powerpc: add support for MPIC message register API
Some MPIC implementations contain one or more blocks of message registers
that are used to send messages between cores via IPIs. A simple API has
been added to access (get/put, read, write, etc ...) these message registers.
The available message registers are initially discovered via nodes in the
device tree. A separate commit contains a binding for the message register
nodes.
Signed-off-by: Meador Inge <meador_inge@mentor.com>
Signed-off-by: Jia Hongtao <B38951@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/mpic_msgr.c b/arch/powerpc/sysdev/mpic_msgr.c
new file mode 100644
index 0000000..6e7fa38
--- /dev/null
+++ b/arch/powerpc/sysdev/mpic_msgr.c
@@ -0,0 +1,282 @@
+/*
+ * 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 MPIC_MSGR_STRIDE 0x10
+#define MPIC_MSGR_MER_OFFSET 0x100
+#define MSGR_INUSE 0
+#define MSGR_FREE 1
+
+static struct mpic_msgr **mpic_msgrs;
+static unsigned int mpic_msgr_count;
+
+static inline void _mpic_msgr_mer_write(struct mpic_msgr *msgr, u32 value)
+{
+ out_be32(msgr->mer, value);
+}
+
+static inline u32 _mpic_msgr_mer_read(struct mpic_msgr *msgr)
+{
+ return in_be32(msgr->mer);
+}
+
+static inline void _mpic_msgr_disable(struct mpic_msgr *msgr)
+{
+ u32 mer = _mpic_msgr_mer_read(msgr);
+
+ _mpic_msgr_mer_write(msgr, mer & ~(1 << msgr->num));
+}
+
+struct mpic_msgr *mpic_msgr_get(unsigned int reg_num)
+{
+ unsigned long flags;
+ struct mpic_msgr *msgr;
+
+ /* Assume busy until proven otherwise. */
+ msgr = ERR_PTR(-EBUSY);
+
+ if (reg_num >= mpic_msgr_count)
+ return ERR_PTR(-ENODEV);
+
+ raw_spin_lock_irqsave(&msgr->lock, flags);
+ if (mpic_msgrs[reg_num]->in_use == MSGR_FREE) {
+ msgr = mpic_msgrs[reg_num];
+ msgr->in_use = MSGR_INUSE;
+ }
+ raw_spin_unlock_irqrestore(&msgr->lock, flags);
+
+ return msgr;
+}
+EXPORT_SYMBOL_GPL(mpic_msgr_get);
+
+void mpic_msgr_put(struct mpic_msgr *msgr)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&msgr->lock, flags);
+ msgr->in_use = MSGR_FREE;
+ _mpic_msgr_disable(msgr);
+ raw_spin_unlock_irqrestore(&msgr->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mpic_msgr_put);
+
+void mpic_msgr_enable(struct mpic_msgr *msgr)
+{
+ unsigned long flags;
+ u32 mer;
+
+ raw_spin_lock_irqsave(&msgr->lock, flags);
+ mer = _mpic_msgr_mer_read(msgr);
+ _mpic_msgr_mer_write(msgr, mer | (1 << msgr->num));
+ raw_spin_unlock_irqrestore(&msgr->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mpic_msgr_enable);
+
+void mpic_msgr_disable(struct mpic_msgr *msgr)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&msgr->lock, flags);
+ _mpic_msgr_disable(msgr);
+ raw_spin_unlock_irqrestore(&msgr->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mpic_msgr_disable);
+
+/* 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)
+{
+ void __iomem *msgr_block_addr;
+ 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_addr = ioremap(rsrc.start, rsrc.end - rsrc.start);
+ if (!msgr_block_addr) {
+ 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->base = msgr_block_addr + i * MPIC_MSGR_STRIDE;
+ msgr->mer = msgr->base + MPIC_MSGR_MER_OFFSET;
+ msgr->in_use = MSGR_FREE;
+ msgr->num = i;
+ raw_spin_lock_init(&msgr->lock);
+
+ 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",
+ reg_number, 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);