PCI: keystone: Add TI Keystone PCIe driver

The Keystone PCIe controller is based on v3.65 version of the Designware
h/w.  Main differences are:

    1. No ATU support
    2. Legacy and MSI IRQ functions are implemented in application register
       space
    3. MSI interrupts are multiplexed over 8 IRQ lines to the Host side.

All of the application register space handing code is organized into
pci-keystone-dw.c and the functions are called from pci-keystone.c to
implement PCI controller driver.  Also add necessary DT documentation and
update the MAINTAINERS file for the driver.

[bhelgaas: spelling and whitespace fixes]
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mohit Kumar <mohit.kumar@st.com>
CC: Pratyush Anand <pratyush.anand@st.com>
CC: Jingoo Han <jg1.han@samsung.com>
CC: Richard Zhu <r65037@freescale.com>
CC: Kishon Vijay Abraham I <kishon@ti.com>
CC: Marek Vasut <marex@denx.de>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Grant Likely <grant.likely@linaro.org>

1 files changed, 386 insertions, 0 deletions

diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
new file mode 100644
index 000000000000..c1cfaef7faf3
--- /dev/null
+++ b/drivers/pci/host/pci-keystone.c
@@ -0,0 +1,386 @@
+/*
+ * PCIe host controller driver for Texas Instruments Keystone SoCs
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@ti.com>
+ * Implementation based on pci-exynos.c and pcie-designware.c
+ *
+ * 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.
+ */
+
+#include <linux/irqchip/chained_irq.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/of.h>
+#include <linux/of_pci.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/resource.h>
+#include <linux/signal.h>
+
+#include "pcie-designware.h"
+#include "pci-keystone.h"
+
+#define DRIVER_NAME	"keystone-pcie"
+
+/* driver specific constants */
+#define MAX_MSI_HOST_IRQS		8
+#define MAX_LEGACY_HOST_IRQS		4
+
+/* RC mode settings masks */
+#define PCIE_RC_MODE		BIT(2)
+#define PCIE_MODE_MASK		(BIT(1) | BIT(2))
+
+/* DEV_STAT_CTRL */
+#define PCIE_CAP_BASE		0x70
+
+#define to_keystone_pcie(x)	container_of(x, struct keystone_pcie, pp)
+
+static int ks_pcie_establish_link(struct keystone_pcie *ks_pcie)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	int count = 200;
+
+	dw_pcie_setup_rc(pp);
+
+	if (dw_pcie_link_up(pp)) {
+		dev_err(pp->dev, "Link already up\n");
+		return 0;
+	}
+
+	ks_dw_pcie_initiate_link_train(ks_pcie);
+	/* check if the link is up or not */
+	while (!dw_pcie_link_up(pp)) {
+		usleep_range(100, 1000);
+		if (--count) {
+			ks_dw_pcie_initiate_link_train(ks_pcie);
+			continue;
+		}
+		dev_err(pp->dev, "phy link never came up\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void ks_pcie_msi_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
+	u32 offset = irq - ks_pcie->msi_host_irqs[0];
+	struct pcie_port *pp = &ks_pcie->pp;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	dev_dbg(pp->dev, "ks_pci_msi_irq_handler, irq %d\n", irq);
+
+	/*
+	 * The chained irq handler installation would have replaced normal
+	 * interrupt driver handler so we need to take care of mask/unmask and
+	 * ack operation.
+	 */
+	chained_irq_enter(chip, desc);
+	ks_dw_pcie_handle_msi_irq(ks_pcie, offset);
+	chained_irq_exit(chip, desc);
+}
+
+/**
+ * ks_pcie_legacy_irq_handler() - Handle legacy interrupt
+ * @irq: IRQ line for legacy interrupts
+ * @desc: Pointer to irq descriptor
+ *
+ * Traverse through pending legacy interrupts and invoke handler for each. Also
+ * takes care of interrupt controller level mask/ack operation.
+ */
+static void ks_pcie_legacy_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
+	struct pcie_port *pp = &ks_pcie->pp;
+	u32 irq_offset = irq - ks_pcie->legacy_host_irqs[0];
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	dev_dbg(pp->dev, ": Handling legacy irq %d\n", irq);
+
+	/*
+	 * The chained irq handler installation would have replaced normal
+	 * interrupt driver handler so we need to take care of mask/unmask and
+	 * ack operation.
+	 */
+	chained_irq_enter(chip, desc);
+	ks_dw_pcie_handle_legacy_irq(ks_pcie, irq_offset);
+	chained_irq_exit(chip, desc);
+}
+
+static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
+					   char *controller, int *num_irqs)
+{
+	int temp, max_host_irqs, legacy = 1, *host_irqs, ret = -EINVAL;
+	struct device *dev = ks_pcie->pp.dev;
+	struct device_node *np_pcie = dev->of_node, **np_temp;
+
+	if (!strcmp(controller, "msi-interrupt-controller"))
+		legacy = 0;
+
+	if (legacy) {
+		np_temp = &ks_pcie->legacy_intc_np;
+		max_host_irqs = MAX_LEGACY_HOST_IRQS;
+		host_irqs = &ks_pcie->legacy_host_irqs[0];
+	} else {
+		np_temp = &ks_pcie->msi_intc_np;
+		max_host_irqs = MAX_MSI_HOST_IRQS;
+		host_irqs =  &ks_pcie->msi_host_irqs[0];
+	}
+
+	/* interrupt controller is in a child node */
+	*np_temp = of_find_node_by_name(np_pcie, controller);
+	if (!(*np_temp)) {
+		dev_err(dev, "Node for %s is absent\n", controller);
+		goto out;
+	}
+	temp = of_irq_count(*np_temp);
+	if (!temp)
+		goto out;
+	if (temp > max_host_irqs)
+		dev_warn(dev, "Too many %s interrupts defined %u\n",
+			(legacy ? "legacy" : "MSI"), temp);
+
+	/*
+	 * support upto max_host_irqs. In dt from index 0 to 3 (legacy) or 0 to
+	 * 7 (MSI)
+	 */
+	for (temp = 0; temp < max_host_irqs; temp++) {
+		host_irqs[temp] = irq_of_parse_and_map(*np_temp, temp);
+		if (host_irqs[temp] < 0)
+			break;
+	}
+	if (temp) {
+		*num_irqs = temp;
+		ret = 0;
+	}
+out:
+	return ret;
+}
+
+static void ks_pcie_setup_interrupts(struct keystone_pcie *ks_pcie)
+{
+	int i;
+
+	/* Legacy IRQ */
+	for (i = 0; i < ks_pcie->num_legacy_host_irqs; i++) {
+		irq_set_handler_data(ks_pcie->legacy_host_irqs[i], ks_pcie);
+		irq_set_chained_handler(ks_pcie->legacy_host_irqs[i],
+					ks_pcie_legacy_irq_handler);
+	}
+	ks_dw_pcie_enable_legacy_irqs(ks_pcie);
+
+	/* MSI IRQ */
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		for (i = 0; i < ks_pcie->num_msi_host_irqs; i++) {
+			irq_set_chained_handler(ks_pcie->msi_host_irqs[i],
+						ks_pcie_msi_irq_handler);
+			irq_set_handler_data(ks_pcie->msi_host_irqs[i],
+					     ks_pcie);
+		}
+	}
+}
+
+/*
+ * When a PCI device does not exist during config cycles, keystone host gets a
+ * bus error instead of returning 0xffffffff. This handler always returns 0
+ * for this kind of faults.
+ */
+static int keystone_pcie_fault(unsigned long addr, unsigned int fsr,
+				struct pt_regs *regs)
+{
+	unsigned long instr = *(unsigned long *) instruction_pointer(regs);
+
+	if ((instr & 0x0e100090) == 0x00100090) {
+		int reg = (instr >> 12) & 15;
+
+		regs->uregs[reg] = -1;
+		regs->ARM_pc += 4;
+	}
+
+	return 0;
+}
+
+static void __init ks_pcie_host_init(struct pcie_port *pp)
+{
+	u32 vendor_device_id, val;
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
+
+	ks_pcie_establish_link(ks_pcie);
+	ks_dw_pcie_setup_rc_app_regs(ks_pcie);
+	ks_pcie_setup_interrupts(ks_pcie);
+	writew(PCI_IO_RANGE_TYPE_32 | (PCI_IO_RANGE_TYPE_32 << 8),
+			pp->dbi_base + PCI_IO_BASE);
+
+	/* update the Vendor ID */
+	vendor_device_id = readl(ks_pcie->va_reg_pciid);
+	writew((vendor_device_id >> 16), pp->dbi_base + PCI_DEVICE_ID);
+
+	/* update the DEV_STAT_CTRL to publish right mrrs */
+	val = readl(pp->dbi_base + PCIE_CAP_BASE + PCI_EXP_DEVCTL);
+	val &= ~PCI_EXP_DEVCTL_READRQ;
+	/* set the mrrs to 256 bytes */
+	val |= BIT(12);
+	writel(val, pp->dbi_base + PCIE_CAP_BASE + PCI_EXP_DEVCTL);
+
+	/*
+	 * PCIe access errors that result into OCP errors are caught by ARM as
+	 * "External aborts"
+	 */
+	hook_fault_code(17, keystone_pcie_fault, SIGBUS, 0,
+			"Asynchronous external abort");
+}
+
+static struct pcie_host_ops keystone_pcie_host_ops = {
+	.rd_other_conf = ks_dw_pcie_rd_other_conf,
+	.wr_other_conf = ks_dw_pcie_wr_other_conf,
+	.link_up = ks_dw_pcie_link_up,
+	.host_init = ks_pcie_host_init,
+	.msi_set_irq = ks_dw_pcie_msi_set_irq,
+	.msi_clear_irq = ks_dw_pcie_msi_clear_irq,
+	.get_msi_data = ks_dw_pcie_get_msi_data,
+	.msi_host_init = ks_dw_pcie_msi_host_init,
+	.scan_bus = ks_dw_pcie_v3_65_scan_bus,
+};
+
+static int __init ks_add_pcie_port(struct keystone_pcie *ks_pcie,
+			 struct platform_device *pdev)
+{
+	struct pcie_port *pp = &ks_pcie->pp;
+	int ret;
+
+	ret = ks_pcie_get_irq_controller_info(ks_pcie,
+					"legacy-interrupt-controller",
+					&ks_pcie->num_legacy_host_irqs);
+	if (ret)
+		return ret;
+
+	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+		ret = ks_pcie_get_irq_controller_info(ks_pcie,
+						"msi-interrupt-controller",
+						&ks_pcie->num_msi_host_irqs);
+		if (ret)
+			return ret;
+	}
+
+	pp->root_bus_nr = -1;
+	pp->ops = &keystone_pcie_host_ops;
+	ret = ks_dw_pcie_host_init(ks_pcie, ks_pcie->msi_intc_np);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize host\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id ks_pcie_of_match[] = {
+	{
+		.type = "pci",
+		.compatible = "ti,keystone-pcie",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
+
+static int __exit ks_pcie_remove(struct platform_device *pdev)
+{
+	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(ks_pcie->clk);
+
+	return 0;
+}
+
+static int __init ks_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct keystone_pcie *ks_pcie;
+	struct pcie_port *pp;
+	struct resource *res;
+	void __iomem *reg_p;
+	struct phy *phy;
+	int ret = 0;
+	u32 val;
+
+	ks_pcie = devm_kzalloc(&pdev->dev, sizeof(*ks_pcie),
+				GFP_KERNEL);
+	if (!ks_pcie) {
+		dev_err(dev, "no memory for keystone pcie\n");
+		return -ENOMEM;
+	}
+	pp = &ks_pcie->pp;
+
+	/* index 2 is the devcfg register for RC mode settings */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	reg_p = devm_ioremap_resource(dev, res);
+	if (IS_ERR(reg_p))
+		return PTR_ERR(reg_p);
+
+	/* enable RC mode in devcfg */
+	val = readl(reg_p);
+	val &= ~PCIE_MODE_MASK;
+	val |= PCIE_RC_MODE;
+	writel(val, reg_p);
+
+	/* initialize SerDes Phy if present */
+	phy = devm_phy_get(dev, "pcie-phy");
+	if (!IS_ERR_OR_NULL(phy)) {
+		ret = phy_init(phy);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* index 3 is to read PCI DEVICE_ID */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+	reg_p = devm_ioremap_resource(dev, res);
+	if (IS_ERR(reg_p))
+		return PTR_ERR(reg_p);
+	ks_pcie->va_reg_pciid = reg_p;
+
+	pp->dev = dev;
+	platform_set_drvdata(pdev, ks_pcie);
+	ks_pcie->clk = devm_clk_get(dev, "pcie");
+	if (IS_ERR(ks_pcie->clk)) {
+		dev_err(dev, "Failed to get pcie rc clock\n");
+		return PTR_ERR(ks_pcie->clk);
+	}
+	ret = clk_prepare_enable(ks_pcie->clk);
+	if (ret)
+		return ret;
+
+	ret = ks_add_pcie_port(ks_pcie, pdev);
+	if (ret < 0)
+		goto fail_clk;
+
+	return 0;
+fail_clk:
+	clk_disable_unprepare(ks_pcie->clk);
+
+	return ret;
+}
+
+static struct platform_driver ks_pcie_driver __refdata = {
+	.probe  = ks_pcie_probe,
+	.remove = __exit_p(ks_pcie_remove),
+	.driver = {
+		.name	= "keystone-pcie",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ks_pcie_of_match),
+	},
+};
+
+module_platform_driver(ks_pcie_driver);
+
+MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
+MODULE_DESCRIPTION("Keystone PCIe host controller driver");
+MODULE_LICENSE("GPL v2");