1 files changed, 480 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
new file mode 100644
index 000000000..5b012abca
--- /dev/null
+++ b/arch/powerpc/platforms/cell/axon_msi.c
@@ -0,0 +1,480 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2007, Michael Ellerman, IBM Corporation.
+ */
+
+
+#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/slab.h>
+#include <linux/debugfs.h>
+#include <linux/of_irq.h>
+
+#include <asm/dcr.h>
+#include <asm/machdep.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(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 %pOF\n",
+			dn);
+		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;
+	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;
+	}
+
+	for (; dn; dn = of_get_next_parent(dn)) {
+		if (!dev->no_64bit_msi) {
+			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");
+		of_node_put(dn);
+		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;
+
+	msi_for_each_desc(entry, &dev->dev, MSI_DESC_NOTASSOCIATED) {
+		virq = irq_create_direct_mapping(msic->irq_domain);
+		if (!virq) {
+			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");
+
+	msi_for_each_desc(entry, &dev->dev, MSI_DESC_ASSOCIATED) {
+		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 %pOF\n",
+		 irq_domain_get_of_node(msic->irq_domain));
+	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 %pOF\n", dn);
+
+	msic = kzalloc(sizeof(*msic), GFP_KERNEL);
+	if (!msic) {
+		printk(KERN_ERR "axon_msi: couldn't allocate msic for %pOF\n",
+		       dn);
+		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 %pOF\n",
+			dn);
+		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 %pOF\n",
+		       dn);
+		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 %pOF\n",
+		       dn);
+		goto out_free_msic;
+	}
+
+	virq = irq_of_parse_and_map(dn, 0);
+	if (!virq) {
+		printk(KERN_ERR "axon_msi: irq parse and map failed for %pOF\n",
+		       dn);
+		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 %pOF\n",
+		       dn);
+		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 %pOF\n", dn);
+
+	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));
+
+	debugfs_create_file(name, 0600, arch_debugfs_dir, msic, &fops_msic);
+}
+#endif /* DEBUG */