xref: /openbmc/linux/arch/mips/pci/ops-loongson2.c (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 1999, 2000, 2004  MIPS Technologies, Inc.
 *	All rights reserved.
 *	Authors: Carsten Langgaard <carstenl@mips.com>
 *		 Maciej W. Rozycki <macro@mips.com>
 *
 * Copyright (C) 2009 Lemote Inc.
 * Author: Wu Zhangjin <wuzhangjin@gmail.com>
 */
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/export.h>

#include <loongson.h>

#ifdef CONFIG_CS5536
#include <cs5536/cs5536_pci.h>
#include <cs5536/cs5536.h>
#endif

#define PCI_ACCESS_READ	 0
#define PCI_ACCESS_WRITE 1

#define CFG_SPACE_REG(offset) \
	(void *)CKSEG1ADDR(LOONGSON_PCICFG_BASE | (offset))
#define ID_SEL_BEGIN 11
#define MAX_DEV_NUM (31 - ID_SEL_BEGIN)


static int loongson_pcibios_config_access(unsigned char access_type,
				      struct pci_bus *bus,
				      unsigned int devfn, int where,
				      u32 *data)
{
	u32 busnum = bus->number;
	u32 addr, type;
	u32 dummy;
	void *addrp;
	int device = PCI_SLOT(devfn);
	int function = PCI_FUNC(devfn);
	int reg = where & ~3;

	if (busnum == 0) {
		/* board-specific part,currently,only fuloong2f,yeeloong2f
		 * use CS5536, fuloong2e use via686b, gdium has no
		 * south bridge
		 */
#ifdef CONFIG_CS5536
		/* cs5536_pci_conf_read4/write4() will call _rdmsr/_wrmsr() to
		 * access the regsters PCI_MSR_ADDR, PCI_MSR_DATA_LO,
		 * PCI_MSR_DATA_HI, which is bigger than PCI_MSR_CTRL, so, it
		 * will not go this branch, but the others. so, no calling dead
		 * loop here.
		 */
		if ((PCI_IDSEL_CS5536 == device) && (reg < PCI_MSR_CTRL)) {
			switch (access_type) {
			case PCI_ACCESS_READ:
				*data = cs5536_pci_conf_read4(function, reg);
				break;
			case PCI_ACCESS_WRITE:
				cs5536_pci_conf_write4(function, reg, *data);
				break;
			}
			return 0;
		}
#endif
		/* Type 0 configuration for onboard PCI bus */
		if (device > MAX_DEV_NUM)
			return -1;

		addr = (1 << (device + ID_SEL_BEGIN)) | (function << 8) | reg;
		type = 0;
	} else {
		/* Type 1 configuration for offboard PCI bus */
		addr = (busnum << 16) | (device << 11) | (function << 8) | reg;
		type = 0x10000;
	}

	/* Clear aborts */
	LOONGSON_PCICMD |= LOONGSON_PCICMD_MABORT_CLR | \
				LOONGSON_PCICMD_MTABORT_CLR;

	LOONGSON_PCIMAP_CFG = (addr >> 16) | type;

	/* Flush Bonito register block */
	dummy = LOONGSON_PCIMAP_CFG;
	mmiowb();

	addrp = CFG_SPACE_REG(addr & 0xffff);
	if (access_type == PCI_ACCESS_WRITE)
		writel(cpu_to_le32(*data), addrp);
	else
		*data = le32_to_cpu(readl(addrp));

	/* Detect Master/Target abort */
	if (LOONGSON_PCICMD & (LOONGSON_PCICMD_MABORT_CLR |
			     LOONGSON_PCICMD_MTABORT_CLR)) {
		/* Error occurred */

		/* Clear bits */
		LOONGSON_PCICMD |= (LOONGSON_PCICMD_MABORT_CLR |
				  LOONGSON_PCICMD_MTABORT_CLR);

		return -1;
	}

	return 0;

}


/*
 * We can't address 8 and 16 bit words directly.  Instead we have to
 * read/write a 32bit word and mask/modify the data we actually want.
 */
static int loongson_pcibios_read(struct pci_bus *bus, unsigned int devfn,
			     int where, int size, u32 *val)
{
	u32 data = 0;

	if ((size == 2) && (where & 1))
		return PCIBIOS_BAD_REGISTER_NUMBER;
	else if ((size == 4) && (where & 3))
		return PCIBIOS_BAD_REGISTER_NUMBER;

	if (loongson_pcibios_config_access(PCI_ACCESS_READ, bus, devfn, where,
				       &data))
		return -1;

	if (size == 1)
		*val = (data >> ((where & 3) << 3)) & 0xff;
	else if (size == 2)
		*val = (data >> ((where & 3) << 3)) & 0xffff;
	else
		*val = data;

	return PCIBIOS_SUCCESSFUL;
}

static int loongson_pcibios_write(struct pci_bus *bus, unsigned int devfn,
			      int where, int size, u32 val)
{
	u32 data = 0;

	if ((size == 2) && (where & 1))
		return PCIBIOS_BAD_REGISTER_NUMBER;
	else if ((size == 4) && (where & 3))
		return PCIBIOS_BAD_REGISTER_NUMBER;

	if (size == 4)
		data = val;
	else {
		if (loongson_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data))
			return -1;

		if (size == 1)
			data = (data & ~(0xff << ((where & 3) << 3))) |
				(val << ((where & 3) << 3));
		else if (size == 2)
			data = (data & ~(0xffff << ((where & 3) << 3))) |
				(val << ((where & 3) << 3));
	}

	if (loongson_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn, where,
				       &data))
		return -1;

	return PCIBIOS_SUCCESSFUL;
}

struct pci_ops loongson_pci_ops = {
	.read = loongson_pcibios_read,
	.write = loongson_pcibios_write
};

#ifdef CONFIG_CS5536
DEFINE_RAW_SPINLOCK(msr_lock);

void _rdmsr(u32 msr, u32 *hi, u32 *lo)
{
	struct pci_bus bus = {
		.number = PCI_BUS_CS5536
	};
	u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
	unsigned long flags;

	raw_spin_lock_irqsave(&msr_lock, flags);
	loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
	loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
	loongson_pcibios_read(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
	raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_rdmsr);

void _wrmsr(u32 msr, u32 hi, u32 lo)
{
	struct pci_bus bus = {
		.number = PCI_BUS_CS5536
	};
	u32 devfn = PCI_DEVFN(PCI_IDSEL_CS5536, 0);
	unsigned long flags;

	raw_spin_lock_irqsave(&msr_lock, flags);
	loongson_pcibios_write(&bus, devfn, PCI_MSR_ADDR, 4, msr);
	loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_LO, 4, lo);
	loongson_pcibios_write(&bus, devfn, PCI_MSR_DATA_HI, 4, hi);
	raw_spin_unlock_irqrestore(&msr_lock, flags);
}
EXPORT_SYMBOL(_wrmsr);
#endif