path: root/drivers/pci/controller/pcie-rcar-host.c

// SPDX-License-Identifier: GPL-2.0
/*
 * PCIe driver for Renesas R-Car SoCs
 *  Copyright (C) 2014-2020 Renesas Electronics Europe Ltd
 *
 * Based on:
 *  arch/sh/drivers/pci/pcie-sh7786.c
 *  arch/sh/drivers/pci/ops-sh7786.c
 *  Copyright (C) 2009 - 2011  Paul Mundt
 *
 * Author: Phil Edworthy <phil.edworthy@renesas.com>
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.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/slab.h>

#include "pcie-rcar.h"

struct rcar_msi {
	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
	struct irq_domain *domain;
	struct msi_controller chip;
	unsigned long pages;
	struct mutex lock;
	int irq1;
	int irq2;
};

static inline struct rcar_msi *to_rcar_msi(struct msi_controller *chip)
{
	return container_of(chip, struct rcar_msi, chip);
}

/* Structure representing the PCIe interface */
struct rcar_pcie_host {
	struct rcar_pcie	pcie;
	struct device		*dev;
	struct phy		*phy;
	void __iomem		*base;
	struct list_head	resources;
	int			root_bus_nr;
	struct clk		*bus_clk;
	struct			rcar_msi msi;
	int			(*phy_init_fn)(struct rcar_pcie_host *host);
};

static u32 rcar_read_conf(struct rcar_pcie *pcie, int where)
{
	unsigned int shift = BITS_PER_BYTE * (where & 3);
	u32 val = rcar_pci_read_reg(pcie, where & ~3);

	return val >> shift;
}

/* Serialization is provided by 'pci_lock' in drivers/pci/access.c */
static int rcar_pcie_config_access(struct rcar_pcie_host *host,
		unsigned char access_type, struct pci_bus *bus,
		unsigned int devfn, int where, u32 *data)
{
	struct rcar_pcie *pcie = &host->pcie;
	unsigned int dev, func, reg, index;

	dev = PCI_SLOT(devfn);
	func = PCI_FUNC(devfn);
	reg = where & ~3;
	index = reg / 4;

	/*
	 * While each channel has its own memory-mapped extended config
	 * space, it's generally only accessible when in endpoint mode.
	 * When in root complex mode, the controller is unable to target
	 * itself with either type 0 or type 1 accesses, and indeed, any
	 * controller initiated target transfer to its own config space
	 * result in a completer abort.
	 *
	 * Each channel effectively only supports a single device, but as
	 * the same channel <-> device access works for any PCI_SLOT()
	 * value, we cheat a bit here and bind the controller's config
	 * space to devfn 0 in order to enable self-enumeration. In this
	 * case the regular ECAR/ECDR path is sidelined and the mangled
	 * config access itself is initiated as an internal bus transaction.
	 */
	if (pci_is_root_bus(bus)) {
		if (dev != 0)
			return PCIBIOS_DEVICE_NOT_FOUND;

		if (access_type == RCAR_PCI_ACCESS_READ) {
			*data = rcar_pci_read_reg(pcie, PCICONF(index));
		} else {
			/* Keep an eye out for changes to the root bus number */
			if (pci_is_root_bus(bus) && (reg == PCI_PRIMARY_BUS))
				host->root_bus_nr = *data & 0xff;

			rcar_pci_write_reg(pcie, *data, PCICONF(index));
		}

		return PCIBIOS_SUCCESSFUL;
	}

	if (host->root_bus_nr < 0)
		return PCIBIOS_DEVICE_NOT_FOUND;

	/* Clear errors */
	rcar_pci_write_reg(pcie, rcar_pci_read_reg(pcie, PCIEERRFR), PCIEERRFR);

	/* Set the PIO address */
	rcar_pci_write_reg(pcie, PCIE_CONF_BUS(bus->number) |
		PCIE_CONF_DEV(dev) | PCIE_CONF_FUNC(func) | reg, PCIECAR);

	/* Enable the configuration access */
	if (bus->parent->number == host->root_bus_nr)
		rcar_pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE0, PCIECCTLR);
	else
		rcar_pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE1, PCIECCTLR);

	/* Check for errors */
	if (rcar_pci_read_reg(pcie, PCIEERRFR) & UNSUPPORTED_REQUEST)
		return PCIBIOS_DEVICE_NOT_FOUND;

	/* Check for master and target aborts */
	if (rcar_read_conf(pcie, RCONF(PCI_STATUS)) &
		(PCI_STATUS_REC_MASTER_ABORT | PCI_STATUS_REC_TARGET_ABORT))
		return PCIBIOS_DEVICE_NOT_FOUND;

	if (access_type == RCAR_PCI_ACCESS_READ)
		*data = rcar_pci_read_reg(pcie, PCIECDR);
	else
		rcar_pci_write_reg(pcie, *data, PCIECDR);

	/* Disable the configuration access */
	rcar_pci_write_reg(pcie, 0, PCIECCTLR);

	return PCIBIOS_SUCCESSFUL;
}

static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn,
			       int where, int size, u32 *val)
{
	struct rcar_pcie_host *host = bus->sysdata;
	int ret;

	ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ,
				      bus