From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e2.ny.us.ibm.com (e2.ny.us.ibm.com [32.97.182.142]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e2.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id BEE5BDDEDE for ; Tue, 4 Nov 2008 07:02:26 +1100 (EST) Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e2.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id mA3K2Hdq010944 for ; Mon, 3 Nov 2008 15:02:17 -0500 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mA3K11Ji043698 for ; Mon, 3 Nov 2008 15:01:01 -0500 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mA3K0oiI027297 for ; Mon, 3 Nov 2008 15:00:51 -0500 Date: Mon, 3 Nov 2008 15:00:55 -0500 From: Josh Boyer To: Hollis Blanchard Subject: Re: [PATCH 1/2] powerpc: add 16K/64K pages support for the 44x PPC32 architectures. Message-ID: <20081103150055.70bd7360@zod.rchland.ibm.com> In-Reply-To: <1225742121.24019.9.camel@localhost.localdomain> References: <1224123753-20907-1-git-send-email-yanok@emcraft.com> <1224123753-20907-2-git-send-email-yanok@emcraft.com> <48FF3889.2030304@linux.vnet.ibm.com> <20081101113018.GA13646@zod.rchland.ibm.com> <1225576502.8004.222.camel@pasglop> <20081102134153.GA1029@zod.rchland.ibm.com> <1225661596.8004.226.camel@pasglop> <20081102193307.32d17e62@zod.rchland.ibm.com> <1225673034.8004.239.camel@pasglop> <1225742121.24019.9.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: Wolfgang Denk , Ilya Yanok , linuxppc-dev@ozlabs.org, pvr@emcraft.com, dzu@denx.de, david@gibson.dropbear.id.au List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 03 Nov 2008 13:55:21 -0600 Hollis Blanchard 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. josh > 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 > > 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); > >