On Fri, Jun 03, 2022 at 05:25:56PM +0200, Ansuel Smith wrote: > On Fri, Jun 03, 2022 at 08:48:06PM +0530, Manivannan Sadhasivam wrote: > > On Thu, May 19, 2022 at 09:01:10PM +0200, Ansuel Smith wrote: > > > 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. > > > > > > > Can you please point me to the downstream/vendor driver that has this > > implementation? > > > > Thanks, > > Mani > > > > Actually found the repo...This is the link [1]. > > My implementation is a variant of this since originally they used a > sysfs entry to swap the ecc configuration. > > [1] https://github.com/marxfang/ipq807x-spf100-cs/blob/master/qsdk/qca/src/linux-4.4/drivers/mtd/nand/qcom_nandc.c > Thanks for the link! After talking internally to Qcom folks, I confirmed that this quirk is only needed on IPQ8064 based platforms. More in the driver patch... Thanks, Mani > > > 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(-) > > > > > > -- > > > 2.34.1 > > > > > > > -- > > மணிவண்ணன் சதாசிவம் > > -- > Ansuel -- மணிவண்ணன் சதாசிவம்
