On Wed, 29 Apr 2020 23:18:31 +0800 "Ramuthevar, Vadivel MuruganX" <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx> wrote: > Hi Boris, > > On 29/4/2020 10:48 pm, Boris Brezillon wrote: > > On Wed, 29 Apr 2020 22:33:37 +0800 > > "Ramuthevar, Vadivel MuruganX" > > <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx> wrote: > > > >> Hi Boris, > >> > >> On 29/4/2020 10:22 pm, Boris Brezillon wrote: > >>> On Wed, 29 Apr 2020 18:42:05 +0800 > >>> "Ramuthevar, Vadivel MuruganX" > >>> <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx> wrote: > >>> > >>>> + > >>>> +#define EBU_ADDR_SEL(n) (0x20 + (n) * 4) > >>>> +#define EBU_ADDR_MASK (5 << 4) > >>> > >>> It's still unclear what ADDR_MASK is for. Can you add a comment > >>> explaining what it does? > >> > >> Thank you Boris, keep review and giving inputs, will update. > > > > Can you please explain it here before sending a new version? > > Memory Region Address Mask: > Specifies the number of right-most bits in the base address that should > be included in the address comparison. bits positions(7:4). Okay, then the macro should be #define EBU_ADDR_MASK(x) ((x) << 4) And now I'd like you to explain why 5 is the right value for that field (I guess that has to do with the position of the CS/ALE/CLE pins). > > >>> > >>>> +#define EBU_ADDR_SEL_REGEN 0x1 > >>> > >>> > >>>> + > >>>> + writel(lower_32_bits(ebu_host->cs[ebu_host->cs_num].nand_pa) | > >>>> + EBU_ADDR_SEL_REGEN | EBU_ADDR_MASK, > >>>> + ebu_host->ebu + EBU_ADDR_SEL(reg)); You set EBU_ADDR_SEL(reg) once here... > >>>> + > >>>> + writel(EBU_MEM_BASE_CS_0 | EBU_ADDR_MASK | EBU_ADDR_SEL_REGEN, > >>>> + ebu_host->ebu + EBU_ADDR_SEL(0)); > >>>> + writel(EBU_MEM_BASE_CS_1 | EBU_ADDR_MASK | EBU_ADDR_SEL_REGEN, > >>>> + ebu_host->ebu + EBU_ADDR_SEL(reg)); ... and a second time here. That sounds like overwriting the EBU_ADDR_SEL(reg) register to me. > >>> > >>> That's super weird. You seem to set EBU_ADDR_SEL(reg) twice. Are you > >>> sure that's needed, and are we setting EBU_ADDR_SEL(0) here? > >> > >> You are right, its weird only, but we need it, since different chip > >> select has different memory region access address. > > > > Well, that doesn't make any sense, the second write to > > EBU_ADDR_SEL(reg) overrides the first one, meaning that nand_pa is > > actually never written to ADDR_SEL(reg). > > it will not overwrite the first one, since two different registers > EBU_ADDR_SEL_0 EBU_ADDR_SEL 20H > EBU_ADDR_SEL_1 EBU_ADDR_SEL 24H See my above. > > it is an internal address selection w.r.t chip select for nand physical > address update. > > > > > >> > >> Yes , we are setting both CS0 and CS1 memory access region, if you have > >> any concern to optimize, please suggest me, Thanks! > > > > If you want to setup both CS, and the address written in EBU_ADDR_SEL(x) > > is really related to the nand_pa address, then retrieve resources for > > all CS ranges. > If it's not related, please explain what those > > EBU_MEM_BASE_CS_X values encode. > > Memory Region Base Address > FPI Bus addresses are compared to this base address in conjunction with > the mask control(EBU_ADDR_MASK). Driver need to program this field! That's not explaining what the base address should be. Is 'nand_pa' the value we should have there?
