Re: [PATCH v2 3/8] usb: chipidea: Add support for Tegra20/30/114/124

[Peter Chen <hzpeterchen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Fri, Jul 28, 2017 at 05:51:16PM +0200, Michał Mirosław wrote:
> On Fri, Jul 28, 2017 at 01:00:32PM +0300, Dmitry Osipenko wrote:
> > On 28.07.2017 01:32, Michał Mirosław wrote:
> > > On Thu, Jul 27, 2017 at 07:46:07PM +0300, Dmitry Osipenko wrote:
> > >> From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> > >>
> > >> All of these Tegra SoC generations have a ChipIdea UDC IP block that can
> > >> be used for device mode communication with a host. Implement rudimentary
> > >> support that doesn't allow switching between host and device modes.
> > >>
> > >> Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> > >> [digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org: rebased patches and added DMA alignment quirk for Tegra20]
> > >> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > >> Acked-by: Peter Chen <peter.chen-3arQi8VN3Tc@public.gmane.org>
> > > 
> > > This works on my Asus TF300T (Tegra3 device). Minor nit below.
> > > 
> > > Tested-by: Michał Mirosław <mirq-linux-CoA6ZxLDdyEEUmgCuDUIdw@public.gmane.org> (on tf300t)
> > > 
> > 
> > Nice, thank you!
> > 
> > > [...]
> > >> diff --git a/drivers/usb/chipidea/ci_hdrc_tegra.c b/drivers/usb/chipidea/ci_hdrc_tegra.c
> > >> new file mode 100644
> > >> index 000000000000..7814500e71fa
> > >> --- /dev/null
> > >> +++ b/drivers/usb/chipidea/ci_hdrc_tegra.c
> > >> @@ -0,0 +1,160 @@
> > > [...]
> > >> +struct tegra_udc_soc_info {
> > >> +	bool supports_unaligned_dma;
> > >> +};
> > > [...]
> > >> +static const struct tegra_udc_soc_info tegra20_udc_soc_info = {
> > >> +	.supports_unaligned_dma = false,
> > >> +};
> > >> +
> > >> +static const struct tegra_udc_soc_info tegra30_udc_soc_info = {
> > >> +	.supports_unaligned_dma = true,
> > >> +};
> > >> +
> > >> +static const struct tegra_udc_soc_info tegra114_udc_soc_info = {
> > >> +	.supports_unaligned_dma = true,
> > >> +};
> > >> +
> > >> +static const struct tegra_udc_soc_info tegra124_udc_soc_info = {
> > >> +	.supports_unaligned_dma = true,
> > >> +};
> > >> +
> > >> +static const struct of_device_id tegra_udc_of_match[] = {
> > >> +	{
> > >> +		.compatible = "nvidia,tegra20-udc",
> > >> +		.data = &tegra20_udc_soc_info,
> > >> +	}, {
> > >> +		.compatible = "nvidia,tegra30-udc",
> > >> +		.data = &tegra30_udc_soc_info,
> > >> +	}, {
> > >> +		.compatible = "nvidia,tegra114-udc",
> > >> +		.data = &tegra114_udc_soc_info,
> > >> +	}, {
> > >> +		.compatible = "nvidia,tegra124-udc",
> > >> +		.data = &tegra124_udc_soc_info,
> > >> +	}, {
> > >> +		/* sentinel */
> > >> +	}
> > >> +};
> > >> +MODULE_DEVICE_TABLE(of, tegra_udc_of_match);
> > > [...]
> > >> +static int tegra_udc_probe(struct platform_device *pdev)
> > >> +{
> > > [...]
> > >> +	/* setup device specific quirks */
> > >> +	soc = id->data;
> > >> +
> > >> +	if (!soc->supports_unaligned_dma)
> > >> +		udc->data.flags |= CI_HDRC_REQUIRES_ALIGNED_DMA;
> > > [...]
> > > 
> > > Some lines would be saved if this was just:
> > > 
> > > udc->data.flags |= id->data;
> > > 

I prefer this way too, and add CI_HDRC_REQUIRES_ALIGNED_DMA as
platform flags for necessary SoCs.

Peter
> > 
> > I think a verbose approach is more preferable and it also more future proof
> > since we may extend soc_info with other stuff later.
> 
> I would just leave that to be done when it's needed. :-)
> 
> Or you could just have udc_flags in struct tegra_udc_soc_info, so
> that it would not need to be translated - again saving code, bugs
> and future developers' time.
> 
> Best Regards,
> Michał Mirosław
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-- 

Best Regards,
Peter Chen