[PATCH v23 13/16] PCI: dwc: rcar-gen4: Add R-Car Gen4 PCIe controller support for host mode

Yoshihiro Shimoda
2023-09-26T12:24:44Z

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: https://lore.kernel.org/linux-pci/20230825093219.2685912-17-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
---
drivers/pci/controller/dwc/Kconfig | 14 +
drivers/pci/controller/dwc/Makefile | 1 +
drivers/pci/controller/dwc/pcie-rcar-gen4.c | 378 ++++++++++++++++++++
3 files changed, 393 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..2fb27e97900b
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -0,0 +1,378 @@
+// 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_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.
+ */
+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 */
+ 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);
+}
+
+static 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");
+ 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 {
+ 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;
+}
+
+static 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);
+}
+
+static 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");
+ pm_runtime_disable(dev);
+ }
+
+ return err;
+}
+
+static void rcar_gen4_pcie_unprepare(struct rcar_gen4_pcie *rcar)
+{
+ struct device *dev = rcar->dw.dev;
+
+ pm_runtime_put(dev);
+ pm_runtime_disable(dev);
+}
+
+static 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,
+};
+
+static struct
+rcar_gen4_pcie *rcar_gen4_pcie_devm_alloc(struct platform_device *pdev)
+{
+ 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);
+
+ /* Enable MSI interrupt signal */
+ val = readl(rcar->base + PCIEINTSTS0EN);
+ val |= MSI_CTRL_INT;
+ writel(val, rcar->base + PCIEINTSTS0EN);
+
+ msleep(PCIE_T_PVPERL_MS); /* pe_rst requires 100msec delay */
+
+ gpiod_set_value_cansleep(dw->pe_rst, 0);
+
+ return 0;
+}
+
+static void rcar_gen4_pcie_host_deinit(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);
+
+ gpiod_set_value_cansleep(dw->pe_rst, 1);
+ rcar_gen4_pcie_common_deinit(rcar);
+}
+
+static const struct dw_pcie_host_ops rcar_gen4_pcie_host_ops = {
+ .host_init = rcar_gen4_pcie_host_init,
+ .host_deinit = rcar_gen4_pcie_host_deinit,
+};
+
+static int rcar_gen4_add_dw_pcie_rp(struct rcar_gen4_pcie *rcar)
+{
+ struct dw_pcie_rp *pp = &rcar->dw.pp;
+
+ pp->num_vectors = MAX_MSI_IRQS;
+ pp->ops = &rcar_gen4_pcie_host_ops;
+ rcar->mode = DW_PCIE_RC_TYPE;
+
+ return dw_pcie_host_init(pp);
+}
+
+static void rcar_gen4_remove_dw_pcie_rp(struct rcar_gen4_pcie *rcar)
+{
+ dw_pcie_host_deinit(&rcar->dw.pp);
+}
+
+static int rcar_gen4_pcie_probe(struct platform_device *pdev)
+{
+ struct rcar_gen4_pcie *rcar;
+ int err;
+
+ rcar = rcar_gen4_pcie_devm_alloc(pdev);
+ if (IS_ERR(rcar))
+ return PTR_ERR(rcar);
+
+ err = rcar_gen4_pcie_get_resources(rcar);
+ if (err)
+ return err;
+
+ err = rcar_gen4_pcie_prepare(rcar);
+ if (err)
+ return err;
+
+ err = rcar_gen4_add_dw_pcie_rp(rcar);
+ if (err)
+ goto err_unprepare;
+
+ return 0;
+
+err_unprepare:
+ rcar_gen4_pcie_unprepare(rcar);
+
+ return err;
+}
+
+static void rcar_gen4_pcie_remove(struct platform_device *pdev)
+{
+ struct rcar_gen4_pcie *rcar = platform_get_drvdata(pdev);
+
+ rcar_gen4_remove_dw_pcie_rp(rcar);
+ rcar_gen4_pcie_unprepare(rcar);
+}
+
+static const struct of_device_id rcar_gen4_pcie_of_match[] = {
+ { .compatible = "renesas,rcar-gen4-pcie", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rcar_gen4_pcie_of_match);
+
+static struct platform_driver rcar_gen4_pcie_driver = {
+ .driver = {
+ .name = "pcie-rcar-gen4",
+ .of_match_table = rcar_gen4_pcie_of_match,
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+ .probe = rcar_gen4_pcie_probe,
+ .remove_new = rcar_gen4_pcie_remove,
+};
+module_platform_driver(rcar_gen4_pcie_driver);
+
+MODULE_DESCRIPTION("Renesas R-Car Gen4 PCIe controller driver");
+MODULE_LICENSE("GPL");
--
2.25.1