[POWERPC] ps3: Add vuart support

Adds support for the PS3 virtual UART (vuart).  The vuart provides a
bi-directional byte stream data link between logical partitions.

This is needed for the ps3 graphics driver and the ps3 power
control support to be able to communicate with the lv1 policy
module.
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/configs/ps3_defconfig

@@ -157,6 +157,7 @@ CONFIG_SPU_BASE=y
 CONFIG_PS3_HTAB_SIZE=20
 CONFIG_PS3_DYNAMIC_DMA=y
 CONFIG_PS3_USE_LPAR_ADDR=y
+CONFIG_PS3_VUART=y
 
 #
 # Kernel options

arch/powerpc/platforms/ps3/Kconfig

@@ -40,4 +40,15 @@ config PS3_USE_LPAR_ADDR
 
 	  If you have any doubt, choose the default y.
 
+config PS3_VUART
+	depends on PPC_PS3
+	bool "PS3 Virtual UART support"
+	default y
+	help
+	  Include support for the PS3 Virtual UART.
+
+	  This support is required for several system services
+	  including the System Manager and AV Settings.  In
+	  general, all users will say Y.
+
 endmenu

drivers/ps3/Makefile

 obj-y += system-bus.o
+obj-$(CONFIG_PS3_VUART) += vuart.o

drivers/ps3/vuart.c

+/*
+ *  PS3 virtual uart
+ *
+ *  Copyright (C) 2006 Sony Computer Entertainment Inc.
+ *  Copyright 2006 Sony Corp.
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <asm/ps3.h>
+
+#include <asm/lv1call.h>
+#include <asm/bitops.h>
+
+#include "vuart.h"
+
+MODULE_AUTHOR("Sony Corporation");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ps3 vuart");
+
+/**
+ * vuart - An inter-partition data link service.
+ *  port 0: PS3 AV Settings.
+ *  port 2: PS3 System Manager.
+ *
+ * The vuart provides a bi-directional byte stream data link between logical
+ * partitions.  Its primary role is as a communications link between the guest
+ * OS and the system policy module.  The current HV does not support any
+ * connections other than those listed.
+ */
+
+enum {PORT_COUNT = 3,};
+
+enum vuart_param {
+	PARAM_TX_TRIGGER = 0,
+	PARAM_RX_TRIGGER = 1,
+	PARAM_INTERRUPT_MASK = 2,
+	PARAM_RX_BUF_SIZE = 3, /* read only */
+	PARAM_RX_BYTES = 4, /* read only */
+	PARAM_TX_BUF_SIZE = 5, /* read only */
+	PARAM_TX_BYTES = 6, /* read only */
+	PARAM_INTERRUPT_STATUS = 7, /* read only */
+};
+
+enum vuart_interrupt_bit {
+	INTERRUPT_BIT_TX = 0,
+	INTERRUPT_BIT_RX = 1,
+	INTERRUPT_BIT_DISCONNECT = 2,
+};
+
+enum vuart_interrupt_mask {
+	INTERRUPT_MASK_TX = 1,
+	INTERRUPT_MASK_RX = 2,
+	INTERRUPT_MASK_DISCONNECT = 4,
+};
+
+/**
+ * struct ports_bmp - bitmap indicating ports needing service.
+ *
+ * A 256 bit read only bitmap indicating ports needing service.  Do not write
+ * to these bits.  Must not cross a page boundary.
+ */
+
+struct ports_bmp {
+	u64 status;
+	u64 unused[3];
+} __attribute__ ((aligned (32)));
+
+/* redefine dev_dbg to do a syntax check */
+
+#if !defined(DEBUG)
+#undef dev_dbg
+static inline int __attribute__ ((format (printf, 2, 3))) dev_dbg(
+	const struct device *_dev, const char *fmt, ...) {return 0;}
+#endif
+
+#define dump_ports_bmp(_b) _dump_ports_bmp(_b, __func__, __LINE__)
+static void __attribute__ ((unused)) _dump_ports_bmp(
+	const struct ports_bmp* bmp, const char* func, int line)
+{
+	pr_debug("%s:%d: ports_bmp: %016lxh\n", func, line, bmp->status);
+}
+
+static int ps3_vuart_match_id_to_port(enum ps3_match_id match_id,
+	unsigned int *port_number)
+{
+	switch(match_id) {
+	case PS3_MATCH_ID_AV_SETTINGS:
+		*port_number = 0;
+		return 0;
+	case PS3_MATCH_ID_SYSTEM_MANAGER:
+		*port_number = 2;
+		return 0;
+	default:
+		WARN_ON(1);
+		*port_number = UINT_MAX;
+		return -EINVAL;
+	};
+}
+
+#define dump_port_params(_b) _dump_port_params(_b, __func__, __LINE__)
+static void __attribute__ ((unused)) _dump_port_params(unsigned int port_number,
+	const char* func, int line)
+{
+#if defined(DEBUG)
+	static const char *strings[] = {
+		"tx_trigger      ",
+		"rx_trigger      ",
+		"interrupt_mask  ",
+		"rx_buf_size     ",
+		"rx_bytes        ",
+		"tx_buf_size     ",
+		"tx_bytes        ",
+		"interrupt_status",
+	};
+	int result;
+	unsigned int i;
+	u64 value;
+
+	for (i = 0; i < ARRAY_SIZE(strings); i++) {
+		result = lv1_get_virtual_uart_param(port_number, i, &value);
+
+		if (result) {
+			pr_debug("%s:%d: port_%u: %s failed: %s\n", func, line,
+				port_number, strings[i], ps3_result(result));
+			continue;
+		}
+		pr_debug("%s:%d: port_%u: %s = %lxh\n",
+			func, line, port_number, strings[i], value);
+	}
+#endif
+}
+
+struct vuart_triggers {
+	unsigned long rx;
+	unsigned long tx;
+};
+
+int ps3_vuart_get_triggers(struct ps3_vuart_port_device *dev,
+	struct vuart_triggers *trig)
+{
+	int result;
+	unsigned long size;
+	unsigned long val;
+
+	result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_TX_TRIGGER, &trig->tx);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: tx_trigger failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_RX_BUF_SIZE, &size);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: tx_buf_size failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_RX_TRIGGER, &val);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: rx_trigger failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	trig->rx = size - val;
+
+	dev_dbg(&dev->core, "%s:%d: tx %lxh, rx %lxh\n", __func__, __LINE__,
+		trig->tx, trig->rx);
+
+	return result;
+}
+
+int ps3_vuart_set_triggers(struct ps3_vuart_port_device *dev, unsigned int tx,
+	unsigned int rx)
+{
+	int result;
+	unsigned long size;
+
+	result = lv1_set_virtual_uart_param(dev->port_number,
+		PARAM_TX_TRIGGER, tx);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: tx_trigger failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_RX_BUF_SIZE, &size);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: tx_buf_size failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	result = lv1_set_virtual_uart_param(dev->port_number,
+		PARAM_RX_TRIGGER, size - rx);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: rx_trigger failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	dev_dbg(&dev->core, "%s:%d: tx %xh, rx %xh\n", __func__, __LINE__,
+		tx, rx);
+
+	return result;
+}
+
+static int ps3_vuart_get_rx_bytes_waiting(struct ps3_vuart_port_device *dev,
+	unsigned long *bytes_waiting)
+{
+	int result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_RX_BYTES, bytes_waiting);
+
+	if (result)
+		dev_dbg(&dev->core, "%s:%d: rx_bytes failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+
+	dev_dbg(&dev->core, "%s:%d: %lxh\n", __func__, __LINE__,
+		*bytes_waiting);
+	return result;
+}
+
+static int ps3_vuart_set_interrupt_mask(struct ps3_vuart_port_device *dev,
+	unsigned long mask)
+{
+	int result;
+
+	dev_dbg(&dev->core, "%s:%d: %lxh\n", __func__, __LINE__, mask);
+
+	dev->interrupt_mask = mask;
+
+	result = lv1_set_virtual_uart_param(dev->port_number,
+		PARAM_INTERRUPT_MASK, dev->interrupt_mask);
+
+	if (result)
+		dev_dbg(&dev->core, "%s:%d: interrupt_mask failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+
+	return result;
+}
+
+static int ps3_vuart_get_interrupt_mask(struct ps3_vuart_port_device *dev,
+	unsigned long *status)
+{
+	int result = lv1_get_virtual_uart_param(dev->port_number,
+		PARAM_INTERRUPT_STATUS, status);
+
+	if (result)
+		dev_dbg(&dev->core, "%s:%d: interrupt_status failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+
+	dev_dbg(&dev->core, "%s:%d: m %lxh, s %lxh, m&s %lxh\n",
+		__func__, __LINE__, dev->interrupt_mask, *status,
+		dev->interrupt_mask & *status);
+
+	return result;
+}
+
+int ps3_vuart_enable_interrupt_tx(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_TX) ? 0
+		: ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		| INTERRUPT_MASK_TX);
+}
+
+int ps3_vuart_enable_interrupt_rx(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_RX) ? 0
+		: ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		| INTERRUPT_MASK_RX);
+}
+
+int ps3_vuart_enable_interrupt_disconnect(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_DISCONNECT) ? 0
+		: ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		| INTERRUPT_MASK_DISCONNECT);
+}
+
+int ps3_vuart_disable_interrupt_tx(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_TX)
+		? ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		& ~INTERRUPT_MASK_TX) : 0;
+}
+
+int ps3_vuart_disable_interrupt_rx(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_RX)
+		? ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		& ~INTERRUPT_MASK_RX) : 0;
+}
+
+int ps3_vuart_disable_interrupt_disconnect(struct ps3_vuart_port_device *dev)
+{
+	return (dev->interrupt_mask & INTERRUPT_MASK_DISCONNECT)
+		? ps3_vuart_set_interrupt_mask(dev, dev->interrupt_mask
+		& ~INTERRUPT_MASK_DISCONNECT) : 0;
+}
+
+/**
+ * ps3_vuart_raw_write - Low level write helper.
+ *
+ * Do not call ps3_vuart_raw_write directly, use ps3_vuart_write.
+ */
+
+static int ps3_vuart_raw_write(struct ps3_vuart_port_device *dev,
+	const void* buf, unsigned int bytes, unsigned long *bytes_written)
+{
+	int result;
+
+	dev_dbg(&dev->core, "%s:%d: %xh\n", __func__, __LINE__, bytes);
+
+	result = lv1_write_virtual_uart(dev->port_number,
+		ps3_mm_phys_to_lpar(__pa(buf)), bytes, bytes_written);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: lv1_write_virtual_uart failed: "
+			"%s\n", __func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	dev->stats.bytes_written += *bytes_written;
+
+	dev_dbg(&dev->core, "%s:%d: wrote %lxh/%xh=>%lxh\n", __func__,
+		__LINE__, *bytes_written, bytes, dev->stats.bytes_written);
+
+	return result;
+}
+
+/**
+ * ps3_vuart_raw_read - Low level read helper.
+ *
+ * Do not call ps3_vuart_raw_read directly, use ps3_vuart_read.
+ */
+
+static int ps3_vuart_raw_read(struct ps3_vuart_port_device *dev, void* buf,
+	unsigned int bytes, unsigned long *bytes_read)
+{
+	int result;
+
+	dev_dbg(&dev->core, "%s:%d: %xh\n", __func__, __LINE__, bytes);
+
+	result = lv1_read_virtual_uart(dev->port_number,
+		ps3_mm_phys_to_lpar(__pa(buf)), bytes, bytes_read);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: lv1_read_virtual_uart failed: %s\n",
+			__func__, __LINE__, ps3_result(result));
+		return result;
+	}
+
+	dev->stats.bytes_read += *bytes_read;
+
+	dev_dbg(&dev->core, "%s:%d: read %lxh/%xh=>%lxh\n", __func__, __LINE__,
+		*bytes_read, bytes, dev->stats.bytes_read);
+
+	return result;
+}
+
+/**
+ * struct list_buffer - An element for a port device fifo buffer list.
+ */
+
+struct list_buffer {
+	struct list_head link;
+	const unsigned char *head;
+	const unsigned char *tail;
+	unsigned long dbg_number;
+	unsigned char data[];
+};
+
+/**
+ * ps3_vuart_write - the entry point for writing data to a port
+ *
+ * If the port is idle on entry as much of the incoming data is written to
+ * the port as the port will accept.  Otherwise a list buffer is created
+ * and any remaning incoming data is copied to that buffer.  The buffer is
+ * then enqueued for transmision via the transmit interrupt.
+ */
+
+int ps3_vuart_write(struct ps3_vuart_port_device *dev, const void* buf,
+	unsigned int bytes)
+{
+	static unsigned long dbg_number;
+	int result;
+	unsigned long flags;
+	struct list_buffer *lb;
+
+	dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
+		bytes, bytes);
+
+	spin_lock_irqsave(&dev->tx_list.lock, flags);
+
+	if (list_empty(&dev->tx_list.head)) {
+		unsigned long bytes_written;
+
+		result = ps3_vuart_raw_write(dev, buf, bytes, &bytes_written);
+
+		spin_unlock_irqrestore(&dev->tx_list.lock, flags);
+
+		if (result) {
+			dev_dbg(&dev->core,
+				"%s:%d: ps3_vuart_raw_write failed\n",
+				__func__, __LINE__);
+			return result;
+		}
+
+		if (bytes_written == bytes) {
+			dev_dbg(&dev->core, "%s:%d: wrote %xh bytes\n",
+				__func__, __LINE__, bytes);
+			return 0;
+		}
+
+		bytes -= bytes_written;
+		buf += bytes_written;
+	} else
+		spin_unlock_irqrestore(&dev->tx_list.lock, flags);
+
+	lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_KERNEL);
+
+	if (!lb) {
+		return -ENOMEM;
+	}
+
+	memcpy(lb->data, buf, bytes);
+	lb->head = lb->data;
+	lb->tail = lb->data + bytes;
+	lb->dbg_number = ++dbg_number;
+
+	spin_lock_irqsave(&dev->tx_list.lock, flags);
+	list_add_tail(&lb->link, &dev->tx_list.head);
+	ps3_vuart_enable_interrupt_tx(dev);
+	spin_unlock_irqrestore(&dev->tx_list.lock, flags);
+
+	dev_dbg(&dev->core, "%s:%d: queued buf_%lu, %xh bytes\n",
+		__func__, __LINE__, lb->dbg_number, bytes);
+
+	return 0;
+}
+
+/**
+ * ps3_vuart_read - the entry point for reading data from a port
+ *
+ * If enough bytes to satisfy the request are held in the buffer list those
+ * bytes are dequeued and copied to the caller's buffer.  Emptied list buffers
+ * are retiered.  If the request cannot be statified by bytes held in the list
+ * buffers -EAGAIN is returned.
+ */
+
+int ps3_vuart_read(struct ps3_vuart_port_device *dev, void* buf,
+	unsigned int bytes)
+{
+	unsigned long flags;
+	struct list_buffer *lb, *n;
+	unsigned long bytes_read;
+
+	dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
+		bytes, bytes);
+
+	spin_lock_irqsave(&dev->rx_list.lock, flags);
+
+	if (dev->rx_list.bytes_held < bytes) {
+		spin_unlock_irqrestore(&dev->rx_list.lock, flags);
+		dev_dbg(&dev->core, "%s:%d: starved for %lxh bytes\n",
+			__func__, __LINE__, bytes - dev->rx_list.bytes_held);
+		return -EAGAIN;
+	}
+
+	list_for_each_entry_safe(lb, n, &dev->rx_list.head, link) {
+		bytes_read = min((unsigned int)(lb->tail - lb->head), bytes);
+
+		memcpy(buf, lb->head, bytes_read);
+		buf += bytes_read;
+		bytes -= bytes_read;
+		dev->rx_list.bytes_held -= bytes_read;
+
+		if (bytes_read < lb->tail - lb->head) {
+			lb->head += bytes_read;
+			spin_unlock_irqrestore(&dev->rx_list.lock, flags);
+
+			dev_dbg(&dev->core,
+				"%s:%d: dequeued buf_%lu, %lxh bytes\n",
+				__func__, __LINE__, lb->dbg_number, bytes_read);
+			return 0;
+		}
+
+		dev_dbg(&dev->core, "%s:%d free buf_%lu\n", __func__, __LINE__,
+			lb->dbg_number);
+
+		list_del(&lb->link);
+		kfree(lb);
+	}
+	spin_unlock_irqrestore(&dev->rx_list.lock, flags);
+
+	dev_dbg(&dev->core, "%s:%d: dequeued buf_%lu, %xh bytes\n",
+		__func__, __LINE__, lb->dbg_number, bytes);
+
+	return 0;
+}
+
+/**
+ * ps3_vuart_handle_interrupt_tx - third stage transmit interrupt handler
+ *
+ * Services the transmit interrupt for the port.  Writes as much data from the
+ * buffer list as the port will accept.  Retires any emptied list buffers and
+ * adjusts the final list buffer state for a partial write.
+ */
+
+static int ps3_vuart_handle_interrupt_tx(struct ps3_vuart_port_device *dev)
+{
+	int result = 0;
+	unsigned long flags;
+	struct list_buffer *lb, *n;
+	unsigned long bytes_total = 0;
+
+	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
+
+	spin_lock_irqsave(&dev->tx_list.lock, flags);
+
+	list_for_each_entry_safe(lb, n, &dev->tx_list.head, link) {
+
+		unsigned long bytes_written;
+
+		result = ps3_vuart_raw_write(dev, lb->head, lb->tail - lb->head,
+			&bytes_written);
+
+		if (result) {
+			dev_dbg(&dev->core,
+				"%s:%d: ps3_vuart_raw_write failed\n",
+				__func__, __LINE__);
+			break;
+		}
+
+		bytes_total += bytes_written;
+
+		if (bytes_written < lb->tail - lb->head) {
+			lb->head += bytes_written;
+			dev_dbg(&dev->core,
+				"%s:%d cleared buf_%lu, %lxh bytes\n",
+				__func__, __LINE__, lb->dbg_number,
+				bytes_written);
+			goto port_full;
+		}
+
+		dev_dbg(&dev->core, "%s:%d free buf_%lu\n", __func__, __LINE__,
+			lb->dbg_number);
+
+		list_del(&lb->link);
+		kfree(lb);
+	}
+
+	ps3_vuart_disable_interrupt_tx(dev);
+port_full:
+	spin_unlock_irqrestore(&dev->tx_list.lock, flags);
+	dev_dbg(&dev->core, "%s:%d wrote %lxh bytes total\n",
+		__func__, __LINE__, bytes_total);
+	return result;
+}
+
+/**
+ * ps3_vuart_handle_interrupt_rx - third stage receive interrupt handler
+ *
+ * Services the receive interrupt for the port.  Creates a list buffer and
+ * copies all waiting port data to that buffer and enqueues the buffer in the
+ * buffer list.  Buffer list data is dequeued via ps3_vuart_read.
+ */
+
+static int ps3_vuart_handle_interrupt_rx(struct ps3_vuart_port_device *dev)
+{
+	static unsigned long dbg_number;
+	int result = 0;
+	unsigned long flags;
+	struct list_buffer *lb;
+	unsigned long bytes;
+
+	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
+
+	result = ps3_vuart_get_rx_bytes_waiting(dev, &bytes);
+
+	if (result)
+		return -EIO;
+
+	BUG_ON(!bytes);
+
+	/* add some extra space for recently arrived data */
+
+	bytes += 128;
+
+	lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_ATOMIC);
+
+	if (!lb)
+		return -ENOMEM;
+
+	ps3_vuart_raw_read(dev, lb->data, bytes, &bytes);
+
+	lb->head = lb->data;
+	lb->tail = lb->data + bytes;
+	lb->dbg_number = ++dbg_number;
+
+	spin_lock_irqsave(&dev->rx_list.lock, flags);
+	list_add_tail(&lb->link, &dev->rx_list.head);
+	dev->rx_list.bytes_held += bytes;
+	spin_unlock_irqrestore(&dev->rx_list.lock, flags);
+
+	dev_dbg(&dev->core, "%s:%d: queued buf_%lu, %lxh bytes\n",
+		__func__, __LINE__, lb->dbg_number, bytes);
+
+	return 0;
+}
+
+static int ps3_vuart_handle_interrupt_disconnect(
+	struct ps3_vuart_port_device *dev)
+{
+	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
+	BUG_ON("no support");
+	return -1;
+}
+
+/**
+ * ps3_vuart_handle_port_interrupt - second stage interrupt handler
+ *
+ * Services any pending interrupt types for the port.  Passes control to the
+ * third stage type specific interrupt handler.  Returns control to the first
+ * stage handler after one iteration.
+ */
+
+static int ps3_vuart_handle_port_interrupt(struct ps3_vuart_port_device *dev)
+{
+	int result;
+	unsigned long status;
+
+	result = ps3_vuart_get_interrupt_mask(dev, &status);
+
+	if (result)
+		return result;
+
+	dev_dbg(&dev->core, "%s:%d: status: %lxh\n", __func__, __LINE__,
+		status);
+
+	if (status & INTERRUPT_MASK_DISCONNECT) {
+		dev->stats.disconnect_interrupts++;
+		result = ps3_vuart_handle_interrupt_disconnect(dev);
+		if (result)
+			ps3_vuart_disable_interrupt_disconnect(dev);
+	}
+
+	if (status & INTERRUPT_MASK_TX) {
+		dev->stats.tx_interrupts++;
+		result = ps3_vuart_handle_interrupt_tx(dev);
+		if (result)
+			ps3_vuart_disable_interrupt_tx(dev);
+	}
+
+	if (status & INTERRUPT_MASK_RX) {
+		dev->stats.rx_interrupts++;
+		result = ps3_vuart_handle_interrupt_rx(dev);
+		if (result)
+			ps3_vuart_disable_interrupt_rx(dev);
+	}
+
+	return 0;
+}
+
+struct vuart_private {
+	unsigned int in_use;
+	unsigned int virq;
+	struct ps3_vuart_port_device *devices[PORT_COUNT];
+	const struct ports_bmp bmp;
+};
+
+/**
+ * ps3_vuart_irq_handler - first stage interrupt handler
+ *
+ * Loops finding any interrupting port and its associated instance data.
+ * Passes control to the second stage port specific interrupt handler.  Loops
+ * until all outstanding interrupts are serviced.
+ */
+
+static irqreturn_t ps3_vuart_irq_handler(int irq, void *_private)
+{
+	struct vuart_private *private;
+
+	BUG_ON(!_private);
+	private = (struct vuart_private *)_private;
+
+	while (1) {
+		unsigned int port;
+
+		dump_ports_bmp(&private->bmp);
+
+		port = (BITS_PER_LONG - 1) - __ilog2(private->bmp.status);
+
+		if (port == BITS_PER_LONG)
+			break;
+
+		BUG_ON(port >= PORT_COUNT);
+		BUG_ON(!private->devices[port]);
+
+		ps3_vuart_handle_port_interrupt(private->devices[port]);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int ps3_vuart_match(struct device *_dev, struct device_driver *_drv)
+{
+	int result;
+	struct ps3_vuart_port_driver *drv = to_ps3_vuart_port_driver(_drv);
+	struct ps3_vuart_port_device *dev = to_ps3_vuart_port_device(_dev);
+
+	result = dev->match_id == drv->match_id;
+
+	dev_info(&dev->core, "%s:%d: dev=%u(%s), drv=%u(%s): %s\n", __func__,
+		__LINE__, dev->match_id, dev->core.bus_id, drv->match_id,
+		drv->core.name, (result ? "match" : "miss"));
+
+	return result;
+}
+
+static struct vuart_private vuart_private;
+
+static int ps3_vuart_probe(struct device *_dev)
+{
+	int result;
+	unsigned long tmp;
+	struct ps3_vuart_port_device *dev = to_ps3_vuart_port_device(_dev);
+	struct ps3_vuart_port_driver *drv =
+		to_ps3_vuart_port_driver(_dev->driver);
+
+	dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
+
+	BUG_ON(!drv);
+
+	result = ps3_vuart_match_id_to_port(dev->match_id, &dev->port_number);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: unknown match_id (%d)\n",
+			__func__, __LINE__, dev->match_id);
+		result = -EINVAL;
+		goto fail_match;
+	}
+
+	if (vuart_private.devices[dev->port_number]) {
+		dev_dbg(&dev->core, "%s:%d: port busy (%d)\n", __func__,
+			__LINE__, dev->port_number);
+		result = -EBUSY;
+		goto fail_match;
+	}
+
+	vuart_private.devices[dev->port_number] = dev;
+
+	INIT_LIST_HEAD(&dev->tx_list.head);
+	spin_lock_init(&dev->tx_list.lock);
+	INIT_LIST_HEAD(&dev->rx_list.head);
+	spin_lock_init(&dev->rx_list.lock);
+
+	vuart_private.in_use++;
+	if (vuart_private.in_use == 1) {
+		result = ps3_alloc_vuart_irq((void*)&vuart_private.bmp.status,
+			&vuart_private.virq);
+
+		if (result) {
+			dev_dbg(&dev->core,
+				"%s:%d: ps3_alloc_vuart_irq failed (%d)\n",
+				__func__, __LINE__, result);
+			result = -EPERM;
+			goto fail_alloc_irq;
+		}
+
+		result = request_irq(vuart_private.virq, ps3_vuart_irq_handler,
+			IRQF_DISABLED, "vuart", &vuart_private);
+
+		if (result) {
+			dev_info(&dev->core, "%s:%d: request_irq failed (%d)\n",
+				__func__, __LINE__, result);
+			goto fail_request_irq;
+		}
+	}
+
+	ps3_vuart_set_interrupt_mask(dev, INTERRUPT_MASK_RX);
+
+	/* clear stale pending interrupts */
+	ps3_vuart_get_interrupt_mask(dev, &tmp);
+
+	ps3_vuart_set_triggers(dev, 1, 1);
+
+	if (drv->probe)
+		result = drv->probe(dev);
+	else {
+		result = 0;
+		dev_info(&dev->core, "%s:%d: no probe method\n", __func__,
+			__LINE__);
+	}
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: drv->probe failed\n",
+			__func__, __LINE__);
+		goto fail_probe;
+	}
+
+	return result;
+
+fail_probe:
+fail_request_irq:
+	vuart_private.in_use--;
+	if (!vuart_private.in_use) {
+		ps3_free_vuart_irq(vuart_private.virq);
+		vuart_private.virq = NO_IRQ;
+	}
+fail_alloc_irq:
+fail_match:
+	dev_dbg(&dev->core, "%s:%d failed\n", __func__, __LINE__);
+	return result;
+}
+
+static int ps3_vuart_remove(struct device *_dev)
+{
+	struct ps3_vuart_port_device *dev = to_ps3_vuart_port_device(_dev);
+	struct ps3_vuart_port_driver *drv =
+		to_ps3_vuart_port_driver(_dev->driver);
+
+	dev_dbg(&dev->core, "%s:%d: %s\n", __func__, __LINE__,
+		dev->core.bus_id);
+
+	BUG_ON(vuart_private.in_use < 1);
+
+	if (drv->remove)
+		drv->remove(dev);
+	else
+		dev_dbg(&dev->core, "%s:%d: %s no remove method\n", __func__,
+			__LINE__, dev->core.bus_id);
+
+	vuart_private.in_use--;
+
+	if (!vuart_private.in_use) {
+		free_irq(vuart_private.virq, &vuart_private);
+		ps3_free_vuart_irq(vuart_private.virq);
+		vuart_private.virq = NO_IRQ;
+	}
+	return 0;
+}
+
+/**
+ * ps3_vuart - The vuart instance.
+ *
+ * The vuart is managed as a bus that port devices connect to.
+ */
+
+struct bus_type ps3_vuart = {
+        .name = "ps3_vuart",
+	.match = ps3_vuart_match,
+	.probe = ps3_vuart_probe,
+	.remove = ps3_vuart_remove,
+};
+
+int __init ps3_vuart_init(void)
+{
+	int result;
+
+	pr_debug("%s:%d:\n", __func__, __LINE__);
+	result = bus_register(&ps3_vuart);
+	BUG_ON(result);
+	return result;
+}
+
+void __exit ps3_vuart_exit(void)
+{
+	pr_debug("%s:%d:\n", __func__, __LINE__);
+	bus_unregister(&ps3_vuart);
+}
+
+core_initcall(ps3_vuart_init);
+module_exit(ps3_vuart_exit);
+
+/**
+ * ps3_vuart_port_release_device - Remove a vuart port device.
+ */
+
+static void ps3_vuart_port_release_device(struct device *_dev)
+{
+	struct ps3_vuart_port_device *dev = to_ps3_vuart_port_device(_dev);
+#if defined(DEBUG)
+	memset(dev, 0xad, sizeof(struct ps3_vuart_port_device));
+#endif
+	kfree(dev);
+}
+
+/**
+ * ps3_vuart_port_device_register - Add a vuart port device.
+ */
+
+int ps3_vuart_port_device_register(struct ps3_vuart_port_device *dev)
+{
+	int result;
+	static unsigned int dev_count = 1;
+
+	dev->core.parent = NULL;
+	dev->core.bus = &ps3_vuart;
+	dev->core.release = ps3_vuart_port_release_device;
+
+	snprintf(dev->core.bus_id, sizeof(dev->core.bus_id), "vuart_%02x",
+		dev_count++);
+
+	dev_dbg(&dev->core, "%s:%d register\n", __func__, __LINE__);
+
+	result = device_register(&dev->core);
+
+	return result;
+}
+
+EXPORT_SYMBOL_GPL(ps3_vuart_port_device_register);
+
+/**
+ * ps3_vuart_port_driver_register - Add a vuart port device driver.
+ */
+
+int ps3_vuart_port_driver_register(struct ps3_vuart_port_driver *drv)
+{
+	int result;
+
+	pr_debug("%s:%d: (%s)\n", __func__, __LINE__, drv->core.name);
+	drv->core.bus = &ps3_vuart;
+	result = driver_register(&drv->core);
+	return result;
+}
+
+EXPORT_SYMBOL_GPL(ps3_vuart_port_driver_register);
+
+/**
+ * ps3_vuart_port_driver_unregister - Remove a vuart port device driver.
+ */
+
+void ps3_vuart_port_driver_unregister(struct ps3_vuart_port_driver *drv)
+{
+	driver_unregister(&drv->core);
+}
+
+EXPORT_SYMBOL_GPL(ps3_vuart_port_driver_unregister);

drivers/ps3/vuart.h

+/*
+ *  PS3 virtual uart
+ *
+ *  Copyright (C) 2006 Sony Computer Entertainment Inc.
+ *  Copyright 2006 Sony Corp.
+ *
+ *  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.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#if !defined(_PS3_VUART_H)
+#define _PS3_VUART_H
+
+struct ps3_vuart_stats {
+	unsigned long bytes_written;
+	unsigned long bytes_read;
+	unsigned long tx_interrupts;
+	unsigned long rx_interrupts;
+	unsigned long disconnect_interrupts;
+};
+
+/**
+ * struct ps3_vuart_port_device - a device on a vuart port
+ */
+
+struct ps3_vuart_port_device {
+	enum ps3_match_id match_id;
+	struct device core;
+
+	/* private driver variables */
+	unsigned int port_number;
+	unsigned long interrupt_mask;
+	struct {
+		spinlock_t lock;
+		struct list_head head;
+	} tx_list;
+	struct {
+		unsigned long bytes_held;
+		spinlock_t lock;
+		struct list_head head;
+	} rx_list;
+	struct ps3_vuart_stats stats;
+};
+
+/**
+ * struct ps3_vuart_port_driver - a driver for a device on a vuart port
+ */
+
+struct ps3_vuart_port_driver {
+	enum ps3_match_id match_id;
+	struct device_driver core;
+	int (*probe)(struct ps3_vuart_port_device *);
+	int (*remove)(struct ps3_vuart_port_device *);
+	int (*tx_event)(struct ps3_vuart_port_device *dev);
+	int (*rx_event)(struct ps3_vuart_port_device *dev);
+	int (*disconnect_event)(struct ps3_vuart_port_device *dev);
+	/* int (*suspend)(struct ps3_vuart_port_device *, pm_message_t); */
+	/* int (*resume)(struct ps3_vuart_port_device *); */
+};
+
+int ps3_vuart_port_device_register(struct ps3_vuart_port_device *dev);
+int ps3_vuart_port_driver_register(struct ps3_vuart_port_driver *drv);
+void ps3_vuart_port_driver_unregister(struct ps3_vuart_port_driver *drv);
+int ps3_vuart_write(struct ps3_vuart_port_device *dev,
+	const void* buf, unsigned int bytes);
+int ps3_vuart_read(struct ps3_vuart_port_device *dev, void* buf,
+	unsigned int bytes);
+static inline struct ps3_vuart_port_driver *to_ps3_vuart_port_driver(
+	struct device_driver *_drv)
+{
+	return container_of(_drv, struct ps3_vuart_port_driver, core);
+}
+static inline struct ps3_vuart_port_device *to_ps3_vuart_port_device(
+	struct device *_dev)
+{
+	return container_of(_dev, struct ps3_vuart_port_device, core);
+}
+
+int ps3_vuart_write(struct ps3_vuart_port_device *dev, const void* buf,
+	unsigned int bytes);
+int ps3_vuart_read(struct ps3_vuart_port_device *dev, void* buf,
+	unsigned int bytes);
+
+#endif