.0

^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2018-05-12 18:30 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <20180512115551.56C6E20787@mail.bootlin.com>
2018-05-12 13:42 ` [PATCH] mtd: nand: Add support for reading ooblayout from device tree Boris Brezillon
2018-05-12 14:38   ` Paul Cercueil
2018-05-12 15:00     ` Boris Brezillon
2018-05-12 17:42       ` Paul Cercueil
2018-05-12 18:02         ` Boris Brezillon
2018-05-12 18:30           ` Paul Cercueil
2018-05-12 11:55 Paul Cercueil
  -- strict thread matches above, loose matches on Subject: below --
2018-05-11 21:29 Paul Cercueil
2018-05-12  5:55 ` Boris Brezillon

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