arch/mips/pci/ops-pmcmsp.c

/*
 * PMC-Sierra MSP board specific pci_ops
 *
 * Copyright 2001 MontaVista Software Inc.
 * Copyright 2005-2007 PMC-Sierra, Inc
 *
 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 *
 * Much of the code is derived from the original DDB5074 port by
 * Geert Uytterhoeven <geert@linux-m68k.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.
 *
 */

#define PCI_COUNTERS	1

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/interrupt.h>

#if defined(CONFIG_PROC_FS) && defined(PCI_COUNTERS)
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#endif /* CONFIG_PROC_FS && PCI_COUNTERS */

#include <linux/kernel.h>
#include <linux/init.h>

#include <asm/byteorder.h>
#if defined(CONFIG_PMC_MSP7120_GW) || defined(CONFIG_PMC_MSP7120_EVAL)
#include <asm/mipsmtregs.h>
#endif

#include <msp_prom.h>
#include <msp_cic_int.h>
#include <msp_pci.h>
#include <msp_regs.h>
#include <msp_regops.h>

#define PCI_ACCESS_READ		0
#define PCI_ACCESS_WRITE	1

#if defined(CONFIG_PROC_FS) && defined(PCI_COUNTERS)
static char proc_init;
extern struct proc_dir_entry *proc_bus_pci_dir;
unsigned int pci_int_count[32];

static void pci_proc_init(void);

/*****************************************************************************
 *
 *  FUNCTION: show_msp_pci_counts
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Prints the count of how many times each PCI
 *		 interrupt has asserted. Can be invoked by the
 *		 /proc filesystem.
 *
 *  INPUTS:	 m	 - synthetic file construction data
 *		 v	 - iterator
 *
 *  RETURNS:	 0 or error
 *
 ****************************************************************************/
static int show_msp_pci_counts(struct seq_file *m, void *v)
{
	int i;
	unsigned int intcount, total = 0;

	for (i = 0; i < 32; ++i) {
		intcount = pci_int_count[i];
		if (intcount != 0) {
			seq_printf(m, "[%d] = %u\n", i, intcount);
			total += intcount;
		}
	}

	seq_printf(m, "total = %u\n", total);
	return 0;
}

static int msp_pci_rd_cnt_open(struct inode *inode, struct file *file)
{
	return single_open(file, show_msp_pci_counts, NULL);
}

static const struct file_operations msp_pci_rd_cnt_fops = {
	.open		= msp_pci_rd_cnt_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

/*****************************************************************************
 *
 *  FUNCTION: gen_pci_cfg_wr_show
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Generates a configuration write cycle for debug purposes.
 *		 The IDSEL line asserted and location and data written are
 *		 immaterial. Just want to be able to prove that a
 *		 configuration write can be correctly generated on the
 *		 PCI bus.  Intent is that this function by invocable from
 *		 the /proc filesystem.
 *
 *  INPUTS:	 m	 - synthetic file construction data
 *		 v	 - iterator
 *
 *  RETURNS:	 0 or error
 *
 ****************************************************************************/
static int gen_pci_cfg_wr_show(struct seq_file *m, void *v)
{
	unsigned char where = 0; /* Write to static Device/Vendor ID */
	unsigned char bus_num = 0; /* Bus 0 */
	unsigned char dev_fn = 0xF; /* Arbitrary device number */
	u32 wr_data = 0xFF00AA00; /* Arbitrary data */
	struct msp_pci_regs *preg = (void *)PCI_BASE_REG;
	unsigned long value;
	int intr;

	seq_puts(m, "PMC MSP PCI: Beginning\n");

	if (proc_init == 0) {
		pci_proc_init();
		proc_init = ~0;
	}

	seq_puts(m, "PMC MSP PCI: Before Cfg Wr\n");

	/*
	 * Generate PCI Configuration Write Cycle
	 */

	/* Clear cause register bits */
	preg->if_status = ~(BPCI_IFSTATUS_BC0F | BPCI_IFSTATUS_BC1F);

	/* Setup address that is to appear on PCI bus */
	preg->config_addr = BPCI_CFGADDR_ENABLE |
		(bus_num << BPCI_CFGADDR_BUSNUM_SHF) |
		(dev_fn << BPCI_CFGADDR_FUNCTNUM_SHF) |
		(where & 0xFC);

	value = cpu_to_le32(wr_data);

	/* Launch the PCI configuration write cycle */
	*PCI_CONFIG_SPACE_REG = value;

	/*
	 * Check if the PCI configuration cycle (rd or wr) succeeded, by
	 * checking the status bits for errors like master or target abort.
	 */
	intr = preg->if_status;

	seq_puts(m, "PMC MSP PCI: After Cfg Wr\n");
	return 0;
}

static int gen_pci_cfg_wr_open(struct inode *inode, struct file *file)
{
	return single_open(file, gen_pci_cfg_wr_show, NULL);
}

static const struct file_operations gen_pci_cfg_wr_fops = {
	.open		= gen_pci_cfg_wr_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

/*****************************************************************************
 *
 *  FUNCTION: pci_proc_init
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Create entries in the /proc filesystem for debug access.
 *
 *  INPUTS:	 none
 *
 *  OUTPUTS:	 none
 *
 *  RETURNS:	 none
 *
 ****************************************************************************/
static void pci_proc_init(void)
{
	proc_create("pmc_msp_pci_rd_cnt", 0, NULL, &msp_pci_rd_cnt_fops);
	proc_create("pmc_msp_pci_cfg_wr", 0, NULL, &gen_pci_cfg_wr_fops);
}
#endif /* CONFIG_PROC_FS && PCI_COUNTERS */

static DEFINE_SPINLOCK(bpci_lock);

/*****************************************************************************
 *
 *  STRUCT: pci_io_resource
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Defines the address range that pciauto() will use to
 *		 assign to the I/O BARs of PCI devices.
 *
 *		 Use the start and end addresses of the MSP7120 PCI Host
 *		 Controller I/O space, in the form that they appear on the
 *		 PCI bus AFTER MSP7120 has performed address translation.
 *
 *		 For I/O accesses, MSP7120 ignores OATRAN and maps I/O
 *		 accesses into the bottom 0xFFF region of address space,
 *		 so that is the range to put into the pci_io_resource
 *		 struct.
 *
 *		 In MSP4200, the start address was 0x04 instead of the
 *		 expected 0x00. Will just assume there was a good reason
 *		 for this!
 *
 *  NOTES:	 Linux, by default, will assign I/O space to the lowest
 *		 region of address space. Since MSP7120 and Linux,
 *		 by default, have no offset in between how they map, the
 *		 io_offset element of pci_controller struct should be set
 *		 to zero.
 *  ELEMENTS:
 *    name	 - String used for a meaningful name.
 *
 *    start	 - Start address of MSP7120's I/O space, as MSP7120 presents
 *		   the address on the PCI bus.
 *
 *    end	 - End address of MSP7120's I/O space, as MSP7120 presents
 *		   the address on the PCI bus.
 *
 *    flags	 - Attributes indicating the type of resource. In this case,
 *		   indicate I/O space.
 *
 ****************************************************************************/
static struct resource pci_io_resource = {
	.name	= "pci IO space",
	.start	= 0x04,
	.end	= 0x0FFF,
	.flags	= IORESOURCE_IO /* I/O space */
};

/*****************************************************************************
 *
 *  STRUCT: pci_mem_resource
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Defines the address range that pciauto() will use to
 *		 assign to the memory BARs of PCI devices.
 *
 *		 The .start and .end values are dependent upon how address
 *		 translation is performed by the OATRAN regiser.
 *
 *		 The values to use for .start and .end are the values
 *		 in the form they appear on the PCI bus AFTER MSP7120 has
 *		 performed OATRAN address translation.
 *
 *  ELEMENTS:
 *    name	 - String used for a meaningful name.
 *
 *    start	 - Start address of MSP7120's memory space, as MSP7120 presents
 *		   the address on the PCI bus.
 *
 *    end	 - End address of MSP7120's memory space, as MSP7120 presents
 *		   the address on the PCI bus.
 *
 *    flags	 - Attributes indicating the type of resource. In this case,
 *		   indicate memory space.
 *
 ****************************************************************************/
static struct resource pci_mem_resource = {
	.name	= "pci memory space",
	.start	= MSP_PCI_SPACE_BASE,
	.end	= MSP_PCI_SPACE_END,
	.flags	= IORESOURCE_MEM	 /* memory space */
};

/*****************************************************************************
 *
 *  FUNCTION: bpci_interrupt
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: PCI status interrupt handler. Updates the count of how
 *		 many times each status bit has been set, then clears
 *		 the status bits. If the appropriate macros are defined,
 *		 these counts can be viewed via the /proc filesystem.
 *
 *  INPUTS:	 irq	 - unused
 *		 dev_id	 - unused
 *		 pt_regs - unused
 *
 *  OUTPUTS:	 none
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL  - success
 *
 ****************************************************************************/
static irqreturn_t bpci_interrupt(int irq, void *dev_id)
{
	struct msp_pci_regs *preg = (void *)PCI_BASE_REG;
	unsigned int stat = preg->if_status;

#if defined(CONFIG_PROC_FS) && defined(PCI_COUNTERS)
	int i;
	for (i = 0; i < 32; ++i) {
		if ((1 << i) & stat)
			++pci_int_count[i];
	}
#endif /* PROC_FS && PCI_COUNTERS */

	/* printk("PCI ISR: Status=%08X\n", stat); */

	/* write to clear all asserted interrupts */
	preg->if_status = stat;

	return IRQ_HANDLED;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_config_access
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Performs a PCI configuration access (rd or wr), then
 *		 checks that the access succeeded by querying MSP7120's
 *		 PCI status bits.
 *
 *  INPUTS:
 *		 access_type  - kind of PCI configuration cycle to perform
 *				(read or write). Legal values are
 *				PCI_ACCESS_WRITE and PCI_ACCESS_READ.
 *
 *		 bus	      - pointer to the bus number of the device to
 *				be targeted for the configuration cycle.
 *				The only element of the pci_bus structure
 *				used is bus->number. This argument determines
 *				if the configuration access will be Type 0 or
 *				Type 1. Since MSP7120 assumes itself to be the
 *				PCI Host, any non-zero bus->number generates
 *				a Type 1 access.
 *
 *		 devfn	      - this is an 8-bit field. The lower three bits
 *				specify the function number of the device to
 *				be targeted for the configuration cycle, with
 *				all three-bit combinations being legal. The
 *				upper five bits specify the device number,
 *				with legal values being 10 to 31.
 *
 *		 where	      - address within the Configuration Header
 *				space to access.
 *
 *		 data	      - for write accesses, contains the data to
 *				write.
 *
 *  OUTPUTS:
 *		 data	      - for read accesses, contains the value read.
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL  - success
 *		 -1		     - access failure
 *
 ****************************************************************************/
int msp_pcibios_config_access(unsigned char access_type,
				struct pci_bus *bus,
				unsigned int devfn,
				unsigned char where,
				u32 *data)
{
	struct msp_pci_regs *preg = (void *)PCI_BASE_REG;
	unsigned char bus_num = bus->number;
	unsigned char dev_fn = (unsigned char)devfn;
	unsigned long flags;
	unsigned long intr;
	unsigned long value;
	static char pciirqflag;
	int ret;
#if defined(CONFIG_PMC_MSP7120_GW) || defined(CONFIG_PMC_MSP7120_EVAL)
	unsigned int	vpe_status;
#endif

#if defined(CONFIG_PROC_FS) && defined(PCI_COUNTERS)
	if (proc_init == 0) {
		pci_proc_init();
		proc_init = ~0;
	}
#endif /* CONFIG_PROC_FS && PCI_COUNTERS */

	/*
	 * Just the first time this function invokes, allocate
	 * an interrupt line for PCI host status interrupts. The
	 * allocation assigns an interrupt handler to the interrupt.
	 */
	if (pciirqflag == 0) {
		ret = request_irq(MSP_INT_PCI,/* Hardcoded internal MSP7120 wiring */
				bpci_interrupt,
				IRQF_SHARED,
				"PMC MSP PCI Host",
				preg);
		if (ret != 0)
			return ret;
		pciirqflag = ~0;
	}

#if defined(CONFIG_PMC_MSP7120_GW) || defined(CONFIG_PMC_MSP7120_EVAL)
	local_irq_save(flags);
	vpe_status = dvpe();
#else
	spin_lock_irqsave(&bpci_lock, flags);
#endif

	/*
	 * Clear PCI cause register bits.
	 *
	 * In Polo, the PCI Host had a dedicated DMA called the
	 * Block Copy (not to be confused with the general purpose Block
	 * Copy Engine block). There appear to have been special interrupts
	 * for this Block Copy, called Block Copy 0 Fault (BC0F) and
	 * Block Copy 1 Fault (BC1F). MSP4200 and MSP7120 don't have this
	 * dedicated Block Copy block, so these two interrupts are now
	 * marked reserved. In case the	 Block Copy is resurrected in a
	 * future design, maintain the code that treats these two interrupts
	 * specially.
	 *
	 * Write to clear all interrupts in the PCI status register, aside
	 * from BC0F and BC1F.
	 */
	preg->if_status = ~(BPCI_IFSTATUS_BC0F | BPCI_IFSTATUS_BC1F);

	/* Setup address that is to appear on PCI bus */
	preg->config_addr = BPCI_CFGADDR_ENABLE |
		(bus_num << BPCI_CFGADDR_BUSNUM_SHF) |
		(dev_fn << BPCI_CFGADDR_FUNCTNUM_SHF) |
		(where & 0xFC);

	/* IF access is a PCI configuration write */
	if (access_type == PCI_ACCESS_WRITE) {
		value = cpu_to_le32(*data);
		*PCI_CONFIG_SPACE_REG = value;
	} else {
		/* ELSE access is a PCI configuration read */
		value = le32_to_cpu(*PCI_CONFIG_SPACE_REG);
		*data = value;
	}

	/*
	 * Check if the PCI configuration cycle (rd or wr) succeeded, by
	 * checking the status bits for errors like master or target abort.
	 */
	intr = preg->if_status;

	/* Clear config access */
	preg->config_addr = 0;

	/* IF error occurred */
	if (intr & ~(BPCI_IFSTATUS_BC0F | BPCI_IFSTATUS_BC1F)) {
		/* Clear status bits */
		preg->if_status = ~(BPCI_IFSTATUS_BC0F | BPCI_IFSTATUS_BC1F);

#if defined(CONFIG_PMC_MSP7120_GW) || defined(CONFIG_PMC_MSP7120_EVAL)
		evpe(vpe_status);
		local_irq_restore(flags);
#else
		spin_unlock_irqrestore(&bpci_lock, flags);
#endif

		return -1;
	}

#if defined(CONFIG_PMC_MSP7120_GW) || defined(CONFIG_PMC_MSP7120_EVAL)
	evpe(vpe_status);
	local_irq_restore(flags);
#else
	spin_unlock_irqrestore(&bpci_lock, flags);
#endif

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_read_config_byte
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Read a byte from PCI configuration address spac
 *		 Since the hardware can't address 8 bit chunks
 *		 directly, read a 32-bit chunk, then mask off extraneous
 *		 bits.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the read is destined for.
 *		 devfn	- device/function combination that the read is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *
 *  OUTPUTS	 val	- read data
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL  - success
 *		 -1		     - read access failure
 *
 ****************************************************************************/
static int
msp_pcibios_read_config_byte(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u32 *val)
{
	u32 data = 0;

	/*
	 * If the config access did not complete normally (e.g., underwent
	 * master abort) do the PCI compliant thing, which is to supply an
	 * all ones value.
	 */
	if (msp_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data)) {
		*val = 0xFFFFFFFF;
		return -1;
	}

	*val = (data >> ((where & 3) << 3)) & 0x0ff;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_read_config_word
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Read a word (16 bits) from PCI configuration address space.
 *		 Since the hardware can't address 16 bit chunks
 *		 directly, read a 32-bit chunk, then mask off extraneous
 *		 bits.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the read is destined for.
 *		 devfn	- device/function combination that the read is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *
 *  OUTPUTS	 val	- read data
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL	      - success
 *		 PCIBIOS_BAD_REGISTER_NUMBER  - bad register address
 *		 -1			      - read access failure
 *
 ****************************************************************************/
static int
msp_pcibios_read_config_word(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u32 *val)
{
	u32 data = 0;

	/* if (where & 1) */	/* Commented out non-compliant code.
				 * Should allow word access to configuration
				 * registers, with only exception being when
				 * the word access would wrap around into
				 * the next dword.
				 */
	if ((where & 3) == 3) {
		*val = 0xFFFFFFFF;
		return PCIBIOS_BAD_REGISTER_NUMBER;
	}

	/*
	 * If the config access did not complete normally (e.g., underwent
	 * master abort) do the PCI compliant thing, which is to supply an
	 * all ones value.
	 */
	if (msp_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data)) {
		*val = 0xFFFFFFFF;
		return -1;
	}

	*val = (data >> ((where & 3) << 3)) & 0x0ffff;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_read_config_dword
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Read a double word (32 bits) from PCI configuration
 *		 address space.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the read is destined for.
 *		 devfn	- device/function combination that the read is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *
 *  OUTPUTS	 val	- read data
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL	      - success
 *		 PCIBIOS_BAD_REGISTER_NUMBER  - bad register address
 *		 -1			      - read access failure
 *
 ****************************************************************************/
static int
msp_pcibios_read_config_dword(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u32 *val)
{
	u32 data = 0;

	/* Address must be dword aligned. */
	if (where & 3) {
		*val = 0xFFFFFFFF;
		return PCIBIOS_BAD_REGISTER_NUMBER;
	}

	/*
	 * If the config access did not complete normally (e.g., underwent
	 * master abort) do the PCI compliant thing, which is to supply an
	 * all ones value.
	 */
	if (msp_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data)) {
		*val = 0xFFFFFFFF;
		return -1;
	}

	*val = data;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_write_config_byte
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Write a byte to PCI configuration address space.
 *		 Since the hardware can't address 8 bit chunks
 *		 directly, a read-modify-write is performed.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the write is destined for.
 *		 devfn	- device/function combination that the write is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *		 val	- value to write
 *
 *  OUTPUTS	 none
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL  - success
 *		 -1		     - write access failure
 *
 ****************************************************************************/
static int
msp_pcibios_write_config_byte(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u8 val)
{
	u32 data = 0;

	/* read config space */
	if (msp_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data))
		return -1;

	/* modify the byte within the dword */
	data = (data & ~(0xff << ((where & 3) << 3))) |
			(val << ((where & 3) << 3));

	/* write back the full dword */
	if (msp_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn,
					where, &data))
		return -1;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_write_config_word
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Write a word (16-bits) to PCI configuration address space.
 *		 Since the hardware can't address 16 bit chunks
 *		 directly, a read-modify-write is performed.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the write is destined for.
 *		 devfn	- device/function combination that the write is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *		 val	- value to write
 *
 *  OUTPUTS	 none
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL	      - success
 *		 PCIBIOS_BAD_REGISTER_NUMBER  - bad register address
 *		 -1			      - write access failure
 *
 ****************************************************************************/
static int
msp_pcibios_write_config_word(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u16 val)
{
	u32 data = 0;

	/* Fixed non-compliance: if (where & 1) */
	if ((where & 3) == 3)
		return PCIBIOS_BAD_REGISTER_NUMBER;

	/* read config space */
	if (msp_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
					where, &data))
		return -1;

	/* modify the word within the dword */
	data = (data & ~(0xffff << ((where & 3) << 3))) |
			(val << ((where & 3) << 3));

	/* write back the full dword */
	if (msp_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn,
					where, &data))
		return -1;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_write_config_dword
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Write a double word (32-bits) to PCI configuration address
 *		 space.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the write is destined for.
 *		 devfn	- device/function combination that the write is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *		 val	- value to write
 *
 *  OUTPUTS	 none
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL	      - success
 *		 PCIBIOS_BAD_REGISTER_NUMBER  - bad register address
 *		 -1			      - write access failure
 *
 ****************************************************************************/
static int
msp_pcibios_write_config_dword(struct pci_bus *bus,
				unsigned int devfn,
				int where,
				u32 val)
{
	/* check that address is dword aligned */
	if (where & 3)
		return PCIBIOS_BAD_REGISTER_NUMBER;

	/* perform write */
	if (msp_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn,
					where, &val))
		return -1;

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_read_config
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Interface the PCI configuration read request with
 *		 the appropriate function, based on how many bytes
 *		 the read request is.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the write is destined for.
 *		 devfn	- device/function combination that the write is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *		 size	- in units of bytes, should be 1, 2, or 4.
 *
 *  OUTPUTS	 val	- value read, with any extraneous bytes masked
 *			  to zero.
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL   - success
 *		 -1		      - failure
 *
 ****************************************************************************/
int
msp_pcibios_read_config(struct pci_bus *bus,
			unsigned int	devfn,
			int where,
			int size,
			u32 *val)
{
	if (size == 1) {
		if (msp_pcibios_read_config_byte(bus, devfn, where, val)) {
			return -1;
		}
	} else if (size == 2) {
		if (msp_pcibios_read_config_word(bus, devfn, where, val)) {
			return -1;
		}
	} else if (size == 4) {
		if (msp_pcibios_read_config_dword(bus, devfn, where, val)) {
			return -1;
		}
	} else {
		*val = 0xFFFFFFFF;
		return -1;
	}

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  FUNCTION: msp_pcibios_write_config
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Interface the PCI configuration write request with
 *		 the appropriate function, based on how many bytes
 *		 the read request is.
 *
 *  INPUTS	 bus	- structure containing attributes for the PCI bus
 *			  that the write is destined for.
 *		 devfn	- device/function combination that the write is
 *			  destined for.
 *		 where	- register within the Configuration Header space
 *			  to access.
 *		 size	- in units of bytes, should be 1, 2, or 4.
 *		 val	- value to write
 *
 *  OUTPUTS:	 none
 *
 *  RETURNS:	 PCIBIOS_SUCCESSFUL   - success
 *		 -1		      - failure
 *
 ****************************************************************************/
int
msp_pcibios_write_config(struct pci_bus *bus,
			unsigned int devfn,
			int where,
			int size,
			u32 val)
{
	if (size == 1) {
		if (msp_pcibios_write_config_byte(bus, devfn,
						where, (u8)(0xFF & val))) {
			return -1;
		}
	} else if (size == 2) {
		if (msp_pcibios_write_config_word(bus, devfn,
						where, (u16)(0xFFFF & val))) {
			return -1;
		}
	} else if (size == 4) {
		if (msp_pcibios_write_config_dword(bus, devfn, where, val)) {
			return -1;
		}
	} else {
		return -1;
	}

	return PCIBIOS_SUCCESSFUL;
}

/*****************************************************************************
 *
 *  STRUCTURE: msp_pci_ops
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: structure to abstract the hardware specific PCI
 *		 configuration accesses.
 *
 *  ELEMENTS:
 *    read	- function for Linux to generate PCI Configuration reads.
 *    write	- function for Linux to generate PCI Configuration writes.
 *
 ****************************************************************************/
struct pci_ops msp_pci_ops = {
	.read = msp_pcibios_read_config,
	.write = msp_pcibios_write_config
};

/*****************************************************************************
 *
 *  STRUCTURE: msp_pci_controller
 *  _________________________________________________________________________
 *
 *  Describes the attributes of the MSP7120 PCI Host Controller
 *
 *  ELEMENTS:
 *    pci_ops	   - abstracts the hardware specific PCI configuration
 *		     accesses.
 *
 *    mem_resource - address range pciauto() uses to assign to PCI device
 *		     memory BARs.
 *
 *    mem_offset   - offset between how MSP7120 outbound PCI memory
 *		     transaction addresses appear on the PCI bus and how Linux
 *		     wants to configure memory BARs of the PCI devices.
 *		     MSP7120 does nothing funky, so just set to zero.
 *
 *    io_resource  - address range pciauto() uses to assign to PCI device
 *		     I/O BARs.
 *
 *    io_offset	   - offset between how MSP7120 outbound PCI I/O
 *		     transaction addresses appear on the PCI bus and how
 *		     Linux defaults to configure I/O BARs of the PCI devices.
 *		     MSP7120 maps outbound I/O accesses into the bottom
 *		     bottom 4K of PCI address space (and ignores OATRAN).
 *		     Since the Linux default is to configure I/O BARs to the
 *		     bottom 4K, no special offset is needed. Just set to zero.
 *
 ****************************************************************************/
static struct pci_controller msp_pci_controller = {
	.pci_ops	= &msp_pci_ops,
	.mem_resource	= &pci_mem_resource,
	.mem_offset	= 0,
	.io_map_base	= MSP_PCI_IOSPACE_BASE,
	.io_resource	= &pci_io_resource,
	.io_offset	= 0
};

/*****************************************************************************
 *
 *  FUNCTION: msp_pci_init
 *  _________________________________________________________________________
 *
 *  DESCRIPTION: Initialize the PCI Host Controller and register it with
 *		 Linux so Linux can seize control of the PCI bus.
 *
 ****************************************************************************/
void __init msp_pci_init(void)
{
	struct msp_pci_regs *preg = (void *)PCI_BASE_REG;
	u32 id;

	/* Extract Device ID */
	id = read_reg32(PCI_JTAG_DEVID_REG, 0xFFFF) >> 12;

	/* Check if JTAG ID identifies MSP7120 */
	if (!MSP_HAS_PCI(id)) {
		printk(KERN_WARNING "PCI: No PCI; id reads as %x\n", id);
		goto no_pci;
	}

	/*
	 * Enable flushing of the PCI-SDRAM queue upon a read
	 * of the SDRAM's Memory Configuration Register.
	 */
	*(unsigned long *)QFLUSH_REG_1 = 3;

	/* Configure PCI Host Controller. */
	preg->if_status = ~0;		/* Clear cause register bits */
	preg->config_addr = 0;		/* Clear config access */
	preg->oatran	= MSP_PCI_OATRAN; /* PCI outbound addr translation */
	preg->if_mask	= 0xF8BF87C0;	/* Enable all PCI status interrupts */

	/* configure so inb(), outb(), and family are functional */
	set_io_port_base(MSP_PCI_IOSPACE_BASE);

	/* Tell Linux the details of the MSP7120 PCI Host Controller */
	register_pci_controller(&msp_pci_controller);

	return;

no_pci:
	/* Disable PCI channel */
	printk(KERN_WARNING "PCI: no host PCI bus detected\n");
}