--- /dev/null
+#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);
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff