smu.c

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/*
 * PowerMac G5 SMU driver
 *
 * Copyright 2004 J. Mayer <[e-mail]>
 * Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *
 * Released under the term of the GNU GPL v2.
 */

/*
 * TODO:
 *  - 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/types.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/dmapool.h>
#include <linux/bootmem.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/sysdev.h>
#include <linux/poll.h>
#include <linux/mutex.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/smu.h>
#include <asm/sections.h>
#include <asm/abs_addr.h>
#include <asm/uaccess.h>
#include <asm/of_device.h>
#include <asm/of_platform.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 of_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 */
	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 struct smu_device	*smu;
static DEFINE_MUTEX(smu_part_access);
static int smu_irq_inited;

static void smu_i2c_retry(unsigned long data);

/*
 * 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: %02x %02x %02x %02x %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],
		((u8 *)cmd->data_buf)[4], ((u8 *)cmd->data_buf)[5],
		((u8 *)cmd->data_buf)[6], ((u8 *)cmd->data_buf)[7]);

	/* 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(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 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 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 == NO_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;
	const u32 *data;

        np = of_find_node_by_type(NULL, "smu");
        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;
	}

	smu = alloc_bootmem(sizeof(struct smu_device));
	if (smu == NULL)
		return -ENOMEM;
	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;

	/* 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 = (struct smu_cmd_buf *)abs_to_virt(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");
		goto fail;
	}
	data = of_get_property(smu->db_node, "reg", NULL);
	if (data == NULL) {
		of_node_put(smu->db_node);
		smu->db_node = NULL;
		printk(KERN_ERR "SMU: Can't find doorbell GPIO address !\n");
		goto fail;
	}

	/* 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;
		data = of_get_property(smu->msg_node, "reg", NULL);
		if (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");
		goto fail;
	}

	sys_ctrler = SYS_CTRLER_SMU;
	return 0;

 fail:
	smu = NULL;
	return -ENXIO;

}


static int smu_late_init(void)
{
	if (!smu)
		return 0;

	init_timer(&smu->i2c_timer);
	smu->i2c_timer.function = smu_i2c_retry;
	smu->i2c_timer.data = (unsigned long)smu;

	if (smu->db_node) {
		smu->db_irq = irq_of_parse_and_map(smu->db_node, 0);
		if (smu->db_irq == NO_IRQ)
			printk(KERN_ERR "smu: failed to map irq for node %s\n",
			       smu->db_node->full_name);
	}
	if (smu->msg_node) {
		smu->msg_irq = irq_of_parse_and_map(smu->msg_node, 0);
		if (smu->msg_irq == NO_IRQ)
			printk(KERN_ERR "smu: failed to map irq for node %s\n",
			       smu->msg_node->full_name);
	}

	/*
	 * Try to request the interrupts
	 */

	if (smu->db_irq != NO_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 = NO_IRQ;
		}
	}

	if (smu->msg_irq != NO_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 = NO_IRQ;
		}
	}

	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 (np = NULL; (np = of_get_next_child(smu->of_node, np)) != NULL;)
		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 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)
{
	/*
	 * Due to sysfs bogosity, a sysdev is not a real device, so
	 * we should in fact create both if we want sysdev semantics