diff options
author | Frank Li <Frank.Li@nxp.com> | 2023-12-04 19:08:27 +0300 |
---|---|---|
committer | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2023-12-12 13:13:30 +0300 |
commit | 6f8a41ba26230f6c04edad7daa25bd1c254c83b4 (patch) | |
tree | 5548ee51c9e1d5c797dd81d95a223bcabfa6edc4 | |
parent | 123971a193d9ac70b207c24c9f4ed6908b837bb6 (diff) | |
download | linux-6f8a41ba26230f6c04edad7daa25bd1c254c83b4.tar.xz |
PCI: layerscape: Add suspend/resume for ls1021a
Add suspend/resume support for Layerscape LS1021a.
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.
Link: https://lore.kernel.org/r/20231204160829.2498703-3-Frank.Li@nxp.com
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Roy Zang <Roy.Zang@nxp.com>
-rw-r--r-- | drivers/pci/controller/dwc/pci-layerscape.c | 83 |
1 files changed, 80 insertions, 3 deletions
diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c index aea89926bcc4..711563777aeb 100644 --- a/drivers/pci/controller/dwc/pci-layerscape.c +++ b/drivers/pci/controller/dwc/pci-layerscape.c @@ -35,11 +35,19 @@ #define PF_MCR_PTOMR BIT(0) #define PF_MCR_EXL2S BIT(1) +/* LS1021A PEXn PM Write Control Register */ +#define SCFG_PEXPMWRCR(idx) (0x5c + (idx) * 0x64) +#define PMXMTTURNOFF BIT(31) +#define SCFG_PEXSFTRSTCR 0x190 +#define PEXSR(idx) BIT(idx) + #define PCIE_IATU_NUM 6 struct ls_pcie_drvdata { const u32 pf_off; + const struct dw_pcie_host_ops *ops; int (*exit_from_l2)(struct dw_pcie_rp *pp); + bool scfg_support; bool pm_support; }; @@ -47,6 +55,8 @@ struct ls_pcie { struct dw_pcie *pci; const struct ls_pcie_drvdata *drvdata; void __iomem *pf_base; + struct regmap *scfg; + int index; bool big_endian; }; @@ -171,18 +181,70 @@ static int ls_pcie_host_init(struct dw_pcie_rp *pp) return 0; } +static void scfg_pcie_send_turnoff_msg(struct regmap *scfg, u32 reg, u32 mask) +{ + /* Send PME_Turn_Off message */ + regmap_write_bits(scfg, reg, mask, mask); + + /* + * There is no specific register to check for PME_To_Ack from endpoint. + * So on the safe side, wait for PCIE_PME_TO_L2_TIMEOUT_US. + */ + mdelay(PCIE_PME_TO_L2_TIMEOUT_US/1000); + + /* + * Layerscape hardware reference manual recommends clearing the PMXMTTURNOFF bit + * to complete the PME_Turn_Off handshake. + */ + regmap_write_bits(scfg, reg, mask, 0); +} + +static void ls1021a_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_PEXPMWRCR(pcie->index), PMXMTTURNOFF); +} + +static int scfg_pcie_exit_from_l2(struct regmap *scfg, u32 reg, u32 mask) +{ + /* Reset the PEX wrapper to bring the link out of L2 */ + regmap_write_bits(scfg, reg, mask, mask); + regmap_write_bits(scfg, reg, mask, 0); + + return 0; +} + +static int ls1021a_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); + + return scfg_pcie_exit_from_l2(pcie->scfg, SCFG_PEXSFTRSTCR, PEXSR(pcie->index)); +} + 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, }; +static const struct dw_pcie_host_ops ls1021a_pcie_host_ops = { + .host_init = ls_pcie_host_init, + .pme_turn_off = ls1021a_pcie_send_turnoff_msg, +}; + static const struct ls_pcie_drvdata ls1021a_drvdata = { - .pm_support = false, + .pm_support = true, + .scfg_support = true, + .ops = &ls1021a_pcie_host_ops, + .exit_from_l2 = ls1021a_pcie_exit_from_l2, }; static const struct ls_pcie_drvdata layerscape_drvdata = { .pf_off = 0xc0000, .pm_support = true, + .ops = &ls_pcie_host_ops, .exit_from_l2 = ls_pcie_exit_from_l2, }; @@ -205,6 +267,8 @@ static int ls_pcie_probe(struct platform_device *pdev) struct dw_pcie *pci; struct ls_pcie *pcie; struct resource *dbi_base; + u32 index[2]; + int ret; pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); if (!pcie) @@ -217,9 +281,8 @@ static int ls_pcie_probe(struct platform_device *pdev) pcie->drvdata = of_device_get_match_data(dev); pci->dev = dev; - pci->pp.ops = &ls_pcie_host_ops; - pcie->pci = pci; + pci->pp.ops = pcie->drvdata->ops; dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs"); pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base); @@ -230,6 +293,20 @@ static int ls_pcie_probe(struct platform_device *pdev) pcie->pf_base = pci->dbi_base + pcie->drvdata->pf_off; + if (pcie->drvdata->scfg_support) { + pcie->scfg = syscon_regmap_lookup_by_phandle(dev->of_node, "fsl,pcie-scfg"); + if (IS_ERR(pcie->scfg)) { + dev_err(dev, "No syscfg phandle specified\n"); + return PTR_ERR(pcie->scfg); + } + + ret = of_property_read_u32_array(dev->of_node, "fsl,pcie-scfg", index, 2); + if (ret) + return ret; + + pcie->index = index[1]; + } + if (!ls_pcie_is_bridge(pcie)) return -ENODEV; |