Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757921Ab3J2BdH (ORCPT ); Mon, 28 Oct 2013 21:33:07 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:63232 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756824Ab3J2BdE (ORCPT ); Mon, 28 Oct 2013 21:33:04 -0400 Date: Mon, 28 Oct 2013 18:32:31 -0700 From: Mark Rutland To: Stephen Boyd Cc: "linux-edac@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , Russell King , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 3/6] ARM: Add Krait L2 accessor functions Message-ID: <20131029013230.GI4763@kartoffel> References: <1383006690-6754-1-git-send-email-sboyd@codeaurora.org> <1383006690-6754-4-git-send-email-sboyd@codeaurora.org> <20131029011942.GG4763@kartoffel> <526F0DB5.8050800@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <526F0DB5.8050800@codeaurora.org> 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: 2435 Lines: 63 On Tue, Oct 29, 2013 at 01:21:57AM +0000, Stephen Boyd wrote: > On 10/28/13 18:19, Mark Rutland wrote: > > On Tue, Oct 29, 2013 at 12:31:27AM +0000, Stephen Boyd wrote: > >> Qualcomm's 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: Russell King > >> Signed-off-by: Stephen Boyd > >> --- > >> arch/arm/common/Kconfig | 3 ++ > >> arch/arm/common/Makefile | 1 + > >> arch/arm/common/krait-l2-accessors.c | 52 +++++++++++++++++++++++++++++++ > >> arch/arm/include/asm/krait-l2-accessors.h | 20 ++++++++++++ > >> 4 files changed, 76 insertions(+) > >> create mode 100644 arch/arm/common/krait-l2-accessors.c > >> create mode 100644 arch/arm/include/asm/krait-l2-accessors.h > > [...] > > > >> +void set_l2_indirect_reg(u32 addr, u32 val) > >> +{ > >> + unsigned long flags; > >> + > >> + raw_spin_lock_irqsave(&krait_l2_lock, flags); > >> + > >> + asm volatile ("mcr p15, 3, %0, c15, c0, 6" : : "r" (addr)); > >> + isb(); > >> + asm volatile ("mcr p15, 3, %0, c15, c0, 7" : : "r" (val)); > >> + isb(); > >> + > >> + raw_spin_unlock_irqrestore(&krait_l2_lock, flags); > >> +} > >> +EXPORT_SYMBOL(set_l2_indirect_reg); > > It might be worth commmenting inline as to what register each of these is > > accessing. Inevitably the commit message will become harder to find and > > associate with the code over time. > > > > Similarly for get_l2_indirect_reg. > > Do you mean with the "@" syntax in the assembly? The 80-character limit > is out to get me. I probably didn't mean inline :) How about a block comment above the first asm block like: /* * Select the L2 window by poking l2cpselr, then write to the window via * l2cpdr. */ Thanks, Mark. -- 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/