Re: [PATCH v2 08/17] PCI: dwc: Add host de-initialization callback

From: Serge Semin <fancer.lancer@gmail.com>
To: Rob Herring <robh@kernel.org>
Cc: "Serge Semin" <Sergey.Semin@baikalelectronics.ru>,
	"Jingoo Han" <jingoohan1@gmail.com>,
	"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Alexey Malahov" <Alexey.Malahov@baikalelectronics.ru>,
	"Pavel Parkhomenko" <Pavel.Parkhomenko@baikalelectronics.ru>,
	"Frank Li" <Frank.Li@nxp.com>,
	"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
	linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 08/17] PCI: dwc: Add host de-initialization callback
Date: Fri, 20 May 2022 13:20:31 +0300	[thread overview]
Message-ID: <20220520102031.xd54d4dcnbhomxdi@mobilestation> (raw)
In-Reply-To: <20220516204828.GF3209795-robh@kernel.org>

On Mon, May 16, 2022 at 03:48:28PM -0500, Rob Herring wrote:
> On Wed, May 04, 2022 at 12:46:29AM +0300, Serge Semin wrote:
> > Seeing the platform-specific DW PCIe host-initialization is performed from
> > within the generic dw_pcie_host_init() method by means of the dedicated
> > dw_pcie_ops.host_init() callback, there must be declared an antagonist
> > which would perform the corresponding cleanups. Let's add such callback
> > then. It will be called in the dw_pcie_host_deinit() method and in the
> > cleanup-on-error path in the dw_pcie_host_init() function.
> 

> I'm not really a fan of .host_init() to begin with as it isn't really 
> clear by the name when it is supposed to be called and what init to do. 
> The drv probe -> dw_pcie_host_init -> drv .host_init() -> return to drv 
> sequence isn't great either. I'd rather see more fine grained and well 
> defined hooks. So I'm hesitant to add a host_deinit()...

What you say is a matter of another change. This patch just fixes the
already defined init-hook interface. Indeed the initializations
performed in the framework of the init-method need to be cleaned up in
case of the PCIe host probe procedure failure. I can't fix the DW PCIe
platform drivers since they may have some specifics I am not aware of,
but at least the interface needs to be provided for the new drivers.
One such low-level driver is submitted for review in this patchset.

What you suggest is a lot of additional work including preliminary
design settling discussions and consequent review. Alas I don't have
time for this anymore especially seeing the need for such finer grained
hooking isn't justified by neither the current platform drivers nor
the driver submitted by me. Sorry I can't fulfill your request.

-Sergey

> 
> Rob