| Message ID | 20220519190112.6344-1-ansuelsmth@gmail.com |
|---|---|
| Headers | show |
| Series | Add support for unprotected spare data page | expand |
On Thu, 19 May 2022 21:01:12 +0200, Ansuel Smith wrote: > Document new qcom,boot-pages binding used to apply special > read/write configuration to boot pages. > > QCOM apply a special configuration where spare data is not protected > by ECC for some special pages (used for boot partition). Add > Documentation on how to declare these special pages. > > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com> > --- > .../devicetree/bindings/mtd/qcom,nandc.yaml | 26 +++++++++++++++++++ > 1 file changed, 26 insertions(+) > Reviewed-by: Rob Herring <robh@kernel.org>
On Tue, Jun 07, 2022 at 09:05:16AM +0200, Ansuel Smith wrote: > On Tue, Jun 07, 2022 at 02:45:22PM +0530, Manivannan Sadhasivam wrote: > > On Thu, May 19, 2022 at 09:01:12PM +0200, Ansuel Smith wrote: > > > Document new qcom,boot-pages binding used to apply special > > > read/write configuration to boot pages. > > > > > > QCOM apply a special configuration where spare data is not protected > > > by ECC for some special pages (used for boot partition). Add > > > Documentation on how to declare these special pages. > > > > > > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com> > > > --- > > > .../devicetree/bindings/mtd/qcom,nandc.yaml | 26 +++++++++++++++++++ > > > 1 file changed, 26 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml b/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml > > > index 84ad7ff30121..a59ae9525f4e 100644 > > > --- a/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml > > > +++ b/Documentation/devicetree/bindings/mtd/qcom,nandc.yaml > > > @@ -102,6 +102,30 @@ allOf: > > > - const: rx > > > - const: cmd > > > > > > + - if: > > > + properties: > > > + compatible: > > > + contains: > > > + enum: > > > + - qcom,ipq806x-nand > > > + > > > + then: > > > + properties: > > > + qcom,boot-pages: > > > > Eventhough the page layout is what making the difference, here the boot > > partition offset and size are getting specified. So how about, changing it > > to "qcom,boot-partitions"? > > > > Thanks, > > Mani > > > > Yep, you are correct and the naming is confusing. Will do the change. > Did you check the code if you notice something to improve / an idea of a > better implementation or better naming? > Just to skip sending multiple revision with small changes. > Yep, I do have some comments. Will share them. Thanks, Mani > > > + $ref: /schemas/types.yaml#/definitions/uint32-matrix > > > + items: > > > + items: > > > + - description: offset > > > + - description: size > > > + description: > > > + Some special page used by boot partition have spare data > > > + not protected by ECC. Use this to declare these special page > > > + by defining first the offset and then the size. > > > + > > > + It's in the form of <offset1 size1 offset2 size2 offset3 ...> > > > + > > > + Refer to the ipq8064 example on how to use this special binding. > > > + > > > required: > > > - compatible > > > - reg > > > @@ -135,6 +159,8 @@ examples: > > > nand-ecc-strength = <4>; > > > nand-bus-width = <8>; > > > > > > + qcom,boot-pages = <0x0 0x58a0000>; > > > + > > > partitions { > > > compatible = "fixed-partitions"; > > > #address-cells = <1>; > > > -- > > > 2.34.1 > > > > > > > -- > > மணிவண்ணன் சதாசிவம் > > -- > Ansuel
Some background about this. On original qsdk ipq8064 based firmware there was a big separation from boot partition and user partition. With boot partition we refer to partition used to init the router (bootloader, spm firmware and other internal stuff) With user partition we refer to linux partition and data partition not used to init the router. When someone had to write to these boot partition a special mode was needed, to switch the nand driver to this special configuration. Upstream version of the nandc driver totally dropped this and the result is that if someone try to read data from these partition a CRC warning is printed and if someone try to write that (if for example someone wants to replace the bootloader) result is a broken system as the data is badly written. This series comes to fix this. A user can declare offset and size of these special partition using the qcom,boot-pages binding. An initial implementation of this assumed that the boot-pages started from the start of the nand but we discover that some device have backup of these special partition and we can have situation where we have this partition scheme - APPSBL (require special mode) - APPSBLENV (doesn't require special mode) - ART - APPSBLBK (back of APPSBL require special mode) - APPSBLENVBK (back of APPSBLENV doesn't require special mode) With this configuration we need to declare sparse boot page and we can't assume boot-pages always starts from the start of the nand. A user can use this form to declare sparse boot pages qcom,boot-pages = <0x0 0x0c80000 0x0c80000 0x0500000>; The driver internally will parse this array, convert it to nand pages and check internally on every read/write if this special configuration should used for that page or the normal one. The reason for all of this is that qcom FOR SOME REASON, disable ECC for spare data only for these boot partition and we need to reflect this special configuration to mute these warning and to permit actually writing to these pages. v4: - Fix wrong compatible set for boot-pages (ipq8074 instead of ipq806x) v3: - Fix typo in Docmunetation commit desription - Add items description for uint32-matrix v2: - Add fixes from Krzysztof in Documentation Ansuel Smith (2): mtd: nand: raw: qcom_nandc: add support for unprotected spare data pages dt-bindings: mtd: qcom_nandc: document qcom,boot-pages binding .../devicetree/bindings/mtd/qcom,nandc.yaml | 26 +++ drivers/mtd/nand/raw/qcom_nandc.c | 148 +++++++++++++++++- 2 files changed, 169 insertions(+), 5 deletions(-)