On Mon, 2008-11-03 at 15:00 -0500, Josh Boyer wrote: > On Mon, 03 Nov 2008 13:55:21 -0600 > Hollis Blanchard <[EMAIL PROTECTED]> wrote: > > > On Mon, 2008-11-03 at 11:43 +1100, Benjamin Herrenschmidt wrote: > > > > Cropping the size of the memory node. That was simplest to do from the > > > > cuboot wrapper at the time. If marking it reserved via a reserve map > > > > is more elegant and correct, we could do that. > > > > > > > > But I will still like to know what about the other way is hairy please. > > > > > > I don't like it :-) Bad feeling ... don't like having a memory > > > node entry that isn't aligned to some large power of two typically. > > > > More specifically, mm/bootmem.c seems to be making the implicit > > assumption that memory size is an even multiple of PAGE_SIZE. With 4K > > pages, 0xffff000 bytes of RAM fits; with 64K pages it does not. > > Hmm.. I dunno what to think about that. Again, how does mem= play > into this? (I will look myself in a bit, but if someone knows offhand > that would be nice..) > > > Using the device tree reserve map stuff does indeed seem to solve the > > problem. However, I really don't understand the layering in > > arch/powerpc/boot at all, so I'll just put this patch out here and > > people can play with wrappers and prototypes all they want: > > This actually looks pretty nice. I'll wait for David to Ack the fdt > parts.
David? -- Hollis Blanchard IBM Linux Technology Center > > powerpc/4xx: work around CHIP11 errata in a more PAGE_SIZE-friendly way > > > > The current CHIP11 errata truncates the device tree memory node, and > > assumes a > > 4K page size. This breaks kernels with non-4K PAGE_SIZE. > > > > Instead, use a device tree memory reservation to reserve only the 256 bytes > > actually affected by the errata, leaving the total memory size unaltered. > > > > Signed-off-by: Hollis Blanchard <[EMAIL PROTECTED]> > > > > diff --git a/arch/powerpc/boot/4xx.c b/arch/powerpc/boot/4xx.c > > --- a/arch/powerpc/boot/4xx.c > > +++ b/arch/powerpc/boot/4xx.c > > @@ -21,7 +21,7 @@ > > #include "reg.h" > > #include "dcr.h" > > > > -static unsigned long chip_11_errata(unsigned long memsize) > > +static void chip_11_errata(unsigned long memsize) > > { > > unsigned long pvr; > > > > @@ -31,13 +31,11 @@ static unsigned long chip_11_errata(unsi > > case 0x40000850: > > case 0x400008d0: > > case 0x200008d0: > > - memsize -= 4096; > > + fdt_reserve_mem(memsize - 256, 256); > > break; > > default: > > break; > > } > > - > > - return memsize; > > } > > > > /* Read the 4xx SDRAM controller to get size of system memory. */ > > @@ -53,7 +51,7 @@ void ibm4xx_sdram_fixup_memsize(void) > > memsize += SDRAM_CONFIG_BANK_SIZE(bank_config); > > } > > > > - memsize = chip_11_errata(memsize); > > + chip_11_errata(memsize); > > dt_fixup_memory(0, memsize); > > } > > > > @@ -219,7 +217,7 @@ void ibm4xx_denali_fixup_memsize(void) > > bank = 4; /* 4 banks */ > > > > memsize = cs * (1 << (col+row)) * bank * dpath; > > - memsize = chip_11_errata(memsize); > > + chip_11_errata(memsize); > > dt_fixup_memory(0, memsize); > > } > > > > diff --git a/arch/powerpc/boot/libfdt-wrapper.c > > b/arch/powerpc/boot/libfdt-wrapper.c > > --- a/arch/powerpc/boot/libfdt-wrapper.c > > +++ b/arch/powerpc/boot/libfdt-wrapper.c > > @@ -167,6 +167,11 @@ static unsigned long fdt_wrapper_finaliz > > return (unsigned long)fdt; > > } > > > > +int fdt_reserve_mem(unsigned long addr, unsigned long bytes) > > +{ > > + return fdt_add_mem_rsv(fdt, addr, bytes); > > +} > > + > > void fdt_init(void *blob) > > { > > int err; > > diff --git a/arch/powerpc/boot/ops.h b/arch/powerpc/boot/ops.h > > --- a/arch/powerpc/boot/ops.h > > +++ b/arch/powerpc/boot/ops.h > > @@ -83,6 +83,7 @@ extern struct loader_info loader_info; > > > > void start(void); > > void fdt_init(void *blob); > > +int fdt_reserve_mem(unsigned long addr, unsigned long bytes); > > int serial_console_init(void); > > int ns16550_console_init(void *devp, struct serial_console_data *scdp); > > int mpsc_console_init(void *devp, struct serial_console_data *scdp); > > > > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev