From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by smtp.subspace.kernel.org (Postfix) with ESMTPS id 481832CA4
	for <llvm@lists.linux.dev>; Mon, 25 Oct 2021 14:34:33 +0000 (UTC)
Received: by mail.kernel.org (Postfix) with ESMTPSA id 6595A60720;
	Mon, 25 Oct 2021 14:34:31 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;
	s=k20201202; t=1635172472;
	bh=BWCI0zBBdH4Ik+znRZ7aJYJUjSobDgePF66QuPV4y90=;
	h=Date:From:To:Cc:Subject:References:In-Reply-To:From;
	b=iSUqk+0YiY3c1g212989NV4QAIxMDM+tPLHJPt+SLcyBHL+o6+9sVm4v7zSac7xjJ
	 J/+MlDFwIW8osmbHYphW6pgggplcV05cpzLouG2KgS6CPPFySbkemjoLoac8TtQZag
	 l4EMJ6YhRG4bxnzT3SrX9YbH86hyWd/DJbDBFGhOWjx4dSuDVFIfh6Wk+2snKT+FyI
	 d22Fn8YtiUzeseiWU/0bGSl5LuSTMNESCAmnFXkTYRsqELKHpZza1OLB6rJ/eglTbj
	 7Gul2+Hx3gTna8TZL7CNIAqltTzJi40sMvjEaR4fdeSkjOoD0GAoOVBus1/OmVng3q
	 AjqzLtYFQOo9A==
Date: Mon, 25 Oct 2021 07:34:28 -0700
From: Nathan Chancellor <nathan@kernel.org>
To: =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <mirq-linux@rere.qmqm.pl>
Cc: Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: Re: [PATCH] soc/tegra: fuse: Fix bitwise vs. logical OR warning
Message-ID: <YXbAdIc1IEDXa7vg@archlinux-ax161>
References: <20211021214500.2388146-1-nathan@kernel.org>
 <YXHh1lVCzVnyTiZv@qmqm.qmqm.pl>
Precedence: bulk
X-Mailing-List: llvm@lists.linux.dev
List-Id: <llvm.lists.linux.dev>
List-Subscribe: <mailto:llvm+subscribe@lists.linux.dev>
List-Unsubscribe: <mailto:llvm+unsubscribe@lists.linux.dev>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <YXHh1lVCzVnyTiZv@qmqm.qmqm.pl>

Hi Michał,

On Thu, Oct 21, 2021 at 11:55:34PM +0200, Michał Mirosław wrote:
> On Thu, Oct 21, 2021 at 02:45:00PM -0700, Nathan Chancellor wrote:
> [...]
> > --- a/drivers/soc/tegra/fuse/speedo-tegra20.c
> > +++ b/drivers/soc/tegra/fuse/speedo-tegra20.c
> > @@ -69,7 +69,7 @@ void __init tegra20_init_speedo_data(struct tegra_sku_info *sku_info)
> >  
> >  	val = 0;
> >  	for (i = CPU_SPEEDO_MSBIT; i >= CPU_SPEEDO_LSBIT; i--) {
> > -		reg = tegra_fuse_read_spare(i) |
> > +		reg = tegra_fuse_read_spare(i) ||
> >  			tegra_fuse_read_spare(i + CPU_SPEEDO_REDUND_OFFS);
> >  		val = (val << 1) | (reg & 0x1);
> >  	}
> > @@ -84,7 +84,7 @@ void __init tegra20_init_speedo_data(struct tegra_sku_info *sku_info)
> >  
> >  	val = 0;
> >  	for (i = SOC_SPEEDO_MSBIT; i >= SOC_SPEEDO_LSBIT; i--) {
> > -		reg = tegra_fuse_read_spare(i) |
> > +		reg = tegra_fuse_read_spare(i) ||
> >  			tegra_fuse_read_spare(i + SOC_SPEEDO_REDUND_OFFS);
> >  		val = (val << 1) | (reg & 0x1);
> >  	}
> 
> It does seem correct, but nevertheless the code looks suspicious. reg is
> already masked with 0x1 as far as I can tell, and there are other places
> which depend on this (like speedo-tegra210.c). Guessing from the use of
> tegra_fuse_read_spare() I would recommend changing its return type as it
> is returing a bit value, not necessarily semantically a boolean.

Yes, I did notice that, as well as the use of tegra_fuse_read_spare()
with boolean operators in tegra-apbmisc.c. I could change it to int if
that is what the maintainers prefer, which would also solve the warning.

Cheers,
Nathan