On 02/19/2013 05:14 PM, Wolfgang Denk wrote: > Dear Rob Herring, > > In message <5123e311.1070...@gmail.com> you wrote: >>
[snip] >> What I would really prefer to do is like powerpc where platforms >> override this if they need the fixup and the default behavior is no >> fixup. But that would require knowing which platforms do and don't need >> the fixup. It only going to get harder to change that. > > Normally we use get_ramsize() to check / verify the amount of > available RAM. And on PPC, we nearly always set the ram size in the > DT. I don't know why you think the default was no fixup; this is not > true. It's the other way round. No it is not. The fixup is in bootm.c for all of arm, yet appears in all the board/soc files for powerpc. It may be nearly always fixed up because every platform duplicates the fixup code, but it is not the default. It is a per platform decision on powerpc and it is not on arm. $ git grep fixup_memory arch/arm/lib/bootm.c:static int fixup_memory_node(void *blob) arch/arm/lib/bootm.c: return fdt_fixup_memory_banks(blob, start, size, CONFIG_NR_DRAM_BANKS); arch/arm/lib/bootm.c: fixup_memory_node(*of_flat_tree); arch/powerpc/cpu/74xx_7xx/cpu.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc512x/cpu.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc5xxx/cpu.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc8260/cpu.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc83xx/fdt.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc85xx/fdt.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc86xx/fdt.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/mpc8xx/fdt.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); arch/powerpc/cpu/ppc4xx/fdt.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); board/exmeritus/hww1u1a/hww1u1a.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/bsc9131rdb/bsc9131rdb.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/corenet_ds/corenet_ds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/mpc7448hpc2/mpc7448hpc2.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); board/freescale/mpc8572ds/mpc8572ds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p1010rdb/p1010rdb.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p1022ds/p1022ds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p1023rds/p1023rds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p1_p2_rdb/p1_p2_rdb.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p1_p2_rdb_pc/p1_p2_rdb_pc.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p2020come/p2020come.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p2020ds/p2020ds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/p2041rdb/p2041rdb.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/freescale/t4qds/t4qds.c: fdt_fixup_memory(blob, (u64)base, (u64)size); board/ipek01/ipek01.c: fdt_fixup_memory (blob, (u64) bd->bi_memstart, (u64) bd->bi_memsize); board/pdm360ng/pdm360ng.c: fdt_fixup_memory(blob, (u64)bd->bi_memstart, (u64)bd->bi_memsize); common/cmd_fdt.c: err = fdt_fixup_memory(working_fdt, addr, size); common/fdt_support.c:int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks) common/fdt_support.c:int fdt_fixup_memory(void *blob, u64 start, u64 size) common/fdt_support.c: return fdt_fixup_memory_banks(blob, &start, &size, 1); include/fdt_support.h:int fdt_fixup_memory(void *blob, u64 start, u64 size); include/fdt_support.h:int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks); >>> Actually you are reaching here a point where it seems necessary that >>> U-Boot itself is able to read the DT to configure itself correctly, >>> i. e. the memory size information it holds should then also be >>> extracted from the DT. >> >> I thought about doing this. That's really an orthogonal issue. The >> problem is you cannot adjust the amount of memory u-boot uses to be >> different than the amount of RAM in the /memory node. If you adjust the >> size in u-boot, the adjusted size is passed to the kernel no matter what. >> >> There's issues with LPAE systems having >4GB of RAM as all the size and >> address values are 32-bit. This could be fixed, but I'm not sure there >> is much value in u-boot knowing about memory above 4GB as it can't >> really access all of it and it would be purely informational. > > Well, let's face it - no matter what you do, if the RAM sizes as used > in U-Boot and in Linux differ, at least one of these is wrong. This > is a bug that should be fixed. What you attempt to do is implementing > a method to paper over such bugs. This is not a good thing to do. We'll probably just have to disagree that u-boot needs to know about memory it can't access on 32-bit PAE system unless you want to implement paging. Rob _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
