Re: [PATCH 6/7] PCI: qcom: Add QCS404 PCIe controller support

[Niklas Cassel]

On Fri, Jan 25, 2019 at 03:45:08PM -0800, Bjorn Andersson wrote:
> The QCS404 platform contains a PCIe controller of version 2.4.0 and a
> Qualcomm PCIe2 PHY. The driver already supports version 2.4.0, for the
> IPQ4019, but this support touches clocks and resets related to the PHY
> as well, and there's no upstream driver for the PHY.
> 
> On QCS404 we must initialize the PHY, so a separate PHY driver is
> implemented to take care of this and the controller driver is updated to
> not require the PHY related resources. This is done by relying on the
> fact that operations in both the clock and reset framework are nops when
> passed NULL, so we can isolate this change to only the get_resource
> function.
> 
> For QCS404 we also need to enable the AHB (iface) clock, in order to
> access the register space of the controller, but as this is not part of
> the IPQ4019 DT binding this is only added for new users of the 2.4.0
> controller.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 64 +++++++++++++++-----------
>  1 file changed, 38 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 9d366fad2b7f..6d4215ddcb42 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -113,7 +113,7 @@ struct qcom_pcie_resources_2_3_2 {
>  };
>  
>  struct qcom_pcie_resources_2_4_0 {
> -	struct clk_bulk_data clks[3];
> +	struct clk_bulk_data clks[4];
>  	int num_clks;
>  	struct reset_control *axi_m_reset;
>  	struct reset_control *axi_s_reset;
> @@ -637,13 +637,16 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
>  	struct qcom_pcie_resources_2_4_0 *res = &pcie->res.v2_4_0;
>  	struct dw_pcie *pci = pcie->pci;
>  	struct device *dev = pci->dev;
> +	bool is_ipq = of_device_is_compatible(dev->of_node, "qcom,pcie-ipq4019");
>  	int ret;
>  
>  	res->clks[0].id = "aux";
>  	res->clks[1].id = "master_bus";
>  	res->clks[2].id = "slave_bus";
> +	res->clks[3].id = "iface";
>  
> -	res->num_clks = 3;
> +	/* qcom,pcie-ipq4019 is defined without "iface" */
> +	res->num_clks = is_ipq ? 3 : 4;
>  
>  	ret = devm_clk_bulk_get(dev, res->num_clks, res->clks);
>  	if (ret < 0)
> @@ -657,27 +660,33 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
>  	if (IS_ERR(res->axi_s_reset))
>  		return PTR_ERR(res->axi_s_reset);
>  
> -	res->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
> -	if (IS_ERR(res->pipe_reset))
> -		return PTR_ERR(res->pipe_reset);
> -
> -	res->axi_m_vmid_reset = devm_reset_control_get_exclusive(dev,
> -								 "axi_m_vmid");
> -	if (IS_ERR(res->axi_m_vmid_reset))
> -		return PTR_ERR(res->axi_m_vmid_reset);
> -
> -	res->axi_s_xpu_reset = devm_reset_control_get_exclusive(dev,
> -								"axi_s_xpu");
> -	if (IS_ERR(res->axi_s_xpu_reset))
> -		return PTR_ERR(res->axi_s_xpu_reset);
> -
> -	res->parf_reset = devm_reset_control_get_exclusive(dev, "parf");
> -	if (IS_ERR(res->parf_reset))
> -		return PTR_ERR(res->parf_reset);
> -
> -	res->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
> -	if (IS_ERR(res->phy_reset))
> -		return PTR_ERR(res->phy_reset);
> +	if (is_ipq) {
> +		/*
> +		 * These resources relates to the PHY, but are controlled here
> +		 * for IPQ4019
> +		 */

This comment makes be believe that all these resouces are related to the
PHY.

"pipe" and "phy" are related to the PHY, but I doubt that the rest of them
relates to the PHY.

If QCS404 lacks these other reset signals, which is very possible, since
it's a completely different SoC, perhaps the comment should also mention
that.

With that:
Reviewed-by: Niklas Cassel <niklas.cassel@xxxxxxxxxx>

> +		res->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
> +		if (IS_ERR(res->pipe_reset))
> +			return PTR_ERR(res->pipe_reset);
> +
> +		res->axi_m_vmid_reset = devm_reset_control_get_exclusive(dev,
> +									 "axi_m_vmid");
> +		if (IS_ERR(res->axi_m_vmid_reset))
> +			return PTR_ERR(res->axi_m_vmid_reset);
> +
> +		res->axi_s_xpu_reset = devm_reset_control_get_exclusive(dev,
> +									"axi_s_xpu");
> +		if (IS_ERR(res->axi_s_xpu_reset))
> +			return PTR_ERR(res->axi_s_xpu_reset);
> +
> +		res->parf_reset = devm_reset_control_get_exclusive(dev, "parf");
> +		if (IS_ERR(res->parf_reset))
> +			return PTR_ERR(res->parf_reset);
> +
> +		res->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
> +		if (IS_ERR(res->phy_reset))
> +			return PTR_ERR(res->phy_reset);
> +	}
>  
>  	res->axi_m_sticky_reset = devm_reset_control_get_exclusive(dev,
>  								   "axi_m_sticky");
> @@ -697,9 +706,11 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
>  	if (IS_ERR(res->ahb_reset))
>  		return PTR_ERR(res->ahb_reset);
>  
> -	res->phy_ahb_reset = devm_reset_control_get_exclusive(dev, "phy_ahb");
> -	if (IS_ERR(res->phy_ahb_reset))
> -		return PTR_ERR(res->phy_ahb_reset);
> +	if (is_ipq) {
> +		res->phy_ahb_reset = devm_reset_control_get_exclusive(dev, "phy_ahb");
> +		if (IS_ERR(res->phy_ahb_reset))
> +			return PTR_ERR(res->phy_ahb_reset);
> +	}
>  
>  	return 0;
>  }
> @@ -1284,6 +1295,7 @@ static const struct of_device_id qcom_pcie_match[] = {
>  	{ .compatible = "qcom,pcie-msm8996", .data = &ops_2_3_2 },
>  	{ .compatible = "qcom,pcie-ipq8074", .data = &ops_2_3_3 },
>  	{ .compatible = "qcom,pcie-ipq4019", .data = &ops_2_4_0 },
> +	{ .compatible = "qcom,pcie-qcs404", .data = &ops_2_4_0 },
>  	{ }
>  };
>  
> -- 
> 2.18.0
>