PCI: Add MCFG quirks for Cavium ThunderX pass2.x host controller

ThunderX PCIe controller to off-chip devices (so-called PEM) is not fully
compliant with ECAM standard. It uses non-standard configuration space
accessors (see thunder_pem_ecam_ops) and custom configuration space
granulation (see bus_shift = 24). In order to access configuration space
and probe PEM as ACPI-based PCI host controller we need to add MCFG quirk
infrastructure. This involves:
1. A new thunder_pem_acpi_init() init function to locate PEM-specific
   register ranges using ACPI.
2. Export PEM thunder_pem_ecam_ops structure so it is visible to MCFG quirk
   code.
3. New quirk entries for each PEM segment. Each contains platform IDs,
   mentioned thunder_pem_ecam_ops and CFG resources.

Quirk is considered for ThunderX silicon pass2.x only which is identified
via MCFG revision 1.

ThunderX pass 2.x requires the following accessors:

  NUMA Node 0 PCI segments  0- 3: pci_generic_ecam_ops (ECAM-compliant)
  NUMA Node 0 PCI segments  4- 9: thunder_pem_ecam_ops (MCFG quirk)
  NUMA Node 1 PCI segments 10-13: pci_generic_ecam_ops (ECAM-compliant)
  NUMA Node 1 PCI segments 14-19: thunder_pem_ecam_ops (MCFG quirk)

[bhelgaas: adapt to use acpi_get_rc_resources(), update Makefile/ifdefs so
quirk doesn't depend on CONFIG_PCI_HOST_THUNDER_PEM]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

3 files changed, 47 insertions, 2 deletions

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index d7e7c0a827c3..1239a8e63368 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -240,7 +240,8 @@ config PCIE_QCOM
 
 config PCI_HOST_THUNDER_PEM
 	bool "Cavium Thunder PCIe controller to off-chip devices"
-	depends on OF && ARM64
+	depends on ARM64
+	depends on OF || (ACPI && PCI_QUIRKS)
 	select PCI_HOST_COMMON
 	help
 	  Say Y here if you want PCIe support for CN88XX Cavium Thunder SoCs.
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 64845f0d6138..97e6bfc55772 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -28,7 +28,7 @@ obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
 obj-$(CONFIG_ARM64) += pcie-hisi.o
 obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
 obj-$(CONFIG_PCI_HOST_THUNDER_ECAM) += pci-thunder-ecam.o
-obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o
+obj-$(CONFIG_ARM64) += pci-thunder-pem.o
 obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
 obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
 obj-$(CONFIG_PCIE_ROCKCHIP) += pcie-rockchip.o
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
index c3276eede82a..af722eb0ca75 100644
--- a/drivers/pci/host/pci-thunder-pem.c
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -18,8 +18,12 @@
 #include <linux/init.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pci-acpi.h>
 #include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
+#include "../pci.h"
+
+#if defined(CONFIG_PCI_HOST_THUNDER_PEM) || (defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS))
 
 #define PEM_CFG_WR 0x28
 #define PEM_CFG_RD 0x30
@@ -313,6 +317,43 @@ static int thunder_pem_init(struct device *dev, struct pci_config_window *cfg,
 	return 0;
 }
 
+#if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
+
+static int thunder_pem_acpi_init(struct pci_config_window *cfg)
+{
+	struct device *dev = cfg->parent;
+	struct acpi_device *adev = to_acpi_device(dev);
+	struct acpi_pci_root *root = acpi_driver_data(adev);
+	struct resource *res_pem;
+	int ret;
+
+	res_pem = devm_kzalloc(&adev->dev, sizeof(*res_pem), GFP_KERNEL);
+	if (!res_pem)
+		return -ENOMEM;
+
+	ret = acpi_get_rc_resources(dev, "THRX0002", root->segment, res_pem);
+	if (ret) {
+		dev_err(dev, "can't get rc base address\n");
+		return ret;
+	}
+
+	return thunder_pem_init(dev, cfg, res_pem);
+}
+
+struct pci_ecam_ops thunder_pem_ecam_ops = {
+	.bus_shift	= 24,
+	.init		= thunder_pem_acpi_init,
+	.pci_ops	= {
+		.map_bus	= pci_ecam_map_bus,
+		.read		= thunder_pem_config_read,
+		.write		= thunder_pem_config_write,
+	}
+};
+
+#endif
+
+#ifdef CONFIG_PCI_HOST_THUNDER_PEM
+
 static int thunder_pem_platform_init(struct pci_config_window *cfg)
 {
 	struct device *dev = cfg->parent;
@@ -364,3 +405,6 @@ static struct platform_driver thunder_pem_driver = {
 	.probe = thunder_pem_probe,
 };
 builtin_platform_driver(thunder_pem_driver);
+
+#endif
+#endif