[PATCH v4 02/10] PCI: dwc: Add support for endpoint mode

[Gustavo Pimentel]

The PCIe controller dual mode is capable of operating in host mode as well
as endpoint mode by configuration, therefore this patch aims to add
endpoint mode support to the designware driver.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
---
Change v1->v2:
 - Removed dw_plat_pcie_stop_link empty function.
 - Implemented Kishon's suggestions about dw-pcie-rc and dw-pcie strings.
compatibility.
 - Added second entry on pci_epf_test_ids structure.
Changes v2->v3:
- Reverted additions in dw_pcie_ep_linkup function.
- Replaced devm_ioremap by devm_ioremap_resource function.
- Moved second entry in pci_epf_test_ids structure into a new patch file.
Changes v3->v4:
- Reverted "snps,dw-pcie-rc" compatible string requested by Rob Herring.

 drivers/pci/dwc/Kconfig                |  45 +++++++---
 drivers/pci/dwc/pcie-designware-plat.c | 149 ++++++++++++++++++++++++++++++---
 2 files changed, 174 insertions(+), 20 deletions(-)

diff --git a/drivers/pci/dwc/Kconfig b/drivers/pci/dwc/Kconfig
index 2f3f5c5..3fd7daf 100644
--- a/drivers/pci/dwc/Kconfig
+++ b/drivers/pci/dwc/Kconfig
@@ -7,8 +7,7 @@ config PCIE_DW
 
 config PCIE_DW_HOST
         bool
-	depends on PCI
-	depends on PCI_MSI_IRQ_DOMAIN
+	depends on PCI && PCI_MSI_IRQ_DOMAIN
         select PCIE_DW
 
 config PCIE_DW_EP
@@ -52,16 +51,42 @@ config PCI_DRA7XX_EP
 
 config PCIE_DW_PLAT
 	bool "Platform bus based DesignWare PCIe Controller"
-	depends on PCI
-	depends on PCI_MSI_IRQ_DOMAIN
-	select PCIE_DW_HOST
-	---help---
-	 This selects the DesignWare PCIe controller support. Select this if
-	 you have a PCIe controller on Platform bus.
+	help
+	  There are two instances of PCIe controller in Designware IP.
+	  This controller can work either as EP or RC. In order to enable
+	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
+	  order to enable device-specific features PCIE_DW_PLAT_EP must be
+	  selected.
 
-	 If you have a controller with this interface, say Y or M here.
+config PCIE_DW_PLAT_HOST
+	bool "Platform bus based DesignWare PCIe Controller - Host mode"
+	depends on PCI && PCI_MSI_IRQ_DOMAIN
+	select PCIE_DW_HOST
+	select PCIE_DW_PLAT
+	default y
+	help
+	  Enables support for the PCIe controller in the Designware IP to
+	  work in host mode. There are two instances of PCIe controller in
+	  Designware IP.
+	  This controller can work either as EP or RC. In order to enable
+	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
+	  order to enable device-specific features PCI_DW_PLAT_EP must be
+	  selected.
 
-	 If unsure, say N.
+config PCIE_DW_PLAT_EP
+	bool "Platform bus based DesignWare PCIe Controller - Endpoint mode"
+	depends on PCI && PCI_MSI_IRQ_DOMAIN
+	depends on PCI_ENDPOINT
+	select PCIE_DW_EP
+	select PCIE_DW_PLAT
+	help
+	  Enables support for the PCIe controller in the Designware IP to
+	  work in endpoint mode. There are two instances of PCIe controller
+	  in Designware IP.
+	  This controller can work either as EP or RC. In order to enable
+	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
+	  order to enable device-specific features PCI_DW_PLAT_EP must be
+	  selected.
 
 config PCI_EXYNOS
 	bool "Samsung Exynos PCIe controller"
diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
index 5416aa8..efc315c 100644
--- a/drivers/pci/dwc/pcie-designware-plat.c
+++ b/drivers/pci/dwc/pcie-designware-plat.c
@@ -12,19 +12,29 @@
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/resource.h>
 #include <linux/signal.h>
 #include <linux/types.h>
+#include <linux/regmap.h>
 
 #include "pcie-designware.h"
 
 struct dw_plat_pcie {
-	struct dw_pcie		*pci;
+	struct dw_pcie			*pci;
+	struct regmap			*regmap;
+	enum dw_pcie_device_mode	mode;
 };
 
+struct dw_plat_pcie_of_data {
+	enum dw_pcie_device_mode	mode;
+};
+
+static const struct of_device_id dw_plat_pcie_of_match[];
+
 static int dw_plat_pcie_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -42,9 +52,53 @@ static const struct dw_pcie_host_ops dw_plat_pcie_host_ops = {
 	.host_init = dw_plat_pcie_host_init,
 };
 
-static int dw_plat_add_pcie_port(struct pcie_port *pp,
+static int dw_plat_pcie_establish_link(struct dw_pcie *pci)
+{
+	return 0;
+}
+
+static const struct dw_pcie_ops dw_pcie_ops = {
+	.start_link = dw_plat_pcie_establish_link,
+};
+
+static void dw_plat_pcie_ep_init(struct dw_pcie_ep *ep)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+	enum pci_barno bar;
+
+	for (bar = BAR_0; bar <= BAR_5; bar++)
+		dw_pcie_ep_reset_bar(pci, bar);
+}
+
+static int dw_plat_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
+				     enum pci_epc_irq_type type,
+				     u8 interrupt_num)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+
+	switch (type) {
+	case PCI_EPC_IRQ_LEGACY:
+		dev_err(pci->dev, "EP cannot trigger legacy IRQs\n");
+		return -EINVAL;
+	case PCI_EPC_IRQ_MSI:
+		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
+	default:
+		dev_err(pci->dev, "UNKNOWN IRQ type\n");
+	}
+
+	return 0;
+}
+
+static struct dw_pcie_ep_ops pcie_ep_ops = {
+	.ep_init = dw_plat_pcie_ep_init,
+	.raise_irq = dw_plat_pcie_ep_raise_irq,
+};
+
+static int dw_plat_add_pcie_port(struct dw_plat_pcie *dw_plat_pcie,
 				 struct platform_device *pdev)
 {
+	struct dw_pcie *pci = dw_plat_pcie->pci;
+	struct pcie_port *pp = &pci->pp;
 	struct device *dev = &pdev->dev;
 	int ret;
 
@@ -63,15 +117,44 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
 
 	ret = dw_pcie_host_init(pp);
 	if (ret) {
-		dev_err(dev, "failed to initialize host\n");
+		dev_err(dev, "Failed to initialize host\n");
 		return ret;
 	}
 
 	return 0;
 }
 
-static const struct dw_pcie_ops dw_pcie_ops = {
-};
+static int dw_plat_add_pcie_ep(struct dw_plat_pcie *dw_plat_pcie,
+			       struct platform_device *pdev)
+{
+	int ret;
+	struct dw_pcie_ep *ep;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct dw_pcie *pci = dw_plat_pcie->pci;
+
+	ep = &pci->ep;
+	ep->ops = &pcie_ep_ops;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
+	pci->dbi_base2 = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pci->dbi_base2))
+		return PTR_ERR(pci->dbi_base2);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
+	if (!res)
+		return -EINVAL;
+
+	ep->phys_base = res->start;
+	ep->addr_size = resource_size(res);
+
+	ret = dw_pcie_ep_init(ep);
+	if (ret) {
+		dev_err(dev, "Failed to initialize endpoint\n");
+		return ret;
+	}
+	return 0;
+}
 
 static int dw_plat_pcie_probe(struct platform_device *pdev)
 {
@@ -80,6 +163,16 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
 	struct dw_pcie *pci;
 	struct resource *res;  /* Resource from DT */
 	int ret;
+	const struct of_device_id *match;
+	const struct dw_plat_pcie_of_data *data;
+	enum dw_pcie_device_mode mode;
+
+	match = of_match_device(dw_plat_pcie_of_match, dev);
+	if (!match)
+		return -EINVAL;
+
+	data = (struct dw_plat_pcie_of_data *)match->data;
+	mode = (enum dw_pcie_device_mode)data->mode;
 
 	dw_plat_pcie = devm_kzalloc(dev, sizeof(*dw_plat_pcie), GFP_KERNEL);
 	if (!dw_plat_pcie)
@@ -93,23 +186,59 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
 	pci->ops = &dw_pcie_ops;
 
 	dw_plat_pcie->pci = pci;
+	dw_plat_pcie->mode = mode;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
+	if (!res)
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pci->dbi_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(pci->dbi_base))
 		return PTR_ERR(pci->dbi_base);
 
 	platform_set_drvdata(pdev, dw_plat_pcie);
 
-	ret = dw_plat_add_pcie_port(&pci->pp, pdev);
-	if (ret < 0)
-		return ret;
+	switch (dw_plat_pcie->mode) {
+	case DW_PCIE_RC_TYPE:
+		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_HOST))
+			return -ENODEV;
+
+		ret = dw_plat_add_pcie_port(dw_plat_pcie, pdev);
+		if (ret < 0)
+			return ret;
+		break;
+	case DW_PCIE_EP_TYPE:
+		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_EP))
+			return -ENODEV;
+
+		ret = dw_plat_add_pcie_ep(dw_plat_pcie, pdev);
+		if (ret < 0)
+			return ret;
+		break;
+	default:
+		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
+	}
 
 	return 0;
 }
 
+static const struct dw_plat_pcie_of_data dw_plat_pcie_rc_of_data = {
+	.mode = DW_PCIE_RC_TYPE,
+};
+
+static const struct dw_plat_pcie_of_data dw_plat_pcie_ep_of_data = {
+	.mode = DW_PCIE_EP_TYPE,
+};
+
 static const struct of_device_id dw_plat_pcie_of_match[] = {
-	{ .compatible = "snps,dw-pcie", },
+	{
+		.compatible = "snps,dw-pcie",
+		.data = &dw_plat_pcie_rc_of_data,
+	},
+	{
+		.compatible = "snps,dw-pcie-ep",
+		.data = &dw_plat_pcie_ep_of_data,
+	},
 	{},
 };
 
-- 
2.7.4