path: root/drivers/macintosh/smu.c

/*
 * PowerMac G5 SMU driver
 *
 * Copyright 2004 J. Mayer <l_indien@magic.fr>
 * 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/config.h>
#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 <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>

#define VERSION "0.6"
#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 */
	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;
};

/*
 * I don't think there will ever be more than one SMU, so
 * for now, just hard code that
 */
static struct smu_device	*smu;


/*
 * 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 ...\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(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, struct pt_regs *regs)
{
	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, w