[PATCH 2/2] PCI: sprd: Add support for Unisoc SoCs' PCIe controller

[Hongtao Wu <wuht06@gmail.com>]

From: Billows Wu <billows.wu@unisoc.com>

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

Signed-off-by: Billows Wu <billows.wu@unisoc.com>
---
 drivers/pci/controller/dwc/Kconfig     |  12 ++
 drivers/pci/controller/dwc/Makefile    |   1 +
 drivers/pci/controller/dwc/pcie-sprd.c | 256 +++++++++++++++++++++++++++++++++
 3 files changed, 269 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 044a376..d26ce94 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -311,4 +311,16 @@ 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 - RC mode"
+       depends on ARCH_SPRD
+       depends on PCI_MSI_IRQ_DOMAIN
+       select PCIE_DW_HOST
+       help
+         Some Uisoc SoCs contain two PCIe controllers as RC: One is gen2,
+         and the other is gen3. While other Unisoc SoCs may have only one
+         PCIe controller which can be configured as an Endpoint(EP) or a Root
+         complex(RC). In order to enable host-specific features PCIE_SPRD must
+         be selected, which uses the Designware core.
+
 endmenu
diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index a751553..eb546e9 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 0000000..cda812d
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-sprd.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host controller driver for Unisoc SoCs
+ *
+ * Copyright (C) 2020 Unisoc corporation. http://www.unisoc.com
+ *
+ * Author: Billows Wu <Billows.Wu@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/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#include "pcie-designware.h"
+
+#define NUM_OF_ARGS 5
+
+struct sprd_pcie {
+       struct dw_pcie *pci;
+};
+
+struct sprd_pcie_of_data {
+       enum dw_pcie_device_mode mode;
+};
+
+static int sprd_pcie_establish_link(struct dw_pcie *pci)
+{
+       return 0;
+}
+
+static const struct dw_pcie_ops sprd_pcie_ops = {
+       .start_link = sprd_pcie_establish_link,
+};
+
+int sprd_pcie_syscon_setting(struct platform_device *pdev, char *env)
+{
+       struct device_node *np = pdev->dev.of_node;
+       int i, count, err;
+       u32 type, delay, reg, mask, val, tmp_val;
+       struct of_phandle_args out_args;
+       struct regmap *iomap;
+       struct device *dev = &pdev->dev;
+
+       if (!of_find_property(np, env, NULL)) {
+               dev_info(dev, "There isn't property %s in dts\n", env);
+               return 0;
+       }
+
+       count = of_property_count_elems_of_size(np, env,
+                               (NUM_OF_ARGS + 1) * sizeof(u32));
+       dev_info(dev, "Property (%s) reg count is %d :\n", env, count);
+
+       for (i = 0; i < count; i++) {
+               err = of_parse_phandle_with_fixed_args(np, env, NUM_OF_ARGS,
+                                                      i, &out_args);
+               if (err < 0)
+                       return err;
+
+               type = out_args.args[0];
+               delay = out_args.args[1];
+               reg = out_args.args[2];
+               mask = out_args.args[3];
+               val = out_args.args[4];
+
+               iomap = syscon_node_to_regmap(out_args.np);
+
+               switch (type) {
+               case 0:
+                       regmap_update_bits(iomap, reg, mask, val);
+                       break;
+
+               case 1:
+                       regmap_read(iomap, reg, &tmp_val);
+                       tmp_val &= (~mask);
+                       tmp_val |= (val & mask);
+                       regmap_write(iomap, reg, tmp_val);
+                       break;
+               default:
+                       break;
+               }
+
+               if (delay)
+                       usleep_range(delay, delay + 10);
+
+               regmap_read(iomap, reg, &tmp_val);
+               dev_dbg(&pdev->dev,
+                       "%2d:reg[0x%8x] mask[0x%8x] val[0x%8x] result[0x%8x]\n",
+                       i, reg, mask, val, tmp_val);
+       }
+
+       return i;
+}
+
+static void sprd_pcie_perst_assert(struct platform_device *pdev)
+{
+       sprd_pcie_syscon_setting(pdev, "sprd,pcie-perst-assert");
+}
+
+static void sprd_pcie_perst_deassert(struct platform_device *pdev)
+{
+       sprd_pcie_syscon_setting(pdev, "sprd,pcie-perst-deassert");
+}
+
+static int sprd_pcie_host_shutdown(struct platform_device *pdev)
+{
+       int ret;
+       struct device *dev = &pdev->dev;
+
+       ret = sprd_pcie_syscon_setting(pdev, "sprd,pcie-shutdown-syscons");
+       if (ret < 0)
+               dev_err(dev,
+                       "Failed to set pcie shutdown syscons, return %d\n",
+                       ret);
+
+       sprd_pcie_perst_assert(pdev);
+
+       ret = pm_runtime_put(&pdev->dev);
+       if (ret < 0)
+               dev_warn(&pdev->dev,
+                        "Failed to put runtime,return %d\n", ret);
+
+       return ret;
+}
+
+static int sprd_pcie_host_init(struct pcie_port *pp)
+{
+       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+       struct platform_device *pdev = to_platform_device(pci->dev);
+
+       sprd_pcie_perst_deassert(pdev);
+
+       dw_pcie_setup_rc(pp);
+
+       if (IS_ENABLED(CONFIG_PCI_MSI))
+               dw_pcie_msi_init(pp);
+
+       if (dw_pcie_wait_for_link(pci)) {
+               dev_warn(pci->dev,
+                        "pcie ep may has not been powered on yet\n");
+               sprd_pcie_host_shutdown(pdev);
+       }
+
+       return 0;
+}
+
+static const struct dw_pcie_host_ops sprd_pcie_host_ops = {
+       .host_init = sprd_pcie_host_init,
+};
+
+static int sprd_add_pcie_port(struct platform_device *pdev)
+{
+       struct resource *res;
+       struct device *dev = &pdev->dev;
+       struct sprd_pcie *ctrl = platform_get_drvdata(pdev);
+       struct dw_pcie *pci = ctrl->pci;
+       struct pcie_port *pp = &pci->pp;
+
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+       if (!res)
+               return -EINVAL;
+
+       pci->dbi_base = devm_ioremap(dev, res->start, resource_size(res));
+       if (!pci->dbi_base)
+               return -ENOMEM;
+
+       pp->ops = &sprd_pcie_host_ops;
+
+       if (IS_ENABLED(CONFIG_PCI_MSI)) {
+               pp->msi_irq = platform_get_irq_byname(pdev, "msi");
+               if (pp->msi_irq < 0) {
+                       dev_err(dev, "Failed to get msi, return %d\n",
+                               pp->msi_irq);
+                       return pp->msi_irq;
+               }
+       }
+
+       return dw_pcie_host_init(pp);
+}
+
+static int sprd_pcie_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct dw_pcie *pci;
+       struct sprd_pcie *ctrl;
+       int ret;
+
+       ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+       if (!ctrl)
+               return -ENOMEM;
+
+       pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
+       if (!pci)
+               return -ENOMEM;
+
+       pci->dev = dev;
+       pci->ops = &sprd_pcie_ops;
+       ctrl->pci = pci;
+
+       platform_set_drvdata(pdev, ctrl);
+
+       pm_runtime_enable(dev);
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0) {
+               dev_err(dev, "Fialed to get runtime sync, return %d\n", ret);
+               goto err_get_sync;
+       }
+
+       ret = sprd_pcie_syscon_setting(pdev, "sprd,pcie-startup-syscons");
+       if (ret < 0) {
+               dev_err(dev, "Failed to get pcie syscons, 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 0;
+
+err_power_off:
+       sprd_pcie_syscon_setting(pdev, "sprd,pcie-shutdown-syscons");
+
+err_get_sync:
+       pm_runtime_put(&pdev->dev);
+       pm_runtime_disable(dev);
+
+       return ret;
+}
+
+static const struct of_device_id sprd_pcie_of_match[] = {
+       {
+               .compatible = "sprd,pcie",
+       },
+       {},
+};
+
+static struct platform_driver sprd_pcie_driver = {
+       .probe = sprd_pcie_probe,
+       .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 v2");
--
2.7.4