fcabdb9b9d
These are cherry-picked & backported from LKML: *https://lkml.org/lkml/2015/3/17/19 They are enabled on both 3.18 and 4.1 kernel. Patches 150 to 154 are applying changes merged since 3.18; they enable mechanisms used by the ADM driver. ADM engine is used by the NAND controller, so it is necessary to bring-up NAND flash support. Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org> SVN-Revision: 46567
63 lines
2.0 KiB
Diff
63 lines
2.0 KiB
Diff
From c4b54a648e682f678c338619df848233a6babc46 Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime.ripard@free-electrons.com>
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Date: Mon, 17 Nov 2014 14:41:59 +0100
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Subject: [PATCH] dmaengine: Make channel allocation callbacks optional
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Nowadays, some drivers don't have anything in there channel allocation
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callbacks anymore.
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Remove the BUG_ON if those callbacks aren't implemented, in order to allow
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drivers to not implement them.
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Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
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Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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---
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drivers/dma/dmaengine.c | 18 +++++++++++-------
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1 file changed, 11 insertions(+), 7 deletions(-)
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--- a/drivers/dma/dmaengine.c
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+++ b/drivers/dma/dmaengine.c
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@@ -235,9 +235,11 @@ static int dma_chan_get(struct dma_chan
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return -ENODEV;
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/* allocate upon first client reference */
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- ret = chan->device->device_alloc_chan_resources(chan);
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- if (ret < 0)
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- goto err_out;
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+ if (chan->device->device_alloc_chan_resources) {
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+ ret = chan->device->device_alloc_chan_resources(chan);
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+ if (ret < 0)
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+ goto err_out;
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+ }
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if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
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balance_ref_count(chan);
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@@ -259,11 +261,15 @@ err_out:
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*/
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static void dma_chan_put(struct dma_chan *chan)
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{
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+ /* This channel is not in use, bail out */
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if (!chan->client_count)
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- return; /* this channel failed alloc_chan_resources */
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+ return;
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+
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chan->client_count--;
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module_put(dma_chan_to_owner(chan));
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- if (chan->client_count == 0)
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+
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+ /* This channel is not in use anymore, free it */
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+ if (!chan->client_count && chan->device->device_free_chan_resources)
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chan->device->device_free_chan_resources(chan);
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}
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@@ -817,8 +823,6 @@ int dma_async_device_register(struct dma
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BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
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!device->device_prep_interleaved_dma);
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- BUG_ON(!device->device_alloc_chan_resources);
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- BUG_ON(!device->device_free_chan_resources);
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BUG_ON(!device->device_tx_status);
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BUG_ON(!device->device_issue_pending);
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BUG_ON(!device->dev);
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