PCI: Add R-Car Gen2 internal PCI support

This adds internal PCI controller driver for R-Car Gen2 SoC.  There are
three PCI controllers available with only a single EHCI/OHCI device
built-in on each PCI bus.  This gives us three USB channels.  Channel 0 is
shared with the USBHS device, while channel 2 is shared with the USBSS.

The PCI controllers do not support I/O port space mapping, and it is not
needed here.

Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

3 files changed, 342 insertions, 0 deletions

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 3d950481112..2e33c2ba825 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -19,4 +19,12 @@ config PCI_TEGRA
 	bool "NVIDIA Tegra PCIe controller"
 	depends on ARCH_TEGRA
 
+config PCI_RCAR_GEN2
+	bool "Renesas R-Car Gen2 Internal PCI controller"
+	depends on ARM && (ARCH_R8A7790 || ARCH_R8A7791 || COMPILE_TEST)
+	help
+	  Say Y here if you want internal PCI support on R-Car Gen2 SoC.
+	  There are 3 internal PCI controllers available with a single
+	  built-in EHCI/OHCI host controller present on each one.
+
 endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index c9a997b2690..63d97277528 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_PCIE_DW) += pcie-designware.o
 obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
+obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
diff --git a/drivers/pci/host/pci-rcar-gen2.c b/drivers/pci/host/pci-rcar-gen2.c
new file mode 100644
index 00000000000..cbaa5c4397e
--- /dev/null
+++ b/drivers/pci/host/pci-rcar-gen2.c
@@ -0,0 +1,333 @@
+/*
+ *  pci-rcar-gen2: internal PCI bus support
+ *
+ * Copyright (C) 2013 Renesas Solutions Corp.
+ * Copyright (C) 2013 Cogent Embedded, Inc.
+ *
+ * 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/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* AHB-PCI Bridge PCI communication registers */
+#define RCAR_AHBPCI_PCICOM_OFFSET	0x800
+
+#define RCAR_PCIAHB_WIN1_CTR_REG	(RCAR_AHBPCI_PCICOM_OFFSET + 0x00)
+#define RCAR_PCIAHB_WIN2_CTR_REG	(RCAR_AHBPCI_PCICOM_OFFSET + 0x04)
+#define RCAR_PCIAHB_PREFETCH0		0x0
+#define RCAR_PCIAHB_PREFETCH4		0x1
+#define RCAR_PCIAHB_PREFETCH8		0x2
+#define RCAR_PCIAHB_PREFETCH16		0x3
+
+#define RCAR_AHBPCI_WIN1_CTR_REG	(RCAR_AHBPCI_PCICOM_OFFSET + 0x10)
+#define RCAR_AHBPCI_WIN2_CTR_REG	(RCAR_AHBPCI_PCICOM_OFFSET + 0x14)
+#define RCAR_AHBPCI_WIN_CTR_MEM		(3 << 1)
+#define RCAR_AHBPCI_WIN_CTR_CFG		(5 << 1)
+#define RCAR_AHBPCI_WIN1_HOST		(1 << 30)
+#define RCAR_AHBPCI_WIN1_DEVICE		(1 << 31)
+
+#define RCAR_PCI_INT_ENABLE_REG		(RCAR_AHBPCI_PCICOM_OFFSET + 0x20)
+#define RCAR_PCI_INT_STATUS_REG		(RCAR_AHBPCI_PCICOM_OFFSET + 0x24)
+#define RCAR_PCI_INT_A			(1 << 16)
+#define RCAR_PCI_INT_B			(1 << 17)
+#define RCAR_PCI_INT_PME		(1 << 19)
+
+#define RCAR_AHB_BUS_CTR_REG		(RCAR_AHBPCI_PCICOM_OFFSET + 0x30)
+#define RCAR_AHB_BUS_MMODE_HTRANS	(1 << 0)
+#define RCAR_AHB_BUS_MMODE_BYTE_BURST	(1 << 1)
+#define RCAR_AHB_BUS_MMODE_WR_INCR	(1 << 2)
+#define RCAR_AHB_BUS_MMODE_HBUS_REQ	(1 << 7)
+#define RCAR_AHB_BUS_SMODE_READYCTR	(1 << 17)
+#define RCAR_AHB_BUS_MODE		(RCAR_AHB_BUS_MMODE_HTRANS |	\
+					RCAR_AHB_BUS_MMODE_BYTE_BURST |	\
+					RCAR_AHB_BUS_MMODE_WR_INCR |	\
+					RCAR_AHB_BUS_MMODE_HBUS_REQ |	\
+					RCAR_AHB_BUS_SMODE_READYCTR)
+
+#define RCAR_USBCTR_REG			(RCAR_AHBPCI_PCICOM_OFFSET + 0x34)
+#define RCAR_USBCTR_USBH_RST		(1 << 0)
+#define RCAR_USBCTR_PCICLK_MASK		(1 << 1)
+#define RCAR_USBCTR_PLL_RST		(1 << 2)
+#define RCAR_USBCTR_DIRPD		(1 << 8)
+#define RCAR_USBCTR_PCIAHB_WIN2_EN	(1 << 9)
+#define RCAR_USBCTR_PCIAHB_WIN1_256M	(0 << 10)
+#define RCAR_USBCTR_PCIAHB_WIN1_512M	(1 << 10)
+#define RCAR_USBCTR_PCIAHB_WIN1_1G	(2 << 10)
+#define RCAR_USBCTR_PCIAHB_WIN1_2G	(3 << 10)
+#define RCAR_USBCTR_PCIAHB_WIN1_MASK	(3 << 10)
+
+#define RCAR_PCI_ARBITER_CTR_REG	(RCAR_AHBPCI_PCICOM_OFFSET + 0x40)
+#define RCAR_PCI_ARBITER_PCIREQ0	(1 << 0)
+#define RCAR_PCI_ARBITER_PCIREQ1	(1 << 1)
+#define RCAR_PCI_ARBITER_PCIBP_MODE	(1 << 12)
+
+#define RCAR_PCI_UNIT_REV_REG		(RCAR_AHBPCI_PCICOM_OFFSET + 0x48)
+
+/* Number of internal PCI controllers */
+#define RCAR_PCI_NR_CONTROLLERS		3
+
+struct rcar_pci_priv {
+	void __iomem *reg;
+	struct resource io_res;
+	struct resource mem_res;
+	struct resource *cfg_res;
+	int irq;
+};
+
+/* PCI configuration space operations */
+static void __iomem *rcar_pci_cfg_base(struct pci_bus *bus, unsigned int devfn,
+				       int where)
+{
+	struct pci_sys_data *sys = bus->sysdata;
+	struct rcar_pci_priv *priv = sys->private_data;
+	int slot, val;
+
+	if (sys->busnr != bus->number || PCI_FUNC(devfn))
+		return NULL;
+
+	/* Only one EHCI/OHCI device built-in */
+	slot = PCI_SLOT(devfn);
+	if (slot > 2)
+		return NULL;
+
+	val = slot ? RCAR_AHBPCI_WIN1_DEVICE | RCAR_AHBPCI_WIN_CTR_CFG :
+		     RCAR_AHBPCI_WIN1_HOST | RCAR_AHBPCI_WIN_CTR_CFG;
+
+	iowrite32(val, priv->reg + RCAR_AHBPCI_WIN1_CTR_REG);
+	return priv->reg + (slot >> 1) * 0x100 + where;
+}
+
+static int rcar_pci_read_config(struct pci_bus *bus, unsigned int devfn,
+				int where, int size, u32 *val)
+{
+	void __iomem *reg = rcar_pci_cfg_base(bus, devfn, where);
+
+	if (!reg)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	switch (size) {
+	case 1:
+		*val = ioread8(reg);
+		break;
+	case 2:
+		*val = ioread16(reg);
+		break;
+	default:
+		*val = ioread32(reg);
+		break;
+	}
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int rcar_pci_write_config(struct pci_bus *bus, unsigned int devfn,
+				 int where, int size, u32 val)
+{
+	void __iomem *reg = rcar_pci_cfg_base(bus, devfn, where);
+
+	if (!reg)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	switch (size) {
+	case 1:
+		iowrite8(val, reg);
+		break;
+	case 2:
+		iowrite16(val, reg);
+		break;
+	default:
+		iowrite32(val, reg);
+		break;
+	}
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+/* PCI interrupt mapping */
+static int __init rcar_pci_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
+{
+	struct pci_sys_data *sys = dev->bus->sysdata;
+	struct rcar_pci_priv *priv = sys->private_data;
+
+	return priv->irq;
+}
+
+/* PCI host controller setup */
+static int __init rcar_pci_setup(int nr, struct pci_sys_data *sys)
+{
+	struct rcar_pci_priv *priv = sys->private_data;
+	void __iomem *reg = priv->reg;
+	u32 val;
+
+	val = ioread32(reg + RCAR_PCI_UNIT_REV_REG);
+	pr_info("PCI: bus%u revision %x\n", sys->busnr, val);
+
+	/* Disable Direct Power Down State and assert reset */
+	val = ioread32(reg + RCAR_USBCTR_REG) & ~RCAR_USBCTR_DIRPD;
+	val |= RCAR_USBCTR_USBH_RST | RCAR_USBCTR_PLL_RST;
+	iowrite32(val, reg + RCAR_USBCTR_REG);
+	udelay(4);
+
+	/* De-assert reset and set PCIAHB window1 size to 1GB */
+	val &= ~(RCAR_USBCTR_PCIAHB_WIN1_MASK | RCAR_USBCTR_PCICLK_MASK |
+		 RCAR_USBCTR_USBH_RST | RCAR_USBCTR_PLL_RST);
+	iowrite32(val | RCAR_USBCTR_PCIAHB_WIN1_1G, reg + RCAR_USBCTR_REG);
+
+	/* Configure AHB master and slave modes */
+	iowrite32(RCAR_AHB_BUS_MODE, reg + RCAR_AHB_BUS_CTR_REG);
+
+	/* Configure PCI arbiter */
+	val = ioread32(reg + RCAR_PCI_ARBITER_CTR_REG);
+	val |= RCAR_PCI_ARBITER_PCIREQ0 | RCAR_PCI_ARBITER_PCIREQ1 |
+	       RCAR_PCI_ARBITER_PCIBP_MODE;
+	iowrite32(val, reg + RCAR_PCI_ARBITER_CTR_REG);
+
+	/* PCI-AHB mapping: 0x40000000-0x80000000 */
+	iowrite32(0x40000000 | RCAR_PCIAHB_PREFETCH16,
+		  reg + RCAR_PCIAHB_WIN1_CTR_REG);
+
+	/* AHB-PCI mapping: OHCI/EHCI registers */
+	val = priv->mem_res.start | RCAR_AHBPCI_WIN_CTR_MEM;
+	iowrite32(val, reg + RCAR_AHBPCI_WIN2_CTR_REG);
+
+	/* Enable AHB-PCI bridge PCI configuration access */
+	iowrite32(RCAR_AHBPCI_WIN1_HOST | RCAR_AHBPCI_WIN_CTR_CFG,
+		  reg + RCAR_AHBPCI_WIN1_CTR_REG);
+	/* Set PCI-AHB Window1 address */
+	iowrite32(0x40000000 | PCI_BASE_ADDRESS_MEM_PREFETCH,
+		  reg + PCI_BASE_ADDRESS_1);
+	/* Set AHB-PCI bridge PCI communication area address */
+	val = priv->cfg_res->start + RCAR_AHBPCI_PCICOM_OFFSET;
+	iowrite32(val, reg + PCI_BASE_ADDRESS_0);
+
+	val = ioread32(reg + PCI_COMMAND);
+	val |= PCI_COMMAND_SERR | PCI_COMMAND_PARITY |
+	       PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER;
+	iowrite32(val, reg + PCI_COMMAND);
+
+	/* Enable PCI interrupts */
+	iowrite32(RCAR_PCI_INT_A | RCAR_PCI_INT_B | RCAR_PCI_INT_PME,
+		  reg + RCAR_PCI_INT_ENABLE_REG);
+
+	/* Add PCI resources */
+	pci_add_resource(&sys->resources, &priv->io_res);
+	pci_add_resource(&sys->resources, &priv->mem_res);
+
+	return 1;
+}
+
+static struct pci_ops rcar_pci_ops = {
+	.read	= rcar_pci_read_config,
+	.write	= rcar_pci_write_config,
+};
+
+static struct hw_pci rcar_hw_pci __initdata = {
+	.map_irq	= rcar_pci_map_irq,
+	.ops		= &rcar_pci_ops,
+	.setup		= rcar_pci_setup,
+};
+
+static int rcar_pci_count __initdata;
+
+static int __init rcar_pci_add_controller(struct rcar_pci_priv *priv)
+{
+	void **private_data;
+	int count;
+
+	if (rcar_hw_pci.nr_controllers < rcar_pci_count)
+		goto add_priv;
+
+	/* (Re)allocate private data pointer array if needed */
+	count = rcar_pci_count + RCAR_PCI_NR_CONTROLLERS;
+	private_data = kzalloc(count * sizeof(void *), GFP_KERNEL);
+	if (!private_data)
+		return -ENOMEM;
+
+	rcar_pci_count = count;
+	if (rcar_hw_pci.private_data) {
+		memcpy(private_data, rcar_hw_pci.private_data,
+		       rcar_hw_pci.nr_controllers * sizeof(void *));
+		kfree(rcar_hw_pci.private_data);
+	}
+
+	rcar_hw_pci.private_data = private_data;
+
+add_priv:
+	/* Add private data pointer to the array */
+	rcar_hw_pci.private_data[rcar_hw_pci.nr_controllers++] = priv;
+	return 0;
+}
+
+static int __init rcar_pci_probe(struct platform_device *pdev)
+{
+	struct resource *cfg_res, *mem_res;
+	struct rcar_pci_priv *priv;
+	void __iomem *reg;
+
+	cfg_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	reg = devm_ioremap_resource(&pdev->dev, cfg_res);
+	if (!reg)
+		return -ENODEV;
+
+	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!mem_res || !mem_res->start)
+		return -ENODEV;
+
+	priv = devm_kzalloc(&pdev->dev,
+			    sizeof(struct rcar_pci_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->mem_res = *mem_res;
+	/*
+	 * The controller does not support/use port I/O,
+	 * so setup a dummy port I/O region here.
+	 */
+	priv->io_res.start = priv->mem_res.start;
+	priv->io_res.end = priv->mem_res.end;
+	priv->io_res.flags = IORESOURCE_IO;
+
+	priv->cfg_res = cfg_res;
+
+	priv->irq = platform_get_irq(pdev, 0);
+	priv->reg = reg;
+
+	return rcar_pci_add_controller(priv);
+}
+
+static struct platform_driver rcar_pci_driver = {
+	.driver = {
+		.name = "pci-rcar-gen2",
+	},
+};
+
+static int __init rcar_pci_init(void)
+{
+	int retval;
+
+	retval = platform_driver_probe(&rcar_pci_driver, rcar_pci_probe);
+	if (!retval)
+		pci_common_init(&rcar_hw_pci);
+
+	/* Private data pointer array is not needed any more */
+	kfree(rcar_hw_pci.private_data);
+	rcar_hw_pci.private_data = NULL;
+
+	return retval;
+}
+
+subsys_initcall(rcar_pci_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas R-Car Gen2 internal PCI");
+MODULE_AUTHOR("Valentine Barshak <valentine.barshak@cogentembedded.com>");