diff mbox series

[v2,1/5] dt-bindings: mtd: add Marvell NAND controller documentation

Message ID 20171219132942.27433-2-miquel.raynal@free-electrons.com
State Superseded
Delegated to: Boris Brezillon
Headers show
Series Marvell NAND controller rework with ->exec_op() | expand

Commit Message

Miquel Raynal Dec. 19, 2017, 1:29 p.m. UTC
Document the legacy and the new bindings for Marvell NAND controller.

The pxa3xx_nand.c driver does only support legacy bindings, which are
incomplete and inaccurate. A rework of this controller (called
marvell_nand.c) does support both.

Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
---
 .../devicetree/bindings/mtd/marvell-nand.txt       | 123 +++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/marvell-nand.txt

Comments

Rob Herring (Arm) Dec. 20, 2017, 9:05 p.m. UTC | #1
On Tue, Dec 19, 2017 at 02:29:38PM +0100, Miquel Raynal wrote:
> Document the legacy and the new bindings for Marvell NAND controller.
> 
> The pxa3xx_nand.c driver does only support legacy bindings, which are
> incomplete and inaccurate. A rework of this controller (called
> marvell_nand.c) does support both.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
> ---
>  .../devicetree/bindings/mtd/marvell-nand.txt       | 123 +++++++++++++++++++++
>  1 file changed, 123 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/marvell-nand.txt
> 
> diff --git a/Documentation/devicetree/bindings/mtd/marvell-nand.txt b/Documentation/devicetree/bindings/mtd/marvell-nand.txt
> new file mode 100644
> index 000000000000..aa6a1ed045b2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/marvell-nand.txt
> @@ -0,0 +1,123 @@
> +Marvell NAND Flash Controller (NFC)
> +
> +Required properties:
> +- compatible: can be one of the following:
> +    * "marvell,armada-8k-nand-controller"
> +    * "marvell,armada370-nand-controller"
> +    * "marvell,pxa3xx-nand-controller"
> +    * "marvell,armada-8k-nand" (deprecated)
> +    * "marvell,armada370-nand" (deprecated)
> +    * "marvell,pxa3xx-nand" (deprecated)
> +  Compatibles marked deprecated support only the old bindings described
> +  at the bottom.
> +- reg: NAND flash controller memory area.
> +- #address-cells: shall be set to 1. Encode the NAND CS.
> +- #size-cells: shall be set to 0.
> +- interrupts: shall define the NAND controller interrupt.
> +- clocks: shall reference the NAND controller clock.
> +- marvell,system-controller: Set to retrieve the syscon node that handles
> +  NAND controller related registers (only required with the
> +  "marvell,armada-8k-nand[-controller]" compatibles).
> +
> +Optional properties:
> +- label: see partition.txt. New platforms shall omit this property.
> +- dmas: shall reference DMA channel associated to the NAND controller.
> +  This property is only used with "marvell,pxa3xx-nand[-controller]"
> +  compatible strings.
> +- dma-names: shall be "rxtx".
> +  This property is only used with "marvell,pxa3xx-nand[-controller]"
> +  compatible strings.
> +
> +Optional children nodes:
> +Children nodes represent the available NAND chips.
> +
> +Required properties:
> +- reg: shall contain the native Chip Select ids (0-3)
> +- marvell,rb: shall contain the native Ready/Busy ids (0-1)

We already have at least 2 other <vendor>,rb properties. Let's not add a 
3rd and make a common one instead.

> +
> +Optional properties:
> +- marvell,nand-keep-config: orders the driver not to take the timings
> +  from the core and leaving them completely untouched. Bootloader
> +  timings will then be used.
> +- label: MTD name.
> +- nand-on-flash-bbt: see nand.txt.
> +- nand-ecc-mode: see nand.txt. Will use hardware ECC if not specified.
> +- nand-ecc-algo: see nand.txt. This property may be added when using
> +  hardware ECC for clarification but will be ignored by the driver
> +  because ECC mode is chosen depending on the page size and the strength
> +  required by the NAND chip. This value may be overwritten with
> +  nand-ecc-strength property.

If not used, then drop it.

> +- nand-ecc-strength: see nand.txt.
> +- nand-ecc-step-size: see nand.txt. This has no effect and will be
> +  ignored by the driver when using hardware ECC because Marvell's NAND
> +  flash controller does use fixed strength (1-bit for Hamming, 16-bit
> +  for BCH), so the step size will shrink or grow in order to fit the
> +  required strength. Step sizes are not completely random for all and
> +  follow certain patterns described in AN-379, "Marvell SoC NFC ECC".

Same here.

> +
> +See Documentation/devicetree/bindings/mtd/nand.txt for more details on
> +generic bindings.
> +
> +
> +Example:
> +nand_controller: nand-controller@d0000 {
> +	compatible = "marvell,armada370-nand-controller";
> +	reg = <0xd0000 0x54>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
> +	clocks = <&coredivclk 0>;
> +
> +	nand@0 {
> +		reg = <0>;
> +		label = "main-storage";
> +		marvell,rb = <0>;
> +		nand-ecc-mode = "hw";
> +		marvell,nand-keep-config;
> +		nand-on-flash-bbt;
> +		nand-ecc-strength = <4>;
> +		nand-ecc-step-size = <512>;
> +
> +		partitions {
> +			compatible = "fixed-partitions";
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +
> +			partition@0 {
> +				label = "Rootfs";
> +				reg = <0x00000000 0x40000000>;
> +			};
> +		};
> +	};
> +};
> +
> +
> +Note on legacy bindings: One can find, in not-updated device trees,
> +bindings slightly differents than described above with other properties

s/differents/different/

> +described below as well as the partitions node at the root of a so
> +called "nand" node (without clear controller/chip separation).
> +
> +Legacy properties:
> +- marvell,nand-enable-arbiter: To enable the arbiter, all boards blindly
> +  used it, this bit was set by the bootloader for many boards and even if
> +  it is marked reserved in several datasheets, it might be needed to set
> +  it (otherwise it is harmless) so whether or not this property is set,
> +  the bit is selected by the driver.
> +- num-cs: Number of chip-select lines to use, all boards blindly set 1
> +  to this and for a reason, other values would have failed. The value of
> +  this property is ignored.
> +
> +Example:
> +
> +	nand0: nand@43100000 {
> +		compatible = "marvell,pxa3xx-nand";
> +		reg = <0x43100000 90>;
> +		interrupts = <45>;
> +		dmas = <&pdma 97 0>;
> +		dma-names = "rxtx";
> +		#address-cells = <1>;
> +		marvell,nand-keep-config;
> +		marvell,nand-enable-arbiter;
> +		num-cs = <1>;
> +		/* Partitions (optional) */
> +       };
> -- 
> 2.11.0
>
Miquel Raynal Jan. 7, 2018, 9:43 p.m. UTC | #2
Hi Rob,

On Wed, 20 Dec 2017 15:05:11 -0600
Rob Herring <robh@kernel.org> wrote:

> On Tue, Dec 19, 2017 at 02:29:38PM +0100, Miquel Raynal wrote:
> > Document the legacy and the new bindings for Marvell NAND
> > controller.
> > 
> > The pxa3xx_nand.c driver does only support legacy bindings, which
> > are incomplete and inaccurate. A rework of this controller (called
> > marvell_nand.c) does support both.
> > 
> > Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
> > ---
> >  .../devicetree/bindings/mtd/marvell-nand.txt       | 123
> > +++++++++++++++++++++ 1 file changed, 123 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/mtd/marvell-nand.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/mtd/marvell-nand.txt
> > b/Documentation/devicetree/bindings/mtd/marvell-nand.txt new file
> > mode 100644 index 000000000000..aa6a1ed045b2
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mtd/marvell-nand.txt
> > @@ -0,0 +1,123 @@
> > +Marvell NAND Flash Controller (NFC)
> > +
> > +Required properties:
> > +- compatible: can be one of the following:
> > +    * "marvell,armada-8k-nand-controller"
> > +    * "marvell,armada370-nand-controller"
> > +    * "marvell,pxa3xx-nand-controller"
> > +    * "marvell,armada-8k-nand" (deprecated)
> > +    * "marvell,armada370-nand" (deprecated)
> > +    * "marvell,pxa3xx-nand" (deprecated)
> > +  Compatibles marked deprecated support only the old bindings
> > described
> > +  at the bottom.
> > +- reg: NAND flash controller memory area.
> > +- #address-cells: shall be set to 1. Encode the NAND CS.
> > +- #size-cells: shall be set to 0.
> > +- interrupts: shall define the NAND controller interrupt.
> > +- clocks: shall reference the NAND controller clock.
> > +- marvell,system-controller: Set to retrieve the syscon node that
> > handles
> > +  NAND controller related registers (only required with the
> > +  "marvell,armada-8k-nand[-controller]" compatibles).
> > +
> > +Optional properties:
> > +- label: see partition.txt. New platforms shall omit this property.
> > +- dmas: shall reference DMA channel associated to the NAND
> > controller.
> > +  This property is only used with
> > "marvell,pxa3xx-nand[-controller]"
> > +  compatible strings.
> > +- dma-names: shall be "rxtx".
> > +  This property is only used with
> > "marvell,pxa3xx-nand[-controller]"
> > +  compatible strings.
> > +
> > +Optional children nodes:
> > +Children nodes represent the available NAND chips.
> > +
> > +Required properties:
> > +- reg: shall contain the native Chip Select ids (0-3)
> > +- marvell,rb: shall contain the native Ready/Busy ids (0-1)  
> 
> We already have at least 2 other <vendor>,rb properties. Let's not
> add a 3rd and make a common one instead.

I switched to "nand-rb", added this property in nand.txt (in another
commit) and updated all the DT accordingly.

> 
> > +
> > +Optional properties:
> > +- marvell,nand-keep-config: orders the driver not to take the
> > timings
> > +  from the core and leaving them completely untouched. Bootloader
> > +  timings will then be used.
> > +- label: MTD name.
> > +- nand-on-flash-bbt: see nand.txt.
> > +- nand-ecc-mode: see nand.txt. Will use hardware ECC if not
> > specified. +- nand-ecc-algo: see nand.txt. This property may be
> > added when using
> > +  hardware ECC for clarification but will be ignored by the driver
> > +  because ECC mode is chosen depending on the page size and the
> > strength
> > +  required by the NAND chip. This value may be overwritten with
> > +  nand-ecc-strength property.  
> 
> If not used, then drop it.

Well, nand-ecc-algo will be useful when not using the ECC
engine, so it cannot be removed. I tried to explain better the
situation.

> 
> > +- nand-ecc-strength: see nand.txt.
> > +- nand-ecc-step-size: see nand.txt. This has no effect and will be
> > +  ignored by the driver when using hardware ECC because Marvell's
> > NAND
> > +  flash controller does use fixed strength (1-bit for Hamming,
> > 16-bit
> > +  for BCH), so the step size will shrink or grow in order to fit
> > the
> > +  required strength. Step sizes are not completely random for all
> > and
> > +  follow certain patterns described in AN-379, "Marvell SoC NFC
> > ECC".  
> 
> Same here.

The comment about being ignored was not accurate, I simply removed
that part.

Thanks,
Miquèl
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/mtd/marvell-nand.txt b/Documentation/devicetree/bindings/mtd/marvell-nand.txt
new file mode 100644
index 000000000000..aa6a1ed045b2
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/marvell-nand.txt
@@ -0,0 +1,123 @@ 
+Marvell NAND Flash Controller (NFC)
+
+Required properties:
+- compatible: can be one of the following:
+    * "marvell,armada-8k-nand-controller"
+    * "marvell,armada370-nand-controller"
+    * "marvell,pxa3xx-nand-controller"
+    * "marvell,armada-8k-nand" (deprecated)
+    * "marvell,armada370-nand" (deprecated)
+    * "marvell,pxa3xx-nand" (deprecated)
+  Compatibles marked deprecated support only the old bindings described
+  at the bottom.
+- reg: NAND flash controller memory area.
+- #address-cells: shall be set to 1. Encode the NAND CS.
+- #size-cells: shall be set to 0.
+- interrupts: shall define the NAND controller interrupt.
+- clocks: shall reference the NAND controller clock.
+- marvell,system-controller: Set to retrieve the syscon node that handles
+  NAND controller related registers (only required with the
+  "marvell,armada-8k-nand[-controller]" compatibles).
+
+Optional properties:
+- label: see partition.txt. New platforms shall omit this property.
+- dmas: shall reference DMA channel associated to the NAND controller.
+  This property is only used with "marvell,pxa3xx-nand[-controller]"
+  compatible strings.
+- dma-names: shall be "rxtx".
+  This property is only used with "marvell,pxa3xx-nand[-controller]"
+  compatible strings.
+
+Optional children nodes:
+Children nodes represent the available NAND chips.
+
+Required properties:
+- reg: shall contain the native Chip Select ids (0-3)
+- marvell,rb: shall contain the native Ready/Busy ids (0-1)
+
+Optional properties:
+- marvell,nand-keep-config: orders the driver not to take the timings
+  from the core and leaving them completely untouched. Bootloader
+  timings will then be used.
+- label: MTD name.
+- nand-on-flash-bbt: see nand.txt.
+- nand-ecc-mode: see nand.txt. Will use hardware ECC if not specified.
+- nand-ecc-algo: see nand.txt. This property may be added when using
+  hardware ECC for clarification but will be ignored by the driver
+  because ECC mode is chosen depending on the page size and the strength
+  required by the NAND chip. This value may be overwritten with
+  nand-ecc-strength property.
+- nand-ecc-strength: see nand.txt.
+- nand-ecc-step-size: see nand.txt. This has no effect and will be
+  ignored by the driver when using hardware ECC because Marvell's NAND
+  flash controller does use fixed strength (1-bit for Hamming, 16-bit
+  for BCH), so the step size will shrink or grow in order to fit the
+  required strength. Step sizes are not completely random for all and
+  follow certain patterns described in AN-379, "Marvell SoC NFC ECC".
+
+See Documentation/devicetree/bindings/mtd/nand.txt for more details on
+generic bindings.
+
+
+Example:
+nand_controller: nand-controller@d0000 {
+	compatible = "marvell,armada370-nand-controller";
+	reg = <0xd0000 0x54>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&coredivclk 0>;
+
+	nand@0 {
+		reg = <0>;
+		label = "main-storage";
+		marvell,rb = <0>;
+		nand-ecc-mode = "hw";
+		marvell,nand-keep-config;
+		nand-on-flash-bbt;
+		nand-ecc-strength = <4>;
+		nand-ecc-step-size = <512>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "Rootfs";
+				reg = <0x00000000 0x40000000>;
+			};
+		};
+	};
+};
+
+
+Note on legacy bindings: One can find, in not-updated device trees,
+bindings slightly differents than described above with other properties
+described below as well as the partitions node at the root of a so
+called "nand" node (without clear controller/chip separation).
+
+Legacy properties:
+- marvell,nand-enable-arbiter: To enable the arbiter, all boards blindly
+  used it, this bit was set by the bootloader for many boards and even if
+  it is marked reserved in several datasheets, it might be needed to set
+  it (otherwise it is harmless) so whether or not this property is set,
+  the bit is selected by the driver.
+- num-cs: Number of chip-select lines to use, all boards blindly set 1
+  to this and for a reason, other values would have failed. The value of
+  this property is ignored.
+
+Example:
+
+	nand0: nand@43100000 {
+		compatible = "marvell,pxa3xx-nand";
+		reg = <0x43100000 90>;
+		interrupts = <45>;
+		dmas = <&pdma 97 0>;
+		dma-names = "rxtx";
+		#address-cells = <1>;
+		marvell,nand-keep-config;
+		marvell,nand-enable-arbiter;
+		num-cs = <1>;
+		/* Partitions (optional) */
+       };