Re: [PATCH v4 7/9] PCI: imx6: Use dwc common suspend resume method

Manivannan Sadhasivam
2024-10-22T17:18:07Z

On Tue, Oct 15, 2024 at 04:33:31PM +0800, Richard Zhu wrote:
> From: Frank Li <Frank.Li@nxp.com>
>
> Call common dwc suspend/resume function. Use dwc common iATU method to send
> out PME_TURN_OFF message. Old platform such as iMX6SX and iMX6QP, iATU
> CTRL2 bit 22 (PCIE_ATU_INHIBIT_PAYLOAD) are reserved. So can't send out MSG
> without data by dummy MMIO write. Without PCIE_ATU_INHIBIT_PAYLOAD, MSGD
> will be sent out instead of MSG. So keep old method to send PME_TURN_OFF
> MSG.
>

This PME_Turn_Off implementation is the only difference between the DWC common
ops and the custom one here? I don't think so. Please describe all the
differences.

> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 97 ++++++++++-----------------
> 1 file changed, 36 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 161daad34a94..baa853d84b4d 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -33,6 +33,7 @@
> #include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
>
> +#include "../../pci.h"
> #include "pcie-designware.h"
>
> #define IMX8MQ_GPR_PCIE_REF_USE_PAD BIT(9)
> @@ -82,6 +83,7 @@ enum imx_pcie_variants {
> #define IMX_PCIE_FLAG_HAS_SERDES BIT(6)
> #define IMX_PCIE_FLAG_SUPPORT_64BIT BIT(7)
> #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP BIT(8)
> +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF BIT(9)
>
> #define imx_check_flag(pci, val) (pci->drvdata->flags & val)
>
> @@ -106,19 +108,18 @@ struct imx_pcie_drvdata {
> int (*init_phy)(struct imx_pcie *pcie);
> int (*enable_ref_clk)(struct imx_pcie *pcie, bool enable);
> int (*core_reset)(struct imx_pcie *pcie, bool assert);
> + const struct dw_pcie_host_ops *ops;
> };
>
> struct imx_pcie {
> struct dw_pcie *pci;
> struct gpio_desc *reset_gpiod;
> - bool link_is_up;
> struct clk_bulk_data clks[IMX_PCIE_MAX_CLKS];
> struct regmap *iomuxc_gpr;
> u16 msi_ctrl;
> u32 controller_id;
> struct reset_control *pciephy_reset;
> struct reset_control *apps_reset;
> - struct reset_control *turnoff_reset;
> u32 tx_deemph_gen1;
> u32 tx_deemph_gen2_3p5db;
> u32 tx_deemph_gen2_6db;
> @@ -898,13 +899,11 @@ static int imx_pcie_start_link(struct dw_pcie *pci)
> dev_info(dev, "Link: Only Gen1 is enabled\n");
> }
>
> - imx_pcie->link_is_up = true;
> tmp = dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKSTA);
> dev_info(dev, "Link up, Gen%i\n", tmp & PCI_EXP_LNKSTA_CLS);
> return 0;
>
> err_reset_phy:
> - imx_pcie->link_is_up = false;
> dev_dbg(dev, "PHY DEBUG_R0=0x%08x DEBUG_R1=0x%08x\n",
> dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG0),
> dw_pcie_readl_dbi(pci, PCIE_PORT_DEBUG1));
> @@ -1023,9 +1022,33 @@ static u64 imx_pcie_cpu_addr_fixup(struct dw_pcie *pcie, u64 cpu_addr)
> return cpu_addr - entry->offset;
> }
>
> +/*
> + * Old dwc iATU ctrl2 bit 22 (PCIE_ATU_INHIBIT_PAYLOAD) are reserved. So can't
> + * send out MSG without data by dummy MMIO write. Without
> + * PCIE_ATU_INHIBIT_PAYLOAD, MSGD will be sent out. So have to keep old method
> + * to send PME_TURN_OFF MSG.

Please reword the comments:

"In Old DWC implementations, PCIE_ATU_INHIBIT_PAYLOAD bit in iATU Ctrl2 register
is reserved. So the generic DWC implementation of sending the PME_Turn_Off
message using a dummy MMIO write cannot be used."

> + */
> +static void imx_pcie_pm_turn_off(struct dw_pcie_rp *pp)

s/pm/pme

> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct imx_pcie *imx_pcie = to_imx_pcie(pci);
> +
> + regmap_set_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> + regmap_clear_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12, IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> +
> + usleep_range(PCIE_PME_TO_L2_TIMEOUT_US/10, PCIE_PME_TO_L2_TIMEOUT_US);
> +}
> +
> +
> static const struct dw_pcie_host_ops imx_pcie_host_ops = {
> .init = imx_pcie_host_init,
> .deinit = imx_pcie_host_exit,
> + .pme_turn_off = imx_pcie_pm_turn_off,
> +};
> +
> +static const struct dw_pcie_host_ops imx_pcie_host_dw_pme_ops = {
> + .init = imx_pcie_host_init,
> + .deinit = imx_pcie_host_exit,
> };
>
> static const struct dw_pcie_ops dw_pcie_ops = {
> @@ -1146,43 +1169,6 @@ static int imx_add_pcie_ep(struct imx_pcie *imx_pcie,
> return 0;
> }
>
> -static void imx_pcie_pm_turnoff(struct imx_pcie *imx_pcie)
> -{
> - struct device *dev = imx_pcie->pci->dev;
> -
> - /* Some variants have a turnoff reset in DT */
> - if (imx_pcie->turnoff_reset) {
> - reset_control_assert(imx_pcie->turnoff_reset);
> - reset_control_deassert(imx_pcie->turnoff_reset);
> - goto pm_turnoff_sleep;
> - }

What about this part of the code? Don't you need it now?

> -
> - /* Others poke directly at IOMUXC registers */
> - switch (imx_pcie->drvdata->variant) {
> - case IMX6SX:
> - case IMX6QP:
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> - IMX6SX_GPR12_PCIE_PM_TURN_OFF,
> - IMX6SX_GPR12_PCIE_PM_TURN_OFF);
> - regmap_update_bits(imx_pcie->iomuxc_gpr, IOMUXC_GPR12,
> - IMX6SX_GPR12_PCIE_PM_TURN_OFF, 0);
> - break;
> - default:
> - dev_err(dev, "PME_Turn_Off not implemented\n");
> - return;
> - }
> -
> - /*
> - * Components with an upstream port must respond to
> - * PME_Turn_Off with PME_TO_Ack but we can't check.
> - *
> - * The standard recommends a 1-10ms timeout after which to
> - * proceed anyway as if acks were received.
> - */
> -pm_turnoff_sleep:
> - usleep_range(1000, 10000);
> -}
> -
> static void imx_pcie_msi_save_restore(struct imx_pcie *imx_pcie, bool save)
> {
> u8 offset;
> @@ -1206,36 +1192,26 @@ static void imx_pcie_msi_save_restore(struct imx_pcie *imx_pcie, bool save)
> static int imx_pcie_suspend_noirq(struct device *dev)
> {
> struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
> - struct dw_pcie_rp *pp = &imx_pcie->pci->pp;
>
> if (!(imx_pcie->drvdata->flags & IMX_PCIE_FLAG_SUPPORTS_SUSPEND))
> return 0;
>
> imx_pcie_msi_save_restore(imx_pcie, true);
> - imx_pcie_pm_turnoff(imx_pcie);
> - imx_pcie_stop_link(imx_pcie->pci);
> - imx_pcie_host_exit(pp);
> -
> - return 0;
> + return dw_pcie_suspend_noirq(imx_pcie->pci);
> }
>
> static int imx_pcie_resume_noirq(struct device *dev)
> {
> int ret;
> struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
> - struct dw_pcie_rp *pp = &imx_pcie->pci->pp;
>
> if (!(imx_pcie->drvdata->flags & IMX_PCIE_FLAG_SUPPORTS_SUSPEND))
> return 0;
>
> - ret = imx_pcie_host_init(pp);
> + ret = dw_pcie_resume_noirq(imx_pcie->pci);
> if (ret)
> return ret;
> imx_pcie_msi_save_restore(imx_pcie, false);
> - dw_pcie_setup_rc(pp);
> -
> - if (imx_pcie->link_is_up)
> - imx_pcie_start_link(imx_pcie->pci);

So this is also not needed? Why? Please explain in the commit message.

- Mani

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