Re: [PATCH v4 09/13] PCI: dw-rockchip: Refactor the driver to prepare for EP mode

From: Manivannan Sadhasivam <mani@kernel.org>
To: Niklas Cassel <cassel@kernel.org>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
	"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Kishon Vijay Abraham I" <kishon@kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Damien Le Moal" <dlemoal@kernel.org>,
	"Jon Lin" <jon.lin@rock-chips.com>,
	"Shawn Lin" <shawn.lin@rock-chips.com>,
	"Simon Xue" <xxm@rock-chips.com>,
	linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v4 09/13] PCI: dw-rockchip: Refactor the driver to prepare for EP mode
Date: Thu, 6 Jun 2024 11:57:18 +0530	[thread overview]
Message-ID: <20240606062718.GB4441@thinkpad> (raw)
In-Reply-To: <ZmCm-Lt3yZpE84EG@ryzen.lan>

On Wed, Jun 05, 2024 at 07:57:12PM +0200, Niklas Cassel wrote:
> On Wed, Jun 05, 2024 at 01:36:40PM +0530, Manivannan Sadhasivam wrote:
> > On Wed, May 29, 2024 at 10:29:03AM +0200, Niklas Cassel wrote:
> > > This refactors the driver to prepare for EP mode.
> > > Add of-match data to the existing compatible, and explicitly define it as
> > > DW_PCIE_RC_TYPE. This way, we will be able to add EP mode in a follow-up
> > > commit in a much less intrusive way, which makes the follup-up commit much
> > > easier to review.
> > > 
> > > No functional change intended.
> > > 
> > > Signed-off-by: Niklas Cassel <cassel@kernel.org>
> > 
> > Few nitpicks below. With those addressed,
> > 
> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > 
> > > ---
> 
> (snip)
> 
> > > @@ -294,13 +292,35 @@ static const struct dw_pcie_ops dw_pcie_ops = {
> > >  	.start_link = rockchip_pcie_start_link,
> > >  };
> > >  
> > > +static int rockchip_pcie_configure_rc(struct rockchip_pcie *rockchip)
> > > +{
> > > +	struct dw_pcie_rp *pp;
> > > +	u32 val;
> > > +
> > > +	/* LTSSM enable control mode */
> > > +	val = HIWORD_UPDATE_BIT(PCIE_LTSSM_ENABLE_ENHANCE);
> > > +	rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_HOT_RESET_CTRL);
> > > +
> > > +	rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_RC_MODE,
> > > +				 PCIE_CLIENT_GENERAL_CONTROL);
> > > +
> > > +	pp = &rockchip->pci.pp;
> > > +	pp->ops = &rockchip_pcie_host_ops;
> > > +
> > > +	return dw_pcie_host_init(pp);
> > > +}
> > > +
> > >  static int rockchip_pcie_probe(struct platform_device *pdev)
> > >  {
> > >  	struct device *dev = &pdev->dev;
> > >  	struct rockchip_pcie *rockchip;
> > > -	struct dw_pcie_rp *pp;
> > > +	const struct rockchip_pcie_of_data *data;
> > >  	int ret;
> > >  
> > > +	data = of_device_get_match_data(dev);
> > > +	if (!data)
> > > +		return -EINVAL;
> > 
> > -ENODATA?
> 
> -EINVAL seems to be most common:
> $ git grep -A 5 of_device_get_match_data drivers/pci/
> 

Yeah, but we abused -EINVAL a lot ;) Nowadays, I prefer to use more apt error
codes.

- Mani

-- 
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