Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754918AbcKIX4y (ORCPT ); Wed, 9 Nov 2016 18:56:54 -0500 Received: from mail-lf0-f50.google.com ([209.85.215.50]:35813 "EHLO mail-lf0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754887AbcKIX4t (ORCPT ); Wed, 9 Nov 2016 18:56:49 -0500 Subject: Re: [PATCH] net: ethernet: ti: davinci_cpdma: fix fixed prio cpdma ctlr configuration To: Grygorii Strashko , mugunthanvnm@ti.com, netdev@vger.kernel.org References: <1478610656-24634-1-git-send-email-ivan.khoronzhuk@linaro.org> Cc: linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org From: Ivan Khoronzhuk Message-ID: <592966c0-ae4c-ba6b-43ba-8ca837e9a700@linaro.org> Date: Thu, 10 Nov 2016 01:56:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2773 Lines: 71 On 09.11.16 23:09, Grygorii Strashko wrote: > > > On 11/08/2016 07:10 AM, Ivan Khoronzhuk wrote: >> The dma ctlr is reseted to 0 while cpdma start, thus cpdma ctlr > > I assume this is because cpdma_ctlr_start() does soft reset. Is it correct? Probably not. I've seen this register doesn't hold any previous settings (just trash) after cpdma_ctlr_stop(), actually after last channel is stopped (inside of cpdma_ctlr_stop()). Then cpdma_ctlr_start() just reset it to 0. > >> cannot be configured after cpdma is stopped. So, restore content >> of cpdma ctlr while off/on procedure. >> >> Based on net-next/master > > ^ remove it sure > >> >> Signed-off-by: Ivan Khoronzhuk >> --- >> drivers/net/ethernet/ti/cpsw.c | 6 +- >> drivers/net/ethernet/ti/davinci_cpdma.c | 103 +++++++++++++++++--------------- >> drivers/net/ethernet/ti/davinci_cpdma.h | 2 + >> 3 files changed, 58 insertions(+), 53 deletions(-) >> >> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c >> index b1ddf89..4d04b8e 100644 >> --- a/drivers/net/ethernet/ti/cpsw.c >> +++ b/drivers/net/ethernet/ti/cpsw.c >> @@ -1376,10 +1376,6 @@ static int cpsw_ndo_open(struct net_device *ndev) >> ALE_ALL_PORTS, ALE_ALL_PORTS, 0, 0); >> >> if (!cpsw_common_res_usage_state(cpsw)) { >> - /* setup tx dma to fixed prio and zero offset */ >> - cpdma_control_set(cpsw->dma, CPDMA_TX_PRIO_FIXED, 1); >> - cpdma_control_set(cpsw->dma, CPDMA_RX_BUFFER_OFFSET, 0); >> - >> /* disable priority elevation */ >> __raw_writel(0, &cpsw->regs->ptype); >> >> @@ -2710,6 +2706,8 @@ static int cpsw_probe(struct platform_device *pdev) >> dma_params.desc_align = 16; >> dma_params.has_ext_regs = true; >> dma_params.desc_hw_addr = dma_params.desc_mem_phys; >> + dma_params.rxbuf_offset = 0; >> + dma_params.fixed_prio = 1; > > Do we really need this new parameters? Do you have plans to use other values? I'm ok if this is static (equally as a bunch of rest in dma_params), no see reason to use other values, it at least now. But the issue is not only in these two parameters and not only in cpsw_ndo_open(). It touches cpsw_set_channels() also, where ctlr stop/start is present. In order to not copy cpdma_control_set(cpsw->dma, CPDMA_TX_PRIO_FIXED, 1)... in all such kind places in eth drivers, better to allow the cpdma to control it's parameters... The cpdma ctlr register holds a little more parameters (but only two of them are set in cpsw) Maybe there is reason to save them also. Actually I'd seen this problem when playing with on/off channel shapers, unfortunately the cpdma ctlr holds this info also, and it was lost while on/off (but I'm going to restore it in chan_start()). > -- Regards, Ivan Khoronzhuk