[PATCH V2 7/7] PCI: host-generic: Add dwc PCIe controller based MSI controller usage

[Mayank Rana <quic_mrana@quicinc.com>]

Add usage of Synopsys Designware PCIe controller based MSI controller to
support MSI functionality with ECAM compliant Synopsys Designware PCIe
controller. To use this functionality add device compatible string as
"snps,dw-pcie-ecam-msi".

Signed-off-by: Mayank Rana <quic_mrana@quicinc.com>
---
 drivers/pci/controller/pci-host-generic.c | 92 ++++++++++++++++++++++++++++++-
 1 file changed, 91 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-host-generic.c b/drivers/pci/controller/pci-host-generic.c
index c2c027f..457ae44 100644
--- a/drivers/pci/controller/pci-host-generic.c
+++ b/drivers/pci/controller/pci-host-generic.c
@@ -8,13 +8,73 @@
  * Author: Will Deacon <will.deacon@arm.com>
  */
 
-#include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of_address.h>
 #include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
+#include "dwc/pcie-designware-msi.h"
+
+struct dw_ecam_pcie {
+	void __iomem *cfg;
+	struct dw_msi *msi;
+	struct pci_host_bridge *bridge;
+};
+
+static u32 dw_ecam_pcie_readl(void *p_data, u32 reg)
+{
+	struct dw_ecam_pcie *ecam_pcie = (struct dw_ecam_pcie *)p_data;
+
+	return readl(ecam_pcie->cfg + reg);
+}
+
+static void dw_ecam_pcie_writel(void *p_data, u32 reg, u32 val)
+{
+	struct dw_ecam_pcie *ecam_pcie = (struct dw_ecam_pcie *)p_data;
+
+	writel(val, ecam_pcie->cfg + reg);
+}
+
+static struct dw_ecam_pcie *dw_pcie_ecam_msi(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dw_ecam_pcie *ecam_pcie;
+	struct dw_msi_ops *msi_ops;
+	u64 addr;
+
+	ecam_pcie = devm_kzalloc(dev, sizeof(*ecam_pcie), GFP_KERNEL);
+	if (!ecam_pcie)
+		return ERR_PTR(-ENOMEM);
+
+	if (of_property_read_reg(dev->of_node, 0, &addr, NULL) < 0) {
+		dev_err(dev, "Failed to get reg address\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	ecam_pcie->cfg = devm_ioremap(dev, addr, PAGE_SIZE);
+	if (ecam_pcie->cfg == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	msi_ops = devm_kzalloc(dev, sizeof(*msi_ops), GFP_KERNEL);
+	if (!msi_ops)
+		return ERR_PTR(-ENOMEM);
+
+	msi_ops->readl_msi = dw_ecam_pcie_readl;
+	msi_ops->writel_msi = dw_ecam_pcie_writel;
+	msi_ops->pp = ecam_pcie;
+	ecam_pcie->msi = dw_pcie_msi_host_init(pdev, msi_ops, 0);
+	if (IS_ERR(ecam_pcie->msi)) {
+		dev_err(dev, "dw_pcie_msi_host_init() failed\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	dw_pcie_msi_init(ecam_pcie->msi);
+	return ecam_pcie;
+}
+
 static const struct pci_ecam_ops gen_pci_cfg_cam_bus_ops = {
 	.bus_shift	= 16,
 	.pci_ops	= {
@@ -73,6 +133,9 @@ static const struct of_device_id gen_pci_of_match[] = {
 	{ .compatible = "snps,dw-pcie-ecam",
 	  .data = &pci_dw_ecam_bus_ops },
 
+	{ .compatible = "snps,dw-pcie-ecam-msi",
+	  .data = &pci_generic_ecam_ops },
+
 	{ },
 };
 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
@@ -80,6 +143,7 @@ MODULE_DEVICE_TABLE(of, gen_pci_of_match);
 static int gen_pcie_ecam_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct dw_ecam_pcie *ecam_pcie = NULL;
 	int ret = 0;
 
 	if (!IS_ERR_OR_NULL(dev->pm_domain)) {
@@ -94,14 +158,30 @@ static int gen_pcie_ecam_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (of_device_is_compatible(dev->of_node, "snps,dw-pcie-ecam-msi")) {
+		ecam_pcie = dw_pcie_ecam_msi(pdev);
+		if (IS_ERR(ecam_pcie)) {
+			ret = -ENODEV;
+			goto err;
+		}
+	}
+
 	ret = pci_host_common_probe(pdev);
 	if (ret) {
 		dev_err(dev, "pci_host_common_probe() failed:%d\n", ret);
 		goto err;
 	}
 
+	if (ecam_pcie) {
+		ecam_pcie->bridge = platform_get_drvdata(pdev);
+		platform_set_drvdata(pdev, ecam_pcie);
+	}
+
 	return ret;
 err:
+	if (!IS_ERR_OR_NULL(ecam_pcie))
+		dw_pcie_free_msi(ecam_pcie->msi);
+
 	if (!IS_ERR_OR_NULL(dev->pm_domain))
 		pm_runtime_put_sync(dev);
 	return ret;
@@ -109,7 +189,17 @@ static int gen_pcie_ecam_probe(struct platform_device *pdev)
 
 static void gen_pcie_ecam_remove(struct platform_device *pdev)
 {
+	struct dw_ecam_pcie *ecam_pcie = NULL;
+
+	if (of_device_is_compatible(pdev->dev.of_node, "snps,dw-pcie-ecam-msi")) {
+		ecam_pcie = platform_get_drvdata(pdev);
+		platform_set_drvdata(pdev, ecam_pcie->bridge);
+	}
+
 	pci_host_common_remove(pdev);
+	if (ecam_pcie)
+		dw_pcie_free_msi(ecam_pcie->msi);
+
 	if (pdev->dev.pm_domain)
 		pm_runtime_put_sync(&pdev->dev);
 }
-- 
2.7.4