Re: [PATCH 08/10] PCI: dwc: artpec6: add support for endpoint mode

[Niklas Cassel <niklas.cassel@axis.com>]

Hello Bjorn

On 10/17/2017 01:43 AM, Bjorn Helgaas wrote:
(snip)
> I see you're copying the DRA7XX style here, but I don't really
> understand it.  I guess the idea is to build pcie-artpec6.o if either
> CONFIG_PCIE_ARTPEC6_HOST or CONFIG_PCIE_ARTPEC6_EP is set (or both).
> 
> Is this really the simplest way to express that in Kconfig?  Both the
> "if PCIE_ARTPEC6" and this ifneq thing are complicated and relatively
> unusual.

I will try Christoph's suggestion.

> 
>>  ifneq ($(filter y,$(CONFIG_PCI_DRA7XX_HOST) $(CONFIG_PCI_DRA7XX_EP)),)
>>          obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
>>  endif
> 
>> +static void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
> 
> Looks funny to have this dw_*() function in pcie-artpec6.c.  Intended?
> Or is this something other endpoint drivers could/should share?

As discussed with Kishon, I make sure that the dw_pcie_ep_reset_bar
in pcie-designware-ep.c is no longer static.

> 
>> +{
>> +	u32 reg;
>> +
>> +	reg = PCI_BASE_ADDRESS_0 + (4 * bar);
>> +	dw_pcie_dbi_ro_wr_en(pci);
>> +	dw_pcie_writel_dbi2(pci, reg, 0x0);
>> +	dw_pcie_writel_dbi(pci, reg, 0x0);
>> +	dw_pcie_dbi_ro_wr_dis(pci);
>> +}
>> +
>> +static void artpec6_pcie_ep_init(struct dw_pcie_ep *ep)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> +	struct artpec6_pcie *artpec6_pcie = to_artpec6_pcie(pci);
>> +	enum pci_barno bar;
>> +
>> +	artpec6_pcie_assert_core_reset(artpec6_pcie);
>> +	artpec6_pcie_init_phy(artpec6_pcie);
>> +	artpec6_pcie_deassert_core_reset(artpec6_pcie);
>> +
>> +	for (bar = BAR_0; bar <= BAR_5; bar++)
>> +		dw_pcie_ep_reset_bar(pci, bar);
>> +}
> 
> I naively expected some of this new code to be #ifdef PCIE_ARTPEC6_EP.
> But I haven't really internalized the endpoint support, so maybe that
> doesn't make sense?

I copied the style from dra7xx.
But after thinking about it, I agree with you.

If we move dw_pcie_ep_reset_bar and artpec6_pcie_raise_msi_irq
to pcie-designware-ep, the functions that are left are:

artpec6_pcie_stop_link
artpec6_pcie_ep_init
artpec6_pcie_raise_irq
artpec6_add_pcie_ep
the compatible in the of match table

The only function I'm hesitant about is .stop_link,
since it is in dw_pcie_ops, however, right now it
is only used in pcie-designware-ep.c

Would you prefer me to make them #ifdef PCIE_ARTPEC6_EP ?

I can do a similar patch for pci-dra7xx.


Regards,
Niklas