On 03/10/2023 14:28, Marek Vasut wrote: > On 9/20/23 14:42, Paul Barker wrote: >> The ARM TrustedFirmware code for the Renesas RZ/G2L SoC family passes a >> devicetree blob to the bootloader as an argument in the same was > > same way (typo) > >> previous R-Car gen3/gen4 SoCs. > > Gen3 / Gen4 > >> This blob contains a compatible string >> which can be used to identify the particular SoC we are running on. > > Why not read the PRR ?
Reading the DEVID & PRR registers is not sufficient to tell the SoCs apart. From page 204 of the datasheet (R01UH0914EJ0130 Rev.1.30) regarding the DEVID register: "Note: RZ/G2L and RZ/G2LC are the same value. If identification between G2L and G2LC is needed, read the value of address H’0_1186_1178. The value is below. H’0000_0000: RZ/G2L H’0000_0001: RZ/G2LC" Address 0x11861178 is in the OTP region which can only be read from the secure world (i.e. TrustedFirmware). So we have to rely on TrustedFirmware to determine the SoC and pass this information to u-boot via an fdt blob. Thanks, Paul
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