linux/arch/mips/pci/ops-rc32434.c

/*
 *  BRIEF MODULE DESCRIPTION
 *     pci_ops for IDT EB434 board
 *
 *  Copyright 2004 IDT Inc. (rischelp@idt.com)
 *  Copyright 2006 Felix Fietkau <nbd@openwrt.org>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  You should have received a copy of the  GNU General Public License along
 *  with this program; if not, write  to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/pci.h>
#include <linux/types.h>

#include <asm/cpu.h>
#include <asm/mach-rc32434/rc32434.h>
#include <asm/mach-rc32434/pci.h>

#define PCI_ACCESS_READ  0
#define PCI_ACCESS_WRITE 1


#define PCI_CFG_SET(bus, slot, func, off) \
	(rc32434_pci->pcicfga = (0x80000000 | \
				((bus) << 16) | ((slot)<<11) | \
				((func)<<8) | (off)))

static inline int config_access(unsigned char access_type,
				struct pci_bus *bus, unsigned int devfn,
				unsigned char where, u32 *data)
{
	unsigned int slot = PCI_SLOT(devfn);
	u8 func = PCI_FUNC(devfn);

	/* Setup address */
	PCI_CFG_SET(bus->number, slot, func, where);
	rc32434_sync();

	if (access_type == PCI_ACCESS_WRITE)
		rc32434_pci->pcicfgd = *data;
	else
		*data = rc32434_pci->pcicfgd;

	rc32434_sync();

	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 read_config_byte(struct pci_bus *bus, unsigned int devfn,
			    int where, u8 *val)
{
	u32 data;
	int ret;

	ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
	*val = (data >> ((where & 3) << 3)) & 0xff;
	return ret;
}

static int read_config_word(struct pci_bus *bus, unsigned int devfn,
			    int where, u16 *val)
{
	u32 data;
	int ret;

	ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
	*val = (data >> ((where & 3) << 3)) & 0xffff;
	return ret;
}

static int read_config_dword(struct pci_bus *bus, unsigned int devfn,
			     int where, u32 *val)
{
	int ret;
	int delay = 1;

	/*
	 * Don't scan too far, else there will be errors with plugged in
	 * daughterboard (rb564).
	 */
	if (bus->number == 0 && PCI_SLOT(devfn) > 21)
		return 0;

retry:
	ret = config_access(PCI_ACCESS_READ, bus, devfn, where, val);

	/*
	 * Certain devices react delayed at device scan time, this
	 * gives them time to settle
	 */
	if (where == PCI_VENDOR_ID) {
		if (ret == 0xffffffff || ret == 0x00000000 ||
		    ret == 0x0000ffff || ret == 0xffff0000) {
			if (delay > 4)
				return 0;
			delay *= 2;
			msleep(delay);
			goto retry;
		}
	}

	return ret;
}

static int
write_config_byte(struct pci_bus *bus, unsigned int devfn, int where,
		  u8 val)
{
	u32 data = 0;

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

	data = (data & ~(0xff << ((where & 3) << 3))) |
	    (val << ((where & 3) << 3));

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

	return PCIBIOS_SUCCESSFUL;
}


static int
write_config_word(struct pci_bus *bus, unsigned int devfn, int where,
		  u16 val)
{
	u32 data = 0;

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

	data = (data & ~(0xffff << ((where & 3) << 3))) |
	    (val << ((where & 3) << 3));

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


	return PCIBIOS_SUCCESSFUL;
}


static int
write_config_dword(struct pci_bus *bus, unsigned int devfn, int where,
		   u32 val)
{
	if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &val))
		return -1;

	return PCIBIOS_SUCCESSFUL;
}

static int pci_config_read(struct pci_bus *bus, unsigned int devfn,
			   int where, int size, u32 *val)
{
	switch (size) {
	case 1:
		return read_config_byte(bus, devfn, where, (u8 *) val);
	case 2:
		return read_config_word(bus, devfn, where, (u16 *) val);
	default:
		return read_config_dword(bus, devfn, where, val);
	}
}

static int pci_config_write(struct pci_bus *bus, unsigned int devfn,
			    int where, int size, u32 val)
{
	switch (size) {
	case 1:
		return write_config_byte(bus, devfn, where, (u8) val);
	case 2:
		return write_config_word(bus, devfn, where, (u16) val);
	default:
		return write_config_dword(bus, devfn, where, val);
	}
}

struct pci_ops rc32434_pci_ops = {
	.read = pci_config_read,
	.write = pci_config_write,
};