From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH v4 3/6] ARM: Add Krait L2 accessor functions Date: Wed, 8 Jan 2014 00:07:25 +0100 Message-ID: <20140107230725.GG4164@pd.tnic> References: <1388434457-4194-1-git-send-email-sboyd@codeaurora.org> <1388434457-4194-4-git-send-email-sboyd@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Received: from mail.skyhub.de ([78.46.96.112]:46321 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753957AbaAGXHa (ORCPT ); Tue, 7 Jan 2014 18:07:30 -0500 Content-Disposition: inline In-Reply-To: <1388434457-4194-4-git-send-email-sboyd@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Stephen Boyd Cc: linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mark Rutland , Russell King On Mon, Dec 30, 2013 at 12:14:14PM -0800, Stephen Boyd wrote: > Krait CPUs have a handful of L2 cache controller registers that > live behind a cp15 based indirection register. First you program > the indirection register (l2cpselr) to point the L2 'window' > register (l2cpdr) at what you want to read/write. Then you > read/write the 'window' register to do what you want. The > l2cpselr register is not banked per-cpu so we must lock around > accesses to it to prevent other CPUs from re-pointing l2cpdr > underneath us. > > Cc: Mark Rutland > Cc: Russell King > Signed-off-by: Stephen Boyd > --- > arch/arm/common/Kconfig | 3 ++ > arch/arm/common/Makefile | 1 + > arch/arm/common/krait-l2-accessors.c | 58 +++++++++++++++++++++++++++++++ > arch/arm/include/asm/krait-l2-accessors.h | 20 +++++++++++ I'm no ARM guy but out of curiosity, why is this code not part of the krait edac driver? IOW, is there a compelling reason for it to be in arch/arm/common/? > 4 files changed, 82 insertions(+) > create mode 100644 arch/arm/common/krait-l2-accessors.c > create mode 100644 arch/arm/include/asm/krait-l2-accessors.h > > diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig > index c3a4e9c..9da52dc 100644 > --- a/arch/arm/common/Kconfig > +++ b/arch/arm/common/Kconfig > @@ -9,6 +9,9 @@ config DMABOUNCE > bool > select ZONE_DMA > > +config KRAIT_L2_ACCESSORS > + bool > + > config SHARP_LOCOMO > bool > > diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile > index 4bdc4162..2836f99 100644 > --- a/arch/arm/common/Makefile > +++ b/arch/arm/common/Makefile > @@ -7,6 +7,7 @@ obj-y += firmware.o > obj-$(CONFIG_ICST) += icst.o > obj-$(CONFIG_SA1111) += sa1111.o > obj-$(CONFIG_DMABOUNCE) += dmabounce.o > +obj-$(CONFIG_KRAIT_L2_ACCESSORS) += krait-l2-accessors.o > obj-$(CONFIG_SHARP_LOCOMO) += locomo.o > obj-$(CONFIG_SHARP_PARAM) += sharpsl_param.o > obj-$(CONFIG_SHARP_SCOOP) += scoop.o > diff --git a/arch/arm/common/krait-l2-accessors.c b/arch/arm/common/krait-l2-accessors.c > new file mode 100644 > index 0000000..f17c361 > --- /dev/null > +++ b/arch/arm/common/krait-l2-accessors.c > @@ -0,0 +1,58 @@ > +/* > + * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 and > + * only version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include > +#include > + > +#include > +#include > + > +static DEFINE_RAW_SPINLOCK(krait_l2_lock); > + > +void set_l2_indirect_reg(u32 addr, u32 val) > +{ > + unsigned long flags; > + > + raw_spin_lock_irqsave(&krait_l2_lock, flags); > + /* > + * Select the L2 window by poking l2cpselr, then write to the window > + * via l2cpdr. > + */ > + asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr)); > + isb(); > + asm volatile ("mcr p15, 3, %0, c15, c0, 7 @ l2cpdr" : : "r" (val)); > + isb(); > + > + raw_spin_unlock_irqrestore(&krait_l2_lock, flags); > +} > +EXPORT_SYMBOL(set_l2_indirect_reg); > + > +u32 get_l2_indirect_reg(u32 addr) > +{ > + u32 val; > + unsigned long flags; > + > + raw_spin_lock_irqsave(&krait_l2_lock, flags); > + /* > + * Select the L2 window by poking l2cpselr, then read from the window > + * via l2cpdr. > + */ > + asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr)); > + isb(); > + asm volatile ("mrc p15, 3, %0, c15, c0, 7 @ l2cpdr" : "=r" (val)); > + > + raw_spin_unlock_irqrestore(&krait_l2_lock, flags); > + > + return val; > +} > +EXPORT_SYMBOL(get_l2_indirect_reg); > diff --git a/arch/arm/include/asm/krait-l2-accessors.h b/arch/arm/include/asm/krait-l2-accessors.h > new file mode 100644 > index 0000000..d5305c4 > --- /dev/null > +++ b/arch/arm/include/asm/krait-l2-accessors.h > @@ -0,0 +1,20 @@ > +/* > + * Copyright (c) 2011-2013, The Linux Foundation. All rights reserved. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 and > + * only version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#ifndef __ASMARM_KRAIT_L2_ACCESSORS_H > +#define __ASMARM_KRAIT_L2_ACCESSORS_H > + > +extern void set_l2_indirect_reg(u32 addr, u32 val); > +extern u32 get_l2_indirect_reg(u32 addr); No need for the "extern"s here. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --