Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751839AbaDUPb5 (ORCPT ); Mon, 21 Apr 2014 11:31:57 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:49302 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751182AbaDUPbx (ORCPT ); Mon, 21 Apr 2014 11:31:53 -0400 Date: Mon, 21 Apr 2014 10:31:13 -0500 From: Nishanth Menon To: Felipe Balbi CC: Santosh Shilimkar , Tony Lindgren , Sricharan R , Sekhar Nori , Rajendra Nayak , Peter Ujfalusi , , , , Subject: Re: [PATCH V2 05/19] bus: omap_l3_noc: switch over to relaxed variants of readl/writel Message-ID: <20140421153113.GA32641@kahuna> References: <1397492726-17203-1-git-send-email-nm@ti.com> <1397767775-10965-1-git-send-email-nm@ti.com> <1397767775-10965-6-git-send-email-nm@ti.com> <20140417215228.GD8504@saruman.home> <53504DFF.7090907@ti.com> <20140417220329.GF8504@saruman.home> <53551A2C.8060404@ti.com> <20140421150919.GE27341@saruman.home> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20140421150919.GE27341@saruman.home> 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 On 10:09-20140421, Felipe Balbi wrote: > On Mon, Apr 21, 2014 at 08:16:28AM -0500, Nishanth Menon wrote: > > On 04/17/2014 05:03 PM, Felipe Balbi wrote: > > > On Thu, Apr 17, 2014 at 05:56:15PM -0400, Santosh Shilimkar wrote: > > >> On Thursday 17 April 2014 05:52 PM, Felipe Balbi wrote: > > >>> Hi, > > >>> > > >>> On Thu, Apr 17, 2014 at 03:49:21PM -0500, Nishanth Menon wrote: > > >>>> Currently we use __raw_readl and writel in this driver, however, there > > >>> > > >>> __raw_* and *_relaxed variants are the same, just have a look > > >>> > > >> Except the relaxed version can take care of endian conversion if > > >> needed. :-) > > > > > > right, but according to commit log, this commit is more concerned about > > > the memory barriers which writel()/readl() add, not endianness. Just a > > > matter of fixing up commit log. > > > > > > > yep, this patch does replace writel with writel_relaxed there is no > > strong need for barriers in the operations that we perform here. > > > > I agree that the commit message should probably be a little more > > detailed at this point. > > > > > > How about: > > Currently we use __raw_readl and writel in this driver. Considering > > there is no specific need for a memory barrier, replacing writel with > > endian-neutral writel_relaxed and replacing __raw_readls with the > > corresponding endian-neutral readl_relaxed allows us to have a > > standard set of register operations for the driver. > > > > While at it, simplify address computation using variables for register. > > reads a lot better, thanks > > Acked-by: Felipe Balbi Thanks. Updated branch with patches with Acked-bys pickedup is available here: https://github.com/nmenon/linux-2.6-playground/commits/l3noc/driver-fixes-v2-repost I have dropped the empty commit while at it. Updated patch below for the record: ------------------8<-----------------8<---------------------------- >From a8198b8c78f2a2731fdd4df1ac540887a4c464be Mon Sep 17 00:00:00 2001 From: Nishanth Menon Date: Fri, 11 Apr 2014 11:21:47 -0500 Subject: [PATCH V2 UPDATE 05/19] bus: omap_l3_noc: switch over to relaxed variants of readl/writel Currently we use __raw_readl and writel in this driver. Considering there is no specific need for a memory barrier, replacing writel with endian-neutral writel_relaxed and replacing __raw_readls with the corresponding endian-neutral readl_relaxed allows us to have a standard set of register operations for the driver. While at it, simplify address computation using variables for register. Signed-off-by: Nishanth Menon Acked-by: Santosh Shilimkar Acked-by: Felipe Balbi --- drivers/bus/omap_l3_noc.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c index 37d71b7..c8facb0 100644 --- a/drivers/bus/omap_l3_noc.c +++ b/drivers/bus/omap_l3_noc.c @@ -55,6 +55,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) int err_src = 0; u32 std_err_main, err_reg, clear, masterid; void __iomem *base, *l3_targ_base; + void __iomem *l3_targ_stderr, *l3_targ_slvofslsb, *l3_targ_mstaddr; char *target_name, *master_name = "UN IDENTIFIED"; /* Get the Type of interrupt */ @@ -66,8 +67,8 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) * to determine the source */ base = l3->l3_base[i]; - err_reg = __raw_readl(base + l3_flagmux[i] + - + L3_FLAGMUX_REGERR0 + (inttype << 3)); + err_reg = readl_relaxed(base + l3_flagmux[i] + + L3_FLAGMUX_REGERR0 + (inttype << 3)); /* Get the corresponding error and analyse */ if (err_reg) { @@ -76,10 +77,14 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) /* Read the stderrlog_main_source from clk domain */ l3_targ_base = base + *(l3_targ[i] + err_src); - std_err_main = __raw_readl(l3_targ_base + - L3_TARG_STDERRLOG_MAIN); - masterid = __raw_readl(l3_targ_base + - L3_TARG_STDERRLOG_MSTADDR); + l3_targ_stderr = l3_targ_base + L3_TARG_STDERRLOG_MAIN; + l3_targ_slvofslsb = l3_targ_base + + L3_TARG_STDERRLOG_SLVOFSLSB; + l3_targ_mstaddr = l3_targ_base + + L3_TARG_STDERRLOG_MSTADDR; + + std_err_main = readl_relaxed(l3_targ_stderr); + masterid = readl_relaxed(l3_targ_mstaddr); switch (std_err_main & CUSTOM_ERROR) { case STANDARD_ERROR: @@ -87,12 +92,10 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) l3_targ_inst_name[i][err_src]; WARN(true, "L3 standard error: TARGET:%s at address 0x%x\n", target_name, - __raw_readl(l3_targ_base + - L3_TARG_STDERRLOG_SLVOFSLSB)); + readl_relaxed(l3_targ_slvofslsb)); /* clear the std error log*/ clear = std_err_main | CLEAR_STDERR_LOG; - writel(clear, l3_targ_base + - L3_TARG_STDERRLOG_MAIN); + writel_relaxed(clear, l3_targ_stderr); break; case CUSTOM_ERROR: @@ -107,8 +110,7 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3) master_name, target_name); /* clear the std error log*/ clear = std_err_main | CLEAR_STDERR_LOG; - writel(clear, l3_targ_base + - L3_TARG_STDERRLOG_MAIN); + writel_relaxed(clear, l3_targ_stderr); break; default: -- 1.7.9.5 -- Regards, Nishanth Menon -- 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/