Re: [PATCH v6 07/12] usb: chipidea: add a usb2 driver for ci13xxx

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tuesday 30 September 2014 20:39:34 Peter Chen wrote:
> Thanks, Arnd. I had not thought setting dma mask is so complicated, yes, it
> should check the return value, two things to confirm:
> 
> - dma_coerce_mask_and_coherent or dma_set_mask_and_coherent, the only difference
> of these two API is the first one do "dev->dma_mask = &dev->coherent_dma_mask;"
> The reason you suggest choosing dma_set_mask_and_coherent is you do not want
> assign dev->dma_mask?

No, that is just the current definition on ARM32 with CONFIG_ARCH_MULTIPLATFORM, and
that is going to change soon to be DT aware.
dma_set_mask_and_coherent() is supposed to check whether the platform can support
the respective mask and return an error if it cannot.

> - The second parameter for dma_set_mask_and_coherent is DMA_BIT_MASK(32), is it
> ok?
> 
> I just a little confused of what's the operation is "hardcoding the dma mask"?

dma_coerce_mask_and_coherent() will hardcode the dma mask and override whatever
the platform says is necessary.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux