// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/core_polaris.c
 *
 * POLARIS chip-specific code
 */

#define __EXTERN_INLINE inline
#include <asm/io.h>
#include <asm/core_polaris.h>
#undef __EXTERN_INLINE

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/init.h>

#include <asm/ptrace.h>

#include "proto.h"
#include "pci_impl.h"

/*
 * BIOS32-style PCI interface:
 */

#define DEBUG_CONFIG 0

#if DEBUG_CONFIG
# define DBG_CFG(args)	printk args
#else
# define DBG_CFG(args)
#endif


/*
 * Given a bus, device, and function number, compute resulting
 * configuration space address.  This is fairly straightforward
 * on POLARIS, since the chip itself generates Type 0 or Type 1
 * cycles automatically depending on the bus number (Bus 0 is
 * hardwired to Type 0, all others are Type 1.  Peer bridges
 * are not supported).
 *
 * All types:
 *
 *  3 3 3 3|3 3 3 3|3 3 2 2|2 2 2 2|2 2 2 2|1 1 1 1|1 1 1 1|1 1 
 *  9 8 7 6|5 4 3 2|1 0 9 8|7 6 5 4|3 2 1 0|9 8 7 6|5 4 3 2|1 0 9 8|7 6 5 4|3 2 1 0
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |1|1|1|1|1|0|0|1|1|1|1|1|1|1|1|0|B|B|B|B|B|B|B|B|D|D|D|D|D|F|F|F|R|R|R|R|R|R|x|x|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 *	23:16	bus number (8 bits = 128 possible buses)
 *	15:11	Device number (5 bits)
 *	10:8	function number
 *	 7:2	register number
 *  
 * Notes:
 *	The function number selects which function of a multi-function device 
 *	(e.g., scsi and ethernet).
 * 
 *	The register selects a DWORD (32 bit) register offset.  Hence it
 *	doesn't get shifted by 2 bits as we want to "drop" the bottom two
 *	bits.
 */

static int
mk_conf_addr(struct pci_bus *pbus, unsigned int device_fn, int where,
	     unsigned long *pci_addr, u8 *type1)
{
	u8 bus = pbus->number;

	*type1 = (bus == 0) ? 0 : 1;
	*pci_addr = (bus << 16) | (device_fn << 8) | (where) |
		    POLARIS_DENSE_CONFIG_BASE;

        DBG_CFG(("mk_conf_addr(bus=%d ,device_fn=0x%x, where=0x%x,"
                 " returning address 0x%p\n"
                 bus, device_fn, where, *pci_addr));

	return 0;
}

static int
polaris_read_config(struct pci_bus *bus, unsigned int devfn, int where,
		    int size, u32 *value)
{
	unsigned long addr;
	unsigned char type1;

	if (mk_conf_addr(bus, devfn, where, &addr, &type1))
                return PCIBIOS_DEVICE_NOT_FOUND;

	switch (size) {
	case 1:
		*value = __kernel_ldbu(*(vucp)addr);
		break;
	case 2:
		*value = __kernel_ldwu(*(vusp)addr);
		break;
	case 4:
		*value = *(vuip)addr;
		break;
	}

	return PCIBIOS_SUCCESSFUL;
}


static int 
polaris_write_config(struct pci_bus *bus, unsigned int devfn, int where,
		     int size, u32 value)
{
	unsigned long addr;
	unsigned char type1;

	if (mk_conf_addr(bus, devfn, where, &addr, &type1))
                return PCIBIOS_DEVICE_NOT_FOUND;

	switch (size) {
	case 1:
		__kernel_stb(value, *(vucp)addr);
		mb();
		__kernel_ldbu(*(vucp)addr);
		break;
	case 2:
		__kernel_stw(value, *(vusp)addr);
		mb();
		__kernel_ldwu(*(vusp)addr);
		break;
	case 4:
		*(vuip)addr = value;
		mb();
		*(vuip)addr;
		break;
	}

	return PCIBIOS_SUCCESSFUL;
}

struct pci_ops polaris_pci_ops = 
{
	.read =		polaris_read_config,
	.write =	polaris_write_config,
};
