[CELL] add support for MSI on Axon-based Cell systems

					   $(spu-priv1-y) \

					   $(spu-manage-y) \

					   spufs/

obj-$(CONFIG_PCI_MSI)			+= axon_msi.o

/*

 * 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/reboot.h>

#include <asm/dcr.h>

#include <asm/machdep.h>

#include <asm/prom.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 device_node *dn;

	struct irq_host *irq_host;

	__le32 *fifo;

	dcr_host_t dcr_host;

	struct list_head list;

	u32 read_offset;

	u32 dcr_base;

};

static LIST_HEAD(axon_msic_list);

static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)

{

	pr_debug("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);

	dcr_write(msic->dcr_host, msic->dcr_base + dcr_n, val);

}

static u32 msic_dcr_read(struct axon_msic *msic, unsigned int dcr_n)

{

	return dcr_read(msic->dcr_host, msic->dcr_base + dcr_n);

}

static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc)

{

	struct axon_msic *msic = get_irq_data(irq);

	u32 write_offset, msi;

	int idx;

	write_offset = msic_dcr_read(msic, MSIC_WRITE_OFFSET_REG);

	pr_debug("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) {

		idx  = msic->read_offset / sizeof(__le32);

		msi  = le32_to_cpu(msic->fifo[idx]);

		msi &= 0xFFFF;

		pr_debug("axon_msi: woff %x roff %x msi %x\n",

			  write_offset, msic->read_offset, msi);

		msic->read_offset += MSIC_FIFO_ENTRY_SIZE;

		msic->read_offset &= MSIC_FIFO_SIZE_MASK;

		if (msi < NR_IRQS && irq_map[msi].host == msic->irq_host)

			generic_handle_irq(msi);

		else

			pr_debug("axon_msi: invalid irq 0x%x!\n", msi);

	}

	desc->chip->eoi(irq);

}

static struct axon_msic *find_msi_translator(struct pci_dev *dev)

{

	struct irq_host *irq_host;

	struct device_node *dn, *tmp;

	const phandle *ph;

	struct axon_msic *msic = NULL;

	dn = pci_device_to_OF_node(dev);

	if (!dn) {

		dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");

		return NULL;

	}

	for (; dn; tmp = of_get_parent(dn), of_node_put(dn), dn = tmp) {

		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);

	if (!dn) {

		dev_dbg(&dev->dev,

			"axon_msi: msi-translator doesn't point to a node\n");

		goto out_error;

	}

	irq_host = irq_find_host(dn);

	if (!irq_host) {

		dev_dbg(&dev->dev, "axon_msi: no irq_host found for node %s\n",

			dn->full_name);

		goto out_error;

	}

	msic = irq_host->host_data;

out_error:

	of_node_put(dn);

	of_node_put(tmp);

	return msic;

}

static int axon_msi_check_device(struct pci_dev *dev, int nvec, int type)

{

	if (!find_msi_translator(dev))

		return -ENODEV;

	return 0;

}

static int setup_msi_msg_address(struct pci_dev *dev, struct msi_msg *msg)

{

	struct device_node *dn, *tmp;

	struct msi_desc *entry;

	int len;

	const u32 *prop;

	dn = 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; tmp = of_get_parent(dn), of_node_put(dn), dn = tmp) {

		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;

	/* We rely on being able to stash a virq in a u16 */

	BUILD_BUG_ON(NR_IRQS > 65536);

	list_for_each_entry(entry, &dev->msi_list, list) {

		virq = irq_create_direct_mapping(msic->irq_host);

		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);

		set_irq_msi(virq, entry);

		msg.data = virq;

		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;

		set_irq_msi(entry->irq, NULL);

		irq_dispose_mapping(entry->irq);

	}

}

static struct irq_chip msic_irq_chip = {

	.mask		= mask_msi_irq,

	.unmask		= unmask_msi_irq,

	.shutdown	= unmask_msi_irq,

	.typename	= "AXON-MSI",

};

static int msic_host_map(struct irq_host *h, unsigned int virq,

			 irq_hw_number_t hw)

{

	set_irq_chip_and_handler(virq, &msic_irq_chip, handle_simple_irq);

	return 0;

}

static int msic_host_match(struct irq_host *host, struct device_node *dn)

{

	struct axon_msic *msic = host->host_data;

	return msic->dn == dn;

}

static struct irq_host_ops msic_host_ops = {

	.match	= msic_host_match,

	.map	= msic_host_map,

};

static int axon_msi_notify_reboot(struct notifier_block *nb,

				  unsigned long code, void *data)

{

	struct axon_msic *msic;

	u32 tmp;

	list_for_each_entry(msic, &axon_msic_list, list) {

		pr_debug("axon_msi: disabling %s\n", msic->dn->full_name);

		tmp  = msic_dcr_read(msic, MSIC_CTRL_REG);

		tmp &= ~MSIC_CTRL_ENABLE & ~MSIC_CTRL_IRQ_ENABLE;

		msic_dcr_write(msic, MSIC_CTRL_REG, tmp);

	}

	return 0;

}

static struct notifier_block axon_msi_reboot_notifier = {

	.notifier_call = axon_msi_notify_reboot

};

static int axon_msi_setup_one(struct device_node *dn)

{

	struct page *page;

	struct axon_msic *msic;

	unsigned int virq;

	int dcr_len;

	pr_debug("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;

	}

	msic->dcr_base = dcr_resource_start(dn, 0);

	dcr_len = dcr_resource_len(dn, 0);

	if (msic->dcr_base == 0 || dcr_len == 0) {

		printk(KERN_ERR

		       "axon_msi: couldn't parse dcr properties on %s\n",

			dn->full_name);

		goto out;

	}

	msic->dcr_host = dcr_map(dn, msic->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;

	}

	page = alloc_pages_node(of_node_to_nid(dn), GFP_KERNEL,

				get_order(MSIC_FIFO_SIZE_BYTES));

	if (!page) {

		printk(KERN_ERR "axon_msi: couldn't allocate fifo for %s\n",

		       dn->full_name);

		goto out_free_msic;

	}

	msic->fifo = page_address(page);

	msic->irq_host = irq_alloc_host(IRQ_HOST_MAP_NOMAP, NR_IRQS,

					&msic_host_ops, 0);

	if (!msic->irq_host) {

		printk(KERN_ERR "axon_msi: couldn't allocate irq_host for %s\n",

		       dn->full_name);

		goto out_free_fifo;

	}

	msic->irq_host->host_data = 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_host;

	}

	msic->dn = of_node_get(dn);

	set_irq_data(virq, msic);

	set_irq_chained_handler(virq, axon_msi_cascade);

	pr_debug("axon_msi: irq 0x%x setup for axon_msi\n", virq);

	/* Enable the MSIC hardware */

	msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, (u64)msic->fifo >> 32);

	msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG,

				  (u64)msic->fifo & 0xFFFFFFFF);

	msic_dcr_write(msic, MSIC_CTRL_REG,

			MSIC_CTRL_IRQ_ENABLE | MSIC_CTRL_ENABLE |

			MSIC_CTRL_FIFO_SIZE);

	list_add(&msic->list, &axon_msic_list);

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

	return 0;

out_free_host:

	kfree(msic->irq_host);

out_free_fifo:

	__free_pages(virt_to_page(msic->fifo), get_order(MSIC_FIFO_SIZE_BYTES));

out_free_msic:

	kfree(msic);

out:

	return -1;

}

static int axon_msi_init(void)

{

	struct device_node *dn;

	int found = 0;

	pr_debug("axon_msi: initialising ...\n");

	for_each_compatible_node(dn, NULL, "ibm,axon-msic") {

		if (axon_msi_setup_one(dn) == 0)

			found++;

	}

	if (found) {

		ppc_md.setup_msi_irqs = axon_msi_setup_msi_irqs;

		ppc_md.teardown_msi_irqs = axon_msi_teardown_msi_irqs;

		ppc_md.msi_check_device = axon_msi_check_device;

		register_reboot_notifier(&axon_msi_reboot_notifier);

		pr_debug("axon_msi: registered callbacks!\n");

	}

	return 0;

}

arch_initcall(axon_msi_init);