PCI: mediatek: Add MediaTek PCIe host controller support

Add support for the MediaTek PCIe Gen2 controller which can be found on
MT7623 series SoCs.

[bhelgaas: fold in mtk_pcie_parse_and_add_res() bugfix from
http://lkml.kernel.org/r/1496644078-27122-1-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: fold in MAINTAINERS update from
http://lkml.kernel.org/r/1497588789-28607-1-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: fold in pci_scan_root_bus_bridge() update and leak fix from
http://lkml.kernel.org/r/1498555451-55073-2-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: fold in powerup fixes from
http://lkml.kernel.org/r/1497866400-41844-2-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: fold in poweroff when link down fixes from
http://lkml.kernel.org/r/1497866400-41844-3-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: fold in optional property fixes from
http://lkml.kernel.org/r/1497866400-41844-4-git-send-email-ryder.lee@mediatek.com]
[bhelgaas: set host->map_irq and host->swizzle_irq and drop
pci_fixup_irqs(), remove unnecessary "return", rename mtk_pcie_link_is_up()
to mtk_pcie_link_up() for consistency, add local struct device pointer]
[bhelgaas: fold in pci_add_flags() removal from
http://lkml.kernel.org/r/1499061300-55951-1-git-send-email-ryder.lee@mediatek.com]
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

4 files changed, 574 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index f7d568b8f133..736648ef5658 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9957,6 +9957,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/pci/pci-thunder-*
 F:	drivers/pci/host/pci-thunder-*
 
+PCIE DRIVER FOR MEDIATEK
+M:      Ryder Lee <ryder.lee@mediatek.com>
+L:      linux-pci@vger.kernel.org
+L:      linux-mediatek@lists.infradead.org
+S:      Supported
+F:      Documentation/devicetree/bindings/pci/mediatek*
+F:      drivers/pci/host/*mediatek*
+
 PCMCIA SUBSYSTEM
 P:	Linux PCMCIA Team
 L:	linux-pcmcia@lists.infradead.org
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 7f47cd5e10a5..0cd5b30dccb1 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -180,6 +180,17 @@ config PCIE_ROCKCHIP
 	  There is 1 internal PCIe port available to support GEN2 with
 	  4 slots.
 
+config PCIE_MEDIATEK
+	bool "MediaTek PCIe controller"
+	depends on ARM && (ARCH_MEDIATEK || COMPILE_TEST)
+	depends on OF
+	depends on PCI
+	select PCIEPORTBUS
+	help
+	  Say Y here if you want to enable PCIe controller support on
+	  MT7623 series SoCs.  There is one single root complex with 3 root
+	  ports available.  Each port supports Gen2 lane x1.
+
 config VMD
 	depends on PCI_MSI && X86_64 && SRCU
 	tristate "Intel Volume Management Device Driver"
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index cab879578003..b10d104c85fd 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
 obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
 obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
 obj-$(CONFIG_PCIE_ROCKCHIP) += pcie-rockchip.o
+obj-$(CONFIG_PCIE_MEDIATEK) += pcie-mediatek.o
 obj-$(CONFIG_VMD) += vmd.o
 
 # The following drivers are for devices that use the generic ACPI
diff --git a/drivers/pci/host/pcie-mediatek.c b/drivers/pci/host/pcie-mediatek.c
new file mode 100644
index 000000000000..5a9d8589ea0b
--- /dev/null
+++ b/drivers/pci/host/pcie-mediatek.c
@@ -0,0 +1,554 @@
+/*
+ * MediaTek PCIe host controller driver.
+ *
+ * Copyright (c) 2017 MediaTek Inc.
+ * Author: Ryder Lee <ryder.lee@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+/* PCIe shared registers */
+#define PCIE_SYS_CFG		0x00
+#define PCIE_INT_ENABLE		0x0c
+#define PCIE_CFG_ADDR		0x20
+#define PCIE_CFG_DATA		0x24
+
+/* PCIe per port registers */
+#define PCIE_BAR0_SETUP		0x10
+#define PCIE_CLASS		0x34
+#define PCIE_LINK_STATUS	0x50
+
+#define PCIE_PORT_INT_EN(x)	BIT(20 + (x))
+#define PCIE_PORT_PERST(x)	BIT(1 + (x))
+#define PCIE_PORT_LINKUP	BIT(0)
+#define PCIE_BAR_MAP_MAX	GENMASK(31, 16)
+
+#define PCIE_BAR_ENABLE		BIT(0)
+#define PCIE_REVISION_ID	BIT(0)
+#define PCIE_CLASS_CODE		(0x60400 << 8)
+#define PCIE_CONF_REG(regn)	(((regn) & GENMASK(7, 2)) | \
+				((((regn) >> 8) & GENMASK(3, 0)) << 24))
+#define PCIE_CONF_FUN(fun)	(((fun) << 8) & GENMASK(10, 8))
+#define PCIE_CONF_DEV(dev)	(((dev) << 11) & GENMASK(15, 11))
+#define PCIE_CONF_BUS(bus)	(((bus) << 16) & GENMASK(23, 16))
+#define PCIE_CONF_ADDR(regn, fun, dev, bus) \
+	(PCIE_CONF_REG(regn) | PCIE_CONF_FUN(fun) | \
+	 PCIE_CONF_DEV(dev) | PCIE_CONF_BUS(bus))
+
+/* MediaTek specific configuration registers */
+#define PCIE_FTS_NUM		0x70c
+#define PCIE_FTS_NUM_MASK	GENMASK(15, 8)
+#define PCIE_FTS_NUM_L0(x)	((x) & 0xff << 8)
+
+#define PCIE_FC_CREDIT		0x73c
+#define PCIE_FC_CREDIT_MASK	(GENMASK(31, 31) | GENMASK(28, 16))
+#define PCIE_FC_CREDIT_VAL(x)	((x) << 16)
+
+/**
+ * struct mtk_pcie_port - PCIe port information
+ * @base: IO mapped register base
+ * @list: port list
+ * @pcie: pointer to PCIe host info
+ * @reset: pointer to port reset control
+ * @sys_ck: pointer to bus clock
+ * @phy: pointer to phy control block
+ * @lane: lane count
+ * @index: port index
+ */
+struct mtk_pcie_port {
+	void __iomem *base;
+	struct list_head list;
+	struct mtk_pcie *pcie;
+	struct reset_control *reset;
+	struct clk *sys_ck;
+	struct phy *phy;
+	u32 lane;
+	u32 index;
+};
+
+/**
+ * struct mtk_pcie - PCIe host information
+ * @dev: pointer to PCIe device
+ * @base: IO mapped register base
+ * @free_ck: free-run reference clock
+ * @io: IO resource
+ * @pio: PIO resource
+ * @mem: non-prefetchable memory resource
+ * @busn: bus range
+ * @offset: IO / Memory offset
+ * @ports: pointer to PCIe port information
+ */
+struct mtk_pcie {
+	struct device *dev;
+	void __iomem *base;
+	struct clk *free_ck;
+
+	struct resource io;
+	struct resource pio;
+	struct resource mem;
+	struct resource busn;
+	struct {
+		resource_size_t mem;
+		resource_size_t io;
+	} offset;
+	struct list_head ports;
+};
+
+static inline bool mtk_pcie_link_up(struct mtk_pcie_port *port)
+{
+	return !!(readl(port->base + PCIE_LINK_STATUS) & PCIE_PORT_LINKUP);
+}
+
+static void mtk_pcie_subsys_powerdown(struct mtk_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+
+	clk_disable_unprepare(pcie->free_ck);
+
+	if (dev->pm_domain) {
+		pm_runtime_put_sync(dev);
+		pm_runtime_disable(dev);
+	}
+}
+
+static void mtk_pcie_port_free(struct mtk_pcie_port *port)
+{
+	struct mtk_pcie *pcie = port->pcie;
+	struct device *dev = pcie->dev;
+
+	devm_iounmap(dev, port->base);
+	list_del(&port->list);
+	devm_kfree(dev, port);
+}
+
+static void mtk_pcie_put_resources(struct mtk_pcie *pcie)
+{
+	struct mtk_pcie_port *port, *tmp;
+
+	list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
+		phy_power_off(port->phy);
+		clk_disable_unprepare(port->sys_ck);
+		mtk_pcie_port_free(port);
+	}
+
+	mtk_pcie_subsys_powerdown(pcie);
+}
+
+static void __iomem *mtk_pcie_map_bus(struct pci_bus *bus,
+				      unsigned int devfn, int where)
+{
+	struct pci_host_bridge *host = pci_find_host_bridge(bus);
+	struct mtk_pcie *pcie = pci_host_bridge_priv(host);
+
+	writel(PCIE_CONF_ADDR(where, PCI_FUNC(devfn), PCI_SLOT(devfn),
+			      bus->number), pcie->base + PCIE_CFG_ADDR);
+
+	return pcie->base + PCIE_CFG_DATA + (where & 3);
+}
+
+static struct pci_ops mtk_pcie_ops = {
+	.map_bus = mtk_pcie_map_bus,
+	.read  = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static void mtk_pcie_configure_rc(struct mtk_pcie_port *port)
+{
+	struct mtk_pcie *pcie = port->pcie;
+	u32 func = PCI_FUNC(port->index << 3);
+	u32 slot = PCI_SLOT(port->index << 3);
+	u32 val;
+
+	/* enable interrupt */
+	val = readl(pcie->base + PCIE_INT_ENABLE);
+	val |= PCIE_PORT_INT_EN(port->index);
+	writel(val, pcie->base + PCIE_INT_ENABLE);
+
+	/* map to all DDR region. We need to set it before cfg operation. */
+	writel(PCIE_BAR_MAP_MAX | PCIE_BAR_ENABLE,
+	       port->base + PCIE_BAR0_SETUP);
+
+	/* configure class code and revision ID */
+	writel(PCIE_CLASS_CODE | PCIE_REVISION_ID, port->base + PCIE_CLASS);
+
+	/* configure FC credit */
+	writel(PCIE_CONF_ADDR(PCIE_FC_CREDIT, func, slot, 0),
+	       pcie->base + PCIE_CFG_ADDR);
+	val = readl(pcie->base + PCIE_CFG_DATA);
+	val &= ~PCIE_FC_CREDIT_MASK;
+	val |= PCIE_FC_CREDIT_VAL(0x806c);
+	writel(PCIE_CONF_ADDR(PCIE_FC_CREDIT, func, slot, 0),
+	       pcie->base + PCIE_CFG_ADDR);
+	writel(val, pcie->base + PCIE_CFG_DATA);
+
+	/* configure RC FTS number to 250 when it leaves L0s */
+	writel(PCIE_CONF_ADDR(PCIE_FTS_NUM, func, slot, 0),
+	       pcie->base + PCIE_CFG_ADDR);
+	val = readl(pcie->base + PCIE_CFG_DATA);
+	val &= ~PCIE_FTS_NUM_MASK;
+	val |= PCIE_FTS_NUM_L0(0x50);
+	writel(PCIE_CONF_ADDR(PCIE_FTS_NUM, func, slot, 0),
+	       pcie->base + PCIE_CFG_ADDR);
+	writel(val, pcie->base + PCIE_CFG_DATA);
+}
+
+static void mtk_pcie_assert_ports(struct mtk_pcie_port *port)
+{
+	struct mtk_pcie *pcie = port->pcie;
+	u32 val;
+
+	/* assert port PERST_N */
+	val = readl(pcie->base + PCIE_SYS_CFG);
+	val |= PCIE_PORT_PERST(port->index);
+	writel(val, pcie->base + PCIE_SYS_CFG);
+
+	/* de-assert port PERST_N */
+	val = readl(pcie->base + PCIE_SYS_CFG);
+	val &= ~PCIE_PORT_PERST(port->index);
+	writel(val, pcie->base + PCIE_SYS_CFG);
+
+	/* PCIe v2.0 need at least 100ms delay to train from Gen1 to Gen2 */
+	msleep(100);
+}
+
+static void mtk_pcie_enable_ports(struct mtk_pcie_port *port)
+{
+	struct device *dev = port->pcie->dev;
+	int err;
+
+	err = clk_prepare_enable(port->sys_ck);
+	if (err) {
+		dev_err(dev, "failed to enable port%d clock\n", port->index);
+		goto err_sys_clk;
+	}
+
+	reset_control_assert(port->reset);
+	reset_control_deassert(port->reset);
+
+	err = phy_power_on(port->phy);
+	if (err) {
+		dev_err(dev, "failed to power on port%d phy\n", port->index);
+		goto err_phy_on;
+	}
+
+	mtk_pcie_assert_ports(port);
+
+	/* if link up, then setup root port configuration space */
+	if (mtk_pcie_link_up(port)) {
+		mtk_pcie_configure_rc(port);
+		return;
+	}
+
+	dev_info(dev, "Port%d link down\n", port->index);
+
+	phy_power_off(port->phy);
+err_phy_on:
+	clk_disable_unprepare(port->sys_ck);
+err_sys_clk:
+	mtk_pcie_port_free(port);
+}
+
+static int mtk_pcie_parse_ports(struct mtk_pcie *pcie,
+				struct device_node *node,
+				int index)
+{
+	struct mtk_pcie_port *port;
+	struct resource *regs;
+	struct device *dev = pcie->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	char name[10];
+	int err;
+
+	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	err = of_property_read_u32(node, "num-lanes", &port->lane);
+	if (err) {
+		dev_err(dev, "missing num-lanes property\n");
+		return err;
+	}
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, index + 1);
+	port->base = devm_ioremap_resource(dev, regs);
+	if (IS_ERR(port->base)) {
+		dev_err(dev, "failed to map port%d base\n", index);
+		return PTR_ERR(port->base);
+	}
+
+	snprintf(name, sizeof(name), "sys_ck%d", index);
+	port->sys_ck = devm_clk_get(dev, name);
+	if (IS_ERR(port->sys_ck)) {
+		dev_err(dev, "failed to get port%d clock\n", index);
+		return PTR_ERR(port->sys_ck);
+	}
+
+	snprintf(name, sizeof(name), "pcie-rst%d", index);
+	port->reset = devm_reset_control_get_optional(dev, name);
+	if (PTR_ERR(port->reset) == -EPROBE_DEFER)
+		return PTR_ERR(port->reset);
+
+	/* some platforms may use default PHY setting */
+	snprintf(name, sizeof(name), "pcie-phy%d", index);
+	port->phy = devm_phy_optional_get(dev, name);
+	if (IS_ERR(port->phy))
+		return PTR_ERR(port->phy);
+
+	port->index = index;
+	port->pcie = pcie;
+
+	INIT_LIST_HEAD(&port->list);
+	list_add_tail(&port->list, &pcie->ports);
+
+	return 0;
+}
+
+static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct resource *regs;
+	int err;
+
+	/* get shared registers */
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pcie->base = devm_ioremap_resource(dev, regs);
+	if (IS_ERR(pcie->base)) {
+		dev_err(dev, "failed to map shared register\n");
+		return PTR_ERR(pcie->base);
+	}
+
+	pcie->free_ck = devm_clk_get(dev, "free_ck");
+	if (IS_ERR(pcie->free_ck)) {
+		if (PTR_ERR(pcie->free_ck) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		pcie->free_ck = NULL;
+	}
+
+	if (dev->pm_domain) {
+		pm_runtime_enable(dev);
+		pm_runtime_get_sync(dev);
+	}
+
+	/* enable top level clock */
+	err = clk_prepare_enable(pcie->free_ck);
+	if (err) {
+		dev_err(dev, "failed to enable free_ck\n");
+		goto err_free_ck;
+	}
+
+	return 0;
+
+err_free_ck:
+	if (dev->pm_domain) {
+		pm_runtime_put_sync(dev);
+		pm_runtime_disable(dev);
+	}
+
+	return err;
+}
+
+static int mtk_pcie_setup(struct mtk_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	struct device_node *node = dev->of_node, *child;
+	struct of_pci_range_parser parser;
+	struct of_pci_range range;
+	struct resource res;
+	struct mtk_pcie_port *port, *tmp;
+	int err;
+
+	if (of_pci_range_parser_init(&parser, node)) {
+		dev_err(dev, "missing \"ranges\" property\n");
+		return -EINVAL;
+	}
+
+	for_each_of_pci_range(&parser, &range) {
+		err = of_pci_range_to_resource(&range, node, &res);
+		if (err < 0)
+			return err;
+
+		switch (res.flags & IORESOURCE_TYPE_BITS) {
+		case IORESOURCE_IO:
+			pcie->offset.io = res.start - range.pci_addr;
+
+			memcpy(&pcie->pio, &res, sizeof(res));
+			pcie->pio.name = node->full_name;
+
+			pcie->io.start = range.cpu_addr;
+			pcie->io.end = range.cpu_addr + range.size - 1;
+			pcie->io.flags = IORESOURCE_MEM;
+			pcie->io.name = "I/O";
+
+			memcpy(&res, &pcie->io, sizeof(res));
+			break;
+
+		case IORESOURCE_MEM:
+			pcie->offset.mem = res.start - range.pci_addr;
+
+			memcpy(&pcie->mem, &res, sizeof(res));
+			pcie->mem.name = "non-prefetchable";
+			break;
+		}
+	}
+
+	err = of_pci_parse_bus_range(node, &pcie->busn);
+	if (err < 0) {
+		dev_err(dev, "failed to parse bus ranges property: %d\n", err);
+		pcie->busn.name = node->name;
+		pcie->busn.start = 0;
+		pcie->busn.end = 0xff;
+		pcie->busn.flags = IORESOURCE_BUS;
+	}
+
+	for_each_available_child_of_node(node, child) {
+		int index;
+
+		err = of_pci_get_devfn(child);
+		if (err < 0) {
+			dev_err(dev, "failed to parse devfn: %d\n", err);
+			return err;
+		}
+
+		index = PCI_SLOT(err);
+
+		err = mtk_pcie_parse_ports(pcie, child, index);
+		if (err)
+			return err;
+	}
+
+	err = mtk_pcie_subsys_powerup(pcie);
+	if (err)
+		return err;
+
+	/* enable each port, and then check link status */
+	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
+		mtk_pcie_enable_ports(port);
+
+	/* power down PCIe subsys if slots are all empty (link down) */
+	if (list_empty(&pcie->ports))
+		mtk_pcie_subsys_powerdown(pcie);
+
+	return 0;
+}
+
+static int mtk_pcie_request_resources(struct mtk_pcie *pcie)
+{
+	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
+	struct list_head *windows = &host->windows;
+	struct device *dev = pcie->dev;
+	int err;
+
+	pci_add_resource_offset(windows, &pcie->pio, pcie->offset.io);
+	pci_add_resource_offset(windows, &pcie->mem, pcie->offset.mem);
+	pci_add_resource(windows, &pcie->busn);
+
+	err = devm_request_pci_bus_resources(dev, windows);
+	if (err < 0)
+		return err;
+
+	pci_remap_iospace(&pcie->pio, pcie->io.start);
+
+	return 0;
+}
+
+static int mtk_pcie_register_host(struct pci_host_bridge *host)
+{
+	struct mtk_pcie *pcie = pci_host_bridge_priv(host);
+	struct pci_bus *child;
+	int err;
+
+	host->busnr = pcie->busn.start;
+	host->dev.parent = pcie->dev;
+	host->ops = &mtk_pcie_ops;
+	host->map_irq = of_irq_parse_and_map_pci;
+	host->swizzle_irq = pci_common_swizzle;
+
+	err = pci_scan_root_bus_bridge(host);
+	if (err < 0)
+		return err;
+
+	pci_bus_size_bridges(host->bus);
+	pci_bus_assign_resources(host->bus);
+
+	list_for_each_entry(child, &host->bus->children, node)
+		pcie_bus_configure_settings(child);
+
+	pci_bus_add_devices(host->bus);
+
+	return 0;
+}
+
+static int mtk_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_pcie *pcie;
+	struct pci_host_bridge *host;
+	int err;
+
+	host = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	if (!host)
+		return -ENOMEM;
+
+	pcie = pci_host_bridge_priv(host);
+
+	pcie->dev = dev;
+	platform_set_drvdata(pdev, pcie);
+	INIT_LIST_HEAD(&pcie->ports);
+
+	err = mtk_pcie_setup(pcie);
+	if (err)
+		return err;
+
+	err = mtk_pcie_request_resources(pcie);
+	if (err)
+		goto put_resources;
+
+	err = mtk_pcie_register_host(host);
+	if (err)
+		goto put_resources;
+
+	return 0;
+
+put_resources:
+	if (!list_empty(&pcie->ports))
+		mtk_pcie_put_resources(pcie);
+
+	return err;
+}
+
+static const struct of_device_id mtk_pcie_ids[] = {
+	{ .compatible = "mediatek,mt7623-pcie"},
+	{ .compatible = "mediatek,mt2701-pcie"},
+	{},
+};
+
+static struct platform_driver mtk_pcie_driver = {
+	.probe = mtk_pcie_probe,
+	.driver = {
+		.name = "mtk-pcie",
+		.of_match_table = mtk_pcie_ids,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(mtk_pcie_driver);