Re: [PATCH v11 3/3] DMA: Freescale: update driver to support 8-channelDMA engine
From: Hongbo Zhang
Date: Mon Nov 11 2013 - 04:12:34 EST
On 11/08/2013 10:45 AM, Dan Williams wrote:
On Mon, Nov 4, 2013 at 6:31 PM, Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx> wrote:
Hi Vinod Koul and Dan Williams,
Ping?
Not much to review from the dmaengine side, just one question below.
It would be helpful if you can send these to the new dmaengine
patchwork at dmaengine@xxxxxxxxxxxxxxx with the Acks you have already
collected.
Sorry didn't notice this new mailing list.
I will resend these patches to it again.
On 10/17/2013 01:56 PM, Hongbo Zhang wrote:
Hi Vinod,
I have gotten ACK from Mark for both the 1/3 and 2/3 patches.
Thanks.
On 09/26/2013 05:33 PM, hongbo.zhang@xxxxxxxxxxxxx wrote:
From: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
This patch adds support to 8-channel DMA engine, thus the driver works
for both
the new 8-channel and the legacy 4-channel DMA engines.
Signed-off-by: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
---
drivers/dma/Kconfig | 9 +++++----
drivers/dma/fsldma.c | 9 ++++++---
drivers/dma/fsldma.h | 2 +-
3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6825957..3979c65 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -89,14 +89,15 @@ config AT_HDMAC
Support the Atmel AHB DMA controller.
config FSL_DMA
- tristate "Freescale Elo and Elo Plus DMA support"
+ tristate "Freescale Elo series DMA support"
depends on FSL_SOC
select DMA_ENGINE
select ASYNC_TX_ENABLE_CHANNEL_SWITCH
---help---
- Enable support for the Freescale Elo and Elo Plus DMA controllers.
- The Elo is the DMA controller on some 82xx and 83xx parts, and the
- Elo Plus is the DMA controller on 85xx and 86xx parts.
+ Enable support for the Freescale Elo series DMA controllers.
+ The Elo is the DMA controller on some mpc82xx and mpc83xx parts,
the
+ EloPlus is on mpc85xx and mpc86xx and Pxxx parts, and the Elo3 is
on
+ some Txxx and Bxxx parts.
config MPC512X_DMA
tristate "Freescale MPC512x built-in DMA engine support"
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 49e8fbd..16a9a48 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -1261,7 +1261,9 @@ static int fsl_dma_chan_probe(struct fsldma_device
*fdev,
WARN_ON(fdev->feature != chan->feature);
chan->dev = fdev->dev;
- chan->id = ((res.start - 0x100) & 0xfff) >> 7;
+ chan->id = (res.start & 0xfff) < 0x300 ?
+ ((res.start - 0x100) & 0xfff) >> 7 :
+ ((res.start - 0x200) & 0xfff) >> 7;
if (chan->id >= FSL_DMA_MAX_CHANS_PER_DEVICE) {
Isn't it a bit fragile to have this based on the resource address?
Can't device tree tell you the channel id directly by an index into
the "dma0: dma@100300" node?
Yes, both this way and putting a "cell-index" into device tree work.
This won't be fragile, because the resource address should always be
defined correctly, otherwise even if we can tell a channel id by
"cell-index" but with wrong resource address, nothing will work.
This piece of code only doesn't seem as neat as using "cell-index", but
we prefer the style that let the device tree describes as true as what
hardware really has. This doesn't mean "cell-index" isn't acceptable, if
it is necessary and unavoidable, we can send another patch to add it,
but currently there is no need and we don't have to do this.
--
Dan
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