On Tue, Apr 18, 2023 at 09:24:00PM +0900, Yoshihiro Shimoda wrote: > Add R-Car Gen4 PCIe Host support. This controller is based on > Synopsys DesignWare PCIe. > It is good to add more details about the controller here like retraining etc... Also, please justify why you have added some helpers in a separate file. If those helpers are going to be used in other drivers now, then it should be mentioned here. NOTE: It may be used in future is not a valid justification. > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > --- > drivers/pci/controller/dwc/Kconfig | 9 + > drivers/pci/controller/dwc/Makefile | 2 + > .../pci/controller/dwc/pcie-rcar-gen4-host.c | 134 +++++++++++++ > drivers/pci/controller/dwc/pcie-rcar-gen4.c | 187 ++++++++++++++++++ > drivers/pci/controller/dwc/pcie-rcar-gen4.h | 49 +++++ > 5 files changed, 381 insertions(+) > create mode 100644 drivers/pci/controller/dwc/pcie-rcar-gen4-host.c > create mode 100644 drivers/pci/controller/dwc/pcie-rcar-gen4.c > create mode 100644 drivers/pci/controller/dwc/pcie-rcar-gen4.h > > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig > index d29551261e80..eb90e2116e59 100644 > --- a/drivers/pci/controller/dwc/Kconfig > +++ b/drivers/pci/controller/dwc/Kconfig > @@ -415,4 +415,13 @@ config PCIE_FU740 > Say Y here if you want PCIe controller support for the SiFive > FU740. > > +config PCIE_RCAR_GEN4 > + tristate "Renesas R-Car Gen4 PCIe Host controller" > + depends on ARCH_RENESAS || COMPILE_TEST > + depends on PCI_MSI > + select PCIE_DW_HOST > + help > + Say Y here if you want PCIe host controller support on R-Car Gen4 SoCs. > + This uses the DesignWare core. > + > endmenu > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile > index bf5c311875a1..486cf706b53d 100644 > --- a/drivers/pci/controller/dwc/Makefile > +++ b/drivers/pci/controller/dwc/Makefile > @@ -26,6 +26,8 @@ obj-$(CONFIG_PCIE_TEGRA194) += pcie-tegra194.o > obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o > obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o > obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o > +pcie-rcar-gen4-host-drv-objs := pcie-rcar-gen4.o pcie-rcar-gen4-host.o > +obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4-host-drv.o > > # The following drivers are for devices that use the generic ACPI > # pci_root.c driver but don't support standard ECAM config access. > diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4-host.c b/drivers/pci/controller/dwc/pcie-rcar-gen4-host.c > new file mode 100644 > index 000000000000..067fbd2a8d50 > --- /dev/null > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4-host.c > @@ -0,0 +1,134 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * PCIe host controller driver for Renesas R-Car Gen4 Series SoCs > + * Copyright (C) 2022-2023 Renesas Electronics Corporation > + */ > + > +#include <linux/interrupt.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/pci.h> > +#include <linux/platform_device.h> > + > +#include "pcie-rcar-gen4.h" > +#include "pcie-designware.h" > + > +static int rcar_gen4_pcie_host_init(struct dw_pcie_rp *pp) > +{ > + struct dw_pcie *dw = to_dw_pcie_from_pp(pp); > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw); > + int ret; > + u32 val; > + Don't you need to assert perst before starting controller config? > + ret = rcar_gen4_pcie_set_device_type(rcar, true, dw->num_lanes); > + if (ret < 0) > + return ret; > + > + dw_pcie_dbi_ro_wr_en(dw); > + > + /* > + * According to the databook, we should disable two BARs to avoid Which databook? Synopsys DWC? > + * unnecessary memory assignment during device enumeration. > + */ > + rcar_gen4_pcie_disable_bar(dw, PCI_BASE_ADDRESS_0); > + rcar_gen4_pcie_disable_bar(dw, PCI_BASE_ADDRESS_1); I don't see a need for this function. With dbi_ro_wr_{en/dis}, it's better to directly use the dbi accessors here. > + > + dw_pcie_dbi_ro_wr_dis(dw); > + > + if (IS_ENABLED(CONFIG_PCI_MSI)) { > + /* Enable MSI interrupt signal */ > + val = readl(rcar->base + PCIEINTSTS0EN); > + val |= MSI_CTRL_INT; > + writel(val, rcar->base + PCIEINTSTS0EN); > + } > + > + gpiod_set_value_cansleep(dw->pe_rst, 0); If you end up adding perst assert above, add a 100ms delay before deassert. > + > + return 0; > +} > + [...] > + > +static struct platform_driver rcar_gen4_pcie_driver = { > + .driver = { > + .name = "pcie-rcar-gen4", > + .of_match_table = rcar_gen4_pcie_of_match, > + }, > + .probe = rcar_gen4_pcie_probe, > + .remove = rcar_gen4_pcie_remove, You should consider adding PROBE_PREFER_ASYNCHRONOUS here to avoid blocking other drivers while waiting for link_up during boot. > +}; > +module_platform_driver(rcar_gen4_pcie_driver); > + > +MODULE_DESCRIPTION("Renesas R-Car Gen4 PCIe host controller driver"); > +MODULE_LICENSE("GPL"); > diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c > new file mode 100644 > index 000000000000..89cec76a41ab > --- /dev/null > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c > @@ -0,0 +1,187 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * PCIe host/endpoint controller driver for Renesas R-Car Gen4 Series SoCs > + * Copyright (C) 2022-2023 Renesas Electronics Corporation > + */ > + > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/of_device.h> > +#include <linux/pci.h> > +#include <linux/pm_runtime.h> > +#include <linux/reset.h> > + > +#include "pcie-rcar-gen4.h" > +#include "pcie-designware.h" > + > +/* Renesas-specific */ > +#define PCIERSTCTRL1 0x0014 > +#define APP_HOLD_PHY_RST BIT(16) > +#define APP_LTSSM_ENABLE BIT(0) > + > +#define RETRAIN_MAX_RETRY 10 > + > +static void rcar_gen4_pcie_ltssm_enable(struct rcar_gen4_pcie *rcar, > + bool enable) > +{ > + u32 val; > + > + val = readl(rcar->base + PCIERSTCTRL1); > + if (enable) { > + val |= APP_LTSSM_ENABLE; > + val &= ~APP_HOLD_PHY_RST; > + } else { > + val &= ~APP_LTSSM_ENABLE; > + val |= APP_HOLD_PHY_RST; > + } > + writel(val, rcar->base + PCIERSTCTRL1); > +} > + > +static bool rcar_gen4_pcie_check_retrain_link(struct dw_pcie *dw) > +{ > + u8 offset = dw_pcie_find_capability(dw, PCI_CAP_ID_EXP); > + u32 lnkcap = dw_pcie_readl_dbi(dw, offset + PCI_EXP_LNKCAP); > + u32 lnkctl = dw_pcie_readl_dbi(dw, offset + PCI_EXP_LNKCTL); > + u16 lnksta = dw_pcie_readw_dbi(dw, offset + PCI_EXP_LNKSTA); > + int i; > + > + if ((lnksta & PCI_EXP_LNKSTA_CLS) == (lnkcap & PCI_EXP_LNKCAP_SLS)) > + return true; > + > + lnkctl |= PCI_EXP_LNKCTL_RL; > + dw_pcie_writel_dbi(dw, offset + PCI_EXP_LNKCTL, lnkctl); > + > + for (i = 0; i < RETRAIN_MAX_RETRY; i++) { > + lnksta = dw_pcie_readw_dbi(dw, offset + PCI_EXP_LNKSTA); > + if (lnksta & PCI_EXP_LNKSTA_LT) > + return true; > + usleep_range(1000, 1100); > + } > + > + return false; > +} > + > +static int rcar_gen4_pcie_link_up(struct dw_pcie *dw) > +{ > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw); > + u32 val, mask; > + > + /* Require retraining here. Otherwise RDLH_LINK_UP may not be set */ Any other platform expected to not require retrain? > + if (rcar->needs_retrain && !rcar_gen4_pcie_check_retrain_link(dw)) > + return 0; > + > + val = readl(rcar->base + PCIEINTSTS0); > + mask = RDLH_LINK_UP | SMLH_LINK_UP; > + > + return (val & mask) == mask; > +} > + > +static int rcar_gen4_pcie_start_link(struct dw_pcie *dw) > +{ > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw); > + > + rcar_gen4_pcie_ltssm_enable(rcar, true); > + > + return 0; > +} > + > +static void rcar_gen4_pcie_stop_link(struct dw_pcie *dw) > +{ > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw); > + > + rcar_gen4_pcie_ltssm_enable(rcar, false); > +} > + > +int rcar_gen4_pcie_set_device_type(struct rcar_gen4_pcie *rcar, bool rc, > + int num_lanes) > +{ > + u32 val; > + > + /* Note: Assume the reset is asserted here */ What about this assumption? > + val = readl(rcar->base + PCIEMSR0); > + if (rc) > + val |= DEVICE_TYPE_RC; > + else > + val |= DEVICE_TYPE_EP; newline > + if (num_lanes < 4) > + val |= BIFUR_MOD_SET_ON; newline > + writel(val, rcar->base + PCIEMSR0); > + > + return reset_control_deassert(rcar->rst); > +} > + > +void rcar_gen4_pcie_disable_bar(struct dw_pcie *dw, u32 bar_mask_reg) > +{ > + dw_pcie_writel_dbi2(dw, bar_mask_reg, 0x0); > +} > + > +int rcar_gen4_pcie_prepare(struct rcar_gen4_pcie *rcar) > +{ > + struct device *dev = rcar->dw.dev; > + int err; > + > + pm_runtime_enable(dev); > + err = pm_runtime_resume_and_get(dev); Why do you need do runtime_resume here? You don't have the runtime PM callbacks implemented. Even if you did, it may end up with a crash as you have't called dw_pcie_host_init(). Overall, I think you don't need to call any of the pm_runtime APIs now. > + if (err < 0) { > + dev_err(dev, "Failed to resume/get Runtime PM\n"); > + pm_runtime_disable(dev); > + } > + > + return err; > +} > + > +void rcar_gen4_pcie_unprepare(struct rcar_gen4_pcie *rcar) > +{ > + struct device *dev = rcar->dw.dev; > + > + if (!reset_control_status(rcar->rst)) > + reset_control_assert(rcar->rst); > + pm_runtime_put(dev); > + pm_runtime_disable(dev); > +} > + > +static int rcar_gen4_pcie_devm_reset_get(struct rcar_gen4_pcie *rcar, > + struct device *dev) > +{ > + rcar->rst = devm_reset_control_get(dev, NULL); > + if (IS_ERR(rcar->rst)) { > + dev_err(dev, "Failed to get Cold-reset\n"); Is this cold-reset or core-reset? - Mani