linux-kernel - [PATCH 4/8] dmaengine: ste_dma40: Do not configure channels during an channel allocation

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Message-Id: <1365532783-27425-4-git-send-email-lee.jones@linaro.org>
Date:	Tue,  9 Apr 2013 19:39:39 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	arnd@...db.de, linus.walleij@...ricsson.com,
	Lee Jones <lee.jones@...aro.org>,
	Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>,
	Per Forlin <per.forlin@...ricsson.com>
Subject: [PATCH 4/8] dmaengine: ste_dma40: Do not configure channels during an channel allocation

According to the DMA documentation allocating a channel and configuring
it are two separate actions. By removing the configuration code from the
channel allocation path we lighten the burden on the information required to
successfully allocate a channel.

Cc: Vinod Koul <vinod.koul@...el.com>
Cc: Dan Williams <djbw@...com>
Cc: Per Forlin <per.forlin@...ricsson.com>
Acked-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/dma/ste_dma40.c |   14 --------------
 1 file changed, 14 deletions(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 2a0a9d4..9e423ad 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -2463,16 +2463,10 @@ static int d40_alloc_chan_resources(struct dma_chan *chan)
 	}
 
 	pm_runtime_get_sync(d40c->base->dev);
-	/* Fill in basic CFG register values */
-	d40_phy_cfg(&d40c->dma_cfg, &d40c->src_def_cfg,
-		    &d40c->dst_def_cfg, chan_is_logical(d40c));
 
 	d40_set_prio_realtime(d40c);
 
 	if (chan_is_logical(d40c)) {
-		d40_log_cfg(&d40c->dma_cfg,
-			    &d40c->log_def.lcsp1, &d40c->log_def.lcsp3);
-
 		if (d40c->dma_cfg.dir == STEDMA40_PERIPH_TO_MEM)
 			d40c->lcpa = d40c->base->lcpa_base +
 				d40c->dma_cfg.src_dev_type * D40_LCPA_CHAN_SIZE;
@@ -2487,14 +2481,6 @@ static int d40_alloc_chan_resources(struct dma_chan *chan)
 		 d40c->phy_chan->num,
 		 d40c->dma_cfg.use_fixed_channel ? ", fixed" : "");
 
-
-	/*
-	 * Only write channel configuration to the DMA if the physical
-	 * resource is free. In case of multiple logical channels
-	 * on the same physical resource, only the first write is necessary.
-	 */
-	if (is_free_phy)
-		d40_config_write(d40c);
 fail:
 	pm_runtime_mark_last_busy(d40c->base->dev);
 	pm_runtime_put_autosuspend(d40c->base->dev);
-- 
1.7.10.4

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