Re: [PATCH v5 2/2] DW DMAC: add multi-block property to device tree

On Thu, 2016-11-24 at 17:58 +0200, Andy Shevchenko wrote:

On Thu, 2016-11-24 at 17:52 +0200, Andy Shevchenko wrote:

quoted

On Thu, 2016-11-24 at 18:04 +0300, Eugeniy Paltsev wrote:

quoted

Several versions of DW DMAC have multi block transfers hardware
support. Hardware support of multi block transfers is disabled
by default if we use DT to configure DMAC and software emulation
of multi block transfers used instead.
Add multi-block property, so it is possible to enable hardware
multi block transfers (if present) via DT.

Switch from per device is_nollp variable to multi_block array
to be able enable/disable multi block transfers separately per
channel.

Thanks for an update. Basically I'm fine with this one.

So, we still have question about autoconfiguration in SPEAr SoCs,
and
your ARC SoC but it's a different story. I would expect once you
will
clarify it.

Another one is minor listed below, otherwise

Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

quoted

@@ -152,6 +154,11 @@ dw_dma_parse_dt(struct platform_device

*pdev)
 			pdata->data_width[tmp] = BIT(arr[tmp] &
0x07);
 	}
 
+	if (!of_property_read_u32_array(np, "multi-block", chan,
nr_channels)) {
+		for (tmp = 0; tmp < nr_channels; tmp++)
+			pdata->multi_block[tmp] = chan[tmp];

...mb (as short of multi-block) would suit better.

Oh, sorry, guys, but one more important thing. If there is no such
property, keep a default to "supported". Otherwise you will break old
(working) DTBs.

Should I remove explicit declaration "multi-block" property from
existing DTS (which I added during v5 patch iteration)?

I mean that:
---------------------->8-----------------------
+			multi-block = <1 1 1 1 1 1 1 1>;
---------------------->8-----------------------

We don't actually need it, if we use use 1 ("supported") as "multi-
block" property default value.

-- 
 Paltsev Eugeniy
_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc