Re: [PATCH v7 10/12] PCI: qcom: Add SM8550 PCIe support

From: Abel Vesa <abel.vesa@linaro.org>
To: Johan Hovold <johan@kernel.org>
Cc: "Andy Gross" <agross@kernel.org>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"vkoul@kernel.org" <vkoul@kernel.org>,
	"Kishon Vijay Abraham I" <kishon@kernel.org>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Johan Hovold" <johan+linaro@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-phy@lists.infradead.org, devicetree@vger.kernel.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 10/12] PCI: qcom: Add SM8550 PCIe support
Date: Wed, 8 Feb 2023 19:10:17 +0200	[thread overview]
Message-ID: <Y+PXeYrBBL3QaznM@linaro.org> (raw)
In-Reply-To: <Y+PQYxh4t/ytOe3+@hovoldconsulting.com>

On 23-02-08 17:40:03, Johan Hovold wrote:
> On Mon, Feb 06, 2023 at 05:11:01PM +0200, Abel Vesa wrote:
> > On 23-02-03 10:49:24, Johan Hovold wrote:
> > > On Fri, Feb 03, 2023 at 10:18:05AM +0200, Abel Vesa wrote:
> > > > Add compatible for both PCIe found on SM8550.
> > > > Also add the cnoc_pcie_sf_axi clock needed by the SM8550.
> > > 
> > > nit: You're now also adding 'noc_aggr'
> > > 
> > > > Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> > > > Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> > > > Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
> > > > ---
> 
> > > > @@ -182,10 +182,10 @@ struct qcom_pcie_resources_2_3_3 {
> > > >  
> > > >  /* 6 clocks typically, 7 for sm8250 */
> > > >  struct qcom_pcie_resources_2_7_0 {
> > > > -	struct clk_bulk_data clks[12];
> > > > +	struct clk_bulk_data clks[14];
> > > >  	int num_clks;
> > > >  	struct regulator_bulk_data supplies[2];
> > > > -	struct reset_control *pci_reset;
> > > > +	struct reset_control *rst;
> > > 
> > > Please name this one 'reset' or 'resets' (e.g. to avoid hard to parse
> > > things like res->rst below).
> > 
> > Well, it would then be inconsitent with 2_3_3 and 2_9_0, which both use
> > rst.
> 
> Yeah, I saw that. Fortunately these resources are completely
> independent, but whatever.

Will do it in the next version then.

>  
> > > >  };
> > > >  
> > > >  struct qcom_pcie_resources_2_9_0 {
> > > > @@ -1177,9 +1177,9 @@ static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
> > > >  	unsigned int idx;
> > > >  	int ret;
> > > >  
> > > > -	res->pci_reset = devm_reset_control_get_exclusive(dev, "pci");
> > > > -	if (IS_ERR(res->pci_reset))
> > > > -		return PTR_ERR(res->pci_reset);
> > > > +	res->rst = devm_reset_control_array_get_exclusive(dev);
> > > > +	if (IS_ERR(res->rst))
> > > > +		return PTR_ERR(res->rst);
> > > 
> > > So the reset array implementation apparently both asserts and deasserts
> > > the resets in the order specified in DT (i.e. does not deassert in
> > > reverse order).
> > > 
> > > Is that ok also for the new "pci" and "link_down" resets?
> > 
> > According to the HPG, yes, this is perfectly fine. It specifically says
> > to assert the pcie reset and then continues saying to assert the
> > link_down reset.
> 
> Ok, but that doesn't really say anything about whether it's ok to
> *deassert* them in the same order, which was what I asked about.

Actually, what I wanted to say is that the HPG says something like this:

"assert pcie reset, then assert link_down"

and then at the end it literaly repeats the same phrase.

> 
> Johan