[RFC/PATCH v2 2/2] drivers: dma-contiguous: add initialization from device tree
Marek Szyprowski
m.szyprowski at samsung.com
Tue Apr 30 04:53:55 EDT 2013
Hello,
On 4/29/2013 11:21 PM, Marc C wrote:
> > /**
> > * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
> > * @limit: End address of the reserved memory (optional, 0 for any).
> > @@ -149,6 +200,10 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> >
> > pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
> >
> > +#ifdef CONFIG_OF
> > + of_scan_flat_dt(cma_fdt_scan, NULL);
> > +#endif
> > +
>
> What is your expectation with the contention between default region
> setup via the kernel config (CONFIG_CMA_SIZE_SEL_*) and via the DT?
> Could the call to 'of_scan_flat_dt()' be done before the setup of the
> kernel config early regions, followed by a return code check
> 'fail-over' scheme, or were you intending for the default region
> setups to be mutually-exclusive?
In the proposed patch the default/global cma region setup from device tree
had higher priority than kernel command line parameter and .config saved
values,
but now as I think of this, it looks that it would make more sense to
have the
following priority for setting up the default cma region:
1. kernel cmd line - if not available, then use:
2. device tree - if not available, then use:
3. kernel compiled .config
I will update this in the next version of the CMA DT patches.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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