Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751872AbaBCIsT (ORCPT ); Mon, 3 Feb 2014 03:48:19 -0500 Received: from navarro.puc.rediris.es ([130.206.18.131]:35210 "EHLO navarro.puc.rediris.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751109AbaBCIsS (ORCPT ); Mon, 3 Feb 2014 03:48:18 -0500 X-Greylist: delayed 922 seconds by postgrey-1.27 at vger.kernel.org; Mon, 03 Feb 2014 03:48:18 EST X-Envelope-From: paubert@iram.es Date: Mon, 3 Feb 2014 09:32:36 +0100 From: Gabriel Paubert To: Michael Moese Cc: Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] powerpc: add ioremap_wt Message-ID: <20140203083236.GA30407@visitor2.iram.es> References: <1391411809-1845-1-git-send-email-michael.moese@men.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1391411809-1845-1-git-send-email-michael.moese@men.de> User-Agent: Mutt/1.5.20 (2009-06-14) X-Spamina-Bogosity: Ham Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 03, 2014 at 08:16:49AM +0100, Michael Moese wrote: > Allow for IO memory to be mapped cacheable for performing > PCI read bursts. > > Signed-off-by: Michael Moese > --- > arch/powerpc/include/asm/io.h | 3 +++ > arch/powerpc/mm/pgtable_32.c | 8 ++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h > index 45698d5..9591fff 100644 > --- a/arch/powerpc/include/asm/io.h > +++ b/arch/powerpc/include/asm/io.h > @@ -631,6 +631,8 @@ static inline void iosync(void) > * > * * ioremap_wc enables write combining > * > + * * ioremap_wc enables write thru Typo: _wc -> _wt Looks fine in principle, but there is a significant difference with wc on x86, where read accesses always go to the bus (no read caching). Gabriel > + * > * * iounmap undoes such a mapping and can be hooked > * > * * __ioremap_at (and the pending __iounmap_at) are low level functions to > @@ -652,6 +654,7 @@ extern void __iomem *ioremap(phys_addr_t address, unsigned long size); > extern void __iomem *ioremap_prot(phys_addr_t address, unsigned long size, > unsigned long flags); > extern void __iomem *ioremap_wc(phys_addr_t address, unsigned long size); > +extern void __iomem *ioremap_wt(phys_addr_t address, unsigned long size); > #define ioremap_nocache(addr, size) ioremap((addr), (size)) > > extern void iounmap(volatile void __iomem *addr); > diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c > index 51f8795..9ab0a54 100644 > --- a/arch/powerpc/mm/pgtable_32.c > +++ b/arch/powerpc/mm/pgtable_32.c > @@ -141,6 +141,14 @@ ioremap_wc(phys_addr_t addr, unsigned long size) > EXPORT_SYMBOL(ioremap_wc); > > void __iomem * > +ioremap_wt(phys_addr_t addr, unsigned long size) > +{ > + return __ioremap_caller(addr, size, _PAGE_WRITETHRU, > + __builtin_return_address(0)); > +} > +EXPORT_SYMBOL(ioremap_wt); > + > +void __iomem * > ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags) > { > /* writeable implies dirty for kernel addresses */ > -- > 1.8.5.3 > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev -- 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/