Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754153Ab1DSIdR (ORCPT ); Tue, 19 Apr 2011 04:33:17 -0400 Received: from eu1sys200aog115.obsmtp.com ([207.126.144.139]:49207 "EHLO eu1sys200aog115.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753985Ab1DSIcs (ORCPT ); Tue, 19 Apr 2011 04:32:48 -0400 From: Viresh Kumar To: , , Cc: , , , , , , Viresh Kumar Subject: [PATCH V2 7/7] dmaengine/dw_dmac: implement pause and resume in dwc_control Date: Tue, 19 Apr 2011 14:02:12 +0530 Message-ID: X-Mailer: git-send-email 1.7.2.2 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2522 Lines: 88 From: Linus Walleij Some peripherals like amba-pl011 needs pause to be implemented in DMA controller drivers. This also returns correct status from dwc_tx_status() in case chan is paused. Signed-off-by: Linus Walleij Signed-off-by: Viresh Kumar --- drivers/dma/dw_dmac.c | 25 +++++++++++++++++++++++-- drivers/dma/dw_dmac_regs.h | 1 + 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index c30f0ba..48d2d7e 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -832,8 +832,7 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, struct dw_desc *desc, *_desc; LIST_HEAD(list); - /* Only supports DMA_TERMINATE_ALL */ - if (cmd != DMA_TERMINATE_ALL) + if (cmd != DMA_TERMINATE_ALL && cmd != DMA_PAUSE && cmd != DMA_RESUME) return -ENXIO; /* @@ -844,11 +843,30 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, */ spin_lock_irqsave(&dwc->lock, dwc->lflags); + if (cmd == DMA_RESUME) { + if (dwc->paused) { + channel_set_bit(dw, CH_EN, dwc->mask); + while (!(dma_readl(dw, CH_EN) & dwc->mask)) + cpu_relax(); + } + spin_unlock_irqrestore(&dwc->lock, dwc->lflags); + return 0; + } + channel_clear_bit(dw, CH_EN, dwc->mask); while (dma_readl(dw, CH_EN) & dwc->mask) cpu_relax(); + if (cmd == DMA_PAUSE) { + dwc->paused = true; + spin_unlock_irqrestore(&dwc->lock, dwc->lflags); + return 0; + } + + /* Terminating a paused transfer */ + dwc->paused = false; + /* active_list entries will end up before queued entries */ list_splice_init(&dwc->queue, &list); list_splice_init(&dwc->active_list, &list); @@ -893,6 +911,9 @@ dwc_tx_status(struct dma_chan *chan, else dma_set_tx_state(txstate, last_complete, last_used, 0); + if (dwc->paused) + return DMA_PAUSED; + return ret; } diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h index 5915743..47138b1 100644 --- a/drivers/dma/dw_dmac_regs.h +++ b/drivers/dma/dw_dmac_regs.h @@ -138,6 +138,7 @@ struct dw_dma_chan { void __iomem *ch_regs; u8 mask; u8 priority; + bool paused; spinlock_t lock; unsigned long lflags; -- 1.7.2.2 -- 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/