Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751412AbbB1Jj5 (ORCPT ); Sat, 28 Feb 2015 04:39:57 -0500 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]:21200 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbbB1Jjx (ORCPT ); Sat, 28 Feb 2015 04:39:53 -0500 Message-ID: <54F18CE9.6090909@marvell.com> Date: Sat, 28 Feb 2015 17:39:53 +0800 From: Qiao Zhou User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 To: Vinod Koul CC: "zhangfei.gao@linaro.org" , "dan.j.williams@intel.com" , "dmaengine@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] dma: mmp-tdma: refine dma disable and dma-pos update References: <1423140859-20074-1-git-send-email-zhouqiao@marvell.com> <20150223112301.GB5208@intel.com> In-Reply-To: <20150223112301.GB5208@intel.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.13.68,1.0.33,0.0.0000 definitions=2015-02-28_01:2015-02-27,2015-02-28,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1502280106 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4531 Lines: 137 On 02/23/2015 07:23 PM, Vinod Koul wrote: > On Thu, Feb 05, 2015 at 08:54:19PM +0800, Qiao Zhou wrote: >> Below are the refinements. >> 1. Set DMA abort bit when disabling dma channel. This will clear >> the remaining data in dma FIFO, to fix channel-swap issue. >> 2. Read DMA HW pointer when updating DMA status. Previously dma >> position is calculated by adding one period size in dma interrupt. >> This is inaccurate/insufficient for some high-quality audio APP. >> Since interrupt bottom half handler has variable schedule delay, >> it causes big error when calculating sample delay. Read the actual >> HW pointer and feedback can improve the accuracy. >> 3. Do some minor code clean. > This fails to apply for me, care to rebase pls > Rebased. Thanks. From b9cd9aca9c7700423276ba7fb49f267e00e63792 Mon Sep 17 00:00:00 2001 From: Qiao Zhou Date: Sat, 28 Feb 2015 17:05:21 +0800 Subject: [PATCH v2] dma: mmp-tdma: refine dma disable and dma-pos update Below are the refinements. 1. Set DMA abort bit when disabling dma channel. This will clear the remaining data in dma FIFO, to fix channel-swap issue. 2. Read DMA HW pointer when updating DMA status. Previously dma position is calculated by adding one period size in dma interrupt. This is inaccurate/insufficient for some high-quality audio APP. Since interrupt bottom half handler has variable schedule delay, it causes big error when calculating sample delay. Read the actual HW pointer and feedback can improve the accuracy. 3. Do some minor code clean. Signed-off-by: Qiao Zhou --- drivers/dma/mmp_tdma.c | 31 +++++++++++++++++++++++++------ 1 files changed, 25 insertions(+), 6 deletions(-) diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c index 70c2fa9..b6f4e1f 100644 --- a/drivers/dma/mmp_tdma.c +++ b/drivers/dma/mmp_tdma.c @@ -110,7 +110,7 @@ struct mmp_tdma_chan { struct tasklet_struct tasklet; struct mmp_tdma_desc *desc_arr; - phys_addr_t desc_arr_phys; + dma_addr_t desc_arr_phys; int desc_num; enum dma_transfer_direction dir; dma_addr_t dev_addr; @@ -166,9 +166,12 @@ static void mmp_tdma_enable_chan(struct mmp_tdma_chan *tdmac) static int mmp_tdma_disable_chan(struct dma_chan *chan) { struct mmp_tdma_chan *tdmac = to_mmp_tdma_chan(chan); + u32 tdcr; - writel(readl(tdmac->reg_base + TDCR) & ~TDCR_CHANEN, - tdmac->reg_base + TDCR); + tdcr = readl(tdmac->reg_base + TDCR); + tdcr |= TDCR_ABR; + tdcr &= ~TDCR_CHANEN; + writel(tdcr, tdmac->reg_base + TDCR); tdmac->status = DMA_COMPLETE; @@ -296,12 +299,27 @@ static int mmp_tdma_clear_chan_irq(struct mmp_tdma_chan *tdmac) return -EAGAIN; } +static size_t mmp_tdma_get_pos(struct mmp_tdma_chan *tdmac) +{ + size_t reg; + + if (tdmac->idx == 0) { + reg = __raw_readl(tdmac->reg_base + TDSAR); + reg -= tdmac->desc_arr[0].src_addr; + } else if (tdmac->idx == 1) { + reg = __raw_readl(tdmac->reg_base + TDDAR); + reg -= tdmac->desc_arr[0].dst_addr; + } else + return -EINVAL; + + return reg; +} + static irqreturn_t mmp_tdma_chan_handler(int irq, void *dev_id) { struct mmp_tdma_chan *tdmac = dev_id; if (mmp_tdma_clear_chan_irq(tdmac) == 0) { - tdmac->pos = (tdmac->pos + tdmac->period_len) % tdmac->buf_len; tasklet_schedule(&tdmac->tasklet); return IRQ_HANDLED; } else @@ -343,7 +361,7 @@ static void mmp_tdma_free_descriptor(struct mmp_tdma_chan *tdmac) int size = tdmac->desc_num * sizeof(struct mmp_tdma_desc); gpool = tdmac->pool; - if (tdmac->desc_arr) + if (gpool && tdmac->desc_arr) gen_pool_free(gpool, (unsigned long)tdmac->desc_arr, size); tdmac->desc_arr = NULL; @@ -499,6 +517,7 @@ static enum dma_status mmp_tdma_tx_status(struct dma_chan *chan, { struct mmp_tdma_chan *tdmac = to_mmp_tdma_chan(chan); + tdmac->pos = mmp_tdma_get_pos(tdmac); dma_set_tx_state(txstate, chan->completed_cookie, chan->cookie, tdmac->buf_len - tdmac->pos); @@ -610,7 +629,7 @@ static int mmp_tdma_probe(struct platform_device *pdev) int i, ret; int irq = 0, irq_num = 0; int chan_num = TDMA_CHANNEL_NUM; - struct gen_pool *pool; + struct gen_pool *pool = NULL; of_id = of_match_device(mmp_tdma_dt_ids, &pdev->dev); if (of_id) -- 1.7.0.4 -- Best Regards Qiao -- 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/