Re: [PATCH v10 03/14] PCI: imx6: Simplify reset handling by using by using *_FLAG_HAS_*_RESET

Lorenzo Pieralisi
2024-02-13T11:41:18Z

On Mon, Feb 05, 2024 at 12:33:24PM -0500, Frank Li wrote:
> Refactors the reset handling logic in the imx6 PCI driver by adding
> IMX6_PCIE_FLAG_HAS_*_RESET bitmask define for drvdata::flags.
>
> The drvdata::flags and a bitmask ensures a cleaner and more scalable
> switch-case structure for handling reset.
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>
> Notes:
> Change from v4 to v5:
> - Add Mani's Reviewed-by tag
> - Fixed MQ_EP's flags
>
> Chagne from v3 to v4:
> - none
> Change from v2 to v3:
> - add Philipp's Reviewed-by tag
> Change from v1 to v2:
> - remove condition check before reset_control_(de)assert() because it is
> none ops if a NULL pointer pass down.
> - still keep condition check at probe to help identify dts file mismatch
> problem.
>
> Change from v1 to v2:
> - remove condition check before reset_control_(de)assert() because it is
> none ops if a NULL pointer pass down.
> - still keep condition check at probe to help identify dts file mismatch
> problem.
>
> drivers/pci/controller/dwc/pci-imx6.c | 105 ++++++++++----------------
> 1 file changed, 39 insertions(+), 66 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 59f117f855c26..a1653b58051b7 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -61,6 +61,8 @@ enum imx6_pcie_variants {
> #define IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE BIT(1)
> #define IMX6_PCIE_FLAG_SUPPORTS_SUSPEND BIT(2)
> #define IMX6_PCIE_FLAG_HAS_PHYDRV BIT(3)
> +#define IMX6_PCIE_FLAG_HAS_APP_RESET BIT(4)
> +#define IMX6_PCIE_FLAG_HAS_PHY_RESET BIT(5)
>
> #define imx6_check_flag(pci, val) (pci->drvdata->flags & val)
>
> @@ -661,18 +663,10 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
>
> static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> {
> + reset_control_assert(imx6_pcie->pciephy_reset);
> + reset_control_assert(imx6_pcie->apps_reset);
> +
> switch (imx6_pcie->drvdata->variant) {
> - case IMX7D:
> - case IMX8MQ:
> - case IMX8MQ_EP:
> - reset_control_assert(imx6_pcie->pciephy_reset);
> - fallthrough;
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> - reset_control_assert(imx6_pcie->apps_reset);
> - break;
> case IMX6SX:
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
> @@ -693,6 +687,8 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
> IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
> break;
> + default:
> + break;
> }
>
> /* Some boards don't have PCIe reset GPIO. */
> @@ -706,14 +702,10 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> struct dw_pcie *pci = imx6_pcie->pci;
> struct device *dev = pci->dev;
>
> + reset_control_deassert(imx6_pcie->pciephy_reset);
> +
> switch (imx6_pcie->drvdata->variant) {
> - case IMX8MQ:
> - case IMX8MQ_EP:
> - reset_control_deassert(imx6_pcie->pciephy_reset);
> - break;
> case IMX7D:
> - reset_control_deassert(imx6_pcie->pciephy_reset);
> -
> /* Workaround for ERR010728, failure of PCI-e PLL VCO to
> * oscillate, especially when cold. This turns off "Duty-cycle
> * Corrector" and other mysterious undocumented things.
> @@ -745,11 +737,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>
> usleep_range(200, 500);
> break;
> - case IMX6Q: /* Nothing to do */
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> + default:
> break;
> }
>
> @@ -796,16 +784,11 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
> IMX6Q_GPR12_PCIE_CTL_2,
> IMX6Q_GPR12_PCIE_CTL_2);
> break;
> - case IMX7D:
> - case IMX8MQ:
> - case IMX8MQ_EP:
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> - reset_control_deassert(imx6_pcie->apps_reset);
> + default:
> break;
> }
> +
> + reset_control_deassert(imx6_pcie->apps_reset);

You rely on the fact that passing NULL is a no-op on platforms where
this wasn't called before (valid question for other hunks in this commit),
correct ?

Just checking, it does not make things much cleaner but I am not opposed to
this change.

Thanks,
Lorenzo

> }
>
> static void imx6_pcie_ltssm_disable(struct device *dev)
> @@ -819,16 +802,11 @@ static void imx6_pcie_ltssm_disable(struct device *dev)
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> IMX6Q_GPR12_PCIE_CTL_2, 0);
> break;
> - case IMX7D:
> - case IMX8MQ:
> - case IMX8MQ_EP:
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> - reset_control_assert(imx6_pcie->apps_reset);
> + default:
> break;
> }
> +
> + reset_control_assert(imx6_pcie->apps_reset);
> }
>
> static int imx6_pcie_start_link(struct dw_pcie *pci)
> @@ -1287,38 +1265,26 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> "failed to get pcie phy\n");
> }
>
> + if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_APP_RESET)) {
> + imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev, "apps");
> + if (IS_ERR(imx6_pcie->apps_reset))
> + return dev_err_probe(dev, PTR_ERR(imx6_pcie->apps_reset),
> + "failed to get pcie apps reset control\n");
> + }
> +
> + if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_PHY_RESET)) {
> + imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev, "pciephy");
> + if (IS_ERR(imx6_pcie->pciephy_reset))
> + return dev_err_probe(dev, PTR_ERR(imx6_pcie->pciephy_reset),
> + "Failed to get PCIEPHY reset control\n");
> + }
> +
> switch (imx6_pcie->drvdata->variant) {
> case IMX8MQ:
> case IMX8MQ_EP:
> case IMX7D:
> if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> imx6_pcie->controller_id = 1;
> -
> - imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
> - "pciephy");
> - if (IS_ERR(imx6_pcie->pciephy_reset)) {
> - dev_err(dev, "Failed to get PCIEPHY reset control\n");
> - return PTR_ERR(imx6_pcie->pciephy_reset);
> - }
> -
> - imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> - "apps");
> - if (IS_ERR(imx6_pcie->apps_reset)) {
> - dev_err(dev, "Failed to get PCIE APPS reset control\n");
> - return PTR_ERR(imx6_pcie->apps_reset);
> - }
> - break;
> - case IMX8MM:
> - case IMX8MM_EP:
> - case IMX8MP:
> - case IMX8MP_EP:
> - imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> - "apps");
> - if (IS_ERR(imx6_pcie->apps_reset))
> - return dev_err_probe(dev, PTR_ERR(imx6_pcie->apps_reset),
> - "failed to get pcie apps reset control\n");
> -
> - break;
> default:
> break;
> }
> @@ -1448,13 +1414,17 @@ static const struct imx6_pcie_drvdata drvdata[] = {
> },
> [IMX7D] = {
> .variant = IMX7D,
> - .flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
> + .flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
> + IMX6_PCIE_FLAG_HAS_APP_RESET |
> + IMX6_PCIE_FLAG_HAS_PHY_RESET,
> .gpr = "fsl,imx7d-iomuxc-gpr",
> .clk_names = imx6q_clks,
> .clks_cnt = ARRAY_SIZE(imx6q_clks),
> },
> [IMX8MQ] = {
> .variant = IMX8MQ,
> + .flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
> + IMX6_PCIE_FLAG_HAS_PHY_RESET,
> .gpr = "fsl,imx8mq-iomuxc-gpr",
> .clk_names = imx8mq_clks,
> .clks_cnt = ARRAY_SIZE(imx8mq_clks),
> @@ -1471,13 +1441,16 @@ static const struct imx6_pcie_drvdata drvdata[] = {
> [IMX8MP] = {
> .variant = IMX8MP,
> .flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
> - IMX6_PCIE_FLAG_HAS_PHYDRV,
> + IMX6_PCIE_FLAG_HAS_PHYDRV |
> + IMX6_PCIE_FLAG_HAS_APP_RESET,
> .gpr = "fsl,imx8mp-iomuxc-gpr",
> .clk_names = imx8mm_clks,
> .clks_cnt = ARRAY_SIZE(imx8mm_clks),
> },
> [IMX8MQ_EP] = {
> .variant = IMX8MQ_EP,
> + .flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
> + IMX6_PCIE_FLAG_HAS_PHY_RESET,
> .mode = DW_PCIE_EP_TYPE,
> .gpr = "fsl,imx8mq-iomuxc-gpr",
> .clk_names = imx8mq_clks,
> --
> 2.34.1
>
>
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