arch/powerpc/platforms/cell/axon_msi.c - linux - Git at Google

 /*
  * Copyright 2007, Michael Ellerman, IBM Corporation.
  *
  * 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.
  */


 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/msi.h>
 #include <linux/export.h>
 #include <linux/of_platform.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>

 #include <asm/dcr.h>
 #include <asm/machdep.h>
 #include <asm/prom.h>

 #include "cell.h"

 /*
  * MSIC registers, specified as offsets from dcr_base
  */
 #define MSIC_CTRL_REG	0x0

 /* Base Address registers specify FIFO location in BE memory */
 #define MSIC_BASE_ADDR_HI_REG	0x3
 #define MSIC_BASE_ADDR_LO_REG	0x4

 /* Hold the read/write offsets into the FIFO */
 #define MSIC_READ_OFFSET_REG	0x5
 #define MSIC_WRITE_OFFSET_REG	0x6


 /* MSIC control register flags */
 #define MSIC_CTRL_ENABLE		0x0001
 #define MSIC_CTRL_FIFO_FULL_ENABLE	0x0002
 #define MSIC_CTRL_IRQ_ENABLE		0x0008
 #define MSIC_CTRL_FULL_STOP_ENABLE	0x0010

 /*
  * The MSIC can be configured to use a FIFO of 32KB, 64KB, 128KB or 256KB.
  * Currently we're using a 64KB FIFO size.
  */
 #define MSIC_FIFO_SIZE_SHIFT	16
 #define MSIC_FIFO_SIZE_BYTES	(1 << MSIC_FIFO_SIZE_SHIFT)

 /*
  * To configure the FIFO size as (1 << n) bytes, we write (n - 15) into bits
  * 8-9 of the MSIC control reg.
  */
 #define MSIC_CTRL_FIFO_SIZE	(((MSIC_FIFO_SIZE_SHIFT - 15) << 8) & 0x300)

 /*
  * We need to mask the read/write offsets to make sure they stay within
  * the bounds of the FIFO. Also they should always be 16-byte aligned.
  */
 #define MSIC_FIFO_SIZE_MASK	((MSIC_FIFO_SIZE_BYTES - 1) & ~0xFu)

 /* Each entry in the FIFO is 16 bytes, the first 4 bytes hold the irq # */
 #define MSIC_FIFO_ENTRY_SIZE	0x10


 struct axon_msic {
 	struct irq_domain *irq_domain;
 	__le32 *fifo_virt;
 	dma_addr_t fifo_phys;
 	dcr_host_t dcr_host;
 	u32 read_offset;
 #ifdef DEBUG
 	u32 __iomem *trigger;
 #endif
 };

 #ifdef DEBUG
 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic);
 #else
 static inline void axon_msi_debug_setup(struct device_node *dn,
 					struct axon_msic *msic) { }
 #endif


 static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)
 {
 	pr_devel("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);

 	dcr_write(msic->dcr_host, dcr_n, val);
 }

 static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc)
 {
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct axon_msic *msic = irq_desc_get_handler_data(desc);
 	u32 write_offset, msi;
 	int idx;
 	int retry = 0;

 	write_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG);
 	pr_devel("axon_msi: original write_offset 0x%x\n", write_offset);

 	/* write_offset doesn't wrap properly, so we have to mask it */
 	write_offset &= MSIC_FIFO_SIZE_MASK;

 	while (msic->read_offset != write_offset && retry < 100) {
 		idx  = msic->read_offset / sizeof(__le32);
 		msi  = le32_to_cpu(msic->fifo_virt[idx]);
 		msi &= 0xFFFF;

 		pr_devel("axon_msi: woff %x roff %x msi %x\n",
 			  write_offset, msic->read_offset, msi);

 		if (msi < nr_irqs && irq_get_chip_data(msi) == msic) {
 			generic_handle_irq(msi);
 			msic->fifo_virt[idx] = cpu_to_le32(0xffffffff);
 		} else {
 			/*
 			 * Reading the MSIC_WRITE_OFFSET_REG does not
 			 * reliably flush the outstanding DMA to the
 			 * FIFO buffer. Here we were reading stale
 			 * data, so we need to retry.
 			 */
 			udelay(1);
 			retry++;
 			pr_devel("axon_msi: invalid irq 0x%x!\n", msi);
 			continue;
 		}

 		if (retry) {
 			pr_devel("axon_msi: late irq 0x%x, retry %d\n",
 				 msi, retry);
 			retry = 0;
 		}

 		msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
 		msic->read_offset &= MSIC_FIFO_SIZE_MASK;
 	}

 	if (retry) {
 		printk(KERN_WARNING "axon_msi: irq timed out\n");

 		msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
 		msic->read_offset &= MSIC_FIFO_SIZE_MASK;
 	}

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

 static struct axon_msic *find_msi_translator(struct pci_dev *dev)
 {
 	struct irq_domain *irq_domain;
 	struct device_node *dn, *tmp;
 	const phandle *ph;
 	struct axon_msic *msic = NULL;

 	dn = of_node_get(pci_device_to_OF_node(dev));
 	if (!dn) {
 		dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
 		return NULL;
 	}

 	for (; dn; dn = of_get_next_parent(dn)) {
 		ph = of_get_property(dn, "msi-translator", NULL);
 		if (ph)
 			break;
 	}

 	if (!ph) {
 		dev_dbg(&dev->dev,
 			"axon_msi: no msi-translator property found\n");
 		goto out_error;
 	}

 	tmp = dn;
 	dn = of_find_node_by_phandle(*ph);
 	of_node_put(tmp);
 	if (!dn) {
 		dev_dbg(&dev->dev,
 			"axon_msi: msi-translator doesn't point to a node\n");
 		goto out_error;
 	}

 	irq_domain = irq_find_host(dn);
 	if (!irq_domain) {
 		dev_dbg(&dev->dev, "axon_msi: no irq_domain found for node %s\n",
 			dn->full_name);
 		goto out_error;
 	}

 	msic = irq_domain->host_data;

 out_error:
 	of_node_put(dn);

 	return msic;
 }

 static int setup_msi_msg_address(struct pci_dev *dev, struct msi_msg *msg)
 {
 	struct device_node *dn;
 	struct msi_desc *entry;
 	int len;
 	const u32 *prop;

 	dn = of_node_get(pci_device_to_OF_node(dev));
 	if (!dn) {
 		dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
 		return -ENODEV;
 	}

 	entry = list_first_entry(&dev->msi_list, struct msi_desc, list);

 	for (; dn; dn = of_get_next_parent(dn)) {
 		if (entry->msi_attrib.is_64) {
 			prop = of_get_property(dn, "msi-address-64", &len);
 			if (prop)
 				break;
 		}

 		prop = of_get_property(dn, "msi-address-32", &len);
 		if (prop)
 			break;
 	}

 	if (!prop) {
 		dev_dbg(&dev->dev,
 			"axon_msi: no msi-address-(32|64) properties found\n");
 		return -ENOENT;
 	}

 	switch (len) {
 	case 8:
 		msg->address_hi = prop[0];
 		msg->address_lo = prop[1];
 		break;
 	case 4:
 		msg->address_hi = 0;
 		msg->address_lo = prop[0];
 		break;
 	default:
 		dev_dbg(&dev->dev,
 			"axon_msi: malformed msi-address-(32|64) property\n");
 		of_node_put(dn);
 		return -EINVAL;
 	}

 	of_node_put(dn);

 	return 0;
 }

 static int axon_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 {
 	unsigned int virq, rc;
 	struct msi_desc *entry;
 	struct msi_msg msg;
 	struct axon_msic *msic;

 	msic = find_msi_translator(dev);
 	if (!msic)
 		return -ENODEV;

 	rc = setup_msi_msg_address(dev, &msg);
 	if (rc)
 		return rc;

 	list_for_each_entry(entry, &dev->msi_list, list) {
 		virq = irq_create_direct_mapping(msic->irq_domain);
 		if (virq == NO_IRQ) {
 			dev_warn(&dev->dev,
 				 "axon_msi: virq allocation failed!\n");
 			return -1;
 		}
 		dev_dbg(&dev->dev, "axon_msi: allocated virq 0x%x\n", virq);

 		irq_set_msi_desc(virq, entry);
 		msg.data = virq;
 		pci_write_msi_msg(virq, &msg);
 	}

 	return 0;
 }

 static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
 {
 	struct msi_desc *entry;

 	dev_dbg(&dev->dev, "axon_msi: tearing down msi irqs\n");

 	list_for_each_entry(entry, &dev->msi_list, list) {
 		if (entry->irq == NO_IRQ)
 			continue;

 		irq_set_msi_desc(entry->irq, NULL);
 		irq_dispose_mapping(entry->irq);
 	}
 }

 static struct irq_chip msic_irq_chip = {
 	.irq_mask	= pci_msi_mask_irq,
 	.irq_unmask	= pci_msi_unmask_irq,
 	.irq_shutdown	= pci_msi_mask_irq,
 	.name		= "AXON-MSI",
 };

 static int msic_host_map(struct irq_domain *h, unsigned int virq,
 			 irq_hw_number_t hw)
 {
 	irq_set_chip_data(virq, h->host_data);
 	irq_set_chip_and_handler(virq, &msic_irq_chip, handle_simple_irq);

 	return 0;
 }

 static const struct irq_domain_ops msic_host_ops = {
 	.map	= msic_host_map,
 };

 static void axon_msi_shutdown(struct platform_device *device)
 {
 	struct axon_msic *msic = dev_get_drvdata(&device->dev);
 	u32 tmp;

 	pr_devel("axon_msi: disabling %s\n",
 		  msic->irq_domain->of_node->full_name);
 	tmp  = dcr_read(msic->dcr_host, MSIC_CTRL_REG);
 	tmp &= ~MSIC_CTRL_ENABLE & ~MSIC_CTRL_IRQ_ENABLE;
 	msic_dcr_write(msic, MSIC_CTRL_REG, tmp);
 }

 static int axon_msi_probe(struct platform_device *device)
 {
 	struct device_node *dn = device->dev.of_node;
 	struct axon_msic *msic;
 	unsigned int virq;
 	int dcr_base, dcr_len;

 	pr_devel("axon_msi: setting up dn %s\n", dn->full_name);

 	msic = kzalloc(sizeof(struct axon_msic), GFP_KERNEL);
 	if (!msic) {
 		printk(KERN_ERR "axon_msi: couldn't allocate msic for %s\n",
 		       dn->full_name);
 		goto out;
 	}

 	dcr_base = dcr_resource_start(dn, 0);
 	dcr_len = dcr_resource_len(dn, 0);

 	if (dcr_base == 0 || dcr_len == 0) {
 		printk(KERN_ERR
 		       "axon_msi: couldn't parse dcr properties on %s\n",
 			dn->full_name);
 		goto out_free_msic;
 	}

 	msic->dcr_host = dcr_map(dn, dcr_base, dcr_len);
 	if (!DCR_MAP_OK(msic->dcr_host)) {
 		printk(KERN_ERR "axon_msi: dcr_map failed for %s\n",
 		       dn->full_name);
 		goto out_free_msic;
 	}

 	msic->fifo_virt = dma_alloc_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES,
 					     &msic->fifo_phys, GFP_KERNEL);
 	if (!msic->fifo_virt) {
 		printk(KERN_ERR "axon_msi: couldn't allocate fifo for %s\n",
 		       dn->full_name);
 		goto out_free_msic;
 	}

 	virq = irq_of_parse_and_map(dn, 0);
 	if (virq == NO_IRQ) {
 		printk(KERN_ERR "axon_msi: irq parse and map failed for %s\n",
 		       dn->full_name);
 		goto out_free_fifo;
 	}
 	memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);

 	/* We rely on being able to stash a virq in a u16, so limit irqs to < 65536 */
 	msic->irq_domain = irq_domain_add_nomap(dn, 65536, &msic_host_ops, msic);
 	if (!msic->irq_domain) {
 		printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %s\n",
 		       dn->full_name);
 		goto out_free_fifo;
 	}

 	irq_set_handler_data(virq, msic);
 	irq_set_chained_handler(virq, axon_msi_cascade);
 	pr_devel("axon_msi: irq 0x%x setup for axon_msi\n", virq);

 	/* Enable the MSIC hardware */
 	msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, msic->fifo_phys >> 32);
 	msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG,
 				  msic->fifo_phys & 0xFFFFFFFF);
 	msic_dcr_write(msic, MSIC_CTRL_REG,
 			MSIC_CTRL_IRQ_ENABLE | MSIC_CTRL_ENABLE |
 			MSIC_CTRL_FIFO_SIZE);

 	msic->read_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG)
 				& MSIC_FIFO_SIZE_MASK;

 	dev_set_drvdata(&device->dev, msic);

 	cell_pci_controller_ops.setup_msi_irqs = axon_msi_setup_msi_irqs;
 	cell_pci_controller_ops.teardown_msi_irqs = axon_msi_teardown_msi_irqs;

 	axon_msi_debug_setup(dn, msic);

 	printk(KERN_DEBUG "axon_msi: setup MSIC on %s\n", dn->full_name);

 	return 0;

 out_free_fifo:
 	dma_free_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, msic->fifo_virt,
 			  msic->fifo_phys);
 out_free_msic:
 	kfree(msic);
 out:

 	return -1;
 }

 static const struct of_device_id axon_msi_device_id[] = {
 	{
 		.compatible	= "ibm,axon-msic"
 	},
 	{}
 };

 static struct platform_driver axon_msi_driver = {
 	.probe		= axon_msi_probe,
 	.shutdown	= axon_msi_shutdown,
 	.driver = {
 		.name = "axon-msi",
 		.of_match_table = axon_msi_device_id,
 	},
 };

 static int __init axon_msi_init(void)
 {
 	return platform_driver_register(&axon_msi_driver);
 }
 subsys_initcall(axon_msi_init);


 #ifdef DEBUG
 static int msic_set(void *data, u64 val)
 {
 	struct axon_msic *msic = data;
 	out_le32(msic->trigger, val);
 	return 0;
 }

 static int msic_get(void *data, u64 *val)
 {
 	*val = 0;
 	return 0;
 }

 DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");

 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)
 {
 	char name[8];
 	u64 addr;

 	addr = of_translate_address(dn, of_get_property(dn, "reg", NULL));
 	if (addr == OF_BAD_ADDR) {
 		pr_devel("axon_msi: couldn't translate reg property\n");
 		return;
 	}

 	msic->trigger = ioremap(addr, 0x4);
 	if (!msic->trigger) {
 		pr_devel("axon_msi: ioremap failed\n");
 		return;
 	}

 	snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));

 	if (!debugfs_create_file(name, 0600, powerpc_debugfs_root,
 				 msic, &fops_msic)) {
 		pr_devel("axon_msi: debugfs_create_file failed!\n");
 		return;
 	}
 }
 #endif /* DEBUG */
	/*
	* Copyright 2007, Michael Ellerman, IBM Corporation.
	*
	* 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.
	*/


	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/pci.h>
	#include <linux/msi.h>
	#include <linux/export.h>
	#include <linux/of_platform.h>
	#include <linux/debugfs.h>
	#include <linux/slab.h>

	#include <asm/dcr.h>
	#include <asm/machdep.h>
	#include <asm/prom.h>

	#include "cell.h"

	/*
	* MSIC registers, specified as offsets from dcr_base
	*/
	#define MSIC_CTRL_REG 0x0

	/* Base Address registers specify FIFO location in BE memory */
	#define MSIC_BASE_ADDR_HI_REG 0x3
	#define MSIC_BASE_ADDR_LO_REG 0x4

	/* Hold the read/write offsets into the FIFO */
	#define MSIC_READ_OFFSET_REG 0x5
	#define MSIC_WRITE_OFFSET_REG 0x6


	/* MSIC control register flags */
	#define MSIC_CTRL_ENABLE 0x0001
	#define MSIC_CTRL_FIFO_FULL_ENABLE 0x0002
	#define MSIC_CTRL_IRQ_ENABLE 0x0008
	#define MSIC_CTRL_FULL_STOP_ENABLE 0x0010

	/*
	* The MSIC can be configured to use a FIFO of 32KB, 64KB, 128KB or 256KB.
	* Currently we're using a 64KB FIFO size.
	*/
	#define MSIC_FIFO_SIZE_SHIFT 16
	#define MSIC_FIFO_SIZE_BYTES (1 << MSIC_FIFO_SIZE_SHIFT)

	/*
	* To configure the FIFO size as (1 << n) bytes, we write (n - 15) into bits
	* 8-9 of the MSIC control reg.
	*/
	#define MSIC_CTRL_FIFO_SIZE (((MSIC_FIFO_SIZE_SHIFT - 15) << 8) & 0x300)

	/*
	* We need to mask the read/write offsets to make sure they stay within
	* the bounds of the FIFO. Also they should always be 16-byte aligned.
	*/
	#define MSIC_FIFO_SIZE_MASK ((MSIC_FIFO_SIZE_BYTES - 1) & ~0xFu)

	/* Each entry in the FIFO is 16 bytes, the first 4 bytes hold the irq # */
	#define MSIC_FIFO_ENTRY_SIZE 0x10


	struct axon_msic {
	struct irq_domain *irq_domain;
	__le32 *fifo_virt;
	dma_addr_t fifo_phys;
	dcr_host_t dcr_host;
	u32 read_offset;
	#ifdef DEBUG
	u32 __iomem *trigger;
	#endif
	};

	#ifdef DEBUG
	void axon_msi_debug_setup(struct device_node dn, struct axon_msic msic);
	#else
	static inline void axon_msi_debug_setup(struct device_node *dn,
	struct axon_msic *msic) { }
	#endif


	static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)
	{
	pr_devel("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);

	dcr_write(msic->dcr_host, dcr_n, val);
	}

	static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc)
	{
	struct irq_chip *chip = irq_desc_get_chip(desc);
	struct axon_msic *msic = irq_desc_get_handler_data(desc);
	u32 write_offset, msi;
	int idx;
	int retry = 0;

	write_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG);
	pr_devel("axon_msi: original write_offset 0x%x\n", write_offset);

	/* write_offset doesn't wrap properly, so we have to mask it */
	write_offset &= MSIC_FIFO_SIZE_MASK;

	while (msic->read_offset != write_offset && retry < 100) {
	idx = msic->read_offset / sizeof(__le32);
	msi = le32_to_cpu(msic->fifo_virt[idx]);
	msi &= 0xFFFF;

	pr_devel("axon_msi: woff %x roff %x msi %x\n",
	write_offset, msic->read_offset, msi);

	if (msi < nr_irqs && irq_get_chip_data(msi) == msic) {
	generic_handle_irq(msi);
	msic->fifo_virt[idx] = cpu_to_le32(0xffffffff);
	} else {
	/*
	* Reading the MSIC_WRITE_OFFSET_REG does not
	* reliably flush the outstanding DMA to the
	* FIFO buffer. Here we were reading stale
	* data, so we need to retry.
	*/
	udelay(1);
	retry++;
	pr_devel("axon_msi: invalid irq 0x%x!\n", msi);
	continue;
	}

	if (retry) {
	pr_devel("axon_msi: late irq 0x%x, retry %d\n",
	msi, retry);
	retry = 0;
	}

	msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
	msic->read_offset &= MSIC_FIFO_SIZE_MASK;
	}

	if (retry) {
	printk(KERN_WARNING "axon_msi: irq timed out\n");

	msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
	msic->read_offset &= MSIC_FIFO_SIZE_MASK;
	}

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

	static struct axon_msic find_msi_translator(struct pci_dev dev)
	{
	struct irq_domain *irq_domain;
	struct device_node dn, tmp;
	const phandle *ph;
	struct axon_msic *msic = NULL;

	dn = of_node_get(pci_device_to_OF_node(dev));
	if (!dn) {
	dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
	return NULL;
	}

	for (; dn; dn = of_get_next_parent(dn)) {
	ph = of_get_property(dn, "msi-translator", NULL);
	if (ph)
	break;
	}

	if (!ph) {
	dev_dbg(&dev->dev,
	"axon_msi: no msi-translator property found\n");
	goto out_error;
	}

	tmp = dn;
	dn = of_find_node_by_phandle(*ph);
	of_node_put(tmp);
	if (!dn) {
	dev_dbg(&dev->dev,
	"axon_msi: msi-translator doesn't point to a node\n");
	goto out_error;
	}

	irq_domain = irq_find_host(dn);
	if (!irq_domain) {
	dev_dbg(&dev->dev, "axon_msi: no irq_domain found for node %s\n",
	dn->full_name);
	goto out_error;
	}

	msic = irq_domain->host_data;

	out_error:
	of_node_put(dn);

	return msic;
	}

	static int setup_msi_msg_address(struct pci_dev dev, struct msi_msg msg)
	{
	struct device_node *dn;
	struct msi_desc *entry;
	int len;
	const u32 *prop;

	dn = of_node_get(pci_device_to_OF_node(dev));
	if (!dn) {
	dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
	return -ENODEV;
	}

	entry = list_first_entry(&dev->msi_list, struct msi_desc, list);

	for (; dn; dn = of_get_next_parent(dn)) {
	if (entry->msi_attrib.is_64) {
	prop = of_get_property(dn, "msi-address-64", &len);
	if (prop)
	break;
	}

	prop = of_get_property(dn, "msi-address-32", &len);
	if (prop)
	break;
	}

	if (!prop) {
	dev_dbg(&dev->dev,
	"axon_msi: no msi-address-(32\|64) properties found\n");
	return -ENOENT;
	}

	switch (len) {
	case 8:
	msg->address_hi = prop[0];
	msg->address_lo = prop[1];
	break;
	case 4:
	msg->address_hi = 0;
	msg->address_lo = prop[0];
	break;
	default:
	dev_dbg(&dev->dev,
	"axon_msi: malformed msi-address-(32\|64) property\n");
	of_node_put(dn);
	return -EINVAL;
	}

	of_node_put(dn);

	return 0;
	}

	static int axon_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
	{
	unsigned int virq, rc;
	struct msi_desc *entry;
	struct msi_msg msg;
	struct axon_msic *msic;

	msic = find_msi_translator(dev);
	if (!msic)
	return -ENODEV;

	rc = setup_msi_msg_address(dev, &msg);
	if (rc)
	return rc;

	list_for_each_entry(entry, &dev->msi_list, list) {
	virq = irq_create_direct_mapping(msic->irq_domain);
	if (virq == NO_IRQ) {
	dev_warn(&dev->dev,
	"axon_msi: virq allocation failed!\n");
	return -1;
	}
	dev_dbg(&dev->dev, "axon_msi: allocated virq 0x%x\n", virq);

	irq_set_msi_desc(virq, entry);
	msg.data = virq;
	pci_write_msi_msg(virq, &msg);
	}

	return 0;
	}

	static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
	{
	struct msi_desc *entry;

	dev_dbg(&dev->dev, "axon_msi: tearing down msi irqs\n");

	list_for_each_entry(entry, &dev->msi_list, list) {
	if (entry->irq == NO_IRQ)
	continue;

	irq_set_msi_desc(entry->irq, NULL);
	irq_dispose_mapping(entry->irq);
	}
	}

	static struct irq_chip msic_irq_chip = {
	.irq_mask = pci_msi_mask_irq,
	.irq_unmask = pci_msi_unmask_irq,
	.irq_shutdown = pci_msi_mask_irq,
	.name = "AXON-MSI",
	};

	static int msic_host_map(struct irq_domain *h, unsigned int virq,
	irq_hw_number_t hw)
	{
	irq_set_chip_data(virq, h->host_data);
	irq_set_chip_and_handler(virq, &msic_irq_chip, handle_simple_irq);

	return 0;
	}

	static const struct irq_domain_ops msic_host_ops = {
	.map = msic_host_map,
	};

	static void axon_msi_shutdown(struct platform_device *device)
	{
	struct axon_msic *msic = dev_get_drvdata(&device->dev);
	u32 tmp;

	pr_devel("axon_msi: disabling %s\n",
	msic->irq_domain->of_node->full_name);
	tmp = dcr_read(msic->dcr_host, MSIC_CTRL_REG);
	tmp &= ~MSIC_CTRL_ENABLE & ~MSIC_CTRL_IRQ_ENABLE;
	msic_dcr_write(msic, MSIC_CTRL_REG, tmp);
	}

	static int axon_msi_probe(struct platform_device *device)
	{
	struct device_node *dn = device->dev.of_node;
	struct axon_msic *msic;
	unsigned int virq;
	int dcr_base, dcr_len;

	pr_devel("axon_msi: setting up dn %s\n", dn->full_name);

	msic = kzalloc(sizeof(struct axon_msic), GFP_KERNEL);
	if (!msic) {
	printk(KERN_ERR "axon_msi: couldn't allocate msic for %s\n",
	dn->full_name);
	goto out;
	}

	dcr_base = dcr_resource_start(dn, 0);
	dcr_len = dcr_resource_len(dn, 0);

	if (dcr_base == 0 \|\| dcr_len == 0) {
	printk(KERN_ERR
	"axon_msi: couldn't parse dcr properties on %s\n",
	dn->full_name);
	goto out_free_msic;
	}

	msic->dcr_host = dcr_map(dn, dcr_base, dcr_len);
	if (!DCR_MAP_OK(msic->dcr_host)) {
	printk(KERN_ERR "axon_msi: dcr_map failed for %s\n",
	dn->full_name);
	goto out_free_msic;
	}

	msic->fifo_virt = dma_alloc_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES,
	&msic->fifo_phys, GFP_KERNEL);
	if (!msic->fifo_virt) {
	printk(KERN_ERR "axon_msi: couldn't allocate fifo for %s\n",
	dn->full_name);
	goto out_free_msic;
	}

	virq = irq_of_parse_and_map(dn, 0);
	if (virq == NO_IRQ) {
	printk(KERN_ERR "axon_msi: irq parse and map failed for %s\n",
	dn->full_name);
	goto out_free_fifo;
	}
	memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);

	/* We rely on being able to stash a virq in a u16, so limit irqs to < 65536 */
	msic->irq_domain = irq_domain_add_nomap(dn, 65536, &msic_host_ops, msic);
	if (!msic->irq_domain) {
	printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %s\n",
	dn->full_name);
	goto out_free_fifo;
	}

	irq_set_handler_data(virq, msic);
	irq_set_chained_handler(virq, axon_msi_cascade);
	pr_devel("axon_msi: irq 0x%x setup for axon_msi\n", virq);

	/* Enable the MSIC hardware */
	msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, msic->fifo_phys >> 32);
	msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG,
	msic->fifo_phys & 0xFFFFFFFF);
	msic_dcr_write(msic, MSIC_CTRL_REG,
	MSIC_CTRL_IRQ_ENABLE \| MSIC_CTRL_ENABLE \|
	MSIC_CTRL_FIFO_SIZE);

	msic->read_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG)
	& MSIC_FIFO_SIZE_MASK;

	dev_set_drvdata(&device->dev, msic);

	cell_pci_controller_ops.setup_msi_irqs = axon_msi_setup_msi_irqs;
	cell_pci_controller_ops.teardown_msi_irqs = axon_msi_teardown_msi_irqs;

	axon_msi_debug_setup(dn, msic);

	printk(KERN_DEBUG "axon_msi: setup MSIC on %s\n", dn->full_name);

	return 0;

	out_free_fifo:
	dma_free_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, msic->fifo_virt,
	msic->fifo_phys);
	out_free_msic:
	kfree(msic);
	out:

	return -1;
	}

	static const struct of_device_id axon_msi_device_id[] = {
	{
	.compatible = "ibm,axon-msic"
	},
	{}
	};

	static struct platform_driver axon_msi_driver = {
	.probe = axon_msi_probe,
	.shutdown = axon_msi_shutdown,
	.driver = {
	.name = "axon-msi",
	.of_match_table = axon_msi_device_id,
	},
	};

	static int __init axon_msi_init(void)
	{
	return platform_driver_register(&axon_msi_driver);
	}
	subsys_initcall(axon_msi_init);


	#ifdef DEBUG
	static int msic_set(void *data, u64 val)
	{
	struct axon_msic *msic = data;
	out_le32(msic->trigger, val);
	return 0;
	}

	static int msic_get(void data, u64 val)
	{
	*val = 0;
	return 0;
	}

	DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");

	void axon_msi_debug_setup(struct device_node dn, struct axon_msic msic)
	{
	char name[8];
	u64 addr;

	addr = of_translate_address(dn, of_get_property(dn, "reg", NULL));
	if (addr == OF_BAD_ADDR) {
	pr_devel("axon_msi: couldn't translate reg property\n");
	return;
	}

	msic->trigger = ioremap(addr, 0x4);
	if (!msic->trigger) {
	pr_devel("axon_msi: ioremap failed\n");
	return;
	}

	snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));

	if (!debugfs_create_file(name, 0600, powerpc_debugfs_root,
	msic, &fops_msic)) {
	pr_devel("axon_msi: debugfs_create_file failed!\n");
	return;
	}
	}
	#endif /* DEBUG */