Hi, ansuelsmth@xxxxxxxxx wrote on Thu, 19 May 2022 21:01:10 +0200: > 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. Manivannan, any feedback on this? > > 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(-) > Thanks, Miquèl
