[PATCH v4 1/1] PCI/ACPI: xgene: Add ECAM quirk for X-Gene PCIe controller

[Duc Dang <dhdang@apm.com>]

PCIe controllers in X-Gene SoCs is not ECAM compliant: software
needs to configure additional controller's register to address
device at bus:dev:function.

The quirk will discover controller MMIO register space and configure
controller registers to select and address the target secondary device.

The quirk will only be applied for X-Gene PCIe MCFG table with
OEM revison 1, 2, 3 or 4 (PCIe controller v1 and v2 on X-Gene SoCs).

Signed-off-by: Duc Dang <dhdang@apm.com>
---
v4:
  - Rebase on top of pci/ecam tree
  - Introduce xgene_get_csr_resource to discover MMIO register space
  (per Mark's test code).
  - Refactor .init functions for pci_ecam_ops to reuse common code
  - Introduce pcie_bus_to_port to extract X-Gene 'port' information
  from 'bus' device.
  - Kconfig/Makefile changes to only compile required code for ACPI
v3:
  - Rebase on top of pci/ecam-v6 tree.
  - Use DEFINE_RES_MEM_NAMED to declare controller register space
  with name "PCIe CSR"
v2:
  RFC v2: https://patchwork.ozlabs.org/patch/686846/
v1:
  RFC v1: https://patchwork.kernel.org/patch/9337115/
---
 drivers/acpi/pci_mcfg.c      |  25 +++++++++
 drivers/pci/host/Kconfig     |   4 +-
 drivers/pci/host/Makefile    |   2 +-
 drivers/pci/host/pci-xgene.c | 127 ++++++++++++++++++++++++++++++++++++++++---
 include/linux/pci-ecam.h     |   2 +
 5 files changed, 150 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index d34d196..7319188 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -108,6 +108,31 @@ struct mcfg_fixup {
 	THUNDER_ECAM_QUIRK(2, 11),
 	THUNDER_ECAM_QUIRK(2, 12),
 	THUNDER_ECAM_QUIRK(2, 13),
+
+#define XGENE_V1_ECAM_MCFG(rev, seg) \
+	{"APM   ", "XGENE   ", rev, seg, MCFG_BUS_ANY, \
+		&xgene_v1_pcie_ecam_ops }
+#define XGENE_V2_ECAM_MCFG(rev, seg) \
+	{"APM   ", "XGENE   ", rev, seg, MCFG_BUS_ANY, \
+		&xgene_v2_pcie_ecam_ops }
+	/* X-Gene SoC with v1 PCIe controller */
+	XGENE_V1_ECAM_MCFG(1, 0),
+	XGENE_V1_ECAM_MCFG(1, 1),
+	XGENE_V1_ECAM_MCFG(1, 2),
+	XGENE_V1_ECAM_MCFG(1, 3),
+	XGENE_V1_ECAM_MCFG(1, 4),
+	XGENE_V1_ECAM_MCFG(2, 0),
+	XGENE_V1_ECAM_MCFG(2, 1),
+	XGENE_V1_ECAM_MCFG(2, 2),
+	XGENE_V1_ECAM_MCFG(2, 3),
+	XGENE_V1_ECAM_MCFG(2, 4),
+	/* X-Gene SoC with v2.1 PCIe controller */
+	XGENE_V2_ECAM_MCFG(3, 0),
+	XGENE_V2_ECAM_MCFG(3, 1),
+	/* X-Gene SoC with v2.2 PCIe controller */
+	XGENE_V2_ECAM_MCFG(4, 0),
+	XGENE_V2_ECAM_MCFG(4, 1),
+	XGENE_V2_ECAM_MCFG(4, 2),
 };
 
 static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index c983892..1fb5518 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -133,8 +133,8 @@ config PCIE_XILINX
 
 config PCI_XGENE
 	bool "X-Gene PCIe controller"
-	depends on ARCH_XGENE
-	depends on OF
+	depends on ARM64
+	depends on OF || (ACPI && PCI_QUIRKS)
 	select PCIEPORTBUS
 	help
 	  Say Y here if you want internal PCI support on APM X-Gene SoC.
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 639494a..6cc84b4 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -15,7 +15,7 @@ obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
 obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
 obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
 obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
-obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
+obj-$(CONFIG_ARM64) += pci-xgene.o
 obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
 obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
 obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
index 1de23d7..6edcac7 100644
--- a/drivers/pci/host/pci-xgene.c
+++ b/drivers/pci/host/pci-xgene.c
@@ -27,6 +27,8 @@
 #include <linux/of_irq.h>
 #include <linux/of_pci.h>
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
+#include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 
@@ -64,7 +66,9 @@
 /* PCIe IP version */
 #define XGENE_PCIE_IP_VER_UNKN		0
 #define XGENE_PCIE_IP_VER_1		1
+#define XGENE_PCIE_IP_VER_2		2
 
+#if defined(CONFIG_PCI_XGENE) || (defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS))
 struct xgene_pcie_port {
 	struct device_node	*node;
 	struct device		*dev;
@@ -91,13 +95,24 @@ static inline u32 pcie_bar_low_val(u32 addr, u32 flags)
 	return (addr & PCI_BASE_ADDRESS_MEM_MASK) | flags;
 }
 
+static inline struct xgene_pcie_port *pcie_bus_to_port(struct pci_bus *bus)
+{
+	struct pci_config_window *cfg;
+
+	if (acpi_disabled)
+		return (struct xgene_pcie_port *)(bus->sysdata);
+
+	cfg = bus->sysdata;
+	return (struct xgene_pcie_port *)(cfg->priv);
+}
+
 /*
  * When the address bit [17:16] is 2'b01, the Configuration access will be
  * treated as Type 1 and it will be forwarded to external PCIe device.
  */
 static void __iomem *xgene_pcie_get_cfg_base(struct pci_bus *bus)
 {
-	struct xgene_pcie_port *port = bus->sysdata;
+	struct xgene_pcie_port *port = pcie_bus_to_port(bus);
 
 	if (bus->number >= (bus->primary + 1))
 		return port->cfg_base + AXI_EP_CFG_ACCESS;
@@ -111,7 +126,7 @@ static void __iomem *xgene_pcie_get_cfg_base(struct pci_bus *bus)
  */
 static void xgene_pcie_set_rtdid_reg(struct pci_bus *bus, uint devfn)
 {
-	struct xgene_pcie_port *port = bus->sysdata;
+	struct xgene_pcie_port *port = pcie_bus_to_port(bus);
 	unsigned int b, d, f;
 	u32 rtdid_val = 0;
 
@@ -158,7 +173,7 @@ static void __iomem *xgene_pcie_map_bus(struct pci_bus *bus, unsigned int devfn,
 static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
 				    int where, int size, u32 *val)
 {
-	struct xgene_pcie_port *port = bus->sysdata;
+	struct xgene_pcie_port *port = pcie_bus_to_port(bus);
 
 	if (pci_generic_config_read32(bus, devfn, where & ~0x3, 4, val) !=
 	    PCIBIOS_SUCCESSFUL)
@@ -182,13 +197,104 @@ static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
 
 	return PCIBIOS_SUCCESSFUL;
 }
+#endif
 
-static struct pci_ops xgene_pcie_ops = {
-	.map_bus = xgene_pcie_map_bus,
-	.read = xgene_pcie_config_read32,
-	.write = pci_generic_config_write32,
+#if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
+static int xgene_get_csr_resource(struct acpi_device *adev,
+				  struct resource *res)
+{
+	struct device *dev = &adev->dev;
+	struct resource_entry *entry;
+	struct list_head list;
+	unsigned long flags;
+	int ret;
+
+	INIT_LIST_HEAD(&list);
+	flags = IORESOURCE_MEM;
+	ret = acpi_dev_get_resources(adev, &list,
+				     acpi_dev_filter_resource_type_cb,
+				     (void *) flags);
+	if (ret < 0) {
+		dev_err(dev, "failed to parse _CRS method, error code %d\n",
+			ret);
+		return ret;
+	}
+
+	if (ret == 0) {
+		dev_err(dev, "no IO and memory resources present in _CRS\n");
+		return -EINVAL;
+	}
+
+	entry = list_first_entry(&list, struct resource_entry, node);
+	*res = *entry->res;
+	acpi_dev_free_resource_list(&list);
+	return 0;
+}
+
+static int xgene_pcie_ecam_init(struct pci_config_window *cfg, u32 ipversion)
+{
+	struct acpi_device *adev = to_acpi_device(cfg->parent);
+	struct device *dev = cfg->parent;
+	struct xgene_pcie_port *port;
+	struct resource csr;
+	int ret;
+
+	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	ret = xgene_get_csr_resource(adev, &csr);
+	if (ret) {
+		dev_err(dev, "can't get CSR resource\n");
+		kfree(port);
+		return ret;
+	}
+	port->csr_base = devm_ioremap_resource(dev, &csr);
+	if (IS_ERR(port->csr_base)) {
+		kfree(port);
+		return -ENOMEM;
+	}
+
+	port->cfg_base = cfg->win;
+	port->version = ipversion;
+
+	cfg->priv = port;
+
+	return 0;
+}
+
+static int xgene_v1_pcie_ecam_init(struct pci_config_window *cfg)
+{
+	return xgene_pcie_ecam_init(cfg, XGENE_PCIE_IP_VER_1);
+}
+
+struct pci_ecam_ops xgene_v1_pcie_ecam_ops = {
+	.bus_shift      = 16,
+	.init           = xgene_v1_pcie_ecam_init,
+	.pci_ops        = {
+		.map_bus        = xgene_pcie_map_bus,
+		.read           = xgene_pcie_config_read32,
+		.write          = pci_generic_config_write,
+	}
+};
+
+static int xgene_v2_pcie_ecam_init(struct pci_config_window *cfg)
+{
+	return xgene_pcie_ecam_init(cfg, XGENE_PCIE_IP_VER_2);
+}
+
+struct pci_ecam_ops xgene_v2_pcie_ecam_ops = {
+	.bus_shift      = 16,
+	.init           = xgene_v2_pcie_ecam_init,
+	.pci_ops        = {
+		.map_bus        = xgene_pcie_map_bus,
+		.read           = xgene_pcie_config_read32,
+		.write          = pci_generic_config_write,
+	}
 };
+#endif
 
+#if defined(CONFIG_PCI_XGENE)
 static u64 xgene_pcie_set_ib_mask(struct xgene_pcie_port *port, u32 addr,
 				  u32 flags, u64 size)
 {
@@ -521,6 +627,12 @@ static int xgene_pcie_setup(struct xgene_pcie_port *port,
 	return 0;
 }
 
+static struct pci_ops xgene_pcie_ops = {
+	.map_bus = xgene_pcie_map_bus,
+	.read = xgene_pcie_config_read32,
+	.write = pci_generic_config_write32,
+};
+
 static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -591,3 +703,4 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 	.probe = xgene_pcie_probe_bridge,
 };
 builtin_platform_driver(xgene_pcie_driver);
+#endif
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index 00eb8eb..f0d2b94 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -64,6 +64,8 @@ void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
 extern struct pci_ecam_ops hisi_pcie_ops;	/* HiSilicon */
 extern struct pci_ecam_ops thunder_pem_ecam_ops; /* Cavium ThunderX 1.x & 2.x */
 extern struct pci_ecam_ops pci_thunder_ecam_ops; /* Cavium ThunderX 1.x */
+extern struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 */
+extern struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */
 #endif
 
 #ifdef CONFIG_PCI_HOST_GENERIC
-- 
1.9.1