2007-08-23 00:12:50

by Shannon Nelson

Subject: [PATCH] IOAT: ioatdma needs to to play nice in a multi-dma-client world

Now that the DMA engine has a multi-client interface, fix the ioatdma
driver to play along. At the same time, remove a couple of unnecessary
reads and writes.

Signed-off-by: Shannon Nelson <[email protected]>
---

drivers/dma/ioatdma.c | 18 ++++--------------
1 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index 2d1f178..41b18c5 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c
@@ -191,17 +191,12 @@ static int ioat_dma_alloc_chan_resources(struct dma_chan *chan)
int i;
LIST_HEAD(tmp_list);

- /*
- * In-use bit automatically set by reading chanctrl
- * If 0, we got it, if 1, someone else did
- */
- chanctrl = readw(ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
- if (chanctrl & IOAT_CHANCTRL_CHANNEL_IN_USE)
- return -EBUSY;
+ /* have we already been set up? */
+ if (!list_empty(&ioat_chan->free_desc))
+ return INITIAL_IOAT_DESC_COUNT;

/* Setup register to interrupt and write completion status on error */
- chanctrl = IOAT_CHANCTRL_CHANNEL_IN_USE |
- IOAT_CHANCTRL_ERR_INT_EN |
+ chanctrl = IOAT_CHANCTRL_ERR_INT_EN |
IOAT_CHANCTRL_ANY_ERR_ABORT_EN |
IOAT_CHANCTRL_ERR_COMPLETION_EN;
writew(chanctrl, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
@@ -282,11 +277,6 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
in_use_descs - 1);

ioat_chan->last_completion = ioat_chan->completion_addr = 0;
-
- /* Tell hw the chan is free */
- chanctrl = readw(ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
- chanctrl &= ~IOAT_CHANCTRL_CHANNEL_IN_USE;
- writew(chanctrl, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
}

static struct dma_async_tx_descriptor *

2007-08-25 06:03:24

by David Miller

Subject: Re: [PATCH] IOAT: ioatdma needs to to play nice in a multi-dma-client world

From: Shannon Nelson <[email protected]>
Date: Wed, 22 Aug 2007 17:12:18 -0700

> Now that the DMA engine has a multi-client interface, fix the ioatdma
> driver to play along. At the same time, remove a couple of unnecessary
> reads and writes.
>
> Signed-off-by: Shannon Nelson <[email protected]>

Applied, thanks Shannon.