Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756263Ab3JHQdc (ORCPT ); Tue, 8 Oct 2013 12:33:32 -0400 Received: from top.free-electrons.com ([176.31.233.9]:34420 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754840Ab3JHQd1 (ORCPT ); Tue, 8 Oct 2013 12:33:27 -0400 Message-ID: <525433D3.2090906@free-electrons.com> Date: Tue, 08 Oct 2013 18:33:23 +0200 From: Gregory CLEMENT User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Sebastian Hesselbarth CC: Mark Rutland , Jason Cooper , Thomas Petazzoni , Arnd Bergmann , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 3/8] ARM: l2x0: add Marvell Tauros3 compatible References: <1381235073-17134-1-git-send-email-sebastian.hesselbarth@gmail.com> <1381235073-17134-4-git-send-email-sebastian.hesselbarth@gmail.com> <20131008134100.GD1412@e106331-lin.cambridge.arm.com> <52542D64.5010800@gmail.com> In-Reply-To: <52542D64.5010800@gmail.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4961 Lines: 111 On 08/10/2013 18:05, Sebastian Hesselbarth wrote: > On 10/08/2013 03:41 PM, Mark Rutland wrote: >> On Tue, Oct 08, 2013 at 01:24:28PM +0100, Sebastian Hesselbarth wrote: >>> This add a compatible for the Marvell Tauros3 cache controller which >>> is compatible with l2x0 cache controllers. While updating the binding >>> documentation, clean up the list of possible compatibles. >>> >>> Signed-off-by: Sebastian Hesselbarth >>> --- > [...] >>> diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt b/Documentation/devicetree/bindings/arm/l2cc.txt >>> index c0c7626..a1d0cbd 100644 >>> --- a/Documentation/devicetree/bindings/arm/l2cc.txt >>> +++ b/Documentation/devicetree/bindings/arm/l2cc.txt >>> @@ -7,20 +7,20 @@ The ARM L2 cache representation in the device tree should be done as follows: >>> Required properties: >>> >>> - compatible : should be one of: >>> - "arm,pl310-cache" >>> - "arm,l220-cache" >>> - "arm,l210-cache" >>> - "marvell,aurora-system-cache": Marvell Controller designed to be >>> + "arm,pl310-cache" >>> + "arm,l220-cache" >>> + "arm,l210-cache" >>> + "bcm,bcm11351-a2-pl310-cache": DEPRECATED by "brcm,bcm11351-a2-pl310-cache" >>> + "brcm,bcm11351-a2-pl310-cache": For Broadcom bcm11351 chipset where an >>> + offset needs to be added to the address before passing down to the L2 >>> + cache controller >>> + "marvell,aurora-system-cache": Marvell Controller designed to be >>> compatible with the ARM one, with system cache mode (meaning >>> maintenance operations on L1 are broadcasted to the L2 and L2 >>> performs the same operation). >>> - "marvell,"aurora-outer-cache: Marvell Controller designed to be >>> - compatible with the ARM one with outer cache mode. >>> - "brcm,bcm11351-a2-pl310-cache": For Broadcom bcm11351 chipset where an >>> - offset needs to be added to the address before passing down to the L2 >>> - cache controller >>> - "bcm,bcm11351-a2-pl310-cache": DEPRECATED by >>> - "brcm,bcm11351-a2-pl310-cache" >>> + "marvell,aurora-outer-cache": Marvell Controller designed to be >>> + compatible with the ARM one with outer cache mode. >>> + "marvell,tauros3-cache": Marvell Tauros3 cache controller. >> >> How does the tauros3 cache differ from the other caches supported by the >> l2x0 driver? > > [added Gregory to Cc] > > Good question. I cannot say at this time. I would have guessed that l2cc > on Armada 1500 and Armada 370/XP are more or less the same, as both use > Marvell's PJ4B CPU. Maybe, Gregory or Thomas can shed some light into > this. > >>> - cache-unified : Specifies the cache is a unified cache. >>> - cache-level : Should be set to 2 for a level 2 cache. >>> - reg : Physical base address and size of cache controller's memory mapped >>> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c >>> index 447da6f..90c776e 100644 >>> --- a/arch/arm/mm/cache-l2x0.c >>> +++ b/arch/arm/mm/cache-l2x0.c >>> @@ -929,6 +929,7 @@ static const struct of_device_id l2x0_ids[] __initconst = { >>> .data = (void *)&aurora_no_outer_data}, >>> { .compatible = "marvell,aurora-outer-cache", >>> .data = (void *)&aurora_with_outer_data}, >>> + { .compatible = "marvell,tauros3-cache", .data = (void *)&l2x0_data }, >> >> Are we intending to handle this differently later? >> >> Or is it 100% compatible with the pl210 or pl220? We could just require >> an entry later in the compatible string list instead... > > No public documentation, no clear answer. > > Tauros3 isn't 100% compatible with any of the ARM l2cc above, it has > additional "features" or "bugs" - call it whatever you want. > > I am not an l2cc expert, but basically I see two options: > a) use (possibly) wrong existing compatible in current mv88de3100.dtsi > now and fix later. > b) add tauros3 compatible now and add (possible) quirks/marvell-specific > properties later. > > IMHO b) is very likely to happen as l2x0_of_init in patch 8/8 already > sets bits, I wasn't able to verify in public ARM l2cc docu. I agree with Sebastian. I don't have more information that Sebastian, but as it is definitely a different controller of the ones from ARM, it should have its own compatible string. Then latter when we will discover new feature and/or bugs, we will be able to manage them without requiring people to update their dtb. If I understood well it is the philosophy behind the device tree. Regards, > > But again, I am very open for suggestions here. > > Sebastian > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- 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/