1 files changed, 141 insertions, 0 deletions
diff --git a/drivers/pci/host/pcie-tango.c b/drivers/pci/host/pcie-tango.c
new file mode 100644
index 0000000..6bbb81f
--- /dev/null
+++ b/drivers/pci/host/pcie-tango.c
@@ -0,0 +1,141 @@
+#include <linux/pci-ecam.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+
+#define SMP8759_MUX		0x48
+#define SMP8759_TEST_OUT	0x74
+
+struct tango_pcie {
+	void __iomem *base;
+};
+
+static int smp8759_config_read(struct pci_bus *bus, unsigned int devfn,
+			       int where, int size, u32 *val)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+	struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
+	int ret;
+
+	/* Reads in configuration space outside devfn 0 return garbage */
+	if (devfn != 0)
+		return PCIBIOS_FUNC_NOT_SUPPORTED;
+
+	/*
+	 * PCI config and MMIO accesses are muxed.  Linux doesn't have a
+	 * mutual exclusion mechanism for config vs. MMIO accesses, so
+	 * concurrent accesses may cause corruption.
+	 */
+	writel_relaxed(1, pcie->base + SMP8759_MUX);
+	ret = pci_generic_config_read(bus, devfn, where, size, val);
+	writel_relaxed(0, pcie->base + SMP8759_MUX);
+
+	return ret;
+}
+
+static int smp8759_config_write(struct pci_bus *bus, unsigned int devfn,
+				int where, int size, u32 val)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+	struct tango_pcie *pcie = dev_get_drvdata(cfg->parent);
+	int ret;
+
+	writel_relaxed(1, pcie->base + SMP8759_MUX);
+	ret = pci_generic_config_write(bus, devfn, where, size, val);
+	writel_relaxed(0, pcie->base + SMP8759_MUX);
+
+	return ret;
+}
+
+static struct pci_ecam_ops smp8759_ecam_ops = {
+	.bus_shift	= 20,
+	.pci_ops	= {
+		.map_bus	= pci_ecam_map_bus,
+		.read		= smp8759_config_read,
+		.write		= smp8759_config_write,
+	}
+};
+
+static int tango_pcie_link_up(struct tango_pcie *pcie)
+{
+	void __iomem *test_out = pcie->base + SMP8759_TEST_OUT;
+	int i;
+
+	writel_relaxed(16, test_out);
+	for (i = 0; i < 10; ++i) {
+		u32 ltssm_state = readl_relaxed(test_out) >> 8;
+		if ((ltssm_state & 0x1f) == 0xf) /* L0 */
+			return 1;
+		usleep_range(3000, 4000);
+	}
+
+	return 0;
+}
+
+static int tango_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct tango_pcie *pcie;
+	struct resource *res;
+	int ret;
+
+	dev_warn(dev, "simultaneous PCI config and MMIO accesses may cause data corruption\n");
+	add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
+
+	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
+	if (!pcie)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	pcie->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pcie->base))
+		return PTR_ERR(pcie->base);
+
+	platform_set_drvdata(pdev, pcie);
+
+	if (!tango_pcie_link_up(pcie))
+		return -ENODEV;
+
+	return pci_host_common_probe(pdev, &smp8759_ecam_ops);
+}
+
+static const struct of_device_id tango_pcie_ids[] = {
+	{ .compatible = "sigma,smp8759-pcie" },
+	{ },
+};
+
+static struct platform_driver tango_pcie_driver = {
+	.probe	= tango_pcie_probe,
+	.driver	= {
+		.name = KBUILD_MODNAME,
+		.of_match_table = tango_pcie_ids,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(tango_pcie_driver);
+
+/*
+ * The root complex advertises the wrong device class.
+ * Header Type 1 is for PCI-to-PCI bridges.
+ */
+static void tango_fixup_class(struct pci_dev *dev)
+{
+	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_class);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_class);
+
+/*
+ * The root complex exposes a "fake" BAR, which is used to filter
+ * bus-to-system accesses.  Only accesses within the range defined by this
+ * BAR are forwarded to the host, others are ignored.
+ *
+ * By default, the DMA framework expects an identity mapping, and DRAM0 is
+ * mapped at 0x80000000.
+ */
+static void tango_fixup_bar(struct pci_dev *dev)
+{
+	dev->non_compliant_bars = true;
+	pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, 0x80000000);
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_bar);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_bar);