[PATCH v7 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[PATCH v7 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Subrahmanya Lingappa]

Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP
 - GPEX 4.0, a PCIe gen4 IP. This IP has upto 8 outbound and inbound windows
 for the address translation.

Signed-off-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: devicetree@vger.kernel.org
---
 drivers/pci/host/pcie-mobiveil.c | 692 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 692 insertions(+)
 create mode 100644 drivers/pci/host/pcie-mobiveil.c

diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
new file mode 100644
index 0000000..28f488b
--- /dev/null
+++ b/drivers/pci/host/pcie-mobiveil.c
@@ -0,0 +1,692 @@
+/*
+ * PCIe host controller driver for Mobiveil PCIe Host controller
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2017 Mobiveil Inc.
+ * Author: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* register offsets and bit positions */
+
+/*
+ * translation tables are grouped into windows, each window registers are
+ * grouped into blocks of 4 or 16 registers each
+ */
+#define PAB_REG_BLOCK_SIZE	16
+#define PAB_EXT_REG_BLOCK_SIZE	4
+
+#define PAB_REG_ADDR(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE))
+#define PAB_EXT_REG_ADDR(offset, win) (offset + (win * PAB_EXT_REG_BLOCK_SIZE))
+
+#define LTSSM_STATUS		0x0404
+#define  LTSSM_STATUS_L0_MASK	0x3f
+#define  LTSSM_STATUS_L0	0x2d
+
+#define PAB_CTRL		0x0808
+#define  AMBA_PIO_ENABLE_SHIFT	0
+#define  PEX_PIO_ENABLE_SHIFT	1
+#define  PAGE_SEL_SHIFT		13
+#define  PAGE_SEL_MASK		0x3f
+#define  PAGE_LO_MASK		0x3ff
+#define  PAGE_SEL_EN		0xc00
+#define  PAGE_SEL_OFFSET_SHIFT	10
+
+#define PAB_AXI_PIO_CTRL	0x0840
+#define  APIO_EN_MASK		0xf
+
+#define PAB_PEX_PIO_CTRL	0x08c0
+#define  PIO_ENABLE_SHIFT	0
+
+#define PAB_INTP_AMBA_MISC_ENB	0x0b0c
+#define PAB_INTP_AMBA_MISC_STAT	0x0b1c
+#define  PAB_INTP_INTX_MASK	0x1e0
+
+#define PAB_AXI_AMAP_CTRL(win)	PAB_REG_ADDR(0x0ba0, win)
+#define  WIN_ENABLE_SHIFT	0
+#define  WIN_TYPE_SHIFT		1
+
+#define PAB_EXT_AXI_AMAP_SIZE(win)	PAB_EXT_REG_ADDR(0xbaf0, win)
+
+#define PAB_AXI_AMAP_AXI_WIN(win)	PAB_REG_ADDR(0x0ba4, win)
+#define  AXI_WINDOW_BASE_SHIFT		2
+
+#define PAB_AXI_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR(0x0ba8, win)
+#define  PAB_BUS_SHIFT			24
+#define  PAB_DEVICE_SHIFT		19
+#define  PAB_FUNCTION_SHIFT		16
+
+#define PAB_AXI_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR(0x0bac, win)
+#define PAB_INTP_AXI_PIO_CLASS		0x474
+
+#define PAB_PEX_AMAP_CTRL(win)		PAB_REG_ADDR(0x4ba0, win)
+#define  AMAP_CTRL_EN_SHIFT		0
+#define  AMAP_CTRL_TYPE_SHIFT		1
+
+#define PAB_EXT_PEX_AMAP_SIZEN(win)	PAB_EXT_REG_ADDR(0xbef0, win)
+#define PAB_PEX_AMAP_AXI_WIN(win)	PAB_REG_ADDR(0x4ba4, win)
+#define PAB_PEX_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR(0x4ba8, win)
+#define PAB_PEX_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR(0x4bac, win)
+
+/* supported number of interrupts */
+#define PCI_NUM_INTX    4
+#define PAB_INTA_POS    5
+
+/* outbound and inbound window definitions */
+#define WIN_NUM_0		0
+#define WIN_NUM_1		1
+#define CFG_WINDOW_TYPE		0
+#define IO_WINDOW_TYPE		1
+#define MEM_WINDOW_TYPE		2
+#define IB_WIN_SIZE		(256 * 1024 * 1024 * 1024)
+#define MAX_PIO_WINDOWS		8
+
+/* Parameters for the waiting for link up routine */
+#define LINK_WAIT_MAX_RETRIES	10
+#define LINK_WAIT_MIN		90000
+#define LINK_WAIT_MAX		100000
+
+struct mobiveil_pcie {
+	struct platform_device *pdev;
+	struct list_head resources;
+	void __iomem *config_axi_slave_base;	/* endpoint config base */
+	void __iomem *csr_axi_slave_base;   /* root port config base */
+	void __iomem *pcie_reg_base;    /* Physical PCIe Controller Base */
+	struct irq_domain *intx_domain;
+	raw_spinlock_t intx_mask_lock;
+	int irq;
+	int apio_wins;
+	int ppio_wins;
+	int ob_wins_configured;	/*  configured outbound windows */
+	int ib_wins_configured;	/*  configured inbound windows */
+	struct resource *ob_io_res;
+	char root_bus_nr;
+};
+
+static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
+		const u32 reg)
+{
+	writel_relaxed(value, pcie->csr_axi_slave_base + reg);
+}
+
+static inline u32 csr_readl(struct mobiveil_pcie *pcie,	const u32 reg)
+{
+	return readl_relaxed(pcie->csr_axi_slave_base + reg);
+}
+
+/*
+ * Routine to check the downstream link status, its recommended to
+ * check the link status before accessing downstream config resources.
+ */
+static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
+{
+	return (csr_readl(pcie, LTSSM_STATUS) &
+		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
+}
+
+static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	/* Check if link is up when trying to access downstream ports */
+	if (bus->number != pcie->root_bus_nr)
+		if (!mobiveil_pcie_link_up(pcie))
+			return false;
+
+	/* Only one device down on each root port */
+	if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	/*
+	 * Do not read more than one device on the bus directly
+	 * attached to RC
+	 */
+	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	return true;
+}
+
+/*
+ * mobiveil_pcie_map_bus - routine to get the configuration base of either
+ * root port or endpoint
+ */
+static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
+					unsigned int devfn, int where)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	if (!mobiveil_pcie_valid_device(bus, devfn))
+		return NULL;
+
+	if (bus->number == pcie->root_bus_nr) {
+		/* RC config access */
+		return pcie->csr_axi_slave_base + where;
+	} else {
+		/*
+		 * EP config access (in Config/APIO space)
+		 * Program PEX Address base (31..16 bits) with appropriate value
+		 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
+		 * Relies on pci_lock serialization
+		 */
+		csr_writel(pcie,
+			bus->number << PAB_BUS_SHIFT |
+			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
+			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
+			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
+		return pcie->config_axi_slave_base + where;
+	}
+}
+
+static struct pci_ops mobiveil_pcie_ops = {
+	.map_bus = mobiveil_pcie_map_bus,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static void mobiveil_pcie_isr(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
+	struct device *dev = &pcie->pdev->dev;
+	unsigned long shifted_status;
+	u32 bit, virq;
+	u32 val, mask;
+
+	/*
+	 * The core provides a single interrupt for both INTx/MSI messages.
+	 * So we'll read both INTx and MSI status
+	 */
+
+	chained_irq_enter(chip, desc);
+
+	/* read INTx status */
+	val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
+	mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	intr_status = val & mask;
+
+	/* Handle INTx */
+	if (intr_status & PAB_INTP_INTX_MASK) {
+		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT) >>
+			PAB_INTA_POS;
+		do {
+			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
+				virq = irq_find_mapping(pcie->intx_domain,
+						bit + 1);
+				if (virq)
+					generic_handle_irq(virq);
+				else
+					dev_err_ratelimited(dev,
+						"unexpected IRQ, INT%d\n", bit);
+
+				/* clear interrupt */
+				csr_writel(pcie, shifted_status << PAB_INTA_POS,
+						PAB_INTP_AMBA_MISC_STAT);
+			}
+		} while ((shifted_status >>  PAB_INTA_POS) != 0);
+	}
+
+	/* Clear the interrupt status */
+	csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);
+	chained_irq_exit(chip, desc);
+}
+
+static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct platform_device *pdev = pcie->pdev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	const char *type;
+
+	type = of_get_property(node, "device_type", NULL);
+	if (!type || strcmp(type, "pci")) {
+		dev_err(dev, "invalid \"device_type\" %s\n", type);
+		return -EINVAL;
+	}
+
+	/* map config resource */
+	res = platform_get_resource_byname(pdev,
+		IORESOURCE_MEM, "config_axi_slave");
+	pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->config_axi_slave_base))
+		return PTR_ERR(pcie->config_axi_slave_base);
+	pcie->ob_io_res = res;
+
+	/* map csr resource */
+	res = platform_get_resource_byname(pdev,
+		IORESOURCE_MEM, "csr_axi_slave");
+	pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->csr_axi_slave_base))
+		return PTR_ERR(pcie->csr_axi_slave_base);
+	pcie->pcie_reg_base = res->start;
+
+	/* read the number of windows requested */
+	if (of_property_read_u32(node, "apio-wins", &pcie->apio_wins))
+		pcie->apio_wins = MAX_PIO_WINDOWS;
+
+	if (of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins))
+		pcie->ppio_wins = MAX_PIO_WINDOWS;
+
+	pcie->irq = platform_get_irq(pdev, 0);
+	if (pcie->irq <= 0) {
+		dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
+		return -ENODEV;
+	}
+
+	irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
+
+	return 0;
+}
+
+/*
+ * select_paged_register - routine to access paged register of root complex
+ *
+ * registers of RC are paged, for this scheme to work
+ * extracted higher 6 bits of the offset will be written to pg_sel
+ * field of PAB_CTRL register and rest of the lower 10 bits enabled with
+ * PAGE_SEL_EN are used as offset of the register.
+ *
+ */
+static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	int pab_ctrl_dw, pg_sel;
+
+	/* clear pg_sel field */
+	pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
+	pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
+
+	/* set pg_sel field */
+	pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
+	pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
+	csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
+}
+
+static void write_paged_register(struct mobiveil_pcie *pcie,
+		u32 val, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	csr_writel(pcie, val, off);
+}
+
+static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	return csr_readl(pcie, off);
+}
+
+static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
+		int pci_addr, u32 type,	int size)
+{
+	int pio_ctrl_val;
+	int amap_ctrl_dw;
+	u64 size64 =  ~(size-1);
+
+	if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max inbound windows reached !\n");
+		return;
+	}
+
+	pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
+	csr_writel(pcie,
+		pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
+	amap_ctrl_dw =	read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
+	amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
+	amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
+
+	write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
+				PAB_PEX_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_PEX_AMAP_SIZEN(win_num));
+
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
+	write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
+}
+
+/*
+ * routine to program the outbound windows
+ */
+static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
+		u64 cpu_addr, u64 pci_addr, u32 config_io_bit,
+		int size)
+{
+
+	u32 value, type;
+	u64 size64 =  ~(size-1);
+
+	if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max outbound windows reached !\n");
+		return;
+	}
+
+	/*
+	 * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
+	 * to 4 KB in PAB_AXI_AMAP_CTRL register
+	 */
+	type = config_io_bit;
+	value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
+	csr_writel(pcie,
+			1 << WIN_ENABLE_SHIFT |
+			type << WIN_TYPE_SHIFT |
+			lower_32_bits(size64),
+			PAB_AXI_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_AXI_AMAP_SIZE(win_num));
+
+	/*
+	 * program AXI window base with appropriate value in
+	 * PAB_AXI_AMAP_AXI_WIN0 register
+	 */
+	value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
+	csr_writel(pcie,
+			cpu_addr >> AXI_WINDOW_BASE_SHIFT <<
+			AXI_WINDOW_BASE_SHIFT, PAB_AXI_AMAP_AXI_WIN(win_num));
+
+	value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	csr_writel(pcie, lower_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_L(win_num));
+	csr_writel(pcie, upper_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	pcie->ob_wins_configured++;
+}
+
+static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
+{
+	int retries;
+
+	/* check if the link is up or not */
+	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+		if (mobiveil_pcie_link_up(pcie))
+			return 0;
+
+		usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
+	}
+	dev_err(&pcie->pdev->dev, "link never came up\n");
+	return -ETIMEDOUT;
+}
+
+static int mobiveil_host_init(struct mobiveil_pcie *pcie)
+{
+	u32 value;
+	u32 type = 0;
+	u32 pab_ctrl;
+	int err;
+	struct resource_entry *win, *tmp;
+
+	err = mobiveil_bringup_link(pcie);
+	if (err) {
+		dev_info(&pcie->pdev->dev, "link bring-up failed\n");
+		return err;
+	}
+
+	/*
+	 * program Bus Master Enable Bit in Command Register in PAB Config
+	 * Space
+	 */
+	value = csr_readl(pcie, PCI_COMMAND);
+	csr_writel(pcie, value | PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
+		PCI_COMMAND_MASTER,	PCI_COMMAND);
+
+	/*
+	 * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
+	 * register
+	 */
+	pab_ctrl = csr_readl(pcie, PAB_CTRL);
+	csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
+		(1 << PEX_PIO_ENABLE_SHIFT),
+		PAB_CTRL);
+
+	csr_writel(pcie, (PAB_INTP_INTX_MASK | PAB_INTP_MSI_MASK),
+		PAB_INTP_AMBA_MISC_ENB);
+
+	/* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
+	 * PAB_AXI_PIO_CTRL Register
+	 */
+	value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
+	csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
+
+	/*
+	 * we'll program one outbound window for config reads and
+	 * another default inbound window for all the upstream traffic
+	 * rest of the outbound windows will be configured according to
+	 * the "ranges" field defined in device tree
+	 */
+
+	/* config outbound translation window */
+	program_ob_windows(pcie, pcie->ob_wins_configured,
+			pcie->ob_io_res->start,	0, CFG_WINDOW_TYPE,
+			resource_size(pcie->ob_io_res));
+
+	/* memory inbound  translation window */
+	program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
+
+	/* Get the I/O and memory ranges from DT */
+	resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
+		type = 0;
+		if (resource_type(win->res) == IORESOURCE_MEM)
+			type = MEM_WINDOW_TYPE;
+		if (resource_type(win->res) == IORESOURCE_IO)
+			type = IO_WINDOW_TYPE;
+		if (type) {
+			/* configure outbound translation window */
+			program_ob_windows(pcie, pcie->ob_wins_configured,
+				win->res->start, 0, type,
+				resource_size(win->res));
+		}
+	}
+
+	return err;
+}
+
+static void mobiveil_mask_intx_irq(struct irq_data *data)
+{
+	struct irq_desc *desc = irq_to_desc(data->irq);
+	struct mobiveil_pcie *pcie;
+	unsigned long flags;
+	u32 mask;
+	u32 shifted_val;
+
+	pcie = irq_desc_get_chip_data(desc);
+	mask = 1 << ((data->hwirq + PAB_INTA_POS) - 1);
+	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
+	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	csr_writel(pcie, (shifted_val & (~mask)), PAB_INTP_AMBA_MISC_ENB);
+	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
+}
+
+static void mobiveil_unmask_intx_irq(struct irq_data *data)
+{
+	struct irq_desc *desc = irq_to_desc(data->irq);
+	struct mobiveil_pcie *pcie;
+	unsigned long flags;
+	u32 shifted_val;
+	u32 mask;
+
+	pcie = irq_desc_get_chip_data(desc);
+	mask = 1 << ((data->hwirq + PAB_INTA_POS) - 1);
+	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
+	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	csr_writel(pcie, (shifted_val | mask), PAB_INTP_AMBA_MISC_ENB);
+	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
+}
+
+static struct irq_chip intx_irq_chip = {
+	.name = "mobiveil_pcie:intx",
+	.irq_enable = mobiveil_unmask_intx_irq,
+	.irq_disable = mobiveil_mask_intx_irq,
+	.irq_mask = mobiveil_mask_intx_irq,
+	.irq_unmask = mobiveil_unmask_intx_irq,
+};
+
+/* routine to setup the INTx related data */
+static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
+		irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &intx_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	return 0;
+}
+
+/* INTx domain operations structure */
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = mobiveil_pcie_intx_map,
+	.xlate = pci_irqd_intx_xlate,
+};
+
+static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+
+	/* setup INTx */
+	pcie->intx_domain = irq_domain_add_linear(node,
+				PCI_NUM_INTX, &intx_domain_ops, pcie);
+
+	if (!pcie->intx_domain) {
+		dev_err(dev, "Failed to get a INTx IRQ domain\n");
+		return -ENODEV;
+	}
+
+	raw_spin_lock_init(&pcie->intx_mask_lock);
+
+	return 0;
+}
+
+static int mobiveil_pcie_probe(struct platform_device *pdev)
+{
+	struct mobiveil_pcie *pcie;
+	struct pci_bus *bus;
+	struct pci_bus *child;
+	struct pci_host_bridge *bridge;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	resource_size_t iobase;
+	int ret;
+
+	/* allocate the PCIe port */
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	if (!bridge)
+		return -ENODEV;
+
+	pcie = pci_host_bridge_priv(bridge);
+	if (!pcie)
+		return -ENOMEM;
+
+	pcie->pdev = pdev;
+
+	ret = mobiveil_pcie_parse_dt(pcie);
+	if (ret) {
+		dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
+		return ret;
+	}
+
+	INIT_LIST_HEAD(&pcie->resources);
+
+	/* parse the host bridge base addresses from the device tree file */
+	ret = of_pci_get_host_bridge_resources(node,
+			0, 0xff, &pcie->resources, &iobase);
+	if (ret) {
+		dev_err(dev, "Getting bridge resources failed\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * configure all inbound and outbound windows and prepare the RC for
+	 * config access
+	 */
+	ret = mobiveil_host_init(pcie);
+	if (ret) {
+		dev_err(dev, "Failed to initialize host\n");
+		goto error;
+	}
+
+	/* fixup for PCIe class register */
+	csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
+
+	/* initialize the IRQ domains */
+	ret = mobiveil_pcie_init_irq_domain(pcie);
+	if (ret) {
+		dev_err(dev, "Failed creating IRQ Domain\n");
+		goto error;
+	}
+
+	ret = devm_request_pci_bus_resources(dev, &pcie->resources);
+	if (ret)
+		goto error;
+
+	/* Initialize bridge */
+	list_splice_init(&pcie->resources, &bridge->windows);
+	bridge->dev.parent = dev;
+	bridge->sysdata = pcie;
+	bridge->busnr = pcie->root_bus_nr;
+	bridge->ops = &mobiveil_pcie_ops;
+	bridge->map_irq = of_irq_parse_and_map_pci;
+	bridge->swizzle_irq = pci_common_swizzle;
+
+	/* setup the kernel resources for the newly added PCIe root bus */
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret)
+		goto error;
+
+	bus = bridge->bus;
+
+	pci_assign_unassigned_bus_resources(bus);
+	list_for_each_entry(child, &bus->children, node)
+		pcie_bus_configure_settings(child);
+	pci_bus_add_devices(bus);
+
+	platform_set_drvdata(pdev, pcie);
+
+	return 0;
+error:
+	pci_free_resource_list(&pcie->resources);
+	return ret;
+}
+
+static const struct of_device_id mobiveil_pcie_of_match[] = {
+	{.compatible = "mbvl,gpex40-pcie",},
+};
+
+MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
+
+static struct platform_driver mobiveil_pcie_driver = {
+	.probe = mobiveil_pcie_probe,
+	.driver = {
+			.name = "mobiveil-pcie",
+			.of_match_table = mobiveil_pcie_of_match,
+			.suppress_bind_attrs = true,
+		},
+};
+
+builtin_platform_driver(mobiveil_pcie_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
+MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>");
-- 
1.8.3.1

Re: [PATCH v7 2/3] PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

[Bjorn Helgaas]

On Tue, Apr 24, 2018 at 10:29:55AM -0400, Subrahmanya Lingappa wrote:
> Adds driver for Mobiveil AXI PCIe Host Bridge Soft IP
>  - GPEX 4.0, a PCIe gen4 IP. This IP has upto 8 outbound and inbound windows
>  for the address translation.
> 
> Signed-off-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: linux-pci@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> ---
>  drivers/pci/host/pcie-mobiveil.c | 692 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 692 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-mobiveil.c
> 
> diff --git a/drivers/pci/host/pcie-mobiveil.c b/drivers/pci/host/pcie-mobiveil.c
> new file mode 100644
> index 0000000..28f488b
> --- /dev/null
> +++ b/drivers/pci/host/pcie-mobiveil.c
> @@ -0,0 +1,692 @@
> +/*
> + * PCIe host controller driver for Mobiveil PCIe Host controller
> + *
> + * SPDX-License-Identifier: GPL-2.0

Incorrect usage of SPDX tag, see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/license-rules.rst

(Must be first line of file, should use "//" comment in C source)

> + * Copyright (c) 2017 Mobiveil Inc.

It's 2018 already, so use 2018 here instead of 2017 in this patch and
then updating it in the next.

> +/* supported number of interrupts */
> +#define PCI_NUM_INTX    4

This is already defined in include/linux/pci.h; you don't need another
one.

> +static inline u32 csr_readl(struct mobiveil_pcie *pcie,	const u32 reg)

Should be space, not tab, after ","

> +/*
> + * Routine to check the downstream link status, its recommended to
> + * check the link status before accessing downstream config resources.

Checking the link status before accessing downstream config resources
is racy because the link may go down after you check the status but
before you actually do the access.

> + */
> +static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
> +{
> +	return (csr_readl(pcie, LTSSM_STATUS) &
> +		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
> +}

> +static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
> +					unsigned int devfn, int where)
> +{
> +	struct mobiveil_pcie *pcie = bus->sysdata;
> +
> +	if (!mobiveil_pcie_valid_device(bus, devfn))
> +		return NULL;
> +
> +	if (bus->number == pcie->root_bus_nr) {
> +		/* RC config access */
> +		return pcie->csr_axi_slave_base + where;
> +	} else {

No "else" needed, since the "if" body always returns.  Then you can
unindent the block below.

> +		/*
> +		 * EP config access (in Config/APIO space)
> +		 * Program PEX Address base (31..16 bits) with appropriate value
> +		 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
> +		 * Relies on pci_lock serialization
> +		 */
> +		csr_writel(pcie,
> +			bus->number << PAB_BUS_SHIFT |
> +			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
> +			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
> +			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
> +		return pcie->config_axi_slave_base + where;
> +	}

> +/*
> + * select_paged_register - routine to access paged register of root complex
> + *
> + * registers of RC are paged, for this scheme to work
> + * extracted higher 6 bits of the offset will be written to pg_sel
> + * field of PAB_CTRL register and rest of the lower 10 bits enabled with
> + * PAGE_SEL_EN are used as offset of the register.
> + *

Remove the extra blank line at the end of the comment.

> + */
> +static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)

> +	value = csr_readl(pcie, PCI_COMMAND);
> +	csr_writel(pcie, value | PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
> +		PCI_COMMAND_MASTER,	PCI_COMMAND);

Use space, not tab, after the comma.

> +	/* program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
> +	 * PAB_AXI_PIO_CTRL Register
> +	 */

Wrong comment style, needs:

  /*
   * Program PIO ...
   * ...
   */

Bjorn