Check DMA addressing limitations as suggested by the DMA API
how-to. This does not fix a particular issue seen but is
considered good style.
Signed-off-by: Stefan Agner <[email protected]>
---
drivers/net/ethernet/freescale/fec_main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index c729665107f5..af0fb200e936 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3146,6 +3146,12 @@ static int fec_enet_init(struct net_device *ndev)
fep->tx_align = 0x3;
#endif
+ /* Check mask of the streaming and coherent API */
+ if (dma_set_mask_and_coherent(&fep->pdev->dev, DMA_BIT_MASK(32))) {
+ dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
+ return -ENODEV;
+ }
+
fec_enet_alloc_queue(ndev);
bd_size = (fep->total_tx_ring_size + fep->total_rx_ring_size) * dsize;
--
2.18.0
From: Stefan Agner <[email protected]> Sent: 2018??8??1?? 19:45
> Check DMA addressing limitations as suggested by the DMA API how-to.
> This does not fix a particular issue seen but is considered good style.
>
> Signed-off-by: Stefan Agner <[email protected]>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index c729665107f5..af0fb200e936 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -3146,6 +3146,12 @@ static int fec_enet_init(struct net_device
> *ndev)
> fep->tx_align = 0x3;
> #endif
>
> + /* Check mask of the streaming and coherent API */
> + if (dma_set_mask_and_coherent(&fep->pdev->dev,
> DMA_BIT_MASK(32))) {
> + dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
> + return -ENODEV;
It is better:
ret = dma_set_mask_and_coherent(&fep->pdev->dev, DMA_BIT_MASK(32));
if (ret < 0) {
dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
return ret;
}
If the patch aim to "OF: Don't set default coherent DMA mask", I think not only this driver need to add the DMA mask limitations, many other drivers also need.
> + }
> +
> fec_enet_alloc_queue(ndev);
>
> bd_size = (fep->total_tx_ring_size + fep->total_rx_ring_size) * dsize;
> --
> 2.18.0
On 02.08.2018 04:00, Andy Duan wrote:
> From: Stefan Agner <[email protected]> Sent: 2018年8月1日 19:45
>> Check DMA addressing limitations as suggested by the DMA API how-to.
>> This does not fix a particular issue seen but is considered good style.
>>
>> Signed-off-by: Stefan Agner <[email protected]>
>> ---
>> drivers/net/ethernet/freescale/fec_main.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>> b/drivers/net/ethernet/freescale/fec_main.c
>> index c729665107f5..af0fb200e936 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -3146,6 +3146,12 @@ static int fec_enet_init(struct net_device
>> *ndev)
>> fep->tx_align = 0x3;
>> #endif
>>
>> + /* Check mask of the streaming and coherent API */
>> + if (dma_set_mask_and_coherent(&fep->pdev->dev,
>> DMA_BIT_MASK(32))) {
>> + dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
>> + return -ENODEV;
> It is better:
>
> ret = dma_set_mask_and_coherent(&fep->pdev->dev, DMA_BIT_MASK(32));
> if (ret < 0) {
> dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
> return ret;
> }
The code comes from the example in Documentation/DMA-API-HOWTO.txt.
I can rearrange if you prefer.
>
>
> If the patch aim to "OF: Don't set default coherent DMA mask", I think
> not only this driver need to add the DMA mask limitations, many other
> drivers also need.
It doesn't exactly address the issue since with that patch DMA mask
wasn't set at all. This code would just make the driver fail with
-ENODEV instead of -ENOMEM.
To force a DMA mask I would have to set the DMA mask using
dma_coerce_mask_and_coherent(). But as discussed with Robin it is safe
to assume that an initial mask is set by the bus code:
http://lkml.kernel.org/r/[email protected]
Setting the DMA mask on DT buses has been addressed by Robin with
"of/platform: Initialise default DMA masks". So everything should be
fine again.
I agree, other drivers need fixing too.
--
Stefan
>
>
>> + }
>> +
>> fec_enet_alloc_queue(ndev);
>>
>> bd_size = (fep->total_tx_ring_size + fep->total_rx_ring_size) * dsize;
>> --
>> 2.18.0
From: Stefan Agner <[email protected]> Sent: 2018年8月2日 15:16
> On 02.08.2018 04:00, Andy Duan wrote:
> > From: Stefan Agner <[email protected]> Sent: 2018年8月1日 19:45
> >> Check DMA addressing limitations as suggested by the DMA API how-to.
> >> This does not fix a particular issue seen but is considered good style.
> >>
> >> Signed-off-by: Stefan Agner <[email protected]>
> >> ---
> >> drivers/net/ethernet/freescale/fec_main.c | 6 ++++++
> >> 1 file changed, 6 insertions(+)
> >>
> >> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> >> b/drivers/net/ethernet/freescale/fec_main.c
> >> index c729665107f5..af0fb200e936 100644
> >> --- a/drivers/net/ethernet/freescale/fec_main.c
> >> +++ b/drivers/net/ethernet/freescale/fec_main.c
> >> @@ -3146,6 +3146,12 @@ static int fec_enet_init(struct net_device
> >> *ndev)
> >> fep->tx_align = 0x3;
> >> #endif
> >>
> >> + /* Check mask of the streaming and coherent API */
> >> + if (dma_set_mask_and_coherent(&fep->pdev->dev,
> >> DMA_BIT_MASK(32))) {
> >> + dev_warn(&fep->pdev->dev, "No suitable DMA
> available\n");
> >> + return -ENODEV;
> > It is better:
> >
> > ret = dma_set_mask_and_coherent(&fep->pdev->dev,
> DMA_BIT_MASK(32)); if
> > (ret < 0) {
> > dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
> > return ret;
> > }
>
> The code comes from the example in
> Documentation/DMA-API-HOWTO.txt.
>
> I can rearrange if you prefer.
>
It is better to return the real error code like -EIO if dma_mask is not initialized.
> >
> >
> > If the patch aim to "OF: Don't set default coherent DMA mask", I think
> > not only this driver need to add the DMA mask limitations, many other
> > drivers also need.
>
> It doesn't exactly address the issue since with that patch DMA mask wasn't
> set at all. This code would just make the driver fail with -ENODEV instead of
> -ENOMEM.
>
Yes, I agree. It doesn't address the issue if no patch "of/platform: Initialise default DMA masks".
For non-DT, it seems dma_coerce_mask_and_coherent() much better.
> To force a DMA mask I would have to set the DMA mask using
> dma_coerce_mask_and_coherent(). But as discussed with Robin it is safe
> to assume that an initial mask is set by the bus code:
> https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flk
> ml.kernel.org%2Fr%2F892f9d14-e6fd-7b1b-d07b-af0be6e623fa%40arm.c
> om&data=02%7C01%7Cfugang.duan%40nxp.com%7C618543fb9b4e
> 4f9fa49908d5f847c47f%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%
> 7C0%7C636687909487381876&sdata=hyeeh0KSC3Fu7VDl4A8JbcCO
> %2FwocUpTEMvTv1hjba0E%3D&reserved=0
>
> Setting the DMA mask on DT buses has been addressed by Robin with
> "of/platform: Initialise default DMA masks". So everything should be fine
> again.
>
Anyway, I am fine with the patch except the return code.
Thanks.
> I agree, other drivers need fixing too.
>
> --
> Stefan
>
> >
> >
> >> + }
> >> +
> >> fec_enet_alloc_queue(ndev);
> >>
> >> bd_size = (fep->total_tx_ring_size + fep->total_rx_ring_size) *
> >> dsize;
> >> --
> >> 2.18.0
On 02.08.2018 09:47, Andy Duan wrote:
> From: Stefan Agner <[email protected]> Sent: 2018年8月2日 15:16
>> On 02.08.2018 04:00, Andy Duan wrote:
>> > From: Stefan Agner <[email protected]> Sent: 2018年8月1日 19:45
>> >> Check DMA addressing limitations as suggested by the DMA API how-to.
>> >> This does not fix a particular issue seen but is considered good style.
>> >>
>> >> Signed-off-by: Stefan Agner <[email protected]>
>> >> ---
>> >> drivers/net/ethernet/freescale/fec_main.c | 6 ++++++
>> >> 1 file changed, 6 insertions(+)
>> >>
>> >> diff --git a/drivers/net/ethernet/freescale/fec_main.c
>> >> b/drivers/net/ethernet/freescale/fec_main.c
>> >> index c729665107f5..af0fb200e936 100644
>> >> --- a/drivers/net/ethernet/freescale/fec_main.c
>> >> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> >> @@ -3146,6 +3146,12 @@ static int fec_enet_init(struct net_device
>> >> *ndev)
>> >> fep->tx_align = 0x3;
>> >> #endif
>> >>
>> >> + /* Check mask of the streaming and coherent API */
>> >> + if (dma_set_mask_and_coherent(&fep->pdev->dev,
>> >> DMA_BIT_MASK(32))) {
>> >> + dev_warn(&fep->pdev->dev, "No suitable DMA
>> available\n");
>> >> + return -ENODEV;
>> > It is better:
>> >
>> > ret = dma_set_mask_and_coherent(&fep->pdev->dev,
>> DMA_BIT_MASK(32)); if
>> > (ret < 0) {
>> > dev_warn(&fep->pdev->dev, "No suitable DMA available\n");
>> > return ret;
>> > }
>>
>> The code comes from the example in
>> Documentation/DMA-API-HOWTO.txt.
>>
>> I can rearrange if you prefer.
>>
> It is better to return the real error code like -EIO if dma_mask is
> not initialized.
Good point. Will send a v2.
--
Stefan
>
>> >
>> >
>> > If the patch aim to "OF: Don't set default coherent DMA mask", I think
>> > not only this driver need to add the DMA mask limitations, many other
>> > drivers also need.
>>
>> It doesn't exactly address the issue since with that patch DMA mask wasn't
>> set at all. This code would just make the driver fail with -ENODEV instead of
>> -ENOMEM.
>>
> Yes, I agree. It doesn't address the issue if no patch "of/platform:
> Initialise default DMA masks".
>
> For non-DT, it seems dma_coerce_mask_and_coherent() much better.
>
>> To force a DMA mask I would have to set the DMA mask using
>> dma_coerce_mask_and_coherent(). But as discussed with Robin it is safe
>> to assume that an initial mask is set by the bus code:
>> https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flk
>> ml.kernel.org%2Fr%2F892f9d14-e6fd-7b1b-d07b-af0be6e623fa%40arm.c
>> om&data=02%7C01%7Cfugang.duan%40nxp.com%7C618543fb9b4e
>> 4f9fa49908d5f847c47f%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%
>> 7C0%7C636687909487381876&sdata=hyeeh0KSC3Fu7VDl4A8JbcCO
>> %2FwocUpTEMvTv1hjba0E%3D&reserved=0
>>
>> Setting the DMA mask on DT buses has been addressed by Robin with
>> "of/platform: Initialise default DMA masks". So everything should be fine
>> again.
>>
> Anyway, I am fine with the patch except the return code.
> Thanks.
>
>> I agree, other drivers need fixing too.
>>
>> --
>> Stefan
>>
>> >
>> >
>> >> + }
>> >> +
>> >> fec_enet_alloc_queue(ndev);
>> >>
>> >> bd_size = (fep->total_tx_ring_size + fep->total_rx_ring_size) *
>> >> dsize;
>> >> --
>> >> 2.18.0