From 740d6c3708a9325a9ae86aee61c666847be27b36 Mon Sep 17 00:00:00 2001 From: Jim Quinlan Date: Fri, 11 Sep 2020 13:52:26 -0400 Subject: [PATCH] PCI: brcmstb: Add control of rescal reset Some STB chips have a special purpose reset controller named RESCAL (reset calibration). The PCIe HW can now control RESCAL to start and stop its operation. On probe(), the RESCAL is deasserted and the driver goes through the sequence of setting registers and reading status in order to start the internal PHY that is required for the PCIe. Link: https://lore.kernel.org/r/20200911175232.19016-7-james.quinlan@broadcom.com Signed-off-by: Jim Quinlan Signed-off-by: Lorenzo Pieralisi Reviewed-by: Rob Herring Acked-by: Florian Fainelli --- drivers/pci/controller/pcie-brcmstb.c | 79 ++++++++++++++++++++++++++++++++++- 1 file changed, 77 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c index 947cf3115eb0..609c10ea5b63 100644 --- a/drivers/pci/controller/pcie-brcmstb.c +++ b/drivers/pci/controller/pcie-brcmstb.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -994,6 +995,52 @@ static void brcm_pcie_enter_l23(struct brcm_pcie *pcie) dev_err(pcie->dev, "failed to enter low-power link state\n"); } +static int brcm_phy_cntl(struct brcm_pcie *pcie, const int start) +{ + static const u32 shifts[PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS] = { + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_SHIFT, + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_SHIFT, + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_SHIFT,}; + static const u32 masks[PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS] = { + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_PWRDN_MASK, + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_RESET_MASK, + PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_DIG_RESET_MASK,}; + const int beg = start ? 0 : PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS - 1; + const int end = start ? PCIE_DVT_PMU_PCIE_PHY_CTRL_DAST_NFLDS : -1; + u32 tmp, combined_mask = 0; + u32 val; + void __iomem *base = pcie->base; + int i, ret; + + for (i = beg; i != end; start ? i++ : i--) { + val = start ? BIT_MASK(shifts[i]) : 0; + tmp = readl(base + PCIE_DVT_PMU_PCIE_PHY_CTRL); + tmp = (tmp & ~masks[i]) | (val & masks[i]); + writel(tmp, base + PCIE_DVT_PMU_PCIE_PHY_CTRL); + usleep_range(50, 200); + combined_mask |= masks[i]; + } + + tmp = readl(base + PCIE_DVT_PMU_PCIE_PHY_CTRL); + val = start ? combined_mask : 0; + + ret = (tmp & combined_mask) == val ? 0 : -EIO; + if (ret) + dev_err(pcie->dev, "failed to %s phy\n", (start ? "start" : "stop")); + + return ret; +} + +static inline int brcm_phy_start(struct brcm_pcie *pcie) +{ + return pcie->rescal ? brcm_phy_cntl(pcie, 1) : 0; +} + +static inline int brcm_phy_stop(struct brcm_pcie *pcie) +{ + return pcie->rescal ? brcm_phy_cntl(pcie, 0) : 0; +} + static void brcm_pcie_turn_off(struct brcm_pcie *pcie) { void __iomem *base = pcie->base; @@ -1021,11 +1068,13 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie) static int brcm_pcie_suspend(struct device *dev) { struct brcm_pcie *pcie = dev_get_drvdata(dev); + int ret; brcm_pcie_turn_off(pcie); + ret = brcm_phy_stop(pcie); clk_disable_unprepare(pcie->clk); - return 0; + return ret; } static int brcm_pcie_resume(struct device *dev) @@ -1038,6 +1087,10 @@ static int brcm_pcie_resume(struct device *dev) base = pcie->base; clk_prepare_enable(pcie->clk); + ret = brcm_phy_start(pcie); + if (ret) + goto err; + /* Take bridge out of reset so we can access the SERDES reg */ pcie->bridge_sw_init_set(pcie, 0); @@ -1051,18 +1104,24 @@ static int brcm_pcie_resume(struct device *dev) ret = brcm_pcie_setup(pcie); if (ret) - return ret; + goto err; if (pcie->msi) brcm_msi_set_regs(pcie->msi); return 0; + +err: + clk_disable_unprepare(pcie->clk); + return ret; } static void __brcm_pcie_remove(struct brcm_pcie *pcie) { brcm_msi_remove(pcie); brcm_pcie_turn_off(pcie); + brcm_phy_stop(pcie); + reset_control_assert(pcie->rescal); clk_disable_unprepare(pcie->clk); } @@ -1142,6 +1201,22 @@ static int brcm_pcie_probe(struct platform_device *pdev) dev_err(&pdev->dev, "could not enable clock\n"); return ret; } + pcie->rescal = devm_reset_control_get_optional_shared(&pdev->dev, "rescal"); + if (IS_ERR(pcie->rescal)) { + clk_disable_unprepare(pcie->clk); + return PTR_ERR(pcie->rescal); + } + + ret = reset_control_deassert(pcie->rescal); + if (ret) + dev_err(&pdev->dev, "failed to deassert 'rescal'\n"); + + ret = brcm_phy_start(pcie); + if (ret) { + reset_control_assert(pcie->rescal); + clk_disable_unprepare(pcie->clk); + return ret; + } ret = brcm_pcie_setup(pcie); if (ret) -- 2.11.0