Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754566AbbFBLEO (ORCPT ); Tue, 2 Jun 2015 07:04:14 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:49821 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751891AbbFBLEE (ORCPT ); Tue, 2 Jun 2015 07:04:04 -0400 Message-ID: <556D8B98.2040703@huawei.com> Date: Tue, 2 Jun 2015 18:55:20 +0800 From: Bintian User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Linus Walleij , Russell King - ARM Linux CC: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , Will Deacon , "devicetree@vger.kernel.org" , Rob Herring , =?UTF-8?B?UGF3ZcWCIE1vbGw=?= , Mark Rutland , "ijc+devicetree@hellion.org.uk" , Kumar Gala , "Kevin Hilman" , Mike Turquette , "Rob Herring" , Zhangfei Gao , Haojian Zhuang , Xu Wei , Jaehoon Chung , Olof Johansson , , Stephen Boyd , , , Tomeu Vizoso , Guodong Xu , , Tyler Baker , Kevin Hilman , Paul Bolle , "Arnd Bergmann" , Marc Zyngier , , , , , , , Xinwei Hu , , Yunlei He , XinWei Kong , , , Subject: Re: [PATCH v9 4/6] Documentation: DT: PL011: hi6220: add compatible string for Hisilicon designed UART References: <1432950661-23060-1-git-send-email-bintian.wang@huawei.com> <1432950661-23060-5-git-send-email-bintian.wang@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.68.103] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1973 Lines: 62 On 2015/6/2 16:59, Linus Walleij wrote: > On Sat, May 30, 2015 at 3:50 AM, Bintian Wang wrote: > >> Hisilicon does some performance enhancements based on PL011(e.g. larger >> FIFO length), so add one compatible string "hisilicon,hi6220-uart" for > > That compatible string in the commit message is not even > the same as in the patch. The UART0 is PL011 compatible, the UART1/2 have some performance enhancements features, so based on Mark's suggestion and I add this compatible string just for future use. > >> future optimisations or workarounds works. >> >> Signed-off-by: Bintian Wang >> Suggested-by: Mark Rutland > > Maybe I missed out on the earlier conversation, but do you > mean that the PrimeCell ID has not been properly set up > to something unique in this HiSilicon version of the PL011 > block? > > Even if so: do not override the compatible string like this, > that is not the PrimeCell style. > > Define an 8 bit vendor ID (like tha ASCII for 'H' 0x48 > or whatever) and encode it for these variants, if the > hardware is just using the ARM default PrimeCell > ID, override it in the device tree like Broadcom > are doing in arch/arm/boot/dts/bcm2835.dtsi: > > arm,primecell-periphid = <0x00241011>; > > Maybe yours would be: > > arm,primecell-periphid = <0x00048011>; > > For a first HiSilicon variant, then do some > : > > enum amba_vendor { > AMBA_VENDOR_ARM = 0x41, > + AMBA_VENDOR_HISILICON = 0x48, > > Then patch drivers/tty/serial/amba_pl011.c to add vendor_hisilicon > and a match table for 0x00048011 just like everyone else. Thanks and BR, Bintian > Yours, > Linus Walleij > > . > -- 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/