Hello Manivannan,
> From: Manivannan Sadhasivam, Sent: Tuesday, October 10, 2023 9:04 PM
>
> On Fri, Sep 22, 2023 at 03:53:28PM +0900, Yoshihiro Shimoda wrote:
> > Add R-Car Gen4 PCIe controller support for host mode.
> >
> > This controller is based on Synopsys DesignWare PCIe. However, this
> > particular controller has a number of vendor-specific registers, and as
> > such, requires initialization code like mode setting and retraining and
> > so on.
> >
> > [kwilczynski: commit log]
> > Link:
<snip URL>
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
> > Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> > ---
> > drivers/pci/controller/dwc/Kconfig | 14 +
> > drivers/pci/controller/dwc/Makefile | 1 +
> > drivers/pci/controller/dwc/pcie-rcar-gen4.c | 380 ++++++++++++++++++++
> > 3 files changed, 395 insertions(+)
> > create mode 100644 drivers/pci/controller/dwc/pcie-rcar-gen4.c
> >
> > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> > index ab96da43e0c2..bc69fcab2e2a 100644
> > --- a/drivers/pci/controller/dwc/Kconfig
> > +++ b/drivers/pci/controller/dwc/Kconfig
> > @@ -415,4 +415,18 @@ config PCIE_VISCONTI_HOST
> > Say Y here if you want PCIe controller support on Toshiba Visconti SoC.
> > This driver supports TMPV7708 SoC.
> >
> > +config PCIE_RCAR_GEN4
> > + tristate
> > +
> > +config PCIE_RCAR_GEN4_HOST
> > + tristate "Renesas R-Car Gen4 PCIe controller (host mode)"
> > + depends on ARCH_RENESAS || COMPILE_TEST
> > + depends on PCI_MSI
> > + select PCIE_DW_HOST
> > + select PCIE_RCAR_GEN4
> > + help
> > + Say Y here if you want PCIe controller (host mode) on R-Car Gen4 SoCs.
> > + To compile this driver as a module, choose M here: the module will be
> > + called pcie-rcar-gen4.ko. This uses the DesignWare core.
> > +
> > endmenu
> > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> > index bf5c311875a1..bac103faa523 100644
> > --- a/drivers/pci/controller/dwc/Makefile
> > +++ b/drivers/pci/controller/dwc/Makefile
> > @@ -26,6 +26,7 @@ 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
> > +obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4.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.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > new file mode 100644
> > index 000000000000..dfff6bb18932
> > --- /dev/null
> > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > @@ -0,0 +1,380 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * PCIe controller driver for Renesas R-Car Gen4 Series SoCs
> > + * Copyright (C) 2022-2023 Renesas Electronics Corporation
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/pci.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/reset.h>
> > +
> > +#include "../../pci.h"
> > +#include "pcie-designware.h"
> > +
> > +/* Renesas-specific */
> > +/* PCIe Mode Setting Register 0 */
> > +#define PCIEMSR0 0x0000
> > +#define BIFUR_MOD_SET_ON BIT(0)
> > +#define DEVICE_TYPE_EP 0
> > +#define DEVICE_TYPE_RC BIT(4)
> > +
> > +/* PCIe Interrupt Status 0 */
> > +#define PCIEINTSTS0 0x0084
> > +
> > +/* PCIe Interrupt Status 0 Enable */
> > +#define PCIEINTSTS0EN 0x0310
> > +#define MSI_CTRL_INT BIT(26)
> > +#define SMLH_LINK_UP BIT(7)
> > +#define RDLH_LINK_UP BIT(6)
> > +
> > +/* PCIe DMA Interrupt Status Enable */
> > +#define PCIEDMAINTSTSEN 0x0314
> > +#define PCIEDMAINTSTSEN_INIT GENMASK(15, 0)
> > +
> > +/* PCIe Reset Control Register 1 */
> > +#define PCIERSTCTRL1 0x0014
> > +#define APP_HOLD_PHY_RST BIT(16)
> > +#define APP_LTSSM_ENABLE BIT(0)
> > +
> > +#define RCAR_NUM_SPEED_CHANGE_RETRIES 10
> > +#define RCAR_MAX_LINK_SPEED 4
> > +
> > +struct rcar_gen4_pcie {
> > + struct dw_pcie dw;
> > + void __iomem *base;
> > + struct platform_device *pdev;
> > + enum dw_pcie_device_mode mode;
> > +};
> > +#define to_rcar_gen4_pcie(_dw) container_of(_dw, struct rcar_gen4_pcie, dw)
> > +
> > +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 {
> > + /*
> > + * Since the datasheet of R-Car doesn't mention how to assert
> > + * the APP_HOLD_PHY_RST, don't assert it again. Otherwise,
> > + * hang-up issue happened in the dw_edma_core_off() when
> > + * the controller didn't detect a PCI device.
> > + */
> > + val &= ~APP_LTSSM_ENABLE;
> > + }
> > + writel(val, rcar->base + PCIERSTCTRL1);
> > +}
> > +
> > +static int rcar_gen4_pcie_link_up(struct dw_pcie *dw)
> > +{
> > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> > + u32 val, mask;
> > +
> > + val = readl(rcar->base + PCIEINTSTS0);
> > + mask = RDLH_LINK_UP | SMLH_LINK_UP;
> > +
> > + return (val & mask) == mask;
> > +}
> > +
> > +/*
> > + * Manually initiate the speed change. Return true if the change succeeded,
> > + * false if the change didn't finish within certain periods.
>
> This function returns 0 in success case and -ETIMEDOUT for failure. So the
> comment should be fixed.
Thank you for your comment! I also got a comment from Bjorn [1]. So,
I'll fix it and submit patch series as v24.
[1] https://lore.kernel.org/linux-pci/20231005150907.GA746291@bhelgaas/
> > + */
> > +static int rcar_gen4_pcie_speed_change(struct dw_pcie *dw)
> > +{
> > + u32 val;
> > + int i;
> > +
> > + val = dw_pcie_readl_dbi(dw, PCIE_LINK_WIDTH_SPEED_CONTROL);
> > + val &= ~PORT_LOGIC_SPEED_CHANGE;
> > + dw_pcie_writel_dbi(dw, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
> > +
> > + val = dw_pcie_readl_dbi(dw, PCIE_LINK_WIDTH_SPEED_CONTROL);
> > + val |= PORT_LOGIC_SPEED_CHANGE;
> > + dw_pcie_writel_dbi(dw, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
> > +
> > + for (i = 0; i < RCAR_NUM_SPEED_CHANGE_RETRIES; i++) {
> > + val = dw_pcie_readl_dbi(dw, PCIE_LINK_WIDTH_SPEED_CONTROL);
> > + if (!(val & PORT_LOGIC_SPEED_CHANGE))
> > + return 0;
> > + usleep_range(10000, 11000);
> > + }
> > +
> > + return -ETIMEDOUT;
> > +}
> > +
> > +/*
> > + * Enable LTSSM of this controller and manually initiate the speed change.
> > + * Always return 0.
> > + */
> > +static int rcar_gen4_pcie_start_link(struct dw_pcie *dw)
> > +{
> > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> > + int i, changes;
> > +
> > + rcar_gen4_pcie_ltssm_enable(rcar, true);
> > +
> > + /*
> > + * Require direct speed change with retrying here if the link_gen is
> > + * PCIe Gen2 or higher.
> > + */
> > + changes = min_not_zero(dw->link_gen, RCAR_MAX_LINK_SPEED) - 1;
> > +
> > + /*
> > + * Since dw_pcie_setup_rc() sets it once, PCIe Gen2 will be trained.
> > + * So, this needs remaining times for up to PCIe Gen4 if RC mode.
> > + */
> > + if (changes && rcar->mode == DW_PCIE_RC_TYPE)
> > + changes--;
> > +
> > + for (i = 0; i < changes; i++) {
> > + /* No error because possible disconnected here if EP mode */
>
> This comment is not grammatically correct.
I'll fix this comment.
> > + if (rcar_gen4_pcie_speed_change(dw))
> > + break;
> > + }
> > +
> > + 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_common_init(struct rcar_gen4_pcie *rcar)
> > +{
> > + struct dw_pcie *dw = &rcar->dw;
> > + u32 val;
> > + int ret;
> > +
> > + ret = clk_bulk_prepare_enable(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
> > + if (ret) {
> > + dev_err(dw->dev, "Failed to enable ref clocks\n");
>
> Not all clocks are reference clocks.
I'll fix this message.
> > + return ret;
> > + }
> > +
> > + if (!reset_control_status(dw->core_rsts[DW_PCIE_PWR_RST].rstc))
> > + reset_control_assert(dw->core_rsts[DW_PCIE_PWR_RST].rstc);
> > +
> > + val = readl(rcar->base + PCIEMSR0);
> > + if (rcar->mode == DW_PCIE_RC_TYPE) {
> > + val |= DEVICE_TYPE_RC;
> > + } else if (rcar->mode == DW_PCIE_EP_TYPE) {
> > + val |= DEVICE_TYPE_EP;
> > + } else {
> > + ret = -EINVAL;
> > + goto err_unprepare;
> > + }
> > +
> > + if (dw->num_lanes < 4)
> > + val |= BIFUR_MOD_SET_ON;
> > +
> > + writel(val, rcar->base + PCIEMSR0);
> > +
> > + ret = reset_control_deassert(dw->core_rsts[DW_PCIE_PWR_RST].rstc);
> > + if (ret)
> > + goto err_unprepare;
> > +
> > + return 0;
> > +
> > +err_unprepare:
> > + clk_bulk_disable_unprepare(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
> > +
> > + return ret;
> > +}
> > +
> > +void rcar_gen4_pcie_common_deinit(struct rcar_gen4_pcie *rcar)
> > +{
> > + struct dw_pcie *dw = &rcar->dw;
> > +
> > + reset_control_assert(dw->core_rsts[DW_PCIE_PWR_RST].rstc);
> > + clk_bulk_disable_unprepare(DW_PCIE_NUM_CORE_CLKS, dw->core_clks);
> > +}
> > +
> > +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);
> > + if (err < 0) {
> > + dev_err(dev, "Failed to resume/get Runtime PM\n");
>
> "Runtime resume failed\n"
Thank you for your suggestion. I'll fix it.
> > + pm_runtime_disable(dev);
> > + }
> > +
> > + return err;
> > +}
> > +
> > +void rcar_gen4_pcie_unprepare(struct rcar_gen4_pcie *rcar)
> > +{
> > + struct device *dev = rcar->dw.dev;
> > +
> > + pm_runtime_put(dev);
> > + pm_runtime_disable(dev);
> > +}
> > +
> > +int rcar_gen4_pcie_get_resources(struct rcar_gen4_pcie *rcar)
> > +{
> > + /* Renesas-specific registers */
> > + rcar->base = devm_platform_ioremap_resource_byname(rcar->pdev, "app");
> > +
> > + return PTR_ERR_OR_ZERO(rcar->base);
> > +}
> > +
> > +static const struct dw_pcie_ops dw_pcie_ops = {
> > + .start_link = rcar_gen4_pcie_start_link,
> > + .stop_link = rcar_gen4_pcie_stop_link,
> > + .link_up = rcar_gen4_pcie_link_up,
> > +};
> > +
> > +struct rcar_gen4_pcie *rcar_gen4_pcie_devm_alloc(struct platform_device *pdev)
>
> You should not name the functions based on the internal APIs. Please use
> something like, rcar_gen4_pcie_drv_alloc() or just rcar_gen4_pcie_alloc().
I got it. I'll rename this function name.
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct rcar_gen4_pcie *rcar;
> > +
> > + rcar = devm_kzalloc(dev, sizeof(*rcar), GFP_KERNEL);
> > + if (!rcar)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + rcar->dw.ops = &dw_pcie_ops;
> > + rcar->dw.dev = dev;
> > + rcar->pdev = pdev;
> > + dw_pcie_cap_set(&rcar->dw, EDMA_UNROLL);
> > + dw_pcie_cap_set(&rcar->dw, REQ_RES);
> > + platform_set_drvdata(pdev, rcar);
> > +
> > + return rcar;
> > +}
> > +
> > +/* Host mode */
> > +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;
> > +
> > + gpiod_set_value_cansleep(dw->pe_rst, 1);
> > +
> > + ret = rcar_gen4_pcie_common_init(rcar);
> > + if (ret)
> > + return ret;
> > +
> > + /*
> > + * According to the section 3.5.7.2 "RC Mode" in DWC PCIe Dual Mode
> > + * Rev.5.20a, we should disable two BARs to avoid unnecessary memory
> > + * assignment during device enumeration.
> > + */
> > + dw_pcie_writel_dbi2(dw, PCI_BASE_ADDRESS_0, 0x0);
> > + dw_pcie_writel_dbi2(dw, PCI_BASE_ADDRESS_1, 0x0);
>
> If this is DWC specific, can we move it to the common code?
Hmm, it seems so. However, I didn't find any similar code on other DWC drivers.
So, for now, moving it to the common code is not needed, I think.
> > +
> > + /* Enable MSI interrupt signal */
> > + val = readl(rcar->base + PCIEINTSTS0EN);
> > + val |= MSI_CTRL_INT;
> > + writel(val, rcar->base + PCIEINTSTS0EN);
> > +
>
> Above should be guarded with:
>
> if (IS_ENABLED(CONFIG_PCI_MSI)) {
> ...
> }
Since this driver depends on PCI_MSI by Kconfig, such a IS_ENABLED is not
needed. This is from your suggestion ;) [2]
[2] https://lore.kernel.org/linux-devicetree/20230724122820.GM6291@thinkpad/
Best regards,
Yoshihiro Shimoda
> - Mani
>
> --
> மணிவண்ணன் சதாசிவம்
