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Message-Id: <1233419203.5959.6.camel@dwillia2-linux.ch.intel.com>
Date: Sat, 31 Jan 2009 09:26:43 -0700
From: Dan Williams <dan.j.williams@...el.com>
To: Atsushi Nemoto <anemo@....ocn.ne.jp>
Cc: "hskinnemoen@...el.com" <hskinnemoen@...el.com>,
"kernel@...32linux.org" <kernel@...32linux.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] atmel-mci: fix initialization of dma slave data
Subject: atmel-mci: fix initialization of dma slave data
From: Dan Williams <dan.j.williams@...el.com>
The conversion of atmel-mci to dma_request_channel missed the
initialization of the channel dma_slave information. The filter_fn
passed to dma_request_channel is responsible for initializing the
channel's private data. This implementation has the additional benefit
of enabling a generic client-channel data passing mechanism.
Reviewed-by: Atsushi Nemoto <anemo@....ocn.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
On Sat, 2009-01-31 at 07:52 -0700, Atsushi Nemoto wrote:
> > Thanks. This patch disclose struct dw_dma_chan to its client. But
> > the struct seems too private for me. Maybe we need some generic
> > method to pass slave information? Any idea or plan?
>
> Also, it seems too late to initialize dwc->dws after returning from
> dma_request_channel(). The alloc_chan_resources routine of dw_dmac
> driver needs dmc->dws and it is called from dma_request_channel() via
> dma_chan_get().
Thanks for the review Atsushi, much appreciated. I thought the
Reviewed-by tag was appropriate.
drivers/dma/dmaengine.c | 2 ++
drivers/dma/dw_dmac.c | 5 ++---
drivers/dma/dw_dmac_regs.h | 2 --
drivers/mmc/host/atmel-mci.c | 5 +++--
include/linux/dmaengine.h | 2 ++
5 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a589930..280a9d2 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -518,6 +518,7 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v
dma_chan_name(chan), err);
else
break;
+ chan->private = NULL;
chan = NULL;
}
}
@@ -536,6 +537,7 @@ void dma_release_channel(struct dma_chan *chan)
WARN_ONCE(chan->client_count != 1,
"chan reference count %d != 1\n", chan->client_count);
dma_chan_put(chan);
+ chan->private = NULL;
mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL_GPL(dma_release_channel);
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 6b702cc..a97c07e 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -560,7 +560,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned long flags)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
- struct dw_dma_slave *dws = dwc->dws;
+ struct dw_dma_slave *dws = chan->private;
struct dw_desc *prev;
struct dw_desc *first;
u32 ctllo;
@@ -790,7 +790,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
cfghi = DWC_CFGH_FIFO_MODE;
cfglo = 0;
- dws = dwc->dws;
+ dws = chan->private;
if (dws) {
/*
* We need controller-specific data to set up slave
@@ -866,7 +866,6 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
spin_lock_bh(&dwc->lock);
list_splice_init(&dwc->free_list, &list);
dwc->descs_allocated = 0;
- dwc->dws = NULL;
/* Disable interrupts */
channel_clear_bit(dw, MASK.XFER, dwc->mask);
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 00fdd18..b252b20 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -139,8 +139,6 @@ struct dw_dma_chan {
struct list_head queue;
struct list_head free_list;
- struct dw_dma_slave *dws;
-
unsigned int descs_allocated;
};
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 76bfe16..2b1196e 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1548,9 +1548,10 @@ static bool filter(struct dma_chan *chan, void *slave)
{
struct dw_dma_slave *dws = slave;
- if (dws->dma_dev == chan->device->dev)
+ if (dws->dma_dev == chan->device->dev) {
+ chan->private = dws;
return true;
- else
+ } else
return false;
}
#endif
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 3e0f64c..494aa0d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -121,6 +121,7 @@ struct dma_chan_percpu {
* @local: per-cpu pointer to a struct dma_chan_percpu
* @client-count: how many clients are using this channel
* @table_count: number of appearances in the mem-to-mem allocation table
+ * @private: private data for certain client-channel associations
*/
struct dma_chan {
struct dma_device *device;
@@ -134,6 +135,7 @@ struct dma_chan {
struct dma_chan_percpu *local;
int client_count;
int table_count;
+ void *private;
};
/**
--
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