On Mon, Mar 13, 2023 at 05:53:20PM +0100, Johan Jonker wrote: > On 3/13/23 14:26, John Keeping wrote: > > On Mon, Mar 13, 2023 at 01:30:57AM +0100, Johan Jonker wrote: > >> The Rockchip SoC rk3288 has 2 types of device trees floating around. > >> A 64bit reg size when synced from Linux and a 32bit for U-boot. > >> A pre-probe function in the syscon class driver assumes only 32bit. > >> For other odd reg structures the regmap must be defined in the individual > >> syscon driver. Store rk3288 platdata in a regmap before pre-probe > >> during bind. > >> > >> Signed-off-by: Johan Jonker <jbx6...@gmail.com> > >> --- > > > > What is special about the rk3288 syscon that means the driver needs this > > handling? Isn't this a general problem for DTs with 64-bit addresses on > > 32-bit systems that could be solved in syscon-uclass.c? > > The dtd structure is only know to the driver with the SoC orientated > compatible string. > I see guessing the "reg" size more as a legacy that we keep using for > existing drivers > and should be deprecated. > > > > > I suspect it's difficult to handle the general case since #memory-cells > > may be difference for difference syscons so a global constant doesn't > > work, but the approach in this patch seems incredibly verbose for > > You are right here, but other then rk3288 I don't see that happen for other > 32bit Rockchip SoCs. > It's more verbose, because struct syscon_uc_info is not there yet in the bind > fase. (ie. calloc)
What about non-Rockchip SoCs using the syscon uclass? > > something that is likely to be needed for many platforms. > > > > > Could we use driver flags with something like: > > > > .flags = of_platdata_reg_size(struct rockchip_rk3288_noc_plat), > > Driver flags might solve only the "reg" size part, but not the > ARRAY_SIZE and the unknown "reg" property location part. Right - but the generic syscon-uclass code assumes a single range and that reg is the first property (at least I think it should be assuming a single range, but it looks like there might be a bug there now). > > and this untested macro: > > > > #define of_platdata_reg_size(s) \ > > ((sizeof(((struct rockchip_rk3288_noc_plat *) 0)->reg) == 64) ? > > \ > > DM_FLAGS_PLATDATA_REG_64BIT : 0) > > This would create a parallel data flow of a "size flag and ARRAY_SIZE > variable + data" in > a structure to the syscon class driver that also must be stored somewhere, > while we could do the thing correct in the regmap structure right away. But the syscon uclass doesn't need any of that extra info - for OF_PLATDATA is makes assumptions and I don't see why that needs to be any different for 32-bit platforms with #memory-cells = <2>. From syscon-uclass.c: /* * With OF_PLATDATA we really have no way of knowing the format of * the device-specific platform data. So we assume that it starts with * a 'reg' member, and this holds a single address and size. Drivers * using OF_PLATDATA will need to ensure that this is true. */ In fact, for RK3288 we can just do: static_assert(sizeof(fdt_val_t) == FIELD_SIZEOF(struct dtd_rockchip_rk3288_grf, reg[0])); and the uclass gets this right.