On Fri, Dec 01, 2023 at 11:17:12AM -0500, Frank Li wrote:
> Add suspend/resume support for Layerscape LS1043a.
>
> In the suspend path, PME_Turn_Off message is sent to the endpoint to
> transition the link to L2/L3_Ready state. In this SoC, there is no way to
> check if the controller has received the PME_To_Ack from the endpoint or
> not. So to be on the safer side, the driver just waits for
> PCIE_PME_TO_L2_TIMEOUT_US before asserting the SoC specific PMXMTTURNOFF
> bit to complete the PME_Turn_Off handshake. Then the link would enter L2/L3
> state depending on the VAUX supply.
>
> In the resume path, the link is brought back from L2 to L0 by doing a
> software reset.
>
> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
- Mani
> ---
>
> Notes:
> Change from v4 to v5
> - update commit message
> - use comments
> /* Reset the PEX wrapper to bring the link out of L2 */
>
> Change from v3 to v4
> - Call scfg_pcie_send_turnoff_msg() shared with ls1021a
> - update commit message
>
> Change from v2 to v3
> - Remove ls_pcie_lut_readl(writel) function
>
> Change from v1 to v2
> - Update subject 'a' to 'A'
>
> drivers/pci/controller/dwc/pci-layerscape.c | 63 ++++++++++++++++++++-
> 1 file changed, 62 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
> index a9151e98fde6f..715365e91f8ef 100644
> --- a/drivers/pci/controller/dwc/pci-layerscape.c
> +++ b/drivers/pci/controller/dwc/pci-layerscape.c
> @@ -41,6 +41,15 @@
> #define SCFG_PEXSFTRSTCR 0x190
> #define PEXSR(idx) BIT(idx)
>
> +/* LS1043A PEX PME control register */
> +#define SCFG_PEXPMECR 0x144
> +#define PEXPME(idx) BIT(31 - (idx) * 4)
> +
> +/* LS1043A PEX LUT debug register */
> +#define LS_PCIE_LDBG 0x7fc
> +#define LDBG_SR BIT(30)
> +#define LDBG_WE BIT(31)
> +
> #define PCIE_IATU_NUM 6
>
> struct ls_pcie_drvdata {
> @@ -224,6 +233,45 @@ static int ls1021a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
> return scfg_pcie_exit_from_l2(pcie->scfg, SCFG_PEXSFTRSTCR, PEXSR(pcie->index));
> }
>
> +static void ls1043a_pcie_send_turnoff_msg(struct dw_pcie_rp *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct ls_pcie *pcie = to_ls_pcie(pci);
> +
> + scfg_pcie_send_turnoff_msg(pcie->scfg, SCFG_PEXPMECR, PEXPME(pcie->index));
> +}
> +
> +static int ls1043a_pcie_exit_from_l2(struct dw_pcie_rp *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct ls_pcie *pcie = to_ls_pcie(pci);
> + u32 val;
> +
> + /*
> + * Reset the PEX wrapper to bring the link out of L2.
> + * LDBG_WE: allows the user to have write access to the PEXDBG[SR] for both setting and
> + * clearing the soft reset on the PEX module.
> + * LDBG_SR: When SR is set to 1, the PEX module enters soft reset.
> + */
> + val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
> + val |= LDBG_WE;
> + ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
> +
> + val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
> + val |= LDBG_SR;
> + ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
> +
> + val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
> + val &= ~LDBG_SR;
> + ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
> +
> + val = ls_pcie_pf_lut_readl(pcie, LS_PCIE_LDBG);
> + val &= ~LDBG_WE;
> + ls_pcie_pf_lut_writel(pcie, LS_PCIE_LDBG, val);
> +
> + return 0;
> +}
> +
> static const struct dw_pcie_host_ops ls_pcie_host_ops = {
> .host_init = ls_pcie_host_init,
> .pme_turn_off = ls_pcie_send_turnoff_msg,
> @@ -241,6 +289,19 @@ static const struct ls_pcie_drvdata ls1021a_drvdata = {
> .exit_from_l2 = ls1021a_pcie_exit_from_l2,
> };
>
> +static const struct dw_pcie_host_ops ls1043a_pcie_host_ops = {
> + .host_init = ls_pcie_host_init,
> + .pme_turn_off = ls1043a_pcie_send_turnoff_msg,
> +};
> +
> +static const struct ls_pcie_drvdata ls1043a_drvdata = {
> + .pf_lut_off = 0x10000,
> + .pm_support = true,
> + .scfg_support = true,
> + .ops = &ls1043a_pcie_host_ops,
> + .exit_from_l2 = ls1043a_pcie_exit_from_l2,
> +};
> +
> static const struct ls_pcie_drvdata layerscape_drvdata = {
> .pf_lut_off = 0xc0000,
> .pm_support = true,
> @@ -252,7 +313,7 @@ static const struct of_device_id ls_pcie_of_match[] = {
> { .compatible = "fsl,ls1012a-pcie", .data = &layerscape_drvdata },
> { .compatible = "fsl,ls1021a-pcie", .data = &ls1021a_drvdata },
> { .compatible = "fsl,ls1028a-pcie", .data = &layerscape_drvdata },
> - { .compatible = "fsl,ls1043a-pcie", .data = &ls1021a_drvdata },
> + { .compatible = "fsl,ls1043a-pcie", .data = &ls1043a_drvdata },
> { .compatible = "fsl,ls1046a-pcie", .data = &layerscape_drvdata },
> { .compatible = "fsl,ls2080a-pcie", .data = &layerscape_drvdata },
> { .compatible = "fsl,ls2085a-pcie", .data = &layerscape_drvdata },
> --
> 2.34.1
>
--
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