[PATCH] ppc64: SMU driver update & i2c support
[linux-2.6.git] / drivers / macintosh / smu.c
index fb53573..a85ac18 100644 (file)
@@ -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>
 #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>
 #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)
 /*
  * 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)
                return;
 
-       spin_lock_irqsave(&smu->lock, flags);
-       smu->cmd_buf->cmd = 0xaa;
-       smu->cmd_buf->length = strlen(command);
-       strcpy(smu->cmd_buf->data, command);
-       smu_do_cmd(smu);
+       if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 9, NULL, NULL,
+                            'S', 'H', 'U', 'T', 'D', 'O', 'W', 'N', 0))
+               return;
+       smu_spinwait_simple(&cmd);
        for (;;)
                ;
-       spin_unlock_irqrestore(&smu->lock, flags);
 }
 
+
 void smu_restart(void)
 {
-       const unsigned char *command = "RESTART";
-       unsigned long flags;
+       struct smu_simple_cmd cmd;
 
        if (smu == NULL)
                return;
 
-       spin_lock_irqsave(&smu->lock, flags);
-       smu->cmd_buf->cmd = 0xaa;
-       smu->cmd_buf->length = strlen(command);
-       strcpy(smu->cmd_buf->data, command);
-       smu_do_cmd(smu);
+       if (smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, NULL, NULL,
+                            'R', 'E', 'S', 'T', 'A', 'R', 'T', 0))
+               return;
+       smu_spinwait_simple(&cmd);
        for (;;)
                ;
-       spin_unlock_irqrestore(&smu->lock, flags);
 }
 
+
 int smu_present(void)
 {
        return smu != NULL;
 }
+EXPORT_SYMBOL(smu_present);
 
 
 int smu_init (void)
@@ -307,6 +447,8 @@ int smu_init (void)
         if (np == NULL)
                return -ENODEV;
 
+       printk(KERN_INFO "SMU driver %s %s\n", VERSION, AUTHOR);
+
        if (smu_cmdbuf_abs == 0) {
                printk(KERN_ERR "SMU: Command buffer not allocated !\n");
                return -EINVAL;
@@ -318,7 +460,13 @@ int smu_init (void)
        memset(smu, 0, sizeof(*smu));
 
        spin_lock_init(&smu->lock);
+       INIT_LIST_HEAD(&smu->cmd_list);
+       INIT_LIST_HEAD(&smu->cmd_i2c_list);
        smu->of_node = np;
+       smu->db_irq = NO_IRQ;
+       smu->msg_irq = NO_IRQ;
+       init_timer(&smu->i2c_timer);
+
        /* smu_cmdbuf_abs is in the low 2G of RAM, can be converted to a
         * 32 bits value safely
         */
@@ -331,8 +479,8 @@ int smu_init (void)
                goto fail;
        }
        data = (u32 *)get_property(np, "reg", NULL);
-       of_node_put(np);
        if (data == NULL) {
+               of_node_put(np);
                printk(KERN_ERR "SMU: Can't find doorbell GPIO address !\n");
                goto fail;
        }
@@ -341,8 +489,31 @@ int smu_init (void)
         * and ack. GPIOs are at 0x50, best would be to find that out
         * in the device-tree though.
         */
-       smu->db_req = 0x50 + *data;
-       smu->db_ack = 0x50 + *data;
+       smu->doorbell = *data;
+       if (smu->doorbell < 0x50)
+               smu->doorbell += 0x50;
+       if (np->n_intrs > 0)
+               smu->db_irq = np->intrs[0].line;
+
+       of_node_put(np);
+
+       /* Now look for the smu-interrupt GPIO */
+       do {
+               np = of_find_node_by_name(NULL, "smu-interrupt");
+               if (np == NULL)
+                       break;
+               data = (u32 *)get_property(np, "reg", NULL);
+               if (data == NULL) {
+                       of_node_put(np);
+                       break;
+               }
+               smu->msg = *data;
+               if (smu->msg < 0x50)
+                       smu->msg += 0x50;
+               if (np->n_intrs > 0)
+                       smu->msg_irq = np->intrs[0].line;
+               of_node_put(np);
+       } while(0);
 
        /* Doorbell buffer is currently hard-coded, I didn't find a proper
         * device-tree entry giving the address. Best would probably to use
@@ -362,3 +533,584 @@ int smu_init (void)
        return -ENXIO;
 
 }
+
+
+static int smu_late_init(void)
+{
+       if (!smu)
+               return 0;
+
+       /*
+        * Try to request the interrupts
+        */
+
+       if (smu->db_irq != NO_IRQ) {
+               if (request_irq(smu->db_irq, smu_db_intr,
+                               SA_SHIRQ, "SMU doorbell", smu) < 0) {
+                       printk(KERN_WARNING "SMU: can't "
+                              "request interrupt %d\n",
+                              smu->db_irq);
+                       smu->db_irq = NO_IRQ;
+               }
+       }
+
+       if (smu->msg_irq != NO_IRQ) {
+               if (request_irq(smu->msg_irq, smu_msg_intr,
+                               SA_SHIRQ, "SMU message", smu) < 0) {
+                       printk(KERN_WARNING "SMU: can't "
+                              "request interrupt %d\n",
+                              smu->msg_irq);
+                       smu->msg_irq = NO_IRQ;
+               }
+       }
+
+       return 0;
+}
+arch_initcall(smu_late_init);
+
+/*
+ * sysfs visibility
+ */
+
+static void smu_expose_childs(void *unused)
+{
+       struct device_node *np;
+
+       for (np = NULL; (np = of_get_next_child(smu->of_node, np)) != NULL;) {
+               if (device_is_compatible(np, "smu-i2c")) {
+                       char name[32];
+                       u32 *reg = (u32 *)get_property(np, "reg", NULL);
+
+                       if (reg == NULL)
+                               continue;
+                       sprintf(name, "smu-i2c-%02x", *reg);
+                       of_platform_device_create(np, name, &smu->of_dev->dev);
+               }
+       }
+
+}
+
+static DECLARE_WORK(smu_expose_childs_work, smu_expose_childs, NULL);
+
+static int smu_platform_probe(struct of_device* dev,
+                             const struct of_device_id *match)
+{
+       if (!smu)
+               return -ENODEV;
+       smu->of_dev = dev;
+
+       /*
+        * Ok, we are matched, now expose all i2c busses. We have to defer
+        * that unfortunately or it would deadlock inside the device model
+        */
+       schedule_work(&smu_expose_childs_work);
+
+       return 0;
+}
+
+static struct of_device_id smu_platform_match[] =
+{
+       {
+               .type           = "smu",
+       },
+       {},
+};
+
+static struct of_platform_driver smu_of_platform_driver =
+{
+       .name           = "smu",
+       .match_table    = smu_platform_match,
+       .probe          = smu_platform_probe,
+};
+
+static int __init smu_init_sysfs(void)
+{
+       int rc;
+
+       /*
+        * Due to sysfs bogosity, a sysdev is not a real device, so
+        * we should in fact create both if we want sysdev semantics
+        * for power management.
+        * For now, we don't power manage machines with an SMU chip,
+        * I'm a bit too far from figuring out how that works with those
+        * new chipsets, but that will come back and bite us
+        */
+       rc = of_register_driver(&smu_of_platform_driver);
+       return 0;
+}
+
+device_initcall(smu_init_sysfs);
+
+struct of_device *smu_get_ofdev(void)
+{
+       if (!smu)
+               return NULL;
+       return smu->of_dev;
+}
+
+EXPORT_SYMBOL_GPL(smu_get_ofdev);
+
+/*
+ * i2c interface
+ */
+
+static void smu_i2c_complete_command(struct smu_i2c_cmd *cmd, int fail)
+{
+       void (*done)(struct smu_i2c_cmd *cmd, void *misc) = cmd->done;
+       void *misc = cmd->misc;
+       unsigned long flags;
+
+       /* Check for read case */
+       if (!fail && cmd->read) {
+               if (cmd->pdata[0] < 1)
+                       fail = 1;
+               else
+                       memcpy(cmd->info.data, &cmd->pdata[1],
+                              cmd->info.datalen);
+       }
+
+       DPRINTK("SMU: completing, success: %d\n", !fail);
+
+       /* Update status and mark no pending i2c command with lock
+        * held so nobody comes in while we dequeue an eventual
+        * pending next i2c command
+        */
+       spin_lock_irqsave(&smu->lock, flags);
+       smu->cmd_i2c_cur = NULL;
+       wmb();
+       cmd->status = fail ? -EIO : 0;
+
+       /* Is there another i2c command waiting ? */
+       if (!list_empty(&smu->cmd_i2c_list)) {
+               struct smu_i2c_cmd *newcmd;
+
+               /* Fetch it, new current, remove from list */
+               newcmd = list_entry(smu->cmd_i2c_list.next,
+                                   struct smu_i2c_cmd, link);
+               smu->cmd_i2c_cur = newcmd;
+               list_del(&cmd->link);
+
+               /* Queue with low level smu */
+               list_add_tail(&cmd->scmd.link, &smu->cmd_list);
+               if (smu->cmd_cur == NULL)
+                       smu_start_cmd();
+       }
+       spin_unlock_irqrestore(&smu->lock, flags);
+
+       /* Call command completion handler if any */
+       if (done)
+               done(cmd, misc);
+
+}
+
+
+static void smu_i2c_retry(unsigned long data)
+{
+       struct smu_i2c_cmd      *cmd = (struct smu_i2c_cmd *)data;
+
+       DPRINTK("SMU: i2c failure, requeuing...\n");
+
+       /* requeue command simply by resetting reply_len */
+       cmd->pdata[0] = 0xff;
+       cmd->scmd.reply_len = 0x10;
+       smu_queue_cmd(&cmd->scmd);
+}
+
+
+static void smu_i2c_low_completion(struct smu_cmd *scmd, void *misc)
+{
+       struct smu_i2c_cmd      *cmd = misc;
+       int                     fail = 0;
+
+       DPRINTK("SMU: i2c compl. stage=%d status=%x pdata[0]=%x rlen: %x\n",
+               cmd->stage, scmd->status, cmd->pdata[0], scmd->reply_len);
+
+       /* Check for possible status */
+       if (scmd->status < 0)
+               fail = 1;
+       else if (cmd->read) {
+               if (cmd->stage == 0)
+                       fail = cmd->pdata[0] != 0;
+               else
+                       fail = cmd->pdata[0] >= 0x80;
+       } else {
+               fail = cmd->pdata[0] != 0;
+       }
+
+       /* Handle failures by requeuing command, after 5ms interval
+        */
+       if (fail && --cmd->retries > 0) {
+               DPRINTK("SMU: i2c failure, starting timer...\n");
+               smu->i2c_timer.function = smu_i2c_retry;
+               smu->i2c_timer.data = (unsigned long)cmd;
+               smu->i2c_timer.expires = jiffies + msecs_to_jiffies(5);
+               add_timer(&smu->i2c_timer);
+               return;
+       }
+
+       /* If failure or stage 1, command is complete */
+       if (fail || cmd->stage != 0) {
+               smu_i2c_complete_command(cmd, fail);
+               return;
+       }
+
+       DPRINTK("SMU: going to stage 1\n");
+
+       /* Ok, initial command complete, now poll status */
+       scmd->reply_buf = cmd->pdata;
+       scmd->reply_len = 0x10;
+       scmd->data_buf = cmd->pdata;
+       scmd->data_len = 1;
+       cmd->pdata[0] = 0;
+       cmd->stage = 1;
+       cmd->retries = 20;
+       smu_queue_cmd(scmd);
+}
+
+
+int smu_queue_i2c(struct smu_i2c_cmd *cmd)
+{
+       unsigned long flags;
+
+       if (smu == NULL)
+               return -ENODEV;
+
+       /* Fill most fields of scmd */
+       cmd->scmd.cmd = SMU_CMD_I2C_COMMAND;
+       cmd->scmd.done = smu_i2c_low_completion;
+       cmd->scmd.misc = cmd;
+       cmd->scmd.reply_buf = cmd->pdata;
+       cmd->scmd.reply_len = 0x10;
+       cmd->scmd.data_buf = (u8 *)(char *)&cmd->info;
+       cmd->scmd.status = 1;
+       cmd->stage = 0;
+       cmd->pdata[0] = 0xff;
+       cmd->retries = 20;
+       cmd->status = 1;
+
+       /* Check transfer type, sanitize some "info" fields
+        * based on transfer type and do more checking
+        */
+       cmd->info.caddr = cmd->info.devaddr;
+       cmd->read = cmd->info.devaddr & 0x01;
+       switch(cmd->info.type) {
+       case SMU_I2C_TRANSFER_SIMPLE:
+               memset(&cmd->info.sublen, 0, 4);
+               break;
+       case SMU_I2C_TRANSFER_COMBINED:
+               cmd->info.devaddr &= 0xfe;
+       case SMU_I2C_TRANSFER_STDSUB:
+               if (cmd->info.sublen > 3)
+                       return -EINVAL;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       /* Finish setting up command based on transfer direction
+        */
+       if (cmd->read) {
+               if (cmd->info.datalen > SMU_I2C_READ_MAX)
+                       return -EINVAL;
+               memset(cmd->info.data, 0xff, cmd->info.datalen);
+               cmd->scmd.data_len = 9;
+       } else {
+               if (cmd->info.datalen > SMU_I2C_WRITE_MAX)
+                       return -EINVAL;
+               cmd->scmd.data_len = 9 + cmd->info.datalen;
+       }
+
+       DPRINTK("SMU: i2c enqueuing command\n");
+       DPRINTK("SMU:   %s, len=%d bus=%x addr=%x sub0=%x type=%x\n",
+               cmd->read ? "read" : "write", cmd->info.datalen,
+               cmd->info.bus, cmd->info.caddr,
+               cmd->info.subaddr[0], cmd->info.type);
+
+
+       /* Enqueue command in i2c list, and if empty, enqueue also in
+        * main command list
+        */
+       spin_lock_irqsave(&smu->lock, flags);
+       if (smu->cmd_i2c_cur == NULL) {
+               smu->cmd_i2c_cur = cmd;
+               list_add_tail(&cmd->scmd.link, &smu->cmd_list);
+               if (smu->cmd_cur == NULL)
+                       smu_start_cmd();
+       } else
+               list_add_tail(&cmd->link, &smu->cmd_i2c_list);
+       spin_unlock_irqrestore(&smu->lock, flags);
+
+       return 0;
+}
+
+
+
+/*
+ * Userland driver interface
+ */
+
+
+static LIST_HEAD(smu_clist);
+static DEFINE_SPINLOCK(smu_clist_lock);
+
+enum smu_file_mode {
+       smu_file_commands,
+       smu_file_events,
+       smu_file_closing
+};
+
+struct smu_private
+{
+       struct list_head        list;
+       enum smu_file_mode      mode;
+       int                     busy;
+       struct smu_cmd          cmd;
+       spinlock_t              lock;
+       wait_queue_head_t       wait;
+       u8                      buffer[SMU_MAX_DATA];
+};
+
+
+static int smu_open(struct inode *inode, struct file *file)
+{
+       struct smu_private *pp;
+       unsigned long flags;
+
+       pp = kmalloc(sizeof(struct smu_private), GFP_KERNEL);
+       if (pp == 0)
+               return -ENOMEM;
+       memset(pp, 0, sizeof(struct smu_private));
+       spin_lock_init(&pp->lock);
+       pp->mode = smu_file_commands;
+       init_waitqueue_head(&pp->wait);
+
+       spin_lock_irqsave(&smu_clist_lock, flags);
+       list_add(&pp->list, &smu_clist);
+       spin_unlock_irqrestore(&smu_clist_lock, flags);
+       file->private_data = pp;
+
+       return 0;
+}
+
+
+static void smu_user_cmd_done(struct smu_cmd *cmd, void *misc)
+{
+       struct smu_private *pp = misc;
+
+       wake_up_all(&pp->wait);
+}
+
+
+static ssize_t smu_write(struct file *file, const char __user *buf,
+                        size_t count, loff_t *ppos)
+{
+       struct smu_private *pp = file->private_data;
+       unsigned long flags;
+       struct smu_user_cmd_hdr hdr;
+       int rc = 0;
+
+       if (pp->busy)
+               return -EBUSY;
+       else if (copy_from_user(&hdr, buf, sizeof(hdr)))
+               return -EFAULT;
+       else if (hdr.cmdtype == SMU_CMDTYPE_WANTS_EVENTS) {
+               pp->mode = smu_file_events;
+               return 0;
+       } else if (hdr.cmdtype != SMU_CMDTYPE_SMU)
+               return -EINVAL;
+       else if (pp->mode != smu_file_commands)
+               return -EBADFD;
+       else if (hdr.data_len > SMU_MAX_DATA)
+               return -EINVAL;
+
+       spin_lock_irqsave(&pp->lock, flags);
+       if (pp->busy) {
+               spin_unlock_irqrestore(&pp->lock, flags);
+               return -EBUSY;
+       }
+       pp->busy = 1;
+       pp->cmd.status = 1;
+       spin_unlock_irqrestore(&pp->lock, flags);
+
+       if (copy_from_user(pp->buffer, buf + sizeof(hdr), hdr.data_len)) {
+               pp->busy = 0;
+               return -EFAULT;
+       }
+
+       pp->cmd.cmd = hdr.cmd;
+       pp->cmd.data_len = hdr.data_len;
+       pp->cmd.reply_len = SMU_MAX_DATA;
+       pp->cmd.data_buf = pp->buffer;
+       pp->cmd.reply_buf = pp->buffer;
+       pp->cmd.done = smu_user_cmd_done;
+       pp->cmd.misc = pp;
+       rc = smu_queue_cmd(&pp->cmd);
+       if (rc < 0)
+               return rc;
+       return count;
+}
+
+
+static ssize_t smu_read_command(struct file *file, struct smu_private *pp,
+                               char __user *buf, size_t count)
+{
+       DECLARE_WAITQUEUE(wait, current);
+       struct smu_user_reply_hdr hdr;
+       unsigned long flags;
+       int size, rc = 0;
+
+       if (!pp->busy)
+               return 0;
+       if (count < sizeof(struct smu_user_reply_hdr))
+               return -EOVERFLOW;
+       spin_lock_irqsave(&pp->lock, flags);
+       if (pp->cmd.status == 1) {
+               if (file->f_flags & O_NONBLOCK)
+                       return -EAGAIN;
+               add_wait_queue(&pp->wait, &wait);
+               for (;;) {
+                       set_current_state(TASK_INTERRUPTIBLE);
+                       rc = 0;
+                       if (pp->cmd.status != 1)
+                               break;
+                       rc = -ERESTARTSYS;
+                       if (signal_pending(current))
+                               break;
+                       spin_unlock_irqrestore(&pp->lock, flags);
+                       schedule();
+                       spin_lock_irqsave(&pp->lock, flags);
+               }
+               set_current_state(TASK_RUNNING);
+               remove_wait_queue(&pp->wait, &wait);
+       }
+       spin_unlock_irqrestore(&pp->lock, flags);
+       if (rc)
+               return rc;
+       if (pp->cmd.status != 0)
+               pp->cmd.reply_len = 0;
+       size = sizeof(hdr) + pp->cmd.reply_len;
+       if (count < size)
+               size = count;
+       rc = size;
+       hdr.status = pp->cmd.status;
+       hdr.reply_len = pp->cmd.reply_len;
+       if (copy_to_user(buf, &hdr, sizeof(hdr)))
+               return -EFAULT;
+       size -= sizeof(hdr);
+       if (size && copy_to_user(buf + sizeof(hdr), pp->buffer, size))
+               return -EFAULT;
+       pp->busy = 0;
+
+       return rc;
+}
+
+
+static ssize_t smu_read_events(struct file *file, struct smu_private *pp,
+                              char __user *buf, size_t count)
+{
+       /* Not implemented */
+       msleep_interruptible(1000);
+       return 0;
+}
+
+
+static ssize_t smu_read(struct file *file, char __user *buf,
+                       size_t count, loff_t *ppos)
+{
+       struct smu_private *pp = file->private_data;
+
+       if (pp->mode == smu_file_commands)
+               return smu_read_command(file, pp, buf, count);
+       if (pp->mode == smu_file_events)
+               return smu_read_events(file, pp, buf, count);
+
+       return -EBADFD;
+}
+
+static unsigned int smu_fpoll(struct file *file, poll_table *wait)
+{
+       struct smu_private *pp = file->private_data;
+       unsigned int mask = 0;
+       unsigned long flags;
+
+       if (pp == 0)
+               return 0;
+
+       if (pp->mode == smu_file_commands) {
+               poll_wait(file, &pp->wait, wait);
+
+               spin_lock_irqsave(&pp->lock, flags);
+               if (pp->busy && pp->cmd.status != 1)
+                       mask |= POLLIN;
+               spin_unlock_irqrestore(&pp->lock, flags);
+       } if (pp->mode == smu_file_events) {
+               /* Not yet implemented */
+       }
+       return mask;
+}
+
+static int smu_release(struct inode *inode, struct file *file)
+{
+       struct smu_private *pp = file->private_data;
+       unsigned long flags;
+       unsigned int busy;
+
+       if (pp == 0)
+               return 0;
+
+       file->private_data = NULL;
+
+       /* Mark file as closing to avoid races with new request */
+       spin_lock_irqsave(&pp->lock, flags);
+       pp->mode = smu_file_closing;
+       busy = pp->busy;
+
+       /* Wait for any pending request to complete */
+       if (busy && pp->cmd.status == 1) {
+               DECLARE_WAITQUEUE(wait, current);
+
+               add_wait_queue(&pp->wait, &wait);
+               for (;;) {
+                       set_current_state(TASK_UNINTERRUPTIBLE);
+                       if (pp->cmd.status != 1)
+                               break;
+                       spin_lock_irqsave(&pp->lock, flags);
+                       schedule();
+                       spin_unlock_irqrestore(&pp->lock, flags);
+               }
+               set_current_state(TASK_RUNNING);
+               remove_wait_queue(&pp->wait, &wait);
+       }
+       spin_unlock_irqrestore(&pp->lock, flags);
+
+       spin_lock_irqsave(&smu_clist_lock, flags);
+       list_del(&pp->list);
+       spin_unlock_irqrestore(&smu_clist_lock, flags);
+       kfree(pp);
+
+       return 0;
+}
+
+
+static struct file_operations smu_device_fops __pmacdata = {
+       .llseek         = no_llseek,
+       .read           = smu_read,
+       .write          = smu_write,
+       .poll           = smu_fpoll,
+       .open           = smu_open,
+       .release        = smu_release,
+};
+
+static struct miscdevice pmu_device __pmacdata = {
+       MISC_DYNAMIC_MINOR, "smu", &smu_device_fops
+};
+
+static int smu_device_init(void)
+{
+       if (!smu)
+               return -ENODEV;
+       if (misc_register(&pmu_device) < 0)
+               printk(KERN_ERR "via-pmu: cannot register misc device.\n");
+       return 0;
+}
+device_initcall(smu_device_init);