[PATCH v3 1/6] PCI: rockchip: Create individual folder for rockchip drivers

Shawn Lin shawn.lin at rock-chips.com
Wed Mar 21 18:03:58 PDT 2018

[+ Greg]

Dear Bjorn, Lorenzo

On 2018/3/22 2:19, Lorenzo Pieralisi wrote:
> On Wed, Mar 21, 2018 at 09:04:21AM +0800, Shawn Lin wrote:
>> Dear Bjorn, Lorenzo
>> On 2018/3/21 1:46, Bjorn Helgaas wrote:
>>> On Tue, Mar 06, 2018 at 10:43:22AM +0800, Shawn Lin wrote:
>>>> In preparation for introducing End-Point driver for Rockchip
>>>> PCIe controller, we create a new folder to follow the convention
>>>> of dwc and cadence. Then we rename the host driver from pcie-rockchip.c
>>>> to pcie-rockchip-host.c, and only leave some common functions in
>>>> pcie-rockchip.c in order to be reused for both of host and EP drivers.
>>>> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
>>>> Tested-by: Jeffy Chen <jeffy.chen at rock-chips.com>
>>>> ...
>>>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>>>> index 34b56a8..b85ad40 100644
>>>> --- a/drivers/pci/Kconfig
>>>> +++ b/drivers/pci/Kconfig
>>>> @@ -141,4 +141,5 @@ source "drivers/pci/cadence/Kconfig"
>>>>   source "drivers/pci/dwc/Kconfig"
>>>>   source "drivers/pci/host/Kconfig"
>>>>   source "drivers/pci/endpoint/Kconfig"
>>>> +source "drivers/pci/rockchip/Kconfig"
>>>>   source "drivers/pci/switch/Kconfig"
>>> Why is this out of order?  This seems exactly analogous to
>>> drivers/pci/cadence and dwc, so they should be next to each other.
>> This confused me as well! I just put "rockchip" before "switch"
>> to keep the order, but I didn't know why "endpoint" wasn't ordered.
>>>> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
>>>> index 9419709..8434afb 100644
>>>> --- a/drivers/pci/Makefile
>>>> +++ b/drivers/pci/Makefile
>>>> @@ -55,6 +55,8 @@ obj-y += switch/
>>>>   obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
>>>> +obj-$(CONFIG_PCIE_ROCKCHIP)	+= rockchip/
>>>> +
>>>>   # Endpoint library must be initialized before its users
>>>>   obj-$(CONFIG_PCIE_CADENCE)	+= cadence/
>>>>   # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
>>> Similarly here.
>>> I admit to still being a little dubious about the idea of a bunch of
>>> vendor-specific directories, each containing a completely trivial
>>> Makefile, a mostly-trivial Kconfig, a header file, a shared .c file, a
>>> host .c file, and an endpoint .c file.
>> So do I.
>>> One alternative would be to keep the single pcie-rockchip.c file with
>>> an #ifdef CONFIG_PCIE_ROCKCHIP_HOST section and an #ifdef
>> I admit I thought this eariler, however, I don't like it personally, as
>> it confuses the new-comer to follow the convention here, if we are
>> alternatives just for "style issue" or "personal taste".
> It would be OK for me to keep files separate too; a separate question
> would then be whether we have to rename drivers/pci/host if we add
> endpoint drivers in there, do we have to?
> At that stage we could well move drivers/pci/dwc and drivers/pci/cadence
> in there too.

I add Greg to this thread, and hope he could shed a light here.

That is completely the same situation annoying me when looking into
drivers/usb where they have drivers/usb/host/ for host drivers,
drivers/usb/gadget/ for device framwork, drivers/usb/gaget/udc for
device drivers, and even surprisingly drivers/usb/dwc2/,
drivers/usb/dwc3/ and drivers/usb/renesas_usbhs/ for supporting both of
host and device functional drivers....

How about renaming drivers/pci/host to drivers/pci/controller,
and then put all pcie-rockchip* files in there, then we don't
need add seperate directory containning trivial Kconfig, Makefile.

>> Certainly, I could do that beased on your suggestion, but I would like
>> to know if this's the final agreement both you and Lorenzo reached. :)
> Or we can add all EP drivers into drivers/pci/endpoint but then the problem
> is how to share code between host and endpoint directories and it starts
> feeling like we are going round in circles.

I would prefer to rename it to endpoint-framwrok or whatever to clearly
states it is for framework but not the drivers. All the drivers
whichever for host or endpoint should be in controller directory.

> I can merge this series as-is as long as we will rework the directory
> structure according to this discussion (given that's already late -rc6
> so directory moves/renames can be disrupting - if feasible at all).

This sounds super great to me to make this series into -next for some
days before hitting into v4.17. Then we could simultaneously head up to
see how we could move forward with this.

> Lorenzo

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