RE: [PATCH v2 2/2] drivers: remove force dma flag from buses

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

 




> -----Original Message-----
> From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, March 21, 2018 15:05
> To: Nipun Gupta <nipun.gupta@xxxxxxx>
> Cc: robin.murphy@xxxxxxx; hch@xxxxxx; linux@xxxxxxxxxxxxxxx;
> m.szyprowski@xxxxxxxxxxx; bhelgaas@xxxxxxxxxx; zajec5@xxxxxxxxx;
> andy.gross@xxxxxxxxxx; david.brown@xxxxxxxxxx; dan.j.williams@xxxxxxxxx;
> vinod.koul@xxxxxxxxx; thierry.reding@xxxxxxxxx; robh+dt@xxxxxxxxxx;
> frowand.list@xxxxxxxxx; jarkko.sakkinen@xxxxxxxxxxxxxxx;
> rafael.j.wysocki@xxxxxxxxx; dmitry.torokhov@xxxxxxxxx; johan@xxxxxxxxxx;
> msuchanek@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; iommu@lists.linux-
> foundation.org; linux-wireless@xxxxxxxxxxxxxxx; linux-arm-
> msm@xxxxxxxxxxxxxxx; linux-soc@xxxxxxxxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx;
> dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-tegra@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; Bharat Bhushan
> <bharat.bhushan@xxxxxxx>; Leo Li <leoyang.li@xxxxxxx>
> Subject: Re: [PATCH v2 2/2] drivers: remove force dma flag from buses
> 
> On Wed, Mar 21, 2018 at 12:25:23PM +0530, Nipun Gupta wrote:
> > With each bus implementing its own DMA configuration callback,
> > there is no need for bus to explicitly have force_dma in its
> > global structure. This patch modifies of_dma_configure API to
> > accept an input parameter which specifies if implicit DMA
> > configuration is required even when it is not described by the
> > firmware.
> 
> Having to "remember" what that bool variable means on the end of the
> function call is a royal pain over time, right?
> 
> Why not just create a new function:
> 	dma_common_configure_force(dma)
> that always does this?  Leave "dma_common_configure()" alone, and then
> wrap the old code with these two helper functions that call the 'core'
> code with the bool set properly?
> 
> That way you do not have to "know" what that parameter is, the function
> name just documents it automatically, so when you see it in the
> bus-specific code, no need to go and have to hunt for anything.  And if
> you are reading the dma core code, it's obvious what is happening as the
> functions are all right there.

How about we do not pass any flag in 'dma_common_configure()', and inside this
API we pass "true" to 'of_dma_configure()'? I am saying this because currently
both the busses (platform and AMBA) which uses 'dma_common_configure()' passes
"true" value. If we create additional 'dma_common_configure_force()', then
'dma_common_configure()' will not be used anytime and will become redundant.

If someday new busses come and they needs to use similar functionality which
'dma_common_configure()' provides, but with passing "false" to 'of_dma_configure()',
then what you suggests of having two separate such API's will be more reasonable
and can be implemented?

Thanks,
Nipun

> 
> thanks,
> 
> greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-soc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux