linux-kernel - Re: [PATCH v3 2/3] PCI: qcom: add support to msm8996 PCIE controller

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Date:   Wed, 9 Nov 2016 16:07:21 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     svarbanov@...sol.com, Bjorn Helgaas <bhelgaas@...gle.com>,
        linux-pci@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v3 2/3] PCI: qcom: add support to msm8996 PCIE controller

Hi,

On Fri, Nov 4, 2016 at 6:29 PM, Srinivas Kandagatla
<srinivas.kandagatla@...aro.org> wrote:
> This patch adds support to msm8996/apq8096 pcie, MSM8996 supports
> Gen 1/2, One lane, 3 pcie root-complex with support to MSI and
> legacy interrupts and it conforms to PCI Express Base 2.1 specification.
>
> This patch adds post_init callback to qcom_pcie_ops, as this is pcie
> pipe clocks are only setup after the phy is powered on.
> It also adds ltssm_enable callback as it is very much different to other
> supported SOCs in the driver.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> ---

Few minor nits.

>  .../devicetree/bindings/pci/qcom,pcie.txt          |  68 +++++++-
>  drivers/pci/host/pcie-qcom.c                       | 177 ++++++++++++++++++++-
>  2 files changed, 239 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.txt b/Documentation/devicetree/bindings/pci/qcom,pcie.txt
> index 4059a6f..4a0538d 100644
> --- a/Documentation/devicetree/bindings/pci/qcom,pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.txt
> @@ -7,6 +7,7 @@
>                         - "qcom,pcie-ipq8064" for ipq8064
>                         - "qcom,pcie-apq8064" for apq8064
>                         - "qcom,pcie-apq8084" for apq8084
> +                       - "qcom,pcie-msm8996" for msm8996 or apq8096

Since this works for both apq8096 and msm8996, compatible -
"qcom,pcie-apq8096" for uniformity ?
[snip]

> @@ -231,3 +242,58 @@
>                 pinctrl-0 = <&pcie0_pins_default>;
>                 pinctrl-names = "default";
>         };
> +
> +* Example for apq8096:
> +
> +       pcie@...08000{
> +               compatible = "qcom,pcie-msm8996", "snps,dw-pcie";

this will change accordingly.

> +               power-domains = <&gcc PCIE1_GDSC>;
> +               bus-range = <0x00 0xff>;
> +               num-lanes = <1>;
> +

[snip]

> +
> +static int qcom_pcie_init_v2(struct qcom_pcie *pcie)
> +{
> +       struct qcom_pcie_resources_v2 *res = &pcie->res.v2;
> +       struct device *dev = pcie->pp.dev;
> +       u32 val;
> +       int ret = 0;

you don't need to initialize ret here.

> +
> +       ret = clk_prepare_enable(res->aux_clk);
> +       if (ret) {
> +               dev_err(dev, "cannot prepare/enable aux clock\n");
> +               return ret;
> +       }

[snip]

> @@ -429,6 +571,17 @@ static int qcom_pcie_link_up(struct pcie_port *pp)
>         return !!(val & PCI_EXP_LNKSTA_DLLLA);
>  }
>
> +static void qcom_pcie_deinit_v2(struct qcom_pcie *pcie)
> +{
> +       struct qcom_pcie_resources_v2 *res = &pcie->res.v2;
> +
> +       clk_disable_unprepare(res->slave_clk);
> +       clk_disable_unprepare(res->master_clk);
> +       clk_disable_unprepare(res->cfg_clk);
> +       clk_disable_unprepare(res->aux_clk);
> +       clk_disable_unprepare(res->pipe_clk);

i am sure, this is not affecting the functionality, but the pipe clock
is enabled after all the clocks.
so it makes sense to disable it in the first place. you can just move
this above slave_clk.

[snip]

> @@ -572,6 +738,7 @@ static const struct of_device_id qcom_pcie_match[] = {
>         { .compatible = "qcom,pcie-ipq8064", .data = &ops_v0 },
>         { .compatible = "qcom,pcie-apq8064", .data = &ops_v0 },
>         { .compatible = "qcom,pcie-apq8084", .data = &ops_v1 },
> +       { .compatible = "qcom,pcie-msm8996", .data = &ops_v2 },

this will change according to earlier comment in bindings.


Thanks
Vivek


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