* [PATCH] ixp4xx_eth: set the device dma_coherent_mask
@ 2013-03-19 15:59 Christophe Aeschlimann
2013-03-19 16:33 ` David Miller
2013-03-19 22:35 ` Krzysztof Halasa
0 siblings, 2 replies; 4+ messages in thread
From: Christophe Aeschlimann @ 2013-03-19 15:59 UTC (permalink / raw)
To: khc; +Cc: netdev, linux-kernel, Christophe Aeschlimann
Without the mask it is impossible to take the network interface up
since it returns the following error:
> net eth1: coherent DMA mask is unset
> ifconfig: SIOCSIFFLAGS: Cannot allocate memory
Tested on an out-of-tree ixp425 based board.
Signed-off-by: Christophe Aeschlimann <c.aeschlimann@acn-group.ch>
---
drivers/net/ethernet/xscale/ixp4xx_eth.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/net/ethernet/xscale/ixp4xx_eth.c b/drivers/net/ethernet/xscale/ixp4xx_eth.c
index 6958a5e..ff23c5c 100644
--- a/drivers/net/ethernet/xscale/ixp4xx_eth.c
+++ b/drivers/net/ethernet/xscale/ixp4xx_eth.c
@@ -1398,6 +1398,7 @@ static int eth_init_one(struct platform_device *pdev)
return -ENOMEM;
SET_NETDEV_DEV(dev, &pdev->dev);
+ dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
port = netdev_priv(dev);
port->netdev = dev;
port->id = pdev->id;
--
1.7.9
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ixp4xx_eth: set the device dma_coherent_mask
2013-03-19 15:59 [PATCH] ixp4xx_eth: set the device dma_coherent_mask Christophe Aeschlimann
@ 2013-03-19 16:33 ` David Miller
2013-03-19 17:04 ` Mugunthan V N
2013-03-19 22:35 ` Krzysztof Halasa
1 sibling, 1 reply; 4+ messages in thread
From: David Miller @ 2013-03-19 16:33 UTC (permalink / raw)
To: aeschlimann; +Cc: khc, netdev, linux-kernel, c.aeschlimann
From: Christophe Aeschlimann <aeschlimann@gmail.com>
Date: Tue, 19 Mar 2013 16:59:25 +0100
> Without the mask it is impossible to take the network interface up
> since it returns the following error:
>
>> net eth1: coherent DMA mask is unset
>> ifconfig: SIOCSIFFLAGS: Cannot allocate memory
>
> Tested on an out-of-tree ixp425 based board.
>
> Signed-off-by: Christophe Aeschlimann <c.aeschlimann@acn-group.ch>
...
> @@ -1398,6 +1398,7 @@ static int eth_init_one(struct platform_device *pdev)
> return -ENOMEM;
>
> SET_NETDEV_DEV(dev, &pdev->dev);
> + dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
Hmmm, shouldn't this be the default value, set by the bus layer or
similar?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ixp4xx_eth: set the device dma_coherent_mask
2013-03-19 16:33 ` David Miller
@ 2013-03-19 17:04 ` Mugunthan V N
0 siblings, 0 replies; 4+ messages in thread
From: Mugunthan V N @ 2013-03-19 17:04 UTC (permalink / raw)
To: David Miller; +Cc: aeschlimann, khc, netdev, linux-kernel, c.aeschlimann
On 3/19/2013 10:03 PM, David Miller wrote:
> From: Christophe Aeschlimann<aeschlimann@gmail.com>
> Date: Tue, 19 Mar 2013 16:59:25 +0100
>
>> >Without the mask it is impossible to take the network interface up
>> >since it returns the following error:
>> >
>>> >>net eth1: coherent DMA mask is unset
>>> >>ifconfig: SIOCSIFFLAGS: Cannot allocate memory
>> >
>> >Tested on an out-of-tree ixp425 based board.
>> >
>> >Signed-off-by: Christophe Aeschlimann<c.aeschlimann@acn-group.ch>
> ...
>> >@@ -1398,6 +1398,7 @@ static int eth_init_one(struct platform_device *pdev)
>> > return -ENOMEM;
>> >
>> > SET_NETDEV_DEV(dev, &pdev->dev);
>> >+ dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> Hmmm, shouldn't this be the default value, set by the bus layer or
> similar?
bus layer or any platform code doesn't init this value. The same issue
applies
to CPSW driver also. Previously the same was done in board or device
file. But
this approach is obsolete now, need to think of how it can be resolved in DT
approach
Regards
Mugunthan V N
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ixp4xx_eth: set the device dma_coherent_mask
2013-03-19 15:59 [PATCH] ixp4xx_eth: set the device dma_coherent_mask Christophe Aeschlimann
2013-03-19 16:33 ` David Miller
@ 2013-03-19 22:35 ` Krzysztof Halasa
1 sibling, 0 replies; 4+ messages in thread
From: Krzysztof Halasa @ 2013-03-19 22:35 UTC (permalink / raw)
To: Christophe Aeschlimann; +Cc: netdev, linux-kernel, Christophe Aeschlimann
Christophe Aeschlimann <aeschlimann@gmail.com> writes:
> Without the mask it is impossible to take the network interface up
> since it returns the following error:
>
>> net eth1: coherent DMA mask is unset
>> ifconfig: SIOCSIFFLAGS: Cannot allocate memory
>
> +++ b/drivers/net/ethernet/xscale/ixp4xx_eth.c
> @@ -1398,6 +1398,7 @@ static int eth_init_one(struct platform_device *pdev)
> return -ENOMEM;
>
> SET_NETDEV_DEV(dev, &pdev->dev);
> + dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> port = netdev_priv(dev);
> port->netdev = dev;
> port->id = pdev->id;
This happens to work but seems to me like a bad "solution". The real
issue is that current ARM coherent_dma_mask (and regular dma_mask)
handling is just broken (at least on platforms with
CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK). I'm thinking how can it be
fixed.
The problematic parts include the dmabouncer (which takes over DMA
operations and provide services similar to swiotlb), the host DMA and
coherent DMA masks (which are property of the buses) and the device
masks, which should be ANDed with bus masks (but aren't).
What the driver should use is:
err = dma_set_coherent_mask(xxx);
(but the subsystem have to be fixed first).
Also, according to DMA-API, 32-bit is the default.
--
Krzysztof Halasa
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-03-19 22:45 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2013-03-19 15:59 [PATCH] ixp4xx_eth: set the device dma_coherent_mask Christophe Aeschlimann
2013-03-19 16:33 ` David Miller
2013-03-19 17:04 ` Mugunthan V N
2013-03-19 22:35 ` Krzysztof Halasa
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