From: Hongtao Wu <billows...@unisoc.com>

This series adds PCIe controller driver for Unisoc SoCs.
This controller is based on DesignWare PCIe IP.

Signed-off-by: Hongtao Wu <billows...@unisoc.com>
Signed-off-by: Chunyan Zhang <zhang.l...@gmail.com>
---
 drivers/pci/controller/dwc/Kconfig     |  12 +
 drivers/pci/controller/dwc/Makefile    |   1 +
 drivers/pci/controller/dwc/pcie-sprd.c | 292 +++++++++++++++++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-sprd.c

diff --git a/drivers/pci/controller/dwc/Kconfig 
b/drivers/pci/controller/dwc/Kconfig
index 22c5529e9a65..61f0b79f963d 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -318,4 +318,16 @@ config PCIE_AL
          required only for DT-based platforms. ACPI platforms with the
          Annapurna Labs PCIe controller don't need to enable this.
 
+config PCIE_SPRD
+       tristate "Unisoc PCIe controller - Host Mode"
+       depends on ARCH_SPRD || COMPILE_TEST
+       depends on PCI_MSI_IRQ_DOMAIN
+       select PCIE_DW_HOST
+       help
+         Unisoc PCIe controller uses the DesignWare core. It can be configured
+         as an Endpoint (EP) or a Root complex (RC). In order to enable host
+         mode (the controller works as RC), PCIE_SPRD must be selected.
+         Say Y or M here if you want to PCIe RC controller support on Unisoc
+         SoCs.
+
 endmenu
diff --git a/drivers/pci/controller/dwc/Makefile 
b/drivers/pci/controller/dwc/Makefile
index a751553fa0db..eb546e97c14a 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_PCI_MESON) += pci-meson.o
 obj-$(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_SPRD) += pcie-sprd.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-sprd.c 
b/drivers/pci/controller/dwc/pcie-sprd.c
new file mode 100644
index 000000000000..2ccb99eda24f
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-sprd.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host controller driver for Unisoc SoCs
+ *
+ * Copyright (C) 2020-2021 Unisoc, Inc.
+ *
+ * Author: Hongtao Wu <billows...@unisoc.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#include "pcie-designware.h"
+
+/* aon apb syscon */
+#define IPA_ACCESS_CFG         0xcd8
+#define  AON_ACCESS_PCIE_EN    BIT(1)
+
+/* pmu apb syscon */
+#define SNPS_PCIE3_SLP_CTRL    0xac
+#define  PERST_N_ASSERT                BIT(1)
+#define  PERST_N_AUTO_EN       BIT(0)
+#define PD_PCIE_CFG_0          0x3e8
+#define  PCIE_FORCE_SHUTDOWN   BIT(25)
+
+#define PCIE_SS_REG_BASE               0xE00
+#define APB_CLKFREQ_TIMEOUT            0x4
+#define  BUSERR_EN                     BIT(12)
+#define  APB_TIMER_DIS                 BIT(10)
+#define  APB_TIMER_LIMIT               GENMASK(31, 16)
+
+#define PE0_GEN_CTRL_3                 0x58
+#define  LTSSM_EN                      BIT(0)
+
+struct sprd_pcie_soc_data {
+       u32 syscon_offset;
+};
+
+static const struct sprd_pcie_soc_data ums9520_syscon_data = {
+       .syscon_offset = 0x1000,        /* The offset of set/clear register */
+};
+
+struct sprd_pcie {
+       u32 syscon_offset;
+       struct device   *dev;
+       struct dw_pcie  *pci;
+       struct regmap   *aon_map;
+       struct regmap   *pmu_map;
+       const struct sprd_pcie_soc_data *socdata;
+};
+
+enum sprd_pcie_syscon_type {
+       normal_syscon,          /* it's not a set/clear register */
+       set_syscon,             /* set a set/clear register */
+       clr_syscon,             /* clear a set/clear register */
+};
+
+static void sprd_pcie_buserr_enable(struct dw_pcie *pci)
+{
+       u32 val;
+
+       val = dw_pcie_readl_dbi(pci, PCIE_SS_REG_BASE + APB_CLKFREQ_TIMEOUT);
+       val &= ~APB_TIMER_DIS;
+       val |= BUSERR_EN;
+       val |= APB_TIMER_LIMIT & (0x1f4 << 16);
+       dw_pcie_writel_dbi(pci, PCIE_SS_REG_BASE + APB_CLKFREQ_TIMEOUT, val);
+}
+
+static void sprd_pcie_ltssm_enable(struct dw_pcie *pci, bool enable)
+{
+       u32 val;
+
+       val = dw_pcie_readl_dbi(pci, PCIE_SS_REG_BASE + PE0_GEN_CTRL_3);
+       if (enable)
+               dw_pcie_writel_dbi(pci, PCIE_SS_REG_BASE + PE0_GEN_CTRL_3,
+                                  val | LTSSM_EN);
+       else
+               dw_pcie_writel_dbi(pci, PCIE_SS_REG_BASE + PE0_GEN_CTRL_3,
+                                  val & ~LTSSM_EN);
+}
+
+static int sprd_pcie_syscon_set(struct sprd_pcie *ctrl, struct regmap *map,
+                               u32 reg, u32 mask, u32 val,
+                               enum sprd_pcie_syscon_type type)
+{
+       int ret = 0;
+       u32 read_val;
+       u32 offset = ctrl->syscon_offset;
+       struct device *dev = ctrl->pci->dev;
+
+       /*
+        * Each set/clear register has three registers:
+        * reg:                 base register
+        * reg + offset:        set register
+        * reg + offset * 2:    clear register
+        */
+       switch (type) {
+       case normal_syscon:
+               ret = regmap_read(map, reg, &read_val);
+               if (ret) {
+                       dev_err(dev, "failed to read register 0x%x\n", reg);
+                       return ret;
+               }
+               read_val &= ~mask;
+               read_val |= (val & mask);
+               ret = regmap_write(map, reg, read_val);
+               break;
+       case set_syscon:
+               reg = reg + offset;
+               ret = regmap_write(map, reg, val);
+               break;
+       case clr_syscon:
+               reg = reg + offset * 2;
+               ret = regmap_write(map, reg, val);
+               break;
+       default:
+               break;
+       }
+
+       if (ret)
+               dev_err(dev, "failed to write register 0x%x\n", reg);
+
+       return ret;
+}
+
+static int sprd_pcie_perst_assert(struct sprd_pcie *ctrl)
+{
+       return sprd_pcie_syscon_set(ctrl, ctrl->pmu_map, SNPS_PCIE3_SLP_CTRL,
+                                   PERST_N_ASSERT, PERST_N_ASSERT, set_syscon);
+}
+
+static int sprd_pcie_perst_deassert(struct sprd_pcie *ctrl)
+{
+       int ret;
+
+       ret = sprd_pcie_syscon_set(ctrl, ctrl->pmu_map, SNPS_PCIE3_SLP_CTRL,
+                                  PERST_N_ASSERT, 0, clr_syscon);
+       usleep_range(2000, 3000);
+
+       return ret;
+}
+
+static int sprd_pcie_power_on(struct platform_device *pdev)
+{
+       int ret;
+       struct sprd_pcie *ctrl = platform_get_drvdata(pdev);
+       struct dw_pcie *pci = ctrl->pci;
+
+       ret = sprd_pcie_syscon_set(ctrl, ctrl->aon_map, PD_PCIE_CFG_0,
+                                  PCIE_FORCE_SHUTDOWN, 0, clr_syscon);
+       if (ret)
+               return ret;
+
+       ret = sprd_pcie_syscon_set(ctrl, ctrl->aon_map, IPA_ACCESS_CFG,
+                                  AON_ACCESS_PCIE_EN, AON_ACCESS_PCIE_EN,
+                                  set_syscon);
+       if (ret)
+               return ret;
+
+       ret = sprd_pcie_perst_deassert(ctrl);
+       if (ret)
+               return ret;
+
+       sprd_pcie_buserr_enable(pci);
+       sprd_pcie_ltssm_enable(pci, true);
+
+       return ret;
+}
+
+static int sprd_pcie_power_off(struct platform_device *pdev)
+{
+       struct sprd_pcie *ctrl = platform_get_drvdata(pdev);
+       struct dw_pcie *pci = ctrl->pci;
+
+       sprd_pcie_ltssm_enable(pci, false);
+
+       sprd_pcie_perst_assert(ctrl);
+       sprd_pcie_syscon_set(ctrl, ctrl->aon_map, PD_PCIE_CFG_0,
+                            PCIE_FORCE_SHUTDOWN, PCIE_FORCE_SHUTDOWN,
+                            set_syscon);
+       sprd_pcie_syscon_set(ctrl, ctrl->aon_map, IPA_ACCESS_CFG,
+                            AON_ACCESS_PCIE_EN, 0, clr_syscon);
+
+       return 0;
+}
+
+static int sprd_add_pcie_port(struct platform_device *pdev)
+{
+       struct sprd_pcie *ctrl = platform_get_drvdata(pdev);
+       struct dw_pcie *pci = ctrl->pci;
+       struct pcie_port *pp = &pci->pp;
+
+       return dw_pcie_host_init(pp);
+}
+
+static int sprd_pcie_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct sprd_pcie *ctrl;
+       struct dw_pcie *pci;
+       int ret;
+
+       ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+       if (!ctrl)
+               return -ENOMEM;
+
+       ctrl->socdata =
+               (struct sprd_pcie_soc_data *)of_device_get_match_data(dev);
+       if (!ctrl->socdata) {
+               dev_warn(dev,
+                        "using the default set/clear register offset address");
+               ctrl->syscon_offset = 0x1000;
+       }
+       ctrl->syscon_offset = ctrl->socdata->syscon_offset;
+
+       ctrl->aon_map = syscon_regmap_lookup_by_phandle(dev->of_node,
+                                                       "sprd, regmap-aon");
+       if (IS_ERR(ctrl->aon_map)) {
+               dev_err(dev, "failed to get syscon regmap aon\n");
+               ret = PTR_ERR(ctrl->aon_map);
+               goto err;
+       }
+
+       ctrl->pmu_map = syscon_regmap_lookup_by_phandle(dev->of_node,
+                                                       "sprd, regmap-pmu");
+       if (IS_ERR(ctrl->pmu_map)) {
+               dev_err(dev, "failed to get syscon regmap pmu\n");
+               ret = PTR_ERR(ctrl->pmu_map);
+               goto err;
+       }
+
+       pci = ctrl->pci;
+       pci->dev = dev;
+
+       platform_set_drvdata(pdev, ctrl);
+
+       ret = sprd_pcie_power_on(pdev);
+       if (ret < 0) {
+               dev_err(dev, "failed to power on, return %d\n",
+                       ret);
+               goto err_power_off;
+       }
+
+       ret = sprd_add_pcie_port(pdev);
+       if (ret) {
+               dev_warn(dev, "failed to initialize RC controller\n");
+               return ret;
+       }
+
+       return 0;
+
+err_power_off:
+       sprd_pcie_power_off(pdev);
+err:
+       return ret;
+}
+
+static int sprd_pcie_remove(struct platform_device *pdev)
+{
+       sprd_pcie_power_off(pdev);
+
+       return 0;
+}
+
+static const struct of_device_id sprd_pcie_of_match[] = {
+       {
+               .compatible = "sprd,ums9520-pcie",
+               .data  = &ums9520_syscon_data,
+       },
+       {},
+};
+
+static struct platform_driver sprd_pcie_driver = {
+       .probe = sprd_pcie_probe,
+       .remove = sprd_pcie_remove,
+       .driver = {
+               .name = "sprd-pcie",
+               .of_match_table = sprd_pcie_of_match,
+       },
+};
+module_platform_driver(sprd_pcie_driver);
+
+MODULE_DESCRIPTION("Unisoc PCIe host controller driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1

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