From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751754AbeDENo1 (ORCPT <rfc822;w@1wt.eu>);
        Thu, 5 Apr 2018 09:44:27 -0400
Received: from smtp16.mail.ru ([94.100.176.153]:52454 "EHLO smtp16.mail.ru"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751593AbeDENoX (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 5 Apr 2018 09:44:23 -0400
Subject: Re: [PATCH v3 3/6] spi: sun6i: restrict transfer length in PIO-mode
To: Mark Brown <broonie@kernel.org>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org
References: <20180403154449.2443-1-ssuloev@orpaltech.com>
 <20180403154449.2443-4-ssuloev@orpaltech.com>
 <20180404065048.n76r3ytuznd6fqsl@flea>
 <a6044902-8977-3ce1-d7d5-c6797341a5d0@orpaltech.com>
 <20180405091913.ky4dnmszoobn2xry@flea>
 <ee4adb1e-caf6-32f6-33d6-d8dd94d232cf@orpaltech.com>
 <20180405131735.GB12349@sirena.org.uk>
From: Sergey Suloev <ssuloev@orpaltech.com>
Message-ID: <8159c3a5-af74-9f13-aedb-7ecc708bdff6@orpaltech.com>
Date: Thu, 5 Apr 2018 16:44:16 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.7.0
MIME-Version: 1.0
In-Reply-To: <20180405131735.GB12349@sirena.org.uk>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Authentication-Results: smtp16.mail.ru; auth=pass smtp.auth=ssuloev@orpaltech.com smtp.mailfrom=ssuloev@orpaltech.com
X-7FA49CB5: 0D63561A33F958A562424A6E3C855EC53453D82D03A234027AB98F46BDEDFE59725E5C173C3A84C3A1C30C8AFC676C8BA9E697674C83CBBDB58781B77DE60D36C4224003CC836476C0CAF46E325F83A50BF2EBBBDD9D6B0F05F538519369F3743B503F486389A921A5CC5B56E945C8DA
X-Mailru-Sender: C5364AD02485212F3ACDC11E67D8491773629529CE441DBAAF7FE6EBE53B8FEB069BFC61DABEEB110841D3AAAB1726C63DDE9B364B0DF289264D2CD8C2503E8C22A194DADEED8EEDCA01A23BA9CD1BE7ED14614B50AE0675
X-Mras: OK
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 04/05/2018 04:17 PM, Mark Brown wrote:
> On Thu, Apr 05, 2018 at 12:59:35PM +0300, Sergey Suloev wrote:
>> On 04/05/2018 12:19 PM, Maxime Ripard wrote:
>>> The point of that patch was precisely to allow to send more data than
>>> the FIFO. You're breaking that behaviour without any justification,
>>> and this is not ok.
>> I am sorry, but you can't. That's a hardware limitation.
> Are you positive about that?  Normally you can add things to hardware
> FIFOs while they're being drained so so long as you can keep data
> flowing in at least as fast as it's being consumed.

Well, normally yes, but this is not the case with the hardware that I 
own. My a20 (BPiM1+) and a31 (BPiM2) boards behaves differently. With a 
transfer larger than FIFO then TC interrupt never happens.