// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Common routines for Tundra Semiconductor TSI108 host bridge.
 *
 * 2004-2005 (c) Tundra Semiconductor Corp.
 * Author: Alex Bounine (alexandreb@tundra.com)
 * Author: Roy Zang (tie-fei.zang@freescale.com)
 * 	   Add pci interrupt router host
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/interrupt.h>
#include <linux/of_address.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <linux/uaccess.h>
#include <asm/machdep.h>
#include <asm/pci-bridge.h>
#include <asm/tsi108.h>
#include <asm/tsi108_pci.h>
#include <asm/tsi108_irq.h>

#undef DEBUG
#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

#define tsi_mk_config_addr(bus, devfunc, offset) \
	((((bus)<<16) | ((devfunc)<<8) | (offset & 0xfc)) + tsi108_pci_cfg_base)

u32 tsi108_pci_cfg_base;
static u32 tsi108_pci_cfg_phys;
u32 tsi108_csr_vir_base;
static struct irq_domain *pci_irq_host;

extern u32 get_vir_csrbase(void);
extern u32 tsi108_read_reg(u32 reg_offset);
extern void tsi108_write_reg(u32 reg_offset, u32 val);

int
tsi108_direct_write_config(struct pci_bus *bus, unsigned int devfunc,
			   int offset, int len, u32 val)
{
	volatile unsigned char *cfg_addr;
	struct pci_controller *hose = pci_bus_to_host(bus);

	if (ppc_md.pci_exclude_device)
		if (ppc_md.pci_exclude_device(hose, bus->number, devfunc))
			return PCIBIOS_DEVICE_NOT_FOUND;

	cfg_addr = (unsigned char *)(tsi_mk_config_addr(bus->number,
							devfunc, offset) |
							(offset & 0x03));

#ifdef DEBUG
	printk("PCI CFG write : ");
	printk("%d:0x%x:0x%x ", bus->number, devfunc, offset);
	printk("%d ADDR=0x%08x ", len, (uint) cfg_addr);
	printk("data = 0x%08x\n", val);
#endif

	switch (len) {
	case 1:
		out_8((u8 *) cfg_addr, val);
		break;
	case 2:
		out_le16((u16 *) cfg_addr, val);
		break;
	default:
		out_le32((u32 *) cfg_addr, val);
		break;
	}

	return PCIBIOS_SUCCESSFUL;
}

void tsi108_clear_pci_error(u32 pci_cfg_base)
{
	u32 err_stat, err_addr, pci_stat;

	/*
	 * Quietly clear PB and PCI error flags set as result
	 * of PCI/X configuration read requests.
	 */

	/* Read PB Error Log Registers */

	err_stat = tsi108_read_reg(TSI108_PB_OFFSET + TSI108_PB_ERRCS);
	err_addr = tsi108_read_reg(TSI108_PB_OFFSET + TSI108_PB_AERR);

	if (err_stat & TSI108_PB_ERRCS_ES) {
		/* Clear error flag */
		tsi108_write_reg(TSI108_PB_OFFSET + TSI108_PB_ERRCS,
				 TSI108_PB_ERRCS_ES);

		/* Clear read error reported in PB_ISR */
		tsi108_write_reg(TSI108_PB_OFFSET + TSI108_PB_ISR,
				 TSI108_PB_ISR_PBS_RD_ERR);

		/* Clear PCI/X bus cfg errors if applicable */
		if ((err_addr & 0xFF000000) == pci_cfg_base) {
			pci_stat =
			    tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_CSR);
			tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_CSR,
					 pci_stat);
		}
	}

	return;
}

#define __tsi108_read_pci_config(x, addr, op)		\
	__asm__ __volatile__(				\
		"	"op" %0,0,%1\n"		\
		"1:	eieio\n"			\
		"2:\n"					\
		".section .fixup,\"ax\"\n"		\
		"3:	li %0,-1\n"			\
		"	b 2b\n"				\
		".previous\n"				\
		EX_TABLE(1b, 3b)			\
		: "=r"(x) : "r"(addr))

int
tsi108_direct_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
			  int len, u32 * val)
{
	volatile unsigned char *cfg_addr;
	struct pci_controller *hose = pci_bus_to_host(bus);
	u32 temp;

	if (ppc_md.pci_exclude_device)
		if (ppc_md.pci_exclude_device(hose, bus->number, devfn))
			return PCIBIOS_DEVICE_NOT_FOUND;

	cfg_addr = (unsigned char *)(tsi_mk_config_addr(bus->number,
							devfn,
							offset) | (offset &
								   0x03));

	switch (len) {
	case 1:
		__tsi108_read_pci_config(temp, cfg_addr, "lbzx");
		break;
	case 2:
		__tsi108_read_pci_config(temp, cfg_addr, "lhbrx");
		break;
	default:
		__tsi108_read_pci_config(temp, cfg_addr, "lwbrx");
		break;
	}

	*val = temp;

#ifdef DEBUG
	if ((0xFFFFFFFF != temp) && (0xFFFF != temp) && (0xFF != temp)) {
		printk("PCI CFG read : ");
		printk("%d:0x%x:0x%x ", bus->number, devfn, offset);
		printk("%d ADDR=0x%08x ", len, (uint) cfg_addr);
		printk("data = 0x%x\n", *val);
	}
#endif
	return PCIBIOS_SUCCESSFUL;
}

void tsi108_clear_pci_cfg_error(void)
{
	tsi108_clear_pci_error(tsi108_pci_cfg_phys);
}

static struct pci_ops tsi108_direct_pci_ops = {
	.read = tsi108_direct_read_config,
	.write = tsi108_direct_write_config,
};

int __init tsi108_setup_pci(struct device_node *dev, u32 cfg_phys, int primary)
{
	int len;
	struct pci_controller *hose;
	struct resource rsrc;
	const int *bus_range;
	int has_address = 0;

	/* PCI Config mapping */
	tsi108_pci_cfg_base = (u32)ioremap(cfg_phys, TSI108_PCI_CFG_SIZE);
	tsi108_pci_cfg_phys = cfg_phys;
	DBG("TSI_PCI: %s tsi108_pci_cfg_base=0x%x\n", __func__,
	    tsi108_pci_cfg_base);

	/* Fetch host bridge registers address */
	has_address = (of_address_to_resource(dev, 0, &rsrc) == 0);

	/* Get bus range if any */
	bus_range = of_get_property(dev, "bus-range", &len);
	if (bus_range == NULL || len < 2 * sizeof(int)) {
		printk(KERN_WARNING "Can't get bus-range for %pOF, assume"
		       " bus 0\n", dev);
	}

	hose = pcibios_alloc_controller(dev);

	if (!hose) {
		printk("PCI Host bridge init failed\n");
		return -ENOMEM;
	}

	hose->first_busno = bus_range ? bus_range[0] : 0;
	hose->last_busno = bus_range ? bus_range[1] : 0xff;

	(hose)->ops = &tsi108_direct_pci_ops;

	pr_info("Found tsi108 PCI host bridge at 0x%pa. Firmware bus number: %d->%d\n",
		&rsrc.start, hose->first_busno, hose->last_busno);

	/* Interpret the "ranges" property */
	/* This also maps the I/O region and sets isa_io/mem_base */
	pci_process_bridge_OF_ranges(hose, dev, primary);
	return 0;
}

/*
 * Low level utility functions
 */

static void tsi108_pci_int_mask(u_int irq)
{
	u_int irp_cfg;
	int int_line = (irq - IRQ_PCI_INTAD_BASE);

	irp_cfg = tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL);
	mb();
	irp_cfg |= (1 << int_line);	/* INTx_DIR = output */
	irp_cfg &= ~(3 << (8 + (int_line * 2)));	/* INTx_TYPE = unused */
	tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL, irp_cfg);
	mb();
	irp_cfg = tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL);
}

static void tsi108_pci_int_unmask(u_int irq)
{
	u_int irp_cfg;
	int int_line = (irq - IRQ_PCI_INTAD_BASE);

	irp_cfg = tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL);
	mb();
	irp_cfg &= ~(1 << int_line);
	irp_cfg |= (3 << (8 + (int_line * 2)));
	tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL, irp_cfg);
	mb();
}

static void __init init_pci_source(void)
{
	tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL,
			0x0000ff00);
	tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE,
			TSI108_PCI_IRP_ENABLE_P_INT);
	mb();
}

static inline unsigned int get_pci_source(void)
{
	u_int temp = 0;
	int irq = -1;
	int i;
	u_int pci_irp_stat;
	static int mask = 0;

	/* Read PCI/X block interrupt status register */
	pci_irp_stat = tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_STAT);
	mb();

	if (pci_irp_stat & TSI108_PCI_IRP_STAT_P_INT) {
		/* Process Interrupt from PCI bus INTA# - INTD# lines */
		temp =
		    tsi108_read_reg(TSI108_PCI_OFFSET +
				    TSI108_PCI_IRP_INTAD) & 0xf;
		mb();
		for (i = 0; i < 4; i++, mask++) {
			if (temp & (1 << mask % 4)) {
				irq = IRQ_PCI_INTA + mask % 4;
				mask++;
				break;
			}
		}

		/* Disable interrupts from PCI block */
		temp = tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE);
		tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE,
				temp & ~TSI108_PCI_IRP_ENABLE_P_INT);
		mb();
		(void)tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE);
		mb();
	}
#ifdef DEBUG
	else {
		printk("TSI108_PIC: error in TSI108_PCI_IRP_STAT\n");
		pci_irp_stat =
		    tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_STAT);
		temp =
		    tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_INTAD);
		mb();
		printk(">> stat=0x%08x intad=0x%08x ", pci_irp_stat, temp);
		temp =
		    tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_CFG_CTL);
		mb();
		printk("cfg_ctl=0x%08x ", temp);
		temp =
		    tsi108_read_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE);
		mb();
		printk("irp_enable=0x%08x\n", temp);
	}
#endif	/* end of DEBUG */

	return irq;
}


/*
 * Linux descriptor level callbacks
 */

static void tsi108_pci_irq_unmask(struct irq_data *d)
{
	tsi108_pci_int_unmask(d->irq);

	/* Enable interrupts from PCI block */
	tsi108_write_reg(TSI108_PCI_OFFSET + TSI108_PCI_IRP_ENABLE,
			 tsi108_read_reg(TSI108_PCI_OFFSET +
					 TSI108_PCI_IRP_ENABLE) |
			 TSI108_PCI_IRP_ENABLE_P_INT);
	mb();
}

static void tsi108_pci_irq_mask(struct irq_data *d)
{
	tsi108_pci_int_mask(d->irq);
}

static void tsi108_pci_irq_ack(struct irq_data *d)
{
	tsi108_pci_int_mask(d->irq);
}

/*
 * Interrupt controller descriptor for cascaded PCI interrupt controller.
 */

static struct irq_chip tsi108_pci_irq = {
	.name = "tsi108_PCI_int",
	.irq_mask = tsi108_pci_irq_mask,
	.irq_ack = tsi108_pci_irq_ack,
	.irq_unmask = tsi108_pci_irq_unmask,
};

static int pci_irq_host_xlate(struct irq_domain *h, struct device_node *ct,
			    const u32 *intspec, unsigned int intsize,
			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
{
	*out_hwirq = intspec[0];
	*out_flags = IRQ_TYPE_LEVEL_HIGH;
	return 0;
}

static int pci_irq_host_map(struct irq_domain *h, unsigned int virq,
			  irq_hw_number_t hw)
{	unsigned int irq;
	DBG("%s(%d, 0x%lx)\n", __func__, virq, hw);
	if ((virq >= 1) && (virq <= 4)){
		irq = virq + IRQ_PCI_INTAD_BASE - 1;
		irq_set_status_flags(irq, IRQ_LEVEL);
		irq_set_chip(irq, &tsi108_pci_irq);
	}
	return 0;
}

static const struct irq_domain_ops pci_irq_domain_ops = {
	.map = pci_irq_host_map,
	.xlate = pci_irq_host_xlate,
};

/*
 * Exported functions
 */

/*
 * The Tsi108 PCI interrupts initialization routine.
 *
 * The INTA# - INTD# interrupts on the PCI bus are reported by the PCI block
 * to the MPIC using single interrupt source (IRQ_TSI108_PCI). Therefore the
 * PCI block has to be treated as a cascaded interrupt controller connected
 * to the MPIC.
 */

void __init tsi108_pci_int_init(struct device_node *node)
{
	DBG("Tsi108_pci_int_init: initializing PCI interrupts\n");

	pci_irq_host = irq_domain_add_legacy(node, NR_IRQS_LEGACY, 0, 0,
					     &pci_irq_domain_ops, NULL);
	if (pci_irq_host == NULL) {
		printk(KERN_ERR "pci_irq_host: failed to allocate irq domain!\n");
		return;
	}

	init_pci_source();
}

void tsi108_irq_cascade(struct irq_desc *desc)
{
	struct irq_chip *chip = irq_desc_get_chip(desc);
	unsigned int cascade_irq = get_pci_source();

	if (cascade_irq)
		generic_handle_irq(cascade_irq);

	chip->irq_eoi(&desc->irq_data);
}