[PATCH] ppc64: SMU driver update & i2c support

The SMU is the "system controller" chip used by Apple recent G5 machines
including the iMac G5.  It drives things like fans, i2c busses, real time
clock, etc...

The current kernel contains a very crude driver that doesn't do much more
than reading the real time clock synchronously.  This is a completely
rewritten driver that provides interrupt based command queuing, a userland
interface, and an i2c/smbus driver for accessing the devices hanging off
the SMU i2c busses like temperature sensors.  This driver is a basic block
for upcoming work on thermal control for those machines, among others.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

15 files changed, 1618 insertions, 163 deletions

diff --git a/arch/ppc/platforms/pmac_setup.c b/arch/ppc/platforms/pmac_setup.c
index b392b9a1598..4c56a4734ae 100644
--- a/arch/ppc/platforms/pmac_setup.c
+++ b/arch/ppc/platforms/pmac_setup.c
@@ -719,7 +719,8 @@ pmac_declare_of_platform_devices(void)
 	if (np) {
 		for (np = np->child; np != NULL; np = np->sibling)
 			if (strncmp(np->name, "i2c", 3) == 0) {
-				of_platform_device_create(np, "uni-n-i2c");
+				of_platform_device_create(np, "uni-n-i2c",
+							  NULL);
 				break;
 			}
 	}
@@ -727,17 +728,18 @@ pmac_declare_of_platform_devices(void)
 	if (np) {
 		for (np = np->child; np != NULL; np = np->sibling)
 			if (strncmp(np->name, "i2c", 3) == 0) {
-				of_platform_device_create(np, "u3-i2c");
+				of_platform_device_create(np, "u3-i2c",
+							  NULL);
 				break;
 			}
 	}
 
 	np = find_devices("valkyrie");
 	if (np)
-		of_platform_device_create(np, "valkyrie");
+		of_platform_device_create(np, "valkyrie", NULL);
 	np = find_devices("platinum");
 	if (np)
-		of_platform_device_create(np, "platinum");
+		of_platform_device_create(np, "platinum", NULL);
 
 	return 0;
 }
diff --git a/arch/ppc/syslib/of_device.c b/arch/ppc/syslib/of_device.c
index da8a0f2128d..93c7231ea70 100644
--- a/arch/ppc/syslib/of_device.c
+++ b/arch/ppc/syslib/of_device.c
@@ -234,7 +234,9 @@ void of_device_unregister(struct of_device *ofdev)
 	device_unregister(&ofdev->dev);
 }
 
-struct of_device* of_platform_device_create(struct device_node *np, const char *bus_id)
+struct of_device* of_platform_device_create(struct device_node *np,
+					    const char *bus_id,
+					    struct device *parent)
 {
 	struct of_device *dev;
 	u32 *reg;
@@ -247,7 +249,7 @@ struct of_device* of_platform_device_create(struct device_node *np, const char *
 	dev->node = of_node_get(np);
 	dev->dma_mask = 0xffffffffUL;
 	dev->dev.dma_mask = &dev->dma_mask;
-	dev->dev.parent = NULL;
+	dev->dev.parent = parent;
 	dev->dev.bus = &of_platform_bus_type;
 	dev->dev.release = of_release_dev;
 
diff --git a/arch/ppc64/kernel/of_device.c b/arch/ppc64/kernel/of_device.c
index da580812ddf..9f200f0f2ad 100644
--- a/arch/ppc64/kernel/of_device.c
+++ b/arch/ppc64/kernel/of_device.c
@@ -233,7 +233,9 @@ void of_device_unregister(struct of_device *ofdev)
 	device_unregister(&ofdev->dev);
 }
 
-struct of_device* of_platform_device_create(struct device_node *np, const char *bus_id)
+struct of_device* of_platform_device_create(struct device_node *np,
+					    const char *bus_id,
+					    struct device *parent)
 {
 	struct of_device *dev;
 
@@ -245,7 +247,7 @@ struct of_device* of_platform_device_create(struct device_node *np, const char *
 	dev->node = np;
 	dev->dma_mask = 0xffffffffUL;
 	dev->dev.dma_mask = &dev->dma_mask;
-	dev->dev.parent = NULL;
+	dev->dev.parent = parent;
 	dev->dev.bus = &of_platform_bus_type;
 	dev->dev.release = of_release_dev;
 
@@ -259,6 +261,7 @@ struct of_device* of_platform_device_create(struct device_node *np, const char *
 	return dev;
 }
 
+
 EXPORT_SYMBOL(of_match_device);
 EXPORT_SYMBOL(of_platform_bus_type);
 EXPORT_SYMBOL(of_register_driver);
diff --git a/arch/ppc64/kernel/pmac_setup.c b/arch/ppc64/kernel/pmac_setup.c
index 325426c7bed..25755252067 100644
--- a/arch/ppc64/kernel/pmac_setup.c
+++ b/arch/ppc64/kernel/pmac_setup.c
@@ -434,15 +434,23 @@ static int pmac_check_legacy_ioport(unsigned int baseport)
 
 static int __init pmac_declare_of_platform_devices(void)
 {
-	struct device_node *np;
+	struct device_node *np, *npp;
 
-	np = find_devices("u3");
-	if (np) {
-		for (np = np->child; np != NULL; np = np->sibling)
+	npp = of_find_node_by_name(NULL, "u3");
+	if (npp) {
+		for (np = NULL; (np = of_get_next_child(npp, np)) != NULL;) {
 			if (strncmp(np->name, "i2c", 3) == 0) {
-				of_platform_device_create(np, "u3-i2c");
+				of_platform_device_create(np, "u3-i2c", NULL);
+				of_node_put(np);
 				break;
 			}
+		}
+		of_node_put(npp);
+	}
+        npp = of_find_node_by_type(NULL, "smu");
+        if (npp) {
+		of_platform_device_create(npp, "smu", NULL);
+		of_node_put(npp);
 	}
 
 	return 0;
diff --git a/arch/ppc64/kernel/pmac_time.c b/arch/ppc64/kernel/pmac_time.c
index 3059edb09cc..41bbb8c5969 100644
--- a/arch/ppc64/kernel/pmac_time.c
+++ b/arch/ppc64/kernel/pmac_time.c
@@ -84,7 +84,7 @@ void __pmac pmac_get_rtc_time(struct rtc_time *tm)
 
 #ifdef CONFIG_PMAC_SMU
 	case SYS_CTRLER_SMU:
-		smu_get_rtc_time(tm);
+		smu_get_rtc_time(tm, 1);
 		break;
 #endif /* CONFIG_PMAC_SMU */
 	default:
@@ -128,7 +128,7 @@ int __pmac pmac_set_rtc_time(struct rtc_time *tm)
 
 #ifdef CONFIG_PMAC_SMU
 	case SYS_CTRLER_SMU:
-		return smu_set_rtc_time(tm);
+		return smu_set_rtc_time(tm, 1);
 #endif /* CONFIG_PMAC_SMU */
 	default:
 		return -ENODEV;
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 8334496a7e0..3badfec75b1 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -245,6 +245,18 @@ config I2C_KEYWEST
 	  This support is also available as a module.  If so, the module 
 	  will be called i2c-keywest.
 
+config I2C_PMAC_SMU
+	tristate "Powermac SMU I2C interface"
+	depends on I2C && PMAC_SMU
+	help
+	  This supports the use of the I2C interface in the SMU
+	  chip on recent Apple machines like the iMac G5.  It is used
+	  among others by the thermal control driver for those machines.
+	  Say Y if you have such a machine.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-pmac-smu.
+
 config I2C_MPC
 	tristate "MPC107/824x/85xx/52xx"
 	depends on I2C && PPC32
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 980b3e98367..f1df00f66c6 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_I2C_ITE)		+= i2c-ite.o
 obj-$(CONFIG_I2C_IXP2000)	+= i2c-ixp2000.o
 obj-$(CONFIG_I2C_IXP4XX)	+= i2c-ixp4xx.o
 obj-$(CONFIG_I2C_KEYWEST)	+= i2c-keywest.o
+obj-$(CONFIG_I2C_PMAC_SMU)	+= i2c-pmac-smu.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MV64XXX)	+= i2c-mv64xxx.o
 obj-$(CONFIG_I2C_NFORCE2)	+= i2c-nforce2.o
diff --git a/drivers/i2c/busses/i2c-pmac-smu.c b/drivers/i2c/busses/i2c-pmac-smu.c
new file mode 100644
index 00000000000..8a9f5648a23
--- /dev/null
+++ b/drivers/i2c/busses/i2c-pmac-smu.c
@@ -0,0 +1,316 @@
+/*
+    i2c Support for Apple SMU Controller
+
+    Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
+                       <benh@kernel.crashing.org>
+
+    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.
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <asm/prom.h>
+#include <asm/of_device.h>
+#include <asm/smu.h>
+
+static int probe;
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("I2C driver for Apple's SMU");
+MODULE_LICENSE("GPL");
+module_param(probe, bool, 0);
+
+
+/* Physical interface */
+struct smu_iface
+{
+	struct i2c_adapter	adapter;
+	struct completion	complete;
+	u32			busid;
+};
+
+static void smu_i2c_done(struct smu_i2c_cmd *cmd, void *misc)
+{
+	struct smu_iface	*iface = misc;
+	complete(&iface->complete);
+}
+
+/*
+ * SMBUS-type transfer entrypoint
+ */
+static s32 smu_smbus_xfer(	struct i2c_adapter*	adap,
+				u16			addr,
+				unsigned short		flags,
+				char			read_write,
+				u8			command,
+				int			size,
+				union i2c_smbus_data*	data)
+{
+	struct smu_iface	*iface = i2c_get_adapdata(adap);
+	struct smu_i2c_cmd	cmd;
+	int			rc = 0;
+	int			read = (read_write == I2C_SMBUS_READ);
+
+	cmd.info.bus = iface->busid;
+	cmd.info.devaddr = (addr << 1) | (read ? 0x01 : 0x00);
+
+	/* Prepare datas & select mode */
+	switch (size) {
+        case I2C_SMBUS_QUICK:
+		cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
+		cmd.info.datalen = 0;
+	    	break;
+        case I2C_SMBUS_BYTE:
+		cmd.info.type = SMU_I2C_TRANSFER_SIMPLE;
+		cmd.info.datalen = 1;
+		if (!read)
+			cmd.info.data[0] = data->byte;
+	    	break;
+        case I2C_SMBUS_BYTE_DATA:
+		cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
+		cmd.info.datalen = 1;
+		cmd.info.sublen = 1;
+		cmd.info.subaddr[0] = command;
+		cmd.info.subaddr[1] = 0;
+		cmd.info.subaddr[2] = 0;
+		if (!read)
+			cmd.info.data[0] = data->byte;
+	    	break;
+        case I2C_SMBUS_WORD_DATA:
+		cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
+		cmd.info.datalen = 2;
+		cmd.info.sublen = 1;
+		cmd.info.subaddr[0] = command;
+		cmd.info.subaddr[1] = 0;
+		cmd.info.subaddr[2] = 0;
+		if (!read) {
+			cmd.info.data[0] = data->byte & 0xff;
+			cmd.info.data[1] = (data->byte >> 8) & 0xff;
+		}
+		break;
+	/* Note that these are broken vs. the expected smbus API where
+	 * on reads, the lenght is actually returned from the function,
+	 * but I think the current API makes no sense and I don't want
+	 * any driver that I haven't verified for correctness to go
+	 * anywhere near a pmac i2c bus anyway ...
+	 */
+        case I2C_SMBUS_BLOCK_DATA:
+		cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
+		cmd.info.datalen = data->block[0] + 1;
+		if (cmd.info.datalen > 6)
+			return -EINVAL;
+		if (!read)
+			memcpy(cmd.info.data, data->block, cmd.info.datalen);
+		cmd.info.sublen = 1;
+		cmd.info.subaddr[0] = command;
+		cmd.info.subaddr[1] = 0;
+		cmd.info.subaddr[2] = 0;
+		break;
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		cmd.info.type = SMU_I2C_TRANSFER_STDSUB;
+		cmd.info.datalen = data->block[0];
+		if (cmd.info.datalen > 7)
+			return -EINVAL;
+		if (!read)
+			memcpy(cmd.info.data, &data->block[1],
+			       cmd.info.datalen);
+		cmd.info.sublen = 1;
+		cmd.info.subaddr[0] = command;
+		cmd.info.subaddr[1] = 0;
+		cmd.info.subaddr[2] = 0;
+		break;
+
+        default:
+	    	return -EINVAL;
+	}
+
+	/* Turn a standardsub read into a combined mode access */
+ 	if (read_write == I2C_SMBUS_READ &&
+	    cmd.info.type == SMU_I2C_TRANSFER_STDSUB)
+		cmd.info.type = SMU_I2C_TRANSFER_COMBINED;
+
+	/* Finish filling command and submit it */
+	cmd.done = smu_i2c_done;
+	cmd.misc = iface;
+	rc = smu_queue_i2c(&cmd);
+	if (rc < 0)
+		return rc;
+	wait_for_completion(&iface->complete);
+	rc = cmd.status;
+
+	if (!read || rc < 0)
+		return rc;
+
+	switch (size) {
+        case I2C_SMBUS_BYTE:
+        case I2C_SMBUS_BYTE_DATA:
+		data->byte = cmd.info.data[0];
+	    	break;
+        case I2C_SMBUS_WORD_DATA:
+		data->word = ((u16)cmd.info.data[1]) << 8;
+		data->word |= cmd.info.data[0];
+		break;
+	/* Note that these are broken vs. the expected smbus API where
+	 * on reads, the lenght is actually returned from the function,
+	 * but I think the current API makes no sense and I don't want
+	 * any driver that I haven't verified for correctness to go
+	 * anywhere near a pmac i2c bus anyway ...
+	 */
+        case I2C_SMBUS_BLOCK_DATA:
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		memcpy(&data->block[0], cmd.info.data, cmd.info.datalen);
+		break;
+	}
+
+	return rc;
+}
+
+static u32
+smu_smbus_func(struct i2c_adapter * adapter)
+{
+	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+	       I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+/* For now, we only handle combined mode (smbus) */
+static struct i2c_algorithm smu_algorithm = {
+	.smbus_xfer	= smu_smbus_xfer,
+	.functionality	= smu_smbus_func,
+};
+
+static int create_iface(struct device_node *np, struct device *dev)
+{
+	struct smu_iface* iface;
+	u32 *reg, busid;
+	int rc;
+
+	reg = (u32 *)get_property(np, "reg", NULL);
+	if (reg == NULL) {
+		printk(KERN_ERR "i2c-pmac-smu: can't find bus number !\n");
+		return -ENXIO;
+	}
+	busid = *reg;
+
+	iface = kmalloc(sizeof(struct smu_iface), GFP_KERNEL);
+	if (iface == NULL) {
+		printk(KERN_ERR "i2c-pmac-smu: can't allocate inteface !\n");
+		return -ENOMEM;
+	}
+	memset(iface, 0, sizeof(struct smu_iface));
+	init_completion(&iface->complete);
+	iface->busid = busid;
+
+	dev_set_drvdata(dev, iface);
+
+	sprintf(iface->adapter.name, "smu-i2c-%02x", busid);
+	iface->adapter.algo = &smu_algorithm;
+	iface->adapter.algo_data = NULL;
+	iface->adapter.client_register = NULL;
+	iface->adapter.client_unregister = NULL;
+	i2c_set_adapdata(&iface->adapter, iface);
+	iface->adapter.dev.parent = dev;
+
+	rc = i2c_add_adapter(&iface->adapter);
+	if (rc) {
+		printk(KERN_ERR "i2c-pamc-smu.c: Adapter %s registration "
+		       "failed\n", iface->adapter.name);
+		i2c_set_adapdata(&iface->adapter, NULL);
+	}
+
+	if (probe) {
+		unsigned char addr;
+		printk("Probe: ");
+		for (addr = 0x00; addr <= 0x7f; addr++) {
+			if (i2c_smbus_xfer(&iface->adapter,addr,
+					   0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
+				printk("%02x ", addr);
+		}
+		printk("\n");
+	}
+
+	printk(KERN_INFO "SMU i2c bus %x registered\n", busid);
+
+	return 0;
+}
+
+static int dispose_iface(struct device *dev)
+{
+	struct smu_iface *iface = dev_get_drvdata(dev);
+	int rc;
+
+	rc = i2c_del_adapter(&iface->adapter);
+	i2c_set_adapdata(&iface->adapter, NULL);
+	/* We aren't that prepared to deal with this... */
+	if (rc)
+		printk("i2c-pmac-smu.c: Failed to remove bus %s !\n",
+		       iface->adapter.name);
+	dev_set_drvdata(dev, NULL);
+	kfree(iface);
+
+	return 0;
+}
+
+
+static int create_iface_of_platform(struct of_device* dev,
+				    const struct of_device_id *match)
+{
+	return create_iface(dev->node, &dev->dev);
+}
+
+
+static int dispose_iface_of_platform(struct of_device* dev)
+{
+	return dispose_iface(&dev->dev);
+}
+
+
+static struct of_device_id i2c_smu_match[] =
+{
+	{
+		.compatible	= "smu-i2c",
+	},
+	{},
+};
+static struct of_platform_driver i2c_smu_of_platform_driver =
+{
+	.name 		= "i2c-smu",
+	.match_table	= i2c_smu_match,
+	.probe		= create_iface_of_platform,
+	.remove		= dispose_iface_of_platform
+};
+
+
+static int __init i2c_pmac_smu_init(void)
+{
+	of_register_driver(&i2c_smu_of_platform_driver);
+	return 0;
+}
+
+
+static void __exit i2c_pmac_smu_cleanup(void)
+{
+	of_unregister_driver(&i2c_smu_of_platform_driver);
+}
+
+module_init(i2c_pmac_smu_init);
+module_exit(i2c_pmac_smu_cleanup);
diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
index fb535737d17..a85ac18dd21 100644
--- a/drivers/macintosh/smu.c
+++ b/drivers/macintosh/smu.c
@@ -8,21 +8,15 @@
  */
 
 /*
- * For now, this driver includes:
- * - RTC get & set
- * - reboot & shutdown commands
- * all synchronous with IRQ disabled (ugh)
- *
  * TODO:
- *   rework in a way the PMU driver works, that is asynchronous
- *   with a queue of commands. I'll do that as soon as I have an
- *   SMU based machine at hand. Some more cleanup is needed too,
- *   like maybe fitting it into a platform device, etc...
- *   Also check what's up with cache coherency, and if we really
- *   can't do better than flushing the cache, maybe build a table
- *   of command len/reply len like the PMU driver to only flush
- *   what is actually necessary.
- *   --BenH.
+ *  - maybe add timeout to commands ?
+ *  - blocking version of time functions
+ *  - polling version of i2c commands (including timer that works with
+ *    interrutps off)
+ *  - maybe avoid some data copies with i2c by directly using the smu cmd
+ *    buffer and a lower level internal interface
+ *  - understand SMU -> CPU events and implement reception of them via
+ *    the userland interface
  */
 
 #include <linux/config.h>
@@ -36,6 +30,11 @@
 #include <linux/jiffies.h>
 #include <linux/interrupt.h>
 #include <linux/rtc.h>
+#include <linux/completion.h>
+#include <linux/miscdevice.h>
+#include <linux/delay.h>
+#include <linux/sysdev.h>
+#include <linux/poll.h>
 
 #include <asm/byteorder.h>
 #include <asm/io.h>
@@ -45,8 +44,13 @@
 #include <asm/smu.h>
 #include <asm/sections.h>
 #include <asm/abs_addr.h>
+#include <asm/uaccess.h>
+#include <asm/of_device.h>
+
+#define VERSION "0.6"
+#define AUTHOR  "(c) 2005 Benjamin Herrenschmidt, IBM Corp."
 
-#define DEBUG_SMU 1
+#undef DEBUG_SMU
 
 #ifdef DEBUG_SMU
 #define DPRINTK(fmt, args...) do { printk(KERN_DEBUG fmt , ##args); } while (0)
@@ -57,20 +61,30 @@
 /*
  * This is the command buffer passed to the SMU hardware
  */
+#define SMU_MAX_DATA	254
+
 struct smu_cmd_buf {
 	u8 cmd;
 	u8 length;
-	u8 data[0x0FFE];
+	u8 data[SMU_MAX_DATA];
 };
 
 struct smu_device {
 	spinlock_t		lock;
 	struct device_node	*of_node;
-	int			db_ack;		/* doorbell ack GPIO */
-	int			db_req;		/* doorbell req GPIO */
+	struct of_device	*of_dev;
+	int			doorbell;	/* doorbell gpio */
 	u32 __iomem		*db_buf;	/* doorbell buffer */
+	int			db_irq;
+	int			msg;
+	int			msg_irq;
 	struct smu_cmd_buf	*cmd_buf;	/* command buffer virtual */
 	u32			cmd_buf_abs;	/* command buffer absolute */
+	struct list_head	cmd_list;
+	struct smu_cmd		*cmd_cur;	/* pending command */
+	struct list_head	cmd_i2c_list;
+	struct smu_i2c_cmd	*cmd_i2c_cur;	/* pending i2c command */
+	struct timer_list	i2c_timer;
 };
 
 /*
@@ -79,113 +93,243 @@ struct smu_device {
  */
 static struct smu_device	*smu;
 
+
 /*
- * SMU low level communication stuff
+ * SMU driver low level stuff
  */
-static inline int smu_cmd_stat(struct smu_cmd_buf *cmd_buf, u8 cmd_ack)
-{
-	rmb();
-	return cmd_buf->cmd == cmd_ack && cmd_buf->length != 0;
-}
 
-static inline u8 smu_save_ack_cmd(struct smu_cmd_buf *cmd_buf)
+static void smu_start_cmd(void)
 {
-	return (~cmd_buf->cmd) & 0xff;
-}
+	unsigned long faddr, fend;
+	struct smu_cmd *cmd;
 
-static void smu_send_cmd(struct smu_device *dev)
-{
-	/* SMU command buf is currently cacheable, we need a physical
-	 * address. This isn't exactly a DMA mapping here, I suspect
+	if (list_empty(&smu->cmd_list))
+		return;
+
+	/* Fetch first command in queue */
+	cmd = list_entry(smu->cmd_list.next, struct smu_cmd, link);
+	smu->cmd_cur = cmd;
+	list_del(&cmd->link);
+
+	DPRINTK("SMU: starting cmd %x, %d bytes data\n", cmd->cmd,
+		cmd->data_len);
+	DPRINTK("SMU: data buffer: %02x %02x %02x %02x ...\n",
+		((u8 *)cmd->data_buf)[0], ((u8 *)cmd->data_buf)[1],
+		((u8 *)cmd->data_buf)[2], ((u8 *)cmd->data_buf)[3]);
+
+	/* Fill the SMU command buffer */
+	smu->cmd_buf->cmd = cmd->cmd;
+	smu->cmd_buf->length = cmd->data_len;
+	memcpy(smu->cmd_buf->data, cmd->data_buf, cmd->data_len);
+
+	/* Flush command and data to RAM */
+	faddr = (unsigned long)smu->cmd_buf;
+	fend = faddr + smu->cmd_buf->length + 2;
+	flush_inval_dcache_range(faddr, fend);
+
+	/* This isn't exactly a DMA mapping here, I suspect
 	 * the SMU is actually communicating with us via i2c to the
 	 * northbridge or the CPU to access RAM.
 	 */
-	writel(dev->cmd_buf_abs, dev->db_buf);
+	writel(smu->cmd_buf_abs, smu->db_buf);
 
 	/* Ring the SMU doorbell */
-	pmac_do_feature_call(PMAC_FTR_WRITE_GPIO, NULL, dev->db_req, 4);
-	pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, dev->db_req, 4);
+	pmac_do_feature_call(PMAC_FTR_WRITE_GPIO, NULL, smu->doorbell, 4);
 }
 
-static int smu_cmd_done(struct smu_device *dev)
+
+static irqreturn_t smu_db_intr(int irq, void *arg, struct pt_regs *regs)
 {
-	unsigned long wait = 0;
-	int gpio;
+	unsigned long flags;
+	struct smu_cmd *cmd;
+	void (*done)(struct smu_cmd *cmd, void *misc) = NULL;
+	void *misc = NULL;
+	u8 gpio;
+	int rc = 0;
 
-	/* Check the SMU doorbell */
-	do  {
-		gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO,
-					    NULL, dev->db_ack);
-		if ((gpio & 7) == 7)
-			return 0;
-		udelay(100);
-	} while(++wait < 10000);
+	/* SMU completed the command, well, we hope, let's make sure
+	 * of it
+	 */
+	spin_lock_irqsave(&smu->lock, flags);
 
-	printk(KERN_ERR "SMU timeout !\n");
-	return -ENXIO;
+	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
+	if ((gpio & 7) != 7)
+		return IRQ_HANDLED;
+
+	cmd = smu->cmd_cur;
+	smu->cmd_cur = NULL;
+	if (cmd == NULL)
+		goto bail;
+
+	if (rc == 0) {
+		unsigned long faddr;
+		int reply_len;
+		u8 ack;
+
+		/* CPU might have brought back the cache line, so we need
+		 * to flush again before peeking at the SMU response. We
+		 * flush the entire buffer for now as we haven't read the
+		 * reply lenght (it's only 2 cache lines anyway)
+		 */
+		faddr = (unsigned long)smu->cmd_buf;
+		flush_inval_dcache_range(faddr, faddr + 256);
+
+		/* Now check ack */
+		ack = (~cmd->cmd) & 0xff;
+		if (ack != smu->cmd_buf->cmd) {
+			DPRINTK("SMU: incorrect ack, want %x got %x\n",
+				ack, smu->cmd_buf->cmd);
+			rc = -EIO;
+		}
+		reply_len = rc == 0 ? smu->cmd_buf->length : 0;
+		DPRINTK("SMU: reply len: %d\n", reply_len);
+		if (reply_len > cmd->reply_len) {
+			printk(KERN_WARNING "SMU: reply buffer too small,"
+			       "got %d bytes for a %d bytes buffer\n",
+			       reply_len, cmd->reply_len);
+			reply_len = cmd->reply_len;
+		}
+		cmd->reply_len = reply_len;
+		if (cmd->reply_buf && reply_len)
+			memcpy(cmd->reply_buf, smu->cmd_buf->data, reply_len);
+	}
+
+	/* Now complete the command. Write status last in order as we lost
+	 * ownership of the command structure as soon as it's no longer -1
+	 */
+	done = cmd->done;
+	misc = cmd->misc;
+	mb();
+	cmd->status = rc;
+ bail:
+	/* Start next command if any */
+	smu_start_cmd();
+	spin_unlock_irqrestore(&smu->lock, flags);
+
+	/* Call command completion handler if any */
+	if (done)
+		done(cmd, misc);
+
+	/* It's an edge interrupt, nothing to do */
+	return IRQ_HANDLED;
 }
 
-static int smu_do_cmd(struct smu_device *dev)
+
+static irqreturn_t smu_msg_intr(int irq, void *arg, struct pt_regs *regs)
 {
-	int rc;
-	u8 cmd_ack;
+	/* I don't quite know what to do with this one, we seem to never
+	 * receive it, so I suspect we have to arm it someway in the SMU
+	 * to start getting events that way.
+	 */
+
+	printk(KERN_INFO "SMU: message interrupt !\n");
 
-	DPRINTK("SMU do_cmd %02x len=%d %02x\n",
-		dev->cmd_buf->cmd, dev->cmd_buf->length,
-		dev->cmd_buf->data[0]);
+	/* It's an edge interrupt, nothing to do */
+	return IRQ_HANDLED;
+}
 
-	cmd_ack = smu_save_ack_cmd(dev->cmd_buf);
 
-	/* Clear cmd_buf cache lines */
-	flush_inval_dcache_range((unsigned long)dev->cmd_buf,
-				 ((unsigned long)dev->cmd_buf) +
-				 sizeof(struct smu_cmd_buf));
-	smu_send_cmd(dev);
-	rc = smu_cmd_done(dev);
-	if (rc == 0)
-		rc = smu_cmd_stat(dev->cmd_buf, cmd_ack) ? 0 : -1;
+/*
+ * Queued command management.
+ *
+ */
 
-	DPRINTK("SMU do_cmd %02x len=%d %02x => %d (%02x)\n",
-		dev->cmd_buf->cmd, dev->cmd_buf->length,
-		dev->cmd_buf->data[0], rc, cmd_ack);
+int smu_queue_cmd(struct smu_cmd *cmd)
+{
+	unsigned long flags;
 
-	return rc;
+	if (smu == NULL)
+		return -ENODEV;
+	if (cmd->data_len > SMU_MAX_DATA ||
+	    cmd->reply_len > SMU_MAX_DATA)
+		return -EINVAL;
+
+	cmd->status = 1;
+	spin_lock_irqsave(&smu->lock, flags);
+	list_add_tail(&cmd->link, &smu->cmd_list);
+	if (smu->cmd_cur == NULL)
+		smu_start_cmd();
+	spin_unlock_irqrestore(&smu->lock, flags);
+
+	return 0;
 }
+EXPORT_SYMBOL(smu_queue_cmd);
 
-/* RTC low level commands */
-static inline int bcd2hex (int n)
+
+int smu_queue_simple(struct smu_simple_cmd *scmd, u8 command,
+		     unsigned int data_len,
+		     void (*done)(struct smu_cmd *cmd, void *misc),
+		     void *misc, ...)
 {
-	return (((n & 0xf0) >> 4) * 10) + (n & 0xf);
+	struct smu_cmd *cmd = &scmd->cmd;
+	va_list list;
+	int i;
+
+	if (data_len > sizeof(scmd->buffer))
+		return -EINVAL;
+
+	memset(scmd, 0, sizeof(*scmd));
+	cmd->cmd = command;
+	cmd->data_len = data_len;
+	cmd->data_buf = scmd->buffer;
+	cmd->reply_len = sizeof(scmd->buffer);
+	cmd->reply_buf = scmd->buffer;
+	cmd->done = done;
+	cmd->misc = misc;
+
+	va_start(list, misc);
+	for (i = 0; i < data_len; ++i)
+		scmd->buffer[i] = (u8)va_arg(list, int);
+	va_end(list);
+
+	return smu_queue_cmd(cmd);
 }
+EXPORT_SYMBOL(smu_queue_simple);
 
-static inline int hex2bcd (int n)
+
+void smu_poll(void)
 {
-	return ((n / 10) << 4) + (n % 10);
+	u8 gpio;
+
+	if (smu == NULL)
+		return;
+
+	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
+	if ((gpio & 7) == 7)
+		smu_db_intr(smu->db_irq, smu, NULL);
 }
+EXPORT_SYMBOL(smu_poll);
+
 
-#if 0
-static inline void smu_fill_set_pwrup_timer_cmd(struct smu_cmd_buf *cmd_buf)
+void smu_done_complete(struct smu_cmd *cmd, void *misc)
 {
-	cmd_buf->cmd = 0x8e;
-	cmd_buf->length = 8;
-	cmd_buf->data[0] = 0x00;
-	memset(cmd_buf->data + 1, 0, 7);
+	struct completion *comp = misc;
+
+	complete(comp);
 }
+EXPORT_SYMBOL(smu_done_complete);
+
 
-static inline void smu_fill_get_pwrup_timer_cmd(struct smu_cmd_buf *cmd_buf)
+void smu_spinwait_cmd(struct smu_cmd *cmd)
 {
-	cmd_buf->cmd = 0x8e;
-	cmd_buf->length = 1;
-	cmd_buf->data[0] = 0x01;
+	while(cmd->status == 1)
+		smu_poll();
+}
+EXPORT_SYMBOL(smu_spinwait_cmd);
+
+
+/* RTC low level commands */
+static inline int bcd2hex (int n)
+{
+	return (((n & 0xf0) >> 4) * 10) + (n & 0xf);
 }
 
-static inline void smu_fill_dis_pwrup_timer_cmd(struct smu_cmd_buf *cmd_buf)
+
+static inline int hex2bcd (int n)
 {
-	cmd_buf->cmd = 0x8e;
-	cmd_buf->length = 1;
-	cmd_buf->data[0] = 0x02;
+	return ((n / 10) << 4) + (n % 10);
 }
-#endif
+
 
 static inline void smu_fill_set_rtc_cmd(struct smu_cmd_buf *cmd_buf,
 					struct rtc_time *time)
@@ -202,100 +346,96 @@ static inline void smu_fill_set_rtc_cmd(struct smu_cmd_buf *cmd_buf,
 	cmd_buf->data[7] = hex2bcd(time->tm_year - 100);
 }
 
-static inline void smu_fill_get_rtc_cmd(struct smu_cmd_buf *cmd_buf)
-{
-	cmd_buf->cmd = 0x8e;
-	cmd_buf->length = 1;
-	cmd_buf->data[0] = 0x81;
-}
 
-static void smu_parse_get_rtc_reply(struct smu_cmd_buf *cmd_buf,
-				    struct rtc_time *time)
+int smu_get_rtc_time(struct rtc_time *time, int spinwait)
 {
-	time->tm_sec = bcd2hex(cmd_buf->data[0]);
-	time->tm_min = bcd2hex(cmd_buf->data[1]);
-	time->tm_hour = bcd2hex(cmd_buf->data[2]);
-	time->tm_wday = bcd2hex(cmd_buf->data[3]);
-	time->tm_mday = bcd2hex(cmd_buf->data[4]);
-	time->tm_mon = bcd2hex(cmd_buf->data[5]) - 1;
-	time->tm_year = bcd2hex(cmd_buf->data[6]) + 100;
-}
-
-int smu_get_rtc_time(struct rtc_time *time)
-{
-	unsigned long flags;
+	struct smu_simple_cmd cmd;
 	int rc;
 
 	if (smu == NULL)
 		return -ENODEV;
 
 	memset(time, 0, sizeof(struct rtc_time));
-	spin_lock_irqsave(&smu->lock, flags);
-	smu_fill_get_rtc_cmd(smu->cmd_buf);
-	rc = smu_do_cmd(smu);
-	if (rc == 0)
-		smu_parse_get_rtc_reply(smu->cmd_buf, time);
-	spin_unlock_irqrestore(&smu->lock, flags);
+	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 1, NULL, NULL,
+			      SMU_CMD_RTC_GET_DATETIME);
+	if (rc)
+		return rc;
+	smu_spinwait_simple(&cmd);
 
-	return rc;
+	time->tm_sec = bcd2hex(cmd.buffer[0]);
+	time->tm_min = bcd2hex(cmd.buffer[1]);
+	time->tm_hour = bcd2hex(cmd.buffer[2]);
+	time->tm_wday = bcd2hex(cmd.buffer[3]);
+	time->tm_mday = bcd2hex(cmd.buffer[4]);
+	time->tm_mon = bcd2hex(cmd.buffer[5]) - 1;
+	time->tm_year = bcd2hex(cmd.buffer[6]) + 100;
+
+	return 0;
 }
 
-int smu_set_rtc_time(struct rtc_time *time)
+
+int smu_set_rtc_time(struct rtc_time *time, int spinwait)
 {
-	unsigned long flags;
+	struct smu_simple_cmd cmd;
 	int rc;
 
 	if (smu == NULL)
 		return -ENODEV;
 
-	spin_lock_irqsave(&smu->lock, flags);
-	smu_fill_set_rtc_cmd(smu->cmd_buf, time);
-	rc = smu_do_cmd(smu);
-	spin_unlock_irqrestore(&smu->lock, flags);
+	rc = smu_queue_simple(&cmd, SMU_CMD_RTC_COMMAND, 8, NULL, NULL,
+			      SMU_CMD_RTC_SET_DATETIME,
+			      hex2bcd(time->tm_sec),
+			      hex2bcd(time->tm_min),
+			      hex2bcd(time->tm_hour),
+			      time->tm_wday,
+			      hex2bcd(time->tm_mday),
+			      hex2bcd(time->tm_mon) + 1,
+			      hex2bcd(time->tm_year - 100));
+	if (rc)
+		return rc;
+	smu_spinwait_simple(&cmd);
 
-	return rc;
+	return 0;
 }
 
+
 void smu_shutdown(void)
 {
-	const unsigned char *command = "SHUTDOWN";
-	unsigned long flags;
+	struct smu_simple_cmd cmd;
 
 	if (smu == NULL)