linux-kernel - Re: [PATCH v3 0/4] Add support for SPI-NOR Macronix OTP

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Message-ID: <CANeKEMO+8=fVx9EXpPoXaLPen79W=7kBTghw3L+9dLwOFOWWoQ@mail.gmail.com>
Date: Sat, 17 Aug 2024 21:30:08 +0200
From: Erez <erezgeva2@...il.com>
To: Miquel Raynal <miquel.raynal@...tlin.com>, Richard Weinberger <richard@....at>, 
	Rob Herring <robh@...nel.org>
Cc: linux-mtd@...ts.infradead.org, Tudor Ambarus <tudor.ambarus@...aro.org>, 
	Pratyush Yadav <pratyush@...nel.org>, Michael Walle <mwalle@...nel.org>, linux-kernel@...r.kernel.org, 
	Vignesh Raghavendra <vigneshr@...com>, devicetree@...r.kernel.org, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>
Subject: Re: [PATCH v3 0/4] Add support for SPI-NOR Macronix OTP

Hi,

Looking in Documentation/devicetree/bindings/mtd/mtd.yaml

I see you are defining OTP in a different way, as partitions.
Each partition is an OTP region which can be user or factory mode
(since many chips do not define or enforce it).

While I try to define the OTP parameters.

I wonder what you think?
Should the parameter be in the partitions?
Do we wish to support asymmetric OTP?
I only found asymmetric OTP (OTP with different region sizes) with old
chips. But perhaps I missed it.

Erez


diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
index 6e3afb42926e..5fde51309b93 100644
--- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
+++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
@@ -90,6 +90,47 @@ properties:
       the SRWD bit while writing the status register. WP# signal hard
strapped to GND
       can be a valid use case.

+  opt_n_regions:
+    type: u32
+    description:
+      Some flash devices need OTP parameters in the device tree.
+      As we can not deduce the parameters based on JEDEC ID,
+       or SFDP.
+      This parameter indicates the number of OTP regions.
+      The value must be larger than 1 and mandatory for OTP.
+
+  otp_len:
+    type: u32
+    description:
+      Some flash devices need OTP parameters in the device tree.
+      As we can not deduce the parameters based on JEDEC ID,
+       or SFDP.
+      This parameter indicates the size (length) in bytes of an OTP region.
+      Currently the driver supports symmetric OTP,
+       which means all regions must use the same size.
+      The value must be positive and mandatory for OTP.
+
+  otp_offset:
+    type: u32
+    description:
+      Some flash devices need OTP parameters in the device tree.
+      As we can not deduce the parameters based on JEDEC ID,
+       or SFDP.
+      This parameter indicates the offset in bytes of
+       an OTP region relative to its previous.
+      User can omit it if the offset equals the length.
+      Or in case we have a single OTP region.
+
+  otp_base:
+    type: u32
+    description:
+      Some flash devices need OTP parameters in the device tree.
+      As we can not deduce the parameters based on JEDEC ID,
+       or SFDP.
+      This parameter indicates the base in bytes of the first OTP region.
+      User can omit it if the base is zero.
+      I.e. the address of the first OTP region starts from 0.
+
   reset-gpios:
     description:
       A GPIO line connected to the RESET (active low) signal of the device.



On Sat, 17 Aug 2024 at 14:42, Erez Geva <erezgeva@...ime.org> wrote:
>
> From: Erez Geva <ErezGeva2@...il.com>
>
> Add support for SPI-NOR Macronix OTP.
> And add MX25L12833F with OTP.
>
> TODO:
> - Test OTP with 'flash_otp_write' and 'flash_otp_lock'
> - Question: Do we need documentation on new DT OTP parameters?
>
> v2:
> Improve description of mx25l12833f.
> Add note about mx25l12833f using the same JEDEC ID as mx25l12805d.
>
> v3:
> Improve description.
> Rename _nor_send_cmd() to spi_nor_send_cmd_internal()
> Remove MX25L12833F specific changes.
> Add reading SFDP to all Macronix chips.
> Add support of reading OTP parameters from device tree.
> Reorgenize patches to 2 SPI-NOR patches and 2 Macronix patches
> Testing with MX25L3233F using BeagleBone Black.
> Test results are in "mtd: spi-nor: macronix: add manufacturer flags" patch
>
> Erez Geva (4):
>   mtd: spi-nor: core: add manufacturer flags
>   mtd: spi-nor: core: add generic functions
>   mtd: spi-nor: macronix: add support for OTP
>   mtd: spi-nor: macronix: add manufacturer flags
>
>  drivers/mtd/spi-nor/core.c     | 166 ++++++++++++++++++++++-------
>  drivers/mtd/spi-nor/core.h     |  34 ++----
>  drivers/mtd/spi-nor/macronix.c | 186 +++++++++++++++++++++++++++++++++
>  drivers/mtd/spi-nor/otp.c      |   6 +-
>  drivers/mtd/spi-nor/winbond.c  |   2 +-
>  include/linux/mtd/spi-nor.h    |  10 ++
>  6 files changed, 336 insertions(+), 68 deletions(-)
>
> --
> 2.39.2
>