Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754898Ab3H1Iyo (ORCPT ); Wed, 28 Aug 2013 04:54:44 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:59768 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752754Ab3H1Iym (ORCPT ); Wed, 28 Aug 2013 04:54:42 -0400 Date: Wed, 28 Aug 2013 09:53:40 +0100 From: Catalin Marinas To: Ezequiel Garcia Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Thomas Petazzoni , Gregory Clement , Lior Amsalem , Baruch Siach , Will Deacon , Sebastian Hesselbarth , Russell King Subject: Re: [PATCH v4 2/4] ARM: Add atomic_io_modify optimized routines Message-ID: <20130828085340.GB58219@MacBook-Pro.local> References: <1377358532-23802-1-git-send-email-ezequiel.garcia@free-electrons.com> <1377358532-23802-3-git-send-email-ezequiel.garcia@free-electrons.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1377358532-23802-3-git-send-email-ezequiel.garcia@free-electrons.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2643 Lines: 76 On Sat, Aug 24, 2013 at 04:35:30PM +0100, Ezequiel Garcia wrote: > Implement arch-specific atomic_io_modify and atomic_io_modify_relaxed, > which are based on writel/readl_relaxed and writel_relaxed/readl_relaxed, > respectively. > In both cases, by relaxing the readl, perfomance can be improved. > > Signed-off-by: Ezequiel Garcia > --- > arch/arm/include/asm/io.h | 4 ++++ > arch/arm/kernel/io.c | 29 +++++++++++++++++++++++++++++ > 2 files changed, 33 insertions(+) > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index d070741..53637b6 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -397,5 +397,9 @@ extern int devmem_is_allowed(unsigned long pfn); > extern void register_isa_ports(unsigned int mmio, unsigned int io, > unsigned int io_shift); > > +#define __HAVE_ARCH_ATOMIC_IO_MODIFY > +extern void atomic_io_modify(void __iomem *reg, u32 mask, u32 set); > +extern void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set); > + > #endif /* __KERNEL__ */ > #endif /* __ASM_ARM_IO_H */ > diff --git a/arch/arm/kernel/io.c b/arch/arm/kernel/io.c > index dcd5b4d..a8c9c9b 100644 > --- a/arch/arm/kernel/io.c > +++ b/arch/arm/kernel/io.c > @@ -1,6 +1,35 @@ > #include > #include > #include > +#include > + > +static DEFINE_RAW_SPINLOCK(__io_lock); > + > +void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set) > +{ > + unsigned long flags; > + u32 value; > + > + raw_spin_lock_irqsave(&__io_lock, flags); > + value = readl_relaxed(reg) & ~mask; > + value |= (set & mask); > + writel_relaxed(value, reg); > + raw_spin_unlock_irqrestore(&__io_lock, flags); > +} > +EXPORT_SYMBOL(atomic_io_modify_relaxed); > + > +void atomic_io_modify(void __iomem *reg, u32 mask, u32 set) > +{ > + unsigned long flags; > + u32 value; > + > + raw_spin_lock_irqsave(&__io_lock, flags); > + value = readl_relaxed(reg) & ~mask; > + value |= (set & mask); > + writel(value, reg); > + raw_spin_unlock_irqrestore(&__io_lock, flags); > +} > +EXPORT_SYMBOL(atomic_io_modify); Is this any different from the generic one introduced in patch 1/4? I would rather just use the generic definition. Similarly, a generic atomic_io_modify_relaxed() but guarded with something like __HAVE_ARCH_RELAXED_IO. -- Catalin -- 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/