Add support for PCIe controller in J721E SoC. The controller uses the
Cadence PCIe core programmed by pcie-cadence*.c. The PCIe controller
will work in both host mode and device mode.
Some of the features of the controller are:
  *) Supports both RC mode and EP mode
  *) Supports MSI and MSI-X support
  *) Supports upto GEN3 speed mode
  *) Supports SR-IOV capability
  *) Ability to route all transactions via SMMU (support will be added
     in a later patch).

Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
---
 drivers/pci/controller/cadence/Kconfig        |  23 +
 drivers/pci/controller/cadence/Makefile       |   1 +
 drivers/pci/controller/cadence/pci-j721e.c    | 490 ++++++++++++++++++
 .../controller/cadence/pcie-cadence-host.c    |   4 +-
 drivers/pci/controller/cadence/pcie-cadence.h |   8 +
 5 files changed, 524 insertions(+), 2 deletions(-)
 create mode 100644 drivers/pci/controller/cadence/pci-j721e.c

diff --git a/drivers/pci/controller/cadence/Kconfig 
b/drivers/pci/controller/cadence/Kconfig
index b76b3cf55ce5..5d30564190e1 100644
--- a/drivers/pci/controller/cadence/Kconfig
+++ b/drivers/pci/controller/cadence/Kconfig
@@ -42,4 +42,27 @@ config PCIE_CADENCE_PLAT_EP
          endpoint mode. This PCIe controller may be embedded into many
          different vendors SoCs.
 
+config PCI_J721E
+       bool
+
+config PCI_J721E_HOST
+       bool "TI J721E PCIe platform host controller"
+       depends on OF
+       select PCIE_CADENCE_HOST
+       select PCI_J721E
+       help
+         Say Y here if you want to support the TI J721E PCIe platform
+         controller in host mode. TI J721E PCIe controller uses Cadence PCIe
+         core.
+
+config PCI_J721E_EP
+       bool "TI J721E PCIe platform endpoint controller"
+       depends on OF
+       depends on PCI_ENDPOINT
+       select PCIE_CADENCE_EP
+       select PCI_J721E
+       help
+         Say Y here if you want to support the TI J721E PCIe platform
+         controller in endpoint mode. TI J721E PCIe controller uses Cadence 
PCIe
+         core.
 endmenu
diff --git a/drivers/pci/controller/cadence/Makefile 
b/drivers/pci/controller/cadence/Makefile
index 232a3f20876a..9bac5fb2f13d 100644
--- a/drivers/pci/controller/cadence/Makefile
+++ b/drivers/pci/controller/cadence/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
 obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
 obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep.o
 obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
+obj-$(CONFIG_PCI_J721E) += pci-j721e.o
diff --git a/drivers/pci/controller/cadence/pci-j721e.c 
b/drivers/pci/controller/cadence/pci-j721e.c
new file mode 100644
index 000000000000..9b3ab880a3c5
--- /dev/null
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * pci-j721e - PCIe controller driver for TI's J721E SoCs
+ *
+ * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Kishon Vijay Abraham I <kis...@ti.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/io.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/pci.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#include "../../pci.h"
+#include "pcie-cadence.h"
+
+#define ENABLE_REG_SYS_2       0x108
+#define STATUS_REG_SYS_2       0x508
+#define STATUS_CLR_REG_SYS_2   0x708
+#define LINK_DOWN              BIT(1)
+
+#define J721E_PCIE_USER_CMD_STATUS     0x4
+#define LINK_TRAINING_ENABLE           BIT(0)
+
+#define J721E_PCIE_USER_LINKSTATUS     0x14
+#define LINK_STATUS                    GENMASK(1, 0)
+
+enum link_status {
+       NO_RECEIVERS_DETECTED,
+       LINK_TRAINING_IN_PROGRESS,
+       LINK_UP_DL_IN_PROGRESS,
+       LINK_UP_DL_COMPLETED,
+};
+
+#define J721E_MODE_RC                  BIT(7)
+#define LANE_COUNT_MASK                        BIT(8)
+#define LANE_COUNT(n)                  ((n) << 8)
+
+#define GENERATION_SEL_MASK            GENMASK(1, 0)
+
+#define MAX_LANES                      2
+
+struct j721e_pcie {
+       struct device           *dev;
+       u32                     mode;
+       u32                     num_lanes;
+       struct cdns_pcie        *cdns_pcie;
+       void __iomem            *user_cfg_base;
+       void __iomem            *intd_cfg_base;
+};
+
+enum j721e_pcie_mode {
+       PCI_MODE_RC,
+       PCI_MODE_EP,
+};
+
+struct j721e_pcie_data {
+       enum j721e_pcie_mode    mode;
+};
+
+static inline u32 j721e_pcie_user_readl(struct j721e_pcie *pcie, u32 offset)
+{
+       return readl(pcie->user_cfg_base + offset);
+}
+
+static inline void j721e_pcie_user_writel(struct j721e_pcie *pcie, u32 offset,
+                                         u32 value)
+{
+       writel(value, pcie->user_cfg_base + offset);
+}
+
+static inline u32 j721e_pcie_intd_readl(struct j721e_pcie *pcie, u32 offset)
+{
+       return readl(pcie->intd_cfg_base + offset);
+}
+
+static inline void j721e_pcie_intd_writel(struct j721e_pcie *pcie, u32 offset,
+                                         u32 value)
+{
+       writel(value, pcie->intd_cfg_base + offset);
+}
+
+static irqreturn_t j721e_pcie_link_irq_handler(int irq, void *priv)
+{
+       struct j721e_pcie *pcie = priv;
+       struct device *dev = pcie->dev;
+       u32 reg;
+
+       reg = j721e_pcie_intd_readl(pcie, STATUS_REG_SYS_2);
+       if (!(reg & LINK_DOWN))
+               return IRQ_NONE;
+
+       dev_err(dev, "LINK DOWN!\n");
+
+       j721e_pcie_intd_writel(pcie, STATUS_CLR_REG_SYS_2, LINK_DOWN);
+       return IRQ_HANDLED;
+}
+
+static void j721e_pcie_config_link_irq(struct j721e_pcie *pcie)
+{
+       u32 reg;
+
+       reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_2);
+       reg |= LINK_DOWN;
+       j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_2, reg);
+}
+
+static int j721e_pcie_start_link(struct cdns_pcie *cdns_pcie)
+{
+       struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
+       u32 reg;
+
+       reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
+       reg |= LINK_TRAINING_ENABLE;
+       j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
+
+       return 0;
+}
+
+static void j721e_pcie_stop_link(struct cdns_pcie *cdns_pcie)
+{
+       struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
+       u32 reg;
+
+       reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_CMD_STATUS);
+       reg &= ~LINK_TRAINING_ENABLE;
+       j721e_pcie_user_writel(pcie, J721E_PCIE_USER_CMD_STATUS, reg);
+}
+
+static bool j721e_pcie_link_up(struct cdns_pcie *cdns_pcie)
+{
+       struct j721e_pcie *pcie = dev_get_drvdata(cdns_pcie->dev);
+       u32 reg;
+
+       reg = j721e_pcie_user_readl(pcie, J721E_PCIE_USER_LINKSTATUS);
+       reg &= LINK_STATUS;
+       if (reg == LINK_UP_DL_COMPLETED)
+               return true;
+
+       return false;
+}
+
+static const struct cdns_pcie_ops j721e_ops_ops = {
+       .start_link = j721e_pcie_start_link,
+       .stop_link = j721e_pcie_stop_link,
+       .link_up = j721e_pcie_link_up,
+};
+
+static int j721e_pcie_set_mode(struct j721e_pcie *pcie, struct regmap *syscon)
+{
+       struct device *dev = pcie->dev;
+       u32 mask = J721E_MODE_RC;
+       u32 mode = pcie->mode;
+       u32 val = 0;
+       int ret = 0;
+
+       if (mode == PCI_MODE_RC)
+               val = J721E_MODE_RC;
+
+       ret = regmap_update_bits(syscon, 0, mask, val);
+       if (ret)
+               dev_err(dev, "failed to set pcie mode\n");
+
+       return ret;
+}
+
+static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
+                                    struct regmap *syscon)
+{
+       struct device *dev = pcie->dev;
+       struct device_node *np = dev->of_node;
+       int link_speed;
+       u32 val = 0;
+       int ret;
+
+       link_speed = of_pci_get_max_link_speed(np);
+       if (link_speed < 2)
+               link_speed = 2;
+
+       val = link_speed - 1;
+       ret = regmap_update_bits(syscon, 0, GENERATION_SEL_MASK, val);
+       if (ret)
+               dev_err(dev, "failed to set link speed\n");
+
+       return ret;
+}
+
+static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
+                                    struct regmap *syscon)
+{
+       struct device *dev = pcie->dev;
+       u32 lanes = pcie->num_lanes;
+       u32 val = 0;
+       int ret;
+
+       val = LANE_COUNT(lanes - 1);
+       ret = regmap_update_bits(syscon, 0, LANE_COUNT_MASK, val);
+       if (ret)
+               dev_err(dev, "failed to set link count\n");
+
+       return ret;
+}
+
+static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie)
+{
+       struct device *dev = pcie->dev;
+       struct device_node *node = dev->of_node;
+       struct regmap *syscon;
+       int ret;
+
+       syscon = syscon_regmap_lookup_by_phandle(node, "ti,syscon-pcie-ctrl");
+       if (IS_ERR(syscon)) {
+               dev_err(dev, "Unable to get ti,syscon-pcie-ctrl regmap\n");
+               return PTR_ERR(syscon);
+       }
+
+       ret = j721e_pcie_set_mode(pcie, syscon);
+       if (ret < 0) {
+               dev_err(dev, "Failed to set pci mode\n");
+               return ret;
+       }
+
+       ret = j721e_pcie_set_link_speed(pcie, syscon);
+       if (ret < 0) {
+               dev_err(dev, "Failed to set link speed\n");
+               return ret;
+       }
+
+       ret = j721e_pcie_set_lane_count(pcie, syscon);
+       if (ret < 0) {
+               dev_err(dev, "Failed to set num-lanes\n");
+               return ret;
+       }
+
+       return 0;
+}
+
+static int cdns_ti_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
+                                   int where, int size, u32 *value)
+{
+       struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
+       struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
+       unsigned int busn = bus->number;
+
+       if (busn == rc->bus_range->start)
+               return pci_generic_config_read32(bus, devfn, where, size,
+                                                value);
+
+       return pci_generic_config_read(bus, devfn, where, size, value);
+}
+
+static int cdns_ti_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
+                                    int where, int size, u32 value)
+{
+       struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
+       struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
+       unsigned int busn = bus->number;
+
+       if (busn == rc->bus_range->start)
+               return pci_generic_config_write32(bus, devfn, where, size,
+                                                 value);
+
+       return pci_generic_config_write(bus, devfn, where, size, value);
+}
+
+static struct pci_ops cdns_ti_pcie_host_ops = {
+       .map_bus        = cdns_pci_map_bus,
+       .read           = cdns_ti_pcie_config_read,
+       .write          = cdns_ti_pcie_config_write,
+};
+
+static const struct j721e_pcie_data j721e_pcie_rc_data = {
+       .mode = PCI_MODE_RC,
+};
+
+static const struct j721e_pcie_data j721e_pcie_ep_data = {
+       .mode = PCI_MODE_EP,
+};
+
+static const struct of_device_id of_j721e_pcie_match[] = {
+       {
+               .compatible = "ti,j721e-pcie-host",
+               .data = &j721e_pcie_rc_data,
+       },
+       {
+               .compatible = "ti,j721e-pcie-ep",
+               .data = &j721e_pcie_ep_data,
+       },
+       {},
+};
+
+static int j721e_pcie_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *node = dev->of_node;
+       struct pci_host_bridge *bridge;
+       struct j721e_pcie_data *data;
+       struct cdns_pcie *cdns_pcie;
+       struct j721e_pcie *pcie;
+       struct cdns_pcie_rc *rc;
+       struct cdns_pcie_ep *ep;
+       struct gpio_desc *gpiod;
+       void __iomem *base;
+       u32 num_lanes;
+       u32 mode;
+       int ret;
+       int irq;
+
+       data = (struct j721e_pcie_data *)of_device_get_match_data(dev);
+       if (!data)
+               return -EINVAL;
+
+       mode = (u32)data->mode;
+
+       pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+       if (!pcie)
+               return -ENOMEM;
+
+       pcie->dev = dev;
+       pcie->mode = mode;
+
+       base = devm_platform_ioremap_resource_byname(pdev, "intd_cfg");
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+       pcie->intd_cfg_base = base;
+
+       base = devm_platform_ioremap_resource_byname(pdev, "user_cfg");
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+       pcie->user_cfg_base = base;
+
+       ret = of_property_read_u32(node, "num-lanes", &num_lanes);
+       if (ret || num_lanes > MAX_LANES)
+               num_lanes = 1;
+       pcie->num_lanes = num_lanes;
+
+       irq = platform_get_irq_byname(pdev, "link_state");
+       if (irq < 0)
+               return irq;
+
+       dev_set_drvdata(dev, pcie);
+       pm_runtime_enable(dev);
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0) {
+               dev_err(dev, "pm_runtime_get_sync failed\n");
+               goto err_get_sync;
+       }
+
+       ret = j721e_pcie_ctrl_init(pcie);
+       if (ret < 0) {
+               dev_err(dev, "pm_runtime_get_sync failed\n");
+               goto err_get_sync;
+       }
+
+       ret = devm_request_irq(dev, irq, j721e_pcie_link_irq_handler, 0,
+                              "j721e-pcie-link-down-irq", pcie);
+       if (ret < 0) {
+               dev_err(dev, "failed to request link state IRQ %d\n", irq);
+               goto err_get_sync;
+       }
+
+       j721e_pcie_config_link_irq(pcie);
+
+       switch (mode) {
+       case PCI_MODE_RC:
+               if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST)) {
+                       ret = -ENODEV;
+                       goto err_get_sync;
+               }
+
+               bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
+               if (!bridge) {
+                       ret = -ENOMEM;
+                       goto err_get_sync;
+               }
+
+               bridge->ops = &cdns_ti_pcie_host_ops;
+               rc = pci_host_bridge_priv(bridge);
+
+               cdns_pcie = &rc->pcie;
+               cdns_pcie->dev = dev;
+               cdns_pcie->ops = &j721e_ops_ops;
+               pcie->cdns_pcie = cdns_pcie;
+
+               gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+               if (IS_ERR(gpiod)) {
+                       ret = PTR_ERR(gpiod);
+                       if (ret != -EPROBE_DEFER)
+                               dev_err(dev, "Failed to get reset GPIO\n");
+                       goto err_get_sync;
+               }
+
+               ret = cdns_pcie_init_phy(dev, cdns_pcie);
+               if (ret) {
+                       dev_err(dev, "Failed to init phy\n");
+                       goto err_get_sync;
+               }
+
+               /*
+                * "Power Sequencing and Reset Signal Timings" table in
+                * PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0
+                * indicates PERST# should be deasserted after minimum of 100us
+                * once REFCLK is stable. The REFCLK to the connector in RC
+                * mode is selected while enabling the PHY. So deassert PERST#
+                * after 100 us.
+                */
+               if (gpiod) {
+                       usleep_range(100, 200);
+                       gpiod_set_value_cansleep(gpiod, 1);
+               }
+
+               ret = cdns_pcie_host_setup(rc);
+               if (ret < 0)
+                       goto err_pcie_setup;
+
+               break;
+       case PCI_MODE_EP:
+               if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP)) {
+                       ret = -ENODEV;
+                       goto err_get_sync;
+               }
+
+               ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
+               if (!ep) {
+                       ret = -ENOMEM;
+                       goto err_get_sync;
+               }
+
+               cdns_pcie = &ep->pcie;
+               cdns_pcie->dev = dev;
+               cdns_pcie->ops = &j721e_ops_ops;
+               pcie->cdns_pcie = cdns_pcie;
+
+               ret = cdns_pcie_init_phy(dev, cdns_pcie);
+               if (ret) {
+                       dev_err(dev, "Failed to init phy\n");
+                       goto err_get_sync;
+               }
+
+               ret = cdns_pcie_ep_setup(ep);
+               if (ret < 0)
+                       goto err_pcie_setup;
+
+               break;
+       default:
+               dev_err(dev, "INVALID device type %d\n", mode);
+       }
+
+       return 0;
+
+err_pcie_setup:
+       cdns_pcie_disable_phy(cdns_pcie);
+
+err_get_sync:
+       pm_runtime_put(dev);
+       pm_runtime_disable(dev);
+
+       return ret;
+}
+
+static int j721e_pcie_remove(struct platform_device *pdev)
+{
+       struct j721e_pcie *pcie = platform_get_drvdata(pdev);
+       struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
+       struct device *dev = &pdev->dev;
+
+       cdns_pcie_disable_phy(cdns_pcie);
+       pm_runtime_put(dev);
+       pm_runtime_disable(dev);
+
+       return 0;
+}
+
+static struct platform_driver j721e_pcie_driver = {
+       .probe  = j721e_pcie_probe,
+       .remove = j721e_pcie_remove,
+       .driver = {
+               .name   = "j721e-pcie",
+               .of_match_table = of_j721e_pcie_match,
+               .suppress_bind_attrs = true,
+       },
+};
+builtin_platform_driver(j721e_pcie_driver);
diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c 
b/drivers/pci/controller/cadence/pcie-cadence-host.c
index 7ee9e06f1285..cf8b34b71b8f 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -17,8 +17,8 @@ static u64 bar_max_size[] = {
        [RP_NO_BAR] = _BITULL(63),
 };
 
-static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
-                                     int where)
+void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
+                              int where)
 {
        struct pci_host_bridge *bridge = pci_find_host_bridge(bus);
        struct cdns_pcie_rc *rc = pci_host_bridge_priv(bridge);
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h 
b/drivers/pci/controller/cadence/pcie-cadence.h
index 1bf7d4e09b8a..f8e8144e222d 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -469,11 +469,19 @@ static inline bool cdns_pcie_link_up(struct cdns_pcie 
*pcie)
 
 #ifdef CONFIG_PCIE_CADENCE_HOST
 int cdns_pcie_host_setup(struct cdns_pcie_rc *rc);
+void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
+                              int where);
 #else
 static inline int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
 {
        return 0;
 }
+
+static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned int devfn,
+                                     int where)
+{
+       return NULL;
+}
 #endif
 
 #ifdef CONFIG_PCIE_CADENCE_EP
-- 
2.17.1

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