Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1337 insertions, 0 deletions

diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
new file mode 100644
index 0000000000..b2b78a53e5
--- /dev/null
+++ b/drivers/macintosh/smu.c
@@ -0,0 +1,1337 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PowerMac G5 SMU driver
+ *
+ * Copyright 2004 J. Mayer <l_indien@magic.fr>
+ * Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
+ */
+
+/*
+ * TODO:
+ *  - maybe add timeout to commands ?
+ *  - blocking version of time functions
+ *  - polling version of i2c commands (including timer that works with
+ *    interrupts 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/types.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/dmapool.h>
+#include <linux/memblock.h>
+#include <linux/vmalloc.h>
+#include <linux/highmem.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/poll.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+
+#include <asm/byteorder.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/pmac_feature.h>
+#include <asm/smu.h>
+#include <asm/sections.h>
+#include <linux/uaccess.h>
+
+#define VERSION "0.7"
+#define AUTHOR  "(c) 2005 Benjamin Herrenschmidt, IBM Corp."
+
+#undef DEBUG_SMU
+
+#ifdef DEBUG_SMU
+#define DPRINTK(fmt, args...) do { printk(KERN_DEBUG fmt , ##args); } while (0)
+#else
+#define DPRINTK(fmt, args...) do { } while (0)
+#endif
+
+/*
+ * 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[SMU_MAX_DATA];
+};
+
+struct smu_device {
+	spinlock_t		lock;
+	struct device_node	*of_node;
+	struct platform_device	*of_dev;
+	int			doorbell;	/* doorbell gpio */
+	u32 __iomem		*db_buf;	/* doorbell buffer */
+	struct device_node	*db_node;
+	unsigned int		db_irq;
+	int			msg;
+	struct device_node	*msg_node;
+	unsigned 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 */
+	int			broken_nap;
+	struct list_head	cmd_i2c_list;
+	struct smu_i2c_cmd	*cmd_i2c_cur;	/* pending i2c command */
+	struct timer_list	i2c_timer;
+};
+
+/*
+ * I don't think there will ever be more than one SMU, so
+ * for now, just hard code that
+ */
+static DEFINE_MUTEX(smu_mutex);
+static struct smu_device	*smu;
+static DEFINE_MUTEX(smu_part_access);
+static int smu_irq_inited;
+static unsigned long smu_cmdbuf_abs;
+
+static void smu_i2c_retry(struct timer_list *t);
+
+/*
+ * SMU driver low level stuff
+ */
+
+static void smu_start_cmd(void)
+{
+	unsigned long faddr, fend;
+	struct smu_cmd *cmd;
+
+	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: %8ph\n", cmd->data_buf);
+
+	/* 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_dcache_range(faddr, fend);
+
+
+	/* We also disable NAP mode for the duration of the command
+	 * on U3 based machines.
+	 * This is slightly racy as it can be written back to 1 by a sysctl
+	 * but that never happens in practice. There seem to be an issue with
+	 * U3 based machines such as the iMac G5 where napping for the
+	 * whole duration of the command prevents the SMU from fetching it
+	 * from memory. This might be related to the strange i2c based
+	 * mechanism the SMU uses to access memory.
+	 */
+	if (smu->broken_nap)
+		powersave_nap = 0;
+
+	/* 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(smu->cmd_buf_abs, smu->db_buf);
+
+	/* Ring the SMU doorbell */
+	pmac_do_feature_call(PMAC_FTR_WRITE_GPIO, NULL, smu->doorbell, 4);
+}
+
+
+static irqreturn_t smu_db_intr(int irq, void *arg)
+{
+	unsigned long flags;
+	struct smu_cmd *cmd;
+	void (*done)(struct smu_cmd *cmd, void *misc) = NULL;
+	void *misc = NULL;
+	u8 gpio;
+	int rc = 0;
+
+	/* SMU completed the command, well, we hope, let's make sure
+	 * of it
+	 */
+	spin_lock_irqsave(&smu->lock, flags);
+
+	gpio = pmac_do_feature_call(PMAC_FTR_READ_GPIO, NULL, smu->doorbell);
+	if ((gpio & 7) != 7) {
+		spin_unlock_irqrestore(&smu->lock, flags);
+		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 length (it's only 2 cache lines anyway)
+		 */
+		faddr = (unsigned long)smu->cmd_buf;
+		flush_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;
+
+	/* Re-enable NAP mode */
+	if (smu->broken_nap)
+		powersave_nap = 1;
+ 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 irqreturn_t smu_msg_intr(int irq, void *arg)
+{
+	/* 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");
+
+	/* It's an edge interrupt, nothing to do */
+	return IRQ_HANDLED;
+}
+
+
+/*
+ * Queued command management.
+ *
+ */
+
+int smu_queue_cmd(struct smu_cmd *cmd)
+{
+	unsigned long flags;
+
+	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);
+
+	/* Workaround for early calls when irq isn't available */
+	if (!smu_irq_inited || !smu->db_irq)
+		smu_spinwait_cmd(cmd);
+
+	return 0;
+}
+EXPORT_SYMBOL(smu_queue_cmd);
+
+
+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, ...)
+{
+	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);
+
+
+void smu_poll(void)
+{
+	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);
+}
+EXPORT_SYMBOL(smu_poll);
+
+
+void smu_done_complete(struct smu_cmd *cmd, void *misc)
+{
+	struct completion *comp = misc;
+
+	complete(comp);
+}
+EXPORT_SYMBOL(smu_done_complete);
+
+
+void smu_spinwait_cmd(struct smu_cmd *cmd)
+{
+	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 int hex2bcd (int n)
+{
+	return ((n / 10) << 4) + (n % 10);
+}
+
+
+static inline void smu_fill_set_rtc_cmd(struct smu_cmd_buf *cmd_buf,
+					struct rtc_time *time)
+{
+	cmd_buf->cmd = 0x8e;
+	cmd_buf->length = 8;
+	cmd_buf->data[0] = 0x80;
+	cmd_buf->data[1] = hex2bcd(time->tm_sec);
+	cmd_buf->data[2] = hex2bcd(time->tm_min);
+	cmd_buf->data[3] = hex2bcd(time->tm_hour);
+	cmd_buf->data[4] = time->tm_wday;
+	cmd_buf->data[5] = hex2bcd(time->tm_mday);
+	cmd_buf->data[6] = hex2bcd(time->tm_mon) + 1;
+	cmd_buf->data[7] = hex2bcd(time->tm_year - 100);
+}
+
+
+int smu_get_rtc_time(struct rtc_time *time, int spinwait)
+{
+	struct smu_simple_cmd cmd;
+	int rc;
+
+	if (smu == NULL)
+		return -ENODEV;
+
+	memset(time, 0, sizeof(struct rtc_time));
+	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);
+
+	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 spinwait)
+{
+	struct smu_simple_cmd cmd;
+	int rc;
+
+	if (smu == NULL)
+		return -ENODEV;
+
+	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 0;
+}
+
+
+void smu_shutdown(void)
+{
+	struct smu_simple_cmd cmd;
+
+	if (smu == NULL)
+		return;
+
+	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 (;;)
+		;
+}
+
+
+void smu_restart(void)
+{
+	struct smu_simple_cmd cmd;
+
+	if (smu == NULL)
+		return;
+
+	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 (;;)
+		;
+}
+
+
+int smu_present(void)
+{
+	return smu != NULL;
+}
+EXPORT_SYMBOL(smu_present);
+
+
+int __init smu_init (void)
+{
+	struct device_node *np;
+	u64 data;
+	int ret = 0;
+
+        np = of_find_node_by_type(NULL, "smu");
+        if (np == NULL)
+		return -ENODEV;
+
+	printk(KERN_INFO "SMU: Driver %s %s\n", VERSION, AUTHOR);
+
+	/*
+	 * SMU based G5s need some memory below 2Gb. Thankfully this is
+	 * called at a time where memblock is still available.
+	 */
+	smu_cmdbuf_abs = memblock_phys_alloc_range(4096, 4096, 0, 0x80000000UL);
+	if (smu_cmdbuf_abs == 0) {
+		printk(KERN_ERR "SMU: Command buffer allocation failed !\n");
+		ret = -EINVAL;
+		goto fail_np;
+	}
+
+	smu = memblock_alloc(sizeof(struct smu_device), SMP_CACHE_BYTES);
+	if (!smu)
+		panic("%s: Failed to allocate %zu bytes\n", __func__,
+		      sizeof(struct smu_device));
+
+	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 = 0;
+	smu->msg_irq = 0;
+
+	/* smu_cmdbuf_abs is in the low 2G of RAM, can be converted to a
+	 * 32 bits value safely
+	 */
+	smu->cmd_buf_abs = (u32)smu_cmdbuf_abs;
+	smu->cmd_buf = __va(smu_cmdbuf_abs);
+
+	smu->db_node = of_find_node_by_name(NULL, "smu-doorbell");
+	if (smu->db_node == NULL) {
+		printk(KERN_ERR "SMU: Can't find doorbell GPIO !\n");
+		ret = -ENXIO;
+		goto fail_bootmem;
+	}
+	if (of_property_read_reg(smu->db_node, 0, &data, NULL)) {
+		printk(KERN_ERR "SMU: Can't find doorbell GPIO address !\n");
+		ret = -ENXIO;
+		goto fail_db_node;
+	}
+
+	/* Current setup has one doorbell GPIO that does both doorbell
+	 * and ack. GPIOs are at 0x50, best would be to find that out
+	 * in the device-tree though.
+	 */
+	smu->doorbell = data;
+	if (smu->doorbell < 0x50)
+		smu->doorbell += 0x50;
+
+	/* Now look for the smu-interrupt GPIO */
+	do {
+		smu->msg_node = of_find_node_by_name(NULL, "smu-interrupt");
+		if (smu->msg_node == NULL)
+			break;
+		if (of_property_read_reg(smu->msg_node, 0, &data, NULL)) {
+			of_node_put(smu->msg_node);
+			smu->msg_node = NULL;
+			break;
+		}
+		smu->msg = data;
+		if (smu->msg < 0x50)
+			smu->msg += 0x50;
+	} 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
+	 * an offset for K2 base though, but let's do it that way for now.
+	 */
+	smu->db_buf = ioremap(0x8000860c, 0x1000);
+	if (smu->db_buf == NULL) {
+		printk(KERN_ERR "SMU: Can't map doorbell buffer pointer !\n");
+		ret = -ENXIO;
+		goto fail_msg_node;
+	}
+
+	/* U3 has an issue with NAP mode when issuing SMU commands */
+	smu->broken_nap = pmac_get_uninorth_variant() < 4;
+	if (smu->broken_nap)
+		printk(KERN_INFO "SMU: using NAP mode workaround\n");
+
+	sys_ctrler = SYS_CTRLER_SMU;
+	return 0;
+
+fail_msg_node:
+	of_node_put(smu->msg_node);
+fail_db_node:
+	of_node_put(smu->db_node);
+fail_bootmem:
+	memblock_free(smu, sizeof(struct smu_device));
+	smu = NULL;
+fail_np:
+	of_node_put(np);
+	return ret;
+}
+
+
+static int smu_late_init(void)
+{
+	if (!smu)
+		return 0;
+
+	timer_setup(&smu->i2c_timer, smu_i2c_retry, 0);
+
+	if (smu->db_node) {
+		smu->db_irq = irq_of_parse_and_map(smu->db_node, 0);
+		if (!smu->db_irq)
+			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
+			       smu->db_node);
+	}
+	if (smu->msg_node) {
+		smu->msg_irq = irq_of_parse_and_map(smu->msg_node, 0);
+		if (!smu->msg_irq)
+			printk(KERN_ERR "smu: failed to map irq for node %pOF\n",
+			       smu->msg_node);
+	}
+
+	/*
+	 * Try to request the interrupts
+	 */
+
+	if (smu->db_irq) {
+		if (request_irq(smu->db_irq, smu_db_intr,
+				IRQF_SHARED, "SMU doorbell", smu) < 0) {
+			printk(KERN_WARNING "SMU: can't "
+			       "request interrupt %d\n",
+			       smu->db_irq);
+			smu->db_irq = 0;
+		}
+	}
+
+	if (smu->msg_irq) {
+		if (request_irq(smu->msg_irq, smu_msg_intr,
+				IRQF_SHARED, "SMU message", smu) < 0) {
+			printk(KERN_WARNING "SMU: can't "
+			       "request interrupt %d\n",
+			       smu->msg_irq);
+			smu->msg_irq = 0;
+		}
+	}
+
+	smu_irq_inited = 1;
+	return 0;
+}
+/* This has to be before arch_initcall as the low i2c stuff relies on the
+ * above having been done before we reach arch_initcalls
+ */
+core_initcall(smu_late_init);
+
+/*
+ * sysfs visibility
+ */
+
+static void smu_expose_childs(struct work_struct *unused)
+{
+	struct device_node *np;
+
+	for_each_child_of_node(smu->of_node, np)
+		if (of_device_is_compatible(np, "smu-sensors"))
+			of_platform_device_create(np, "smu-sensors",
+						  &smu->of_dev->dev);
+}
+
+static DECLARE_WORK(smu_expose_childs_work, smu_expose_childs);
+
+static int smu_platform_probe(struct platform_device* dev)
+{
+	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 const struct of_device_id smu_platform_match[] =
+{
+	{
+		.type		= "smu",
+	},
+	{},
+};
+
+static struct platform_driver smu_of_platform_driver =
+{
+	.driver = {
+		.name = "smu",
+		.of_match_table = smu_platform_match,
+	},
+	.probe		= smu_platform_probe,
+};
+
+static int __init smu_init_sysfs(void)
+{
+	/*
+	 * 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
+	 */
+	platform_driver_register(&smu_of_platform_driver);
+	return 0;
+}
+
+device_initcall(smu_init_sysfs);
+
+struct platform_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(struct timer_list *unused)
+{
+	struct smu_i2c_cmd	*cmd = smu->cmd_i2c_cur;
+
+	DPRINTK("SMU: i2c failure, requeuing...\n");
+
+	/* requeue command simply by resetting reply_len */
+	cmd->pdata[0] = 0xff;
+	cmd->scmd.reply_len = sizeof(cmd->pdata);
+	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");
+		BUG_ON(cmd != smu->cmd_i2c_cur);
+		if (!smu_irq_inited) {
+			mdelay(5);
+			smu_i2c_retry(NULL);
+			return;
+		}
+		mod_timer(&smu->i2c_timer, jiffies + msecs_to_jiffies(5));
+		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 = sizeof(cmd->pdata);
+	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 = sizeof(cmd->pdata);
+	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:
+		cmd->info.sublen = 0;
+		memset(cmd->info.subaddr, 0, sizeof(cmd->info.subaddr));
+		break;
+	case SMU_I2C_TRANSFER_COMBINED:
+		cmd->info.devaddr &= 0xfe;
+		fallthrough;
+	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;
+}
+
+/*
+ * Handling of "partitions"
+ */
+
+static int smu_read_datablock(u8 *dest, unsigned int addr, unsigned int len)
+{
+	DECLARE_COMPLETION_ONSTACK(comp);
+	unsigned int chunk;
+	struct smu_cmd cmd;
+	int rc;
+	u8 params[8];
+
+	/* We currently use a chunk size of 0xe. We could check the
+	 * SMU firmware version and use bigger sizes though
+	 */
+	chunk = 0xe;
+
+	while (len) {
+		unsigned int clen = min(len, chunk);
+
+		cmd.cmd = SMU_CMD_MISC_ee_COMMAND;
+		cmd.data_len = 7;
+		cmd.data_buf = params;
+		cmd.reply_len = chunk;
+		cmd.reply_buf = dest;
+		cmd.done = smu_done_complete;
+		cmd.misc = &comp;
+		params[0] = SMU_CMD_MISC_ee_GET_DATABLOCK_REC;
+		params[1] = 0x4;
+		*((u32 *)&params[2]) = addr;
+		params[6] = clen;
+
+		rc = smu_queue_cmd(&cmd);
+		if (rc)
+			return rc;
+		wait_for_completion(&comp);
+		if (cmd.status != 0)
+			return rc;
+		if (cmd.reply_len != clen) {
+			printk(KERN_DEBUG "SMU: short read in "
+			       "smu_read_datablock, got: %d, want: %d\n",
+			       cmd.reply_len, clen);
+			return -EIO;
+		}
+		len -= clen;
+		addr += clen;
+		dest += clen;
+	}
+	return 0;
+}
+
+static struct smu_sdbp_header *smu_create_sdb_partition(int id)
+{
+	DECLARE_COMPLETION_ONSTACK(comp);
+	struct smu_simple_cmd cmd;
+	unsigned int addr, len, tlen;
+	struct smu_sdbp_header *hdr;
+	struct property *prop;
+
+	/* First query the partition info */
+	DPRINTK("SMU: Query partition infos ... (irq=%d)\n", smu->db_irq);
+	smu_queue_simple(&cmd, SMU_CMD_PARTITION_COMMAND, 2,
+			 smu_done_complete, &comp,
+			 SMU_CMD_PARTITION_LATEST, id);
+	wait_for_completion(&comp);
+	DPRINTK("SMU: done, status: %d, reply_len: %d\n",
+		cmd.cmd.status, cmd.cmd.reply_len);
+
+	/* Partition doesn't exist (or other error) */
+	if (cmd.cmd.status != 0 || cmd.cmd.reply_len != 6)
+		return NULL;
+
+	/* Fetch address and length from reply */
+	addr = *((u16 *)cmd.buffer);
+	len = cmd.buffer[3] << 2;
+	/* Calucluate total length to allocate, including the 17 bytes
+	 * for "sdb-partition-XX" that we append at the end of the buffer
+	 */
+	tlen = sizeof(struct property) + len + 18;
+
+	prop = kzalloc(tlen, GFP_KERNEL);
+	if (prop == NULL)
+		return NULL;
+	hdr = (struct smu_sdbp_header *)(prop + 1);
+	prop->name = ((char *)prop) + tlen - 18;
+	sprintf(prop->name, "sdb-partition-%02x", id);
+	prop->length = len;
+	prop->value = hdr;
+	prop->next = NULL;
+
+	/* Read the datablock */
+	if (smu_read_datablock((u8 *)hdr, addr, len)) {
+		printk(KERN_DEBUG "SMU: datablock read failed while reading "
+		       "partition %02x !\n", id);
+		goto failure;
+	}
+
+	/* Got it, check a few things and create the property */
+	if (hdr->id != id) {
+		printk(KERN_DEBUG "SMU: Reading partition %02x and got "
+		       "%02x !\n", id, hdr->id);
+		goto failure;
+	}
+	if (of_add_property(smu->of_node, prop)) {
+		printk(KERN_DEBUG "SMU: Failed creating sdb-partition-%02x "
+		       "property !\n", id);
+		goto failure;
+	}
+
+	return hdr;
+ failure:
+	kfree(prop);
+	return NULL;
+}
+
+/* Note: Only allowed to return error code in pointers (using ERR_PTR)
+ * when interruptible is 1
+ */
+static const struct smu_sdbp_header *__smu_get_sdb_partition(int id,
+		unsigned int *size, int interruptible)
+{
+	char pname[32];
+	const struct smu_sdbp_header *part;
+
+	if (!smu)
+		return NULL;
+
+	sprintf(pname, "sdb-partition-%02x", id);
+
+	DPRINTK("smu_get_sdb_partition(%02x)\n", id);
+
+	if (interruptible) {
+		int rc;
+		rc = mutex_lock_interruptible(&smu_part_access);
+		if (rc)
+			return ERR_PTR(rc);
+	} else
+		mutex_lock(&smu_part_access);
+
+	part = of_get_property(smu->of_node, pname, size);
+	if (part == NULL) {
+		DPRINTK("trying to extract from SMU ...\n");
+		part = smu_create_sdb_partition(id);
+		if (part != NULL && size)
+			*size = part->len << 2;
+	}
+	mutex_unlock(&smu_part_access);
+	return part;
+}
+
+const struct smu_sdbp_header *smu_get_sdb_partition(int id, unsigned int *size)
+{
+	return __smu_get_sdb_partition(id, size, 0);
+}
+EXPORT_SYMBOL(smu_get_sdb_partition);
+
+
+/*
+ * 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 = kzalloc(sizeof(struct smu_private), GFP_KERNEL);
+	if (!pp)
+		return -ENOMEM;
+	spin_lock_init(&pp->lock);
+	pp->mode = smu_file_commands;
+	init_waitqueue_head(&pp->wait);
+
+	mutex_lock(&smu_mutex);
+	spin_lock_irqsave(&smu_clist_lock, flags);
+	list_add(&pp->list, &smu_clist);
+	spin_unlock_irqrestore(&smu_clist_lock, flags);
+	file->private_data = pp;
+	mutex_unlock(&smu_mutex);
+
+	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_GET_PARTITION) {
+		const struct smu_sdbp_header *part;
+		part = __smu_get_sdb_partition(hdr.cmd, NULL, 1);
+		if (part == NULL)
+			return -EINVAL;
+		else if (IS_ERR(part))
+			return PTR_ERR(part);
+		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) {
+			spin_unlock_irqrestore(&pp->lock, flags);
+			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 __poll_t smu_fpoll(struct file *file, poll_table *wait)
+{
+	struct smu_private *pp = file->private_data;
+	__poll_t mask = 0;
+	unsigned long flags;
+
+	if (!pp)
+		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 |= EPOLLIN;
+		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)
+		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_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);
+
+	spin_lock_irqsave(&smu_clist_lock, flags);
+	list_del(&pp->list);
+	spin_unlock_irqrestore(&smu_clist_lock, flags);
+	kfree(pp);
+
+	return 0;
+}
+
+
+static const struct file_operations smu_device_fops = {
+	.llseek		= no_llseek,
+	.read		= smu_read,
+	.write		= smu_write,
+	.poll		= smu_fpoll,
+	.open		= smu_open,
+	.release	= smu_release,
+};
+
+static struct miscdevice pmu_device = {
+	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);