Re: [PATCH v3 1/2] PCI: qcom: fix IPQ8074 Gen2 support

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Jun 23, 2022 at 05:50:03PM +0200, Robert Marko wrote:
> Currently the Gen2 port in IPQ8074 will cause the system to hang as its
> using DBI registers in the .init and those are only accesible after
> phy_power_on().
> 
> So solve this by splitting the DBI read/writes to .post_init.
> 
> Fixes: a0fd361db8e5 ("PCI: dwc: Move "dbi", "dbi2", and "addr_space" resource setup into common code")

Does v5.11 or some v5.11-based stable kernel contain IPQ8074 support?
If so, I'll mark this for backporting to stable.

> Signed-off-by: Robert Marko <robimarko@gmail.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
> Changes in v3:
> * Make sure it applies onto 5.19-rc3
> * Update the commit description to make it clear this only affects the
> Gen2 port
> 
> Changes in v2:
> * Rebase onto next-20220621
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 48 +++++++++++++++-----------
>  1 file changed, 28 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index a1f1aca2fb59..24708d5d817d 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1061,9 +1061,7 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
>  	struct qcom_pcie_resources_2_3_3 *res = &pcie->res.v2_3_3;
>  	struct dw_pcie *pci = pcie->pci;
>  	struct device *dev = pci->dev;
> -	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
>  	int i, ret;
> -	u32 val;
>  
>  	for (i = 0; i < ARRAY_SIZE(res->rst); i++) {
>  		ret = reset_control_assert(res->rst[i]);
> @@ -1120,6 +1118,33 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
>  		goto err_clk_aux;
>  	}
>  
> +	return 0;
> +
> +err_clk_aux:
> +	clk_disable_unprepare(res->ahb_clk);
> +err_clk_ahb:
> +	clk_disable_unprepare(res->axi_s_clk);
> +err_clk_axi_s:
> +	clk_disable_unprepare(res->axi_m_clk);
> +err_clk_axi_m:
> +	clk_disable_unprepare(res->iface);
> +err_clk_iface:
> +	/*
> +	 * Not checking for failure, will anyway return
> +	 * the original failure in 'ret'.
> +	 */
> +	for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> +		reset_control_assert(res->rst[i]);
> +
> +	return ret;
> +}
> +
> +static int qcom_pcie_post_init_2_3_3(struct qcom_pcie *pcie)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> +	u32 val;
> +
>  	writel(SLV_ADDR_SPACE_SZ,
>  		pcie->parf + PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE);
>  
> @@ -1147,24 +1172,6 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
>  		PCI_EXP_DEVCTL2);
>  
>  	return 0;
> -
> -err_clk_aux:
> -	clk_disable_unprepare(res->ahb_clk);
> -err_clk_ahb:
> -	clk_disable_unprepare(res->axi_s_clk);
> -err_clk_axi_s:
> -	clk_disable_unprepare(res->axi_m_clk);
> -err_clk_axi_m:
> -	clk_disable_unprepare(res->iface);
> -err_clk_iface:
> -	/*
> -	 * Not checking for failure, will anyway return
> -	 * the original failure in 'ret'.
> -	 */
> -	for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> -		reset_control_assert(res->rst[i]);
> -
> -	return ret;
>  }
>  
>  static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
> @@ -1596,6 +1603,7 @@ static const struct qcom_pcie_ops ops_2_4_0 = {
>  static const struct qcom_pcie_ops ops_2_3_3 = {
>  	.get_resources = qcom_pcie_get_resources_2_3_3,
>  	.init = qcom_pcie_init_2_3_3,
> +	.post_init = qcom_pcie_post_init_2_3_3,
>  	.deinit = qcom_pcie_deinit_2_3_3,
>  	.ltssm_enable = qcom_pcie_2_3_2_ltssm_enable,
>  };
> -- 
> 2.36.1
>