[PATCH v3 2/2] powerpc: add support for MPIC message register API

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2011-2012, Meador Inge, Mentor Graphics 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; version 2 of the
+ * License.
+ *
+ */
+
+#ifndef _ASM_MPIC_MSGR_H
+#define _ASM_MPIC_MSGR_H
+
+#include <linux/types.h>
+
+struct mpic_msgr {
+	u32 __iomem *addr;
+	u32 __iomem *mer;
+	u32 __iomem	*msr;
+	int irq;
+	atomic_t in_use;
+	int num;
+};
+
+extern struct mpic_msgr* mpic_msgr_get(unsigned int reg_num);
+extern void mpic_msgr_put(struct mpic_msgr* msgr);
+extern void mpic_msgr_enable(struct mpic_msgr *msgr);
+extern void mpic_msgr_disable(struct mpic_msgr *msgr);
+extern void mpic_msgr_write(struct mpic_msgr *msgr, u32 message);
+extern u32 mpic_msgr_read(struct mpic_msgr *msgr);
+extern void mpic_msgr_clear(struct mpic_msgr *msgr);
+extern void mpic_msgr_set_destination(struct mpic_msgr *msgr, u32 cpu_num);
+extern int mpic_msgr_get_irq(struct mpic_msgr *msgr);
+
+#endif

@@ -78,6 +78,14 @@ config MPIC_WEIRD
 	bool
 	default n
 
+config MPIC_MSGR
+	bool "MPIC message register support"
+	depends on MPIC
+	default n
+	help
+	  Enables support for the MPIC message registers.  These
+	  registers are used for inter-processor communication.
+
 config PPC_I8259
 	bool
 	default n

@@ -3,7 +3,8 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
 ccflags-$(CONFIG_PPC64)		:= -mno-minimal-toc
 
 mpic-msi-obj-$(CONFIG_PCI_MSI)	+= mpic_msi.o mpic_u3msi.o mpic_pasemi_msi.o
-obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y)
+mpic-msgr-obj-$(CONFIG_MPIC_MSGR)	+= mpic_msgr.o
+obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
 fsl-msi-obj-$(CONFIG_PCI_MSI)	+= fsl_msi.o
 obj-$(CONFIG_PPC_MSI_BITMAP)	+= msi_bitmap.o
 

@@ -0,0 +1,279 @@
+/*
+ * Copyright 2011-2012, Meador Inge, Mentor Graphics Corporation.
+ *
+ * Some ideas based on un-pushed work done by Vivek Mahajan, Jason Jin, and
+ * Mingkai Hu from Freescale Semiconductor, Inc.
+ *
+ * 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; version 2 of the
+ * License.
+ *
+ */
+
+#include <linux/list.h>
+#include <linux/of_platform.h>
+#include <linux/errno.h>
+#include <asm/prom.h>
+#include <asm/hw_irq.h>
+#include <asm/ppc-pci.h>
+#include <asm/mpic_msgr.h>
+
+#define MPIC_MSGR_REGISTERS_PER_BLOCK 4
+#define MSGR_INUSE 0
+#define MSGR_FREE 1
+
+/* Internal structure used *only* for IO mapping register blocks. */
+struct mpic_msgr_block {
+	struct msgr {
+		u32 msgr;
+		u8 res[12];
+	} msgrs[MPIC_MSGR_REGISTERS_PER_BLOCK];
+	u8 res0[192];
+	u32 mer;
+	u8 res1[12];
+	u32 msr;
+};
+
+static struct mpic_msgr **mpic_msgrs = 0;
+static unsigned int mpic_msgr_count = 0;
+
+struct mpic_msgr* mpic_msgr_get(unsigned int reg_num)
+{
+	struct mpic_msgr* msgr;
+
+	if (reg_num >= mpic_msgr_count)
+		return ERR_PTR(-ENODEV);
+
+	msgr = mpic_msgrs[reg_num];
+
+	if (atomic_cmpxchg(&msgr->in_use, MSGR_FREE, MSGR_INUSE) == MSGR_FREE)
+		return msgr;
+
+	return ERR_PTR(-EBUSY);
+}
+EXPORT_SYMBOL(mpic_msgr_get);
+
+void mpic_msgr_put(struct mpic_msgr* msgr)
+{
+	atomic_set(&msgr->in_use, MSGR_FREE);
+}
+EXPORT_SYMBOL(mpic_msgr_put);
+
+void mpic_msgr_enable(struct mpic_msgr *msgr)
+{
+	out_be32(msgr->mer, in_be32(msgr->mer) | (1 << msgr->num));
+}
+EXPORT_SYMBOL(mpic_msgr_enable);
+
+void mpic_msgr_disable(struct mpic_msgr *msgr)
+{
+	out_be32(msgr->mer, in_be32(msgr->mer) & ~(1 << msgr->num));
+}
+EXPORT_SYMBOL(mpic_msgr_disable);
+
+void mpic_msgr_write(struct mpic_msgr *msgr, u32 message)
+{
+	out_be32(msgr->addr, message);
+}
+EXPORT_SYMBOL(mpic_msgr_write);
+
+u32 mpic_msgr_read(struct mpic_msgr *msgr)
+{
+	return in_be32(msgr->addr);
+}
+EXPORT_SYMBOL(mpic_msgr_read);
+
+void mpic_msgr_clear(struct mpic_msgr *msgr)
+{
+	(void) mpic_msgr_read(msgr);
+}
+EXPORT_SYMBOL(mpic_msgr_clear);
+
+void mpic_msgr_set_destination(struct mpic_msgr *msgr, u32 cpu_num)
+{
+	out_be32(msgr->addr, 1 << cpu_num);
+}
+EXPORT_SYMBOL(mpic_msgr_set_destination);
+
+int mpic_msgr_get_irq(struct mpic_msgr *msgr)
+{
+	return msgr->irq;
+}
+EXPORT_SYMBOL(mpic_msgr_get_irq);
+
+/* The following three functions are used to compute the order and number of
+ * the message register blocks.  They are clearly very inefficent.  However,
+ * they are called *only* a few times during device initialization.
+ */
+static unsigned int mpic_msgr_number_of_blocks(void)
+{
+	unsigned int count;
+	struct device_node *aliases;
+
+	count = 0;
+	aliases = of_find_node_by_name(NULL, "aliases");
+
+	if (aliases) {
+		char buf[32];
+
+		for (;;) {
+			snprintf(buf, sizeof(buf), "mpic-msgr-block%d", count);
+			if (!of_find_property(aliases, buf, NULL))
+				break;
+
+			count += 1;
+		}
+	}
+
+	return count;
+}
+
+static unsigned int mpic_msgr_number_of_registers(void)
+{
+	return mpic_msgr_number_of_blocks() * MPIC_MSGR_REGISTERS_PER_BLOCK;
+}
+
+static int mpic_msgr_block_number(struct device_node *node)
+{
+	struct device_node *aliases;
+	unsigned int index, number_of_blocks;
+	char buf[64];
+
+	number_of_blocks = mpic_msgr_number_of_blocks();
+	aliases = of_find_node_by_name(NULL, "aliases");
+	if (!aliases)
+		return -1;
+
+	for (index = 0; index < number_of_blocks; ++index) {
+		struct property *prop;
+
+		snprintf(buf, sizeof(buf), "mpic-msgr-block%d", index);
+		prop = of_find_property(aliases, buf, NULL);
+		if (node == of_find_node_by_path(prop->value))
+			break;
+	}
+
+	return index == number_of_blocks ? -1 : index;
+}
+
+/* The probe function for a single message register block.
+ */
+static __devinit int mpic_msgr_probe(struct platform_device *dev)
+{
+	struct mpic_msgr_block __iomem *msgr_block;
+	int block_number;
+	struct resource rsrc;
+	unsigned int i;
+	unsigned int irq_index;
+	struct device_node *np = dev->dev.of_node;
+	unsigned int receive_mask;
+	const unsigned int *prop;
+
+	if (!np) {
+		dev_err(&dev->dev, "Device OF-Node is NULL");
+		return -EFAULT;
+	}
+
+	/* Allocate the message register array upon the first device
+	 * registered.
+	 */
+	if (!mpic_msgrs) {
+		mpic_msgr_count = mpic_msgr_number_of_registers();
+		dev_info(&dev->dev, "Found %d message registers\n", mpic_msgr_count);
+
+		mpic_msgrs = kzalloc(sizeof(struct mpic_msgr) * mpic_msgr_count,
+							 GFP_KERNEL);
+		if (!mpic_msgrs) {
+			dev_err(&dev->dev, "No memory for message register blocks\n");
+			return -ENOMEM;
+		}
+	}
+	dev_info(&dev->dev, "Of-device full name %s\n", np->full_name);
+
+	/* IO map the message register block. */
+	of_address_to_resource(np, 0, &rsrc);
+	msgr_block = ioremap(rsrc.start, rsrc.end - rsrc.start);
+	if (!msgr_block) {
+		dev_err(&dev->dev, "Failed to iomap MPIC message registers");
+		return -EFAULT;
+	}
+
+	/* Ensure the block has a defined order. */
+	block_number = mpic_msgr_block_number(np);
+	if (block_number < 0) {
+		dev_err(&dev->dev, "Failed to find message register block alias\n");
+		return -ENODEV;
+	}
+	dev_info(&dev->dev, "Setting up message register block %d\n", block_number);
+
+	/* Grab the receive mask which specifies what registers can receive
+	 * interrupts.
+	 */
+	prop = of_get_property(np, "mpic-msgr-receive-mask", NULL);
+	receive_mask = (prop) ? *prop : 0xF;
+
+	/* Build up the appropriate message register data structures. */
+	for (i = 0, irq_index = 0; i < MPIC_MSGR_REGISTERS_PER_BLOCK; ++i) {
+		struct mpic_msgr *msgr;
+		unsigned int reg_number;
+
+		msgr = kzalloc(sizeof(struct mpic_msgr), GFP_KERNEL);
+		if (!msgr) {
+			dev_err(&dev->dev, "No memory for message register\n");
+			return -ENOMEM;
+		}
+
+		reg_number = block_number * MPIC_MSGR_REGISTERS_PER_BLOCK + i;
+		msgr->addr = &msgr_block->msgrs[i].msgr;
+		msgr->mer = &msgr_block->mer;
+		msgr->msr = &msgr_block->msr;
+		atomic_set(&msgr->in_use, MSGR_FREE);
+		msgr->num = reg_number;
+
+		if (receive_mask & (1 << i)) {
+			struct resource irq;
+
+			if (of_irq_to_resource(np, irq_index, &irq) == NO_IRQ) {
+				dev_err(&dev->dev, "Missing interrupt specifier");
+				kfree(msgr);
+				return -EFAULT;
+			}
+			msgr->irq = irq.start;
+			irq_index += 1;
+		} else {
+			msgr->irq = NO_IRQ;
+		}
+
+		mpic_msgrs[reg_number] = msgr;
+		mpic_msgr_disable(msgr);
+		dev_info(&dev->dev, "Register %d initialized: irq %d\n",
+				 msgr->num, msgr->irq);
+	
+	}
+
+	return 0;
+}
+
+static const struct of_device_id mpic_msgr_ids[] = {
+	{
+		.compatible = "fsl,mpic-v3.1-msgr",
+		.data = NULL,
+	},
+	{}
+};
+
+static struct platform_driver mpic_msgr_driver = {
+	.driver = {
+		.name = "mpic-msgr",
+		.owner = THIS_MODULE,
+		.of_match_table = mpic_msgr_ids,
+	},
+	.probe = mpic_msgr_probe,
+};
+
+static __init int mpic_msgr_init(void)
+{
+	return platform_driver_register(&mpic_msgr_driver);
+}
+subsys_initcall(mpic_msgr_init);