1 files changed, 341 insertions, 0 deletions
diff --git a/drivers/pci/controller/pcie-tango.c b/drivers/pci/controller/pcie-tango.c
new file mode 100644
index 000000000..21a208da3
--- /dev/null
+++ b/drivers/pci/controller/pcie-tango.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/pci-ecam.h>
+#include <linux/delay.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+
+#define MSI_MAX			256
+
+#define SMP8759_MUX		0x48
+#define SMP8759_TEST_OUT	0x74
+#define SMP8759_DOORBELL	0x7c
+#define SMP8759_STATUS		0x80
+#define SMP8759_ENABLE		0xa0
+
+struct tango_pcie {
+	DECLARE_BITMAP(used_msi, MSI_MAX);
+	u64			msi_doorbell;
+	spinlock_t		used_msi_lock;
+	void __iomem		*base;
+	struct irq_domain	*dom;
+};
+
+static void tango_msi_isr(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct tango_pcie *pcie = irq_desc_get_handler_data(desc);
+	unsigned long status, base, virq, idx, pos = 0;
+
+	chained_irq_enter(chip, desc);
+	spin_lock(&pcie->used_msi_lock);
+
+	while ((pos = find_next_bit(pcie->used_msi, MSI_MAX, pos)) < MSI_MAX) {
+		base = round_down(pos, 32);
+		status = readl_relaxed(pcie->base + SMP8759_STATUS + base / 8);
+		for_each_set_bit(idx, &status, 32) {
+			virq = irq_find_mapping(pcie->dom, base + idx);
+			generic_handle_irq(virq);
+		}
+		pos = base + 32;
+	}
+
+	spin_unlock(&pcie->used_msi_lock);
+	chained_irq_exit(chip, desc);
+}
+
+static void tango_ack(struct irq_data *d)
+{
+	struct tango_pcie *pcie = d->chip_data;
+	u32 offset = (d->hwirq / 32) * 4;
+	u32 bit = BIT(d->hwirq % 32);
+
+	writel_relaxed(bit, pcie->base + SMP8759_STATUS + offset);
+}
+
+static void update_msi_enable(struct irq_data *d, bool unmask)
+{
+	unsigned long flags;
+	struct tango_pcie *pcie = d->chip_data;
+	u32 offset = (d->hwirq / 32) * 4;
+	u32 bit = BIT(d->hwirq % 32);
+	u32 val;
+
+	spin_lock_irqsave(&pcie->used_msi_lock, flags);
+	val = readl_relaxed(pcie->base + SMP8759_ENABLE + offset);
+	val = unmask ? val | bit : val & ~bit;
+	writel_relaxed(val, pcie->base + SMP8759_ENABLE + offset);
+	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+}
+
+static void tango_mask(struct irq_data *d)
+{
+	update_msi_enable(d, false);
+}
+
+static void tango_unmask(struct irq_data *d)
+{
+	update_msi_enable(d, true);
+}
+
+static int tango_set_affinity(struct irq_data *d, const struct cpumask *mask,
+			      bool force)
+{
+	return -EINVAL;
+}
+
+static void tango_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	struct tango_pcie *pcie = d->chip_data;
+	msg->address_lo = lower_32_bits(pcie->msi_doorbell);
+	msg->address_hi = upper_32_bits(pcie->msi_doorbell);
+	msg->data = d->hwirq;
+}
+
+static struct irq_chip tango_chip = {
+	.irq_ack		= tango_ack,
+	.irq_mask		= tango_mask,
+	.irq_unmask		= tango_unmask,
+	.irq_set_affinity	= tango_set_affinity,
+	.irq_compose_msi_msg	= tango_compose_msi_msg,
+};
+
+static void msi_ack(struct irq_data *d)
+{
+	irq_chip_ack_parent(d);
+}
+
+static void msi_mask(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void msi_unmask(struct irq_data *d)
+{
+	pci_msi_unmask_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip msi_chip = {
+	.name = "MSI",
+	.irq_ack = msi_ack,
+	.irq_mask = msi_mask,
+	.irq_unmask = msi_unmask,
+};
+
+static struct msi_domain_info msi_dom_info = {
+	.flags	= MSI_FLAG_PCI_MSIX
+		| MSI_FLAG_USE_DEF_DOM_OPS
+		| MSI_FLAG_USE_DEF_CHIP_OPS,
+	.chip	= &msi_chip,
+};
+
+static int tango_irq_domain_alloc(struct irq_domain *dom, unsigned int virq,
+				  unsigned int nr_irqs, void *args)
+{
+	struct tango_pcie *pcie = dom->host_data;
+	unsigned long flags;
+	int pos;
+
+	spin_lock_irqsave(&pcie->used_msi_lock, flags);
+	pos = find_first_zero_bit(pcie->used_msi, MSI_MAX);
+	if (pos >= MSI_MAX) {
+		spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+		return -ENOSPC;
+	}
+	__set_bit(pos, pcie->used_msi);
+	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+	irq_domain_set_info(dom, virq, pos, &tango_chip,
+			pcie, handle_edge_irq, NULL, NULL);
+
+	return 0;
+}
+
+static void tango_irq_domain_free(struct irq_domain *dom, unsigned int virq,
+				  unsigned int nr_irqs)
+{
+	unsigned long flags;
+	struct irq_data *d = irq_domain_get_irq_data(dom, virq);
+	struct tango_pcie *pcie = d->chip_data;
+
+	spin_lock_irqsave(&pcie->used_msi_lock, flags);
+	__clear_bit(d->hwirq, pcie->used_msi);
+	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+}
+
+static const struct irq_domain_ops dom_ops = {
+	.alloc	= tango_irq_domain_alloc,
+	.free	= tango_irq_domain_free,
+};
+
+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;
+	struct fwnode_handle *fwnode = of_node_to_fwnode(dev->of_node);
+	struct irq_domain *msi_dom, *irq_dom;
+	struct of_pci_range_parser parser;
+	struct of_pci_range range;
+	int virq, offset;
+
+	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;
+
+	if (of_pci_dma_range_parser_init(&parser, dev->of_node) < 0)
+		return -ENOENT;
+
+	if (of_pci_range_parser_one(&parser, &range) == NULL)
+		return -ENOENT;
+
+	range.pci_addr += range.size;
+	pcie->msi_doorbell = range.pci_addr + res->start + SMP8759_DOORBELL;
+
+	for (offset = 0; offset < MSI_MAX / 8; offset += 4)
+		writel_relaxed(0, pcie->base + SMP8759_ENABLE + offset);
+
+	virq = platform_get_irq(pdev, 1);
+	if (virq <= 0) {
+		dev_err(dev, "Failed to map IRQ\n");
+		return -ENXIO;
+	}
+
+	irq_dom = irq_domain_create_linear(fwnode, MSI_MAX, &dom_ops, pcie);
+	if (!irq_dom) {
+		dev_err(dev, "Failed to create IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	msi_dom = pci_msi_create_irq_domain(fwnode, &msi_dom_info, irq_dom);
+	if (!msi_dom) {
+		dev_err(dev, "Failed to create MSI domain\n");
+		irq_domain_remove(irq_dom);
+		return -ENOMEM;
+	}
+
+	pcie->dom = irq_dom;
+	spin_lock_init(&pcie->used_msi_lock);
+	irq_set_chained_handler_and_data(virq, tango_msi_isr, pcie);
+
+	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);