Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933447Ab2JWUJa (ORCPT ); Tue, 23 Oct 2012 16:09:30 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:63055 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757450Ab2JWUJ0 (ORCPT ); Tue, 23 Oct 2012 16:09:26 -0400 Message-ID: <5086F973.6050309@gmail.com> Date: Tue, 23 Oct 2012 15:09:23 -0500 From: Rob Herring User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: Arnd Bergmann CC: Josh Cartwright , arm@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, John Linn Subject: Re: [PATCH v2 2/4] zynq: move static peripheral mappings References: <20121022211219.GC31538@beefymiracle.amer.corp.natinst.com> <201210231450.11540.arnd@arndb.de> In-Reply-To: <201210231450.11540.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3301 Lines: 87 On 10/23/2012 09:50 AM, Arnd Bergmann wrote: > On Monday 22 October 2012, Josh Cartwright wrote: >> Shifting them up into the vmalloc region prevents the following warning, >> when booting a zynq qemu target with more than 512mb of RAM: >> >> BUG: mapping for 0xe0000000 at 0xe0000000 out of vmalloc space >> >> In addition, it allows for reuse of these mappings when the proper >> drivers issue requests via ioremap(). >> >> Signed-off-by: Josh Cartwright > > This looks like a bug fix that should be backported to older kernels, > so it would be good to add 'Cc: stable@vger.kernel.org' below your > Signed-off-by. > > >> diff --git a/arch/arm/mach-zynq/include/mach/zynq_soc.h b/arch/arm/mach-zynq/include/mach/zynq_soc.h >> index d0d3f8f..ae3b236 100644 >> --- a/arch/arm/mach-zynq/include/mach/zynq_soc.h >> +++ b/arch/arm/mach-zynq/include/mach/zynq_soc.h >> @@ -15,33 +15,37 @@ >> #ifndef __MACH_XILINX_SOC_H__ >> #define __MACH_XILINX_SOC_H__ >> >> +#include >> + >> #define PERIPHERAL_CLOCK_RATE 2500000 >> >> -/* For now, all mappings are flat (physical = virtual) >> +/* Static peripheral mappings are mapped at the top of the >> + * vmalloc region >> */ >> -#define UART0_PHYS 0xE0000000 >> -#define UART0_VIRT UART0_PHYS >> +#define UART0_PHYS 0xE0000000 >> +#define UART0_SIZE SZ_4K >> +#define UART0_VIRT (VMALLOC_END - UART0_SIZE) > > There are plans to move the uart location into a fixed virtual > address in the future, but it hasn't been decided yet. > It will still need a fixed mapping though, just to a different > address. > >> -#define TTC0_PHYS 0xF8001000 >> -#define TTC0_VIRT TTC0_PHYS >> +#define TTC0_PHYS 0xF8001000 >> +#define TTC0_SIZE SZ_4K >> +#define TTC0_VIRT (UART0_VIRT - TTC0_SIZE) > > It's quite likely that this does not have to be a fixed mapping > any more. Just have a look at how drivers/clocksource/dw_apb_timer_of.c > calls of_iomap() to get the address. > >> -#define PL310_L2CC_PHYS 0xF8F02000 >> -#define PL310_L2CC_VIRT PL310_L2CC_PHYS >> +#define PL310_L2CC_PHYS 0xF8F02000 >> +#define PL310_L2CC_SIZE SZ_4K >> +#define PL310_L2CC_VIRT (TTC0_VIRT - PL310_L2CC_SIZE) > > This address would not need a fixed mapping by calling l2x0_of_init > rather than l2x0_init. > >> -#define SCU_PERIPH_PHYS 0xF8F00000 >> -#define SCU_PERIPH_VIRT SCU_PERIPH_PHYS >> +#define SCU_PERIPH_PHYS 0xF8F00000 >> +#define SCU_PERIPH_SIZE SZ_8K >> +#define SCU_PERIPH_VIRT (PL310_L2CC_VIRT - SCU_PERIPH_SIZE) > > And your patch 3 already obsoletes this mapping. Actually, it's probably still needed. The smp platform code typically reads the number of cores from the SCU and the mapping has to be in place before ioremap is up. I don't think there is an architected way to get the number of cores, but it would be nice to avoid this early SCU access. We could also mandate getting the core count from DT instead. Also, the physical address can be read with this on A9's: asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base)); Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/