On Friday, October 06, 2017, Christoph Hellwig wrote: > This is still missing a proper API for accessing the file system, > as said before specifying a physical address in the mount command > line is a an absolute non-no. > > Either work with the mtd folks to get the mtd core down to an absolute > minimum suitable for you, or figure out a way to specify fs nodes > through DT or similar. On my system, the QSPI Flash is memory mapped and set up by the boot loader. In order to test the upstream kernel, I use a squashfs image and mtd-rom. So, 0x18000000 is the physical address of flash as it is seen by the CPU. Is there any benefit to doing something similar to this? /* File System */ /* Requires CONFIG_MTD_ROM=y */ qspi@18000000 { compatible = "mtd-rom"; probe-type = "map_rom"; reg = <0x18000000 0x4000000>; /* 64 MB*/ bank-width = <4>; device-width = <1>; #address-cells = <1>; #size-cells = <1>; partition@800000 { label ="user"; reg = <0x0800000 0x800000>; /* 8MB @ 0x18800000 */ read-only; }; }; Of course this basically ioremaps the entire space on probe, but I think what you really want to do is just ioremap pages at a time (maybe..I might not be following your code correctly) Chris -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href