Adding upstream version 5.10.209.upstream/5.10.209upstream

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

1 files changed, 1127 insertions, 0 deletions

diff --git a/drivers/input/serio/hp_sdc.c b/drivers/input/serio/hp_sdc.c
new file mode 100644
index 000000000..13eacf6ab
--- /dev/null
+++ b/drivers/input/serio/hp_sdc.c
@@ -0,0 +1,1127 @@
+/*
+ * HP i8042-based System Device Controller driver.
+ *
+ * Copyright (c) 2001 Brian S. Julin
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL").
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ *
+ * References:
+ * System Device Controller Microprocessor Firmware Theory of Operation
+ *      for Part Number 1820-4784 Revision B.  Dwg No. A-1820-4784-2
+ * Helge Deller's original hilkbd.c port for PA-RISC.
+ *
+ *
+ * Driver theory of operation:
+ *
+ * hp_sdc_put does all writing to the SDC.  ISR can run on a different
+ * CPU than hp_sdc_put, but only one CPU runs hp_sdc_put at a time
+ * (it cannot really benefit from SMP anyway.)  A tasket fit this perfectly.
+ *
+ * All data coming back from the SDC is sent via interrupt and can be read
+ * fully in the ISR, so there are no latency/throughput problems there.
+ * The problem is with output, due to the slow clock speed of the SDC
+ * compared to the CPU.  This should not be too horrible most of the time,
+ * but if used with HIL devices that support the multibyte transfer command,
+ * keeping outbound throughput flowing at the 6500KBps that the HIL is
+ * capable of is more than can be done at HZ=100.
+ *
+ * Busy polling for IBF clear wastes CPU cycles and bus cycles.  hp_sdc.ibf
+ * is set to 0 when the IBF flag in the status register has cleared.  ISR
+ * may do this, and may also access the parts of queued transactions related
+ * to reading data back from the SDC, but otherwise will not touch the
+ * hp_sdc state. Whenever a register is written hp_sdc.ibf is set to 1.
+ *
+ * The i8042 write index and the values in the 4-byte input buffer
+ * starting at 0x70 are kept track of in hp_sdc.wi, and .r7[], respectively,
+ * to minimize the amount of IO needed to the SDC.  However these values
+ * do not need to be locked since they are only ever accessed by hp_sdc_put.
+ *
+ * A timer task schedules the tasklet once per second just to make
+ * sure it doesn't freeze up and to allow for bad reads to time out.
+ */
+
+#include <linux/hp_sdc.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/time.h>
+#include <linux/semaphore.h>
+#include <linux/slab.h>
+#include <linux/hil.h>
+#include <asm/io.h>
+
+/* Machine-specific abstraction */
+
+#if defined(__hppa__)
+# include <asm/parisc-device.h>
+# define sdc_readb(p)		gsc_readb(p)
+# define sdc_writeb(v,p)	gsc_writeb((v),(p))
+#elif defined(__mc68000__)
+#include <linux/uaccess.h>
+# define sdc_readb(p)		in_8(p)
+# define sdc_writeb(v,p)	out_8((p),(v))
+#else
+# error "HIL is not supported on this platform"
+#endif
+
+#define PREFIX "HP SDC: "
+
+MODULE_AUTHOR("Brian S. Julin <bri@calyx.com>");
+MODULE_DESCRIPTION("HP i8042-based SDC Driver");
+MODULE_LICENSE("Dual BSD/GPL");
+
+EXPORT_SYMBOL(hp_sdc_request_timer_irq);
+EXPORT_SYMBOL(hp_sdc_request_hil_irq);
+EXPORT_SYMBOL(hp_sdc_request_cooked_irq);
+
+EXPORT_SYMBOL(hp_sdc_release_timer_irq);
+EXPORT_SYMBOL(hp_sdc_release_hil_irq);
+EXPORT_SYMBOL(hp_sdc_release_cooked_irq);
+
+EXPORT_SYMBOL(__hp_sdc_enqueue_transaction);
+EXPORT_SYMBOL(hp_sdc_enqueue_transaction);
+EXPORT_SYMBOL(hp_sdc_dequeue_transaction);
+
+static bool hp_sdc_disabled;
+module_param_named(no_hpsdc, hp_sdc_disabled, bool, 0);
+MODULE_PARM_DESC(no_hpsdc, "Do not enable HP SDC driver.");
+
+static hp_i8042_sdc	hp_sdc;	/* All driver state is kept in here. */
+
+/*************** primitives for use in any context *********************/
+static inline uint8_t hp_sdc_status_in8(void)
+{
+	uint8_t status;
+	unsigned long flags;
+
+	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
+	status = sdc_readb(hp_sdc.status_io);
+	if (!(status & HP_SDC_STATUS_IBF))
+		hp_sdc.ibf = 0;
+	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
+
+	return status;
+}
+
+static inline uint8_t hp_sdc_data_in8(void)
+{
+	return sdc_readb(hp_sdc.data_io);
+}
+
+static inline void hp_sdc_status_out8(uint8_t val)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
+	hp_sdc.ibf = 1;
+	if ((val & 0xf0) == 0xe0)
+		hp_sdc.wi = 0xff;
+	sdc_writeb(val, hp_sdc.status_io);
+	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
+}
+
+static inline void hp_sdc_data_out8(uint8_t val)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&hp_sdc.ibf_lock, flags);
+	hp_sdc.ibf = 1;
+	sdc_writeb(val, hp_sdc.data_io);
+	write_unlock_irqrestore(&hp_sdc.ibf_lock, flags);
+}
+
+/*	Care must be taken to only invoke hp_sdc_spin_ibf when
+ *	absolutely needed, or in rarely invoked subroutines.
+ *	Not only does it waste CPU cycles, it also wastes bus cycles.
+ */
+static inline void hp_sdc_spin_ibf(void)
+{
+	unsigned long flags;
+	rwlock_t *lock;
+
+	lock = &hp_sdc.ibf_lock;
+
+	read_lock_irqsave(lock, flags);
+	if (!hp_sdc.ibf) {
+		read_unlock_irqrestore(lock, flags);
+		return;
+	}
+	read_unlock(lock);
+	write_lock(lock);
+	while (sdc_readb(hp_sdc.status_io) & HP_SDC_STATUS_IBF)
+		{ }
+	hp_sdc.ibf = 0;
+	write_unlock_irqrestore(lock, flags);
+}
+
+
+/************************ Interrupt context functions ************************/
+static void hp_sdc_take(int irq, void *dev_id, uint8_t status, uint8_t data)
+{
+	hp_sdc_transaction *curr;
+
+	read_lock(&hp_sdc.rtq_lock);
+	if (hp_sdc.rcurr < 0) {
+		read_unlock(&hp_sdc.rtq_lock);
+		return;
+	}
+	curr = hp_sdc.tq[hp_sdc.rcurr];
+	read_unlock(&hp_sdc.rtq_lock);
+
+	curr->seq[curr->idx++] = status;
+	curr->seq[curr->idx++] = data;
+	hp_sdc.rqty -= 2;
+	hp_sdc.rtime = ktime_get();
+
+	if (hp_sdc.rqty <= 0) {
+		/* All data has been gathered. */
+		if (curr->seq[curr->actidx] & HP_SDC_ACT_SEMAPHORE)
+			if (curr->act.semaphore)
+				up(curr->act.semaphore);
+
+		if (curr->seq[curr->actidx] & HP_SDC_ACT_CALLBACK)
+			if (curr->act.irqhook)
+				curr->act.irqhook(irq, dev_id, status, data);
+
+		curr->actidx = curr->idx;
+		curr->idx++;
+		/* Return control of this transaction */
+		write_lock(&hp_sdc.rtq_lock);
+		hp_sdc.rcurr = -1;
+		hp_sdc.rqty = 0;
+		write_unlock(&hp_sdc.rtq_lock);
+		tasklet_schedule(&hp_sdc.task);
+	}
+}
+
+static irqreturn_t hp_sdc_isr(int irq, void *dev_id)
+{
+	uint8_t status, data;
+
+	status = hp_sdc_status_in8();
+	/* Read data unconditionally to advance i8042. */
+	data =   hp_sdc_data_in8();
+
+	/* For now we are ignoring these until we get the SDC to behave. */
+	if (((status & 0xf1) == 0x51) && data == 0x82)
+		return IRQ_HANDLED;
+
+	switch (status & HP_SDC_STATUS_IRQMASK) {
+	case 0: /* This case is not documented. */
+		break;
+
+	case HP_SDC_STATUS_USERTIMER:
+	case HP_SDC_STATUS_PERIODIC:
+	case HP_SDC_STATUS_TIMER:
+		read_lock(&hp_sdc.hook_lock);
+		if (hp_sdc.timer != NULL)
+			hp_sdc.timer(irq, dev_id, status, data);
+		read_unlock(&hp_sdc.hook_lock);
+		break;
+
+	case HP_SDC_STATUS_REG:
+		hp_sdc_take(irq, dev_id, status, data);
+		break;
+
+	case HP_SDC_STATUS_HILCMD:
+	case HP_SDC_STATUS_HILDATA:
+		read_lock(&hp_sdc.hook_lock);
+		if (hp_sdc.hil != NULL)
+			hp_sdc.hil(irq, dev_id, status, data);
+		read_unlock(&hp_sdc.hook_lock);
+		break;
+
+	case HP_SDC_STATUS_PUP:
+		read_lock(&hp_sdc.hook_lock);
+		if (hp_sdc.pup != NULL)
+			hp_sdc.pup(irq, dev_id, status, data);
+		else
+			printk(KERN_INFO PREFIX "HP SDC reports successful PUP.\n");
+		read_unlock(&hp_sdc.hook_lock);
+		break;
+
+	default:
+		read_lock(&hp_sdc.hook_lock);
+		if (hp_sdc.cooked != NULL)
+			hp_sdc.cooked(irq, dev_id, status, data);
+		read_unlock(&hp_sdc.hook_lock);
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+
+static irqreturn_t hp_sdc_nmisr(int irq, void *dev_id)
+{
+	int status;
+
+	status = hp_sdc_status_in8();
+	printk(KERN_WARNING PREFIX "NMI !\n");
+
+#if 0
+	if (status & HP_SDC_NMISTATUS_FHS) {
+		read_lock(&hp_sdc.hook_lock);
+		if (hp_sdc.timer != NULL)
+			hp_sdc.timer(irq, dev_id, status, 0);
+		read_unlock(&hp_sdc.hook_lock);
+	} else {
+		/* TODO: pass this on to the HIL handler, or do SAK here? */
+		printk(KERN_WARNING PREFIX "HIL NMI\n");
+	}
+#endif
+
+	return IRQ_HANDLED;
+}
+
+
+/***************** Kernel (tasklet) context functions ****************/
+
+unsigned long hp_sdc_put(void);
+
+static void hp_sdc_tasklet(unsigned long foo)
+{
+	write_lock_irq(&hp_sdc.rtq_lock);
+
+	if (hp_sdc.rcurr >= 0) {
+		ktime_t now = ktime_get();
+
+		if (ktime_after(now, ktime_add_us(hp_sdc.rtime,
+						  HP_SDC_MAX_REG_DELAY))) {
+			hp_sdc_transaction *curr;
+			uint8_t tmp;
+
+			curr = hp_sdc.tq[hp_sdc.rcurr];
+			/* If this turns out to be a normal failure mode
+			 * we'll need to figure out a way to communicate
+			 * it back to the application. and be less verbose.
+			 */
+			printk(KERN_WARNING PREFIX "read timeout (%lldus)!\n",
+			       ktime_us_delta(now, hp_sdc.rtime));
+			curr->idx += hp_sdc.rqty;
+			hp_sdc.rqty = 0;
+			tmp = curr->seq[curr->actidx];
+			curr->seq[curr->actidx] |= HP_SDC_ACT_DEAD;
+			if (tmp & HP_SDC_ACT_SEMAPHORE)
+				if (curr->act.semaphore)
+					up(curr->act.semaphore);
+
+			if (tmp & HP_SDC_ACT_CALLBACK) {
+				/* Note this means that irqhooks may be called
+				 * in tasklet/bh context.
+				 */
+				if (curr->act.irqhook)
+					curr->act.irqhook(0, NULL, 0, 0);
+			}
+
+			curr->actidx = curr->idx;
+			curr->idx++;
+			hp_sdc.rcurr = -1;
+		}
+	}
+	write_unlock_irq(&hp_sdc.rtq_lock);
+	hp_sdc_put();
+}
+
+unsigned long hp_sdc_put(void)
+{
+	hp_sdc_transaction *curr;
+	uint8_t act;
+	int idx, curridx;
+
+	int limit = 0;
+
+	write_lock(&hp_sdc.lock);
+
+	/* If i8042 buffers are full, we cannot do anything that
+	   requires output, so we skip to the administrativa. */
+	if (hp_sdc.ibf) {
+		hp_sdc_status_in8();
+		if (hp_sdc.ibf)
+			goto finish;
+	}
+
+ anew:
+	/* See if we are in the middle of a sequence. */
+	if (hp_sdc.wcurr < 0)
+		hp_sdc.wcurr = 0;
+	read_lock_irq(&hp_sdc.rtq_lock);
+	if (hp_sdc.rcurr == hp_sdc.wcurr)
+		hp_sdc.wcurr++;
+	read_unlock_irq(&hp_sdc.rtq_lock);
+	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
+		hp_sdc.wcurr = 0;
+	curridx = hp_sdc.wcurr;
+
+	if (hp_sdc.tq[curridx] != NULL)
+		goto start;
+
+	while (++curridx != hp_sdc.wcurr) {
+		if (curridx >= HP_SDC_QUEUE_LEN) {
+			curridx = -1; /* Wrap to top */
+			continue;
+		}
+		read_lock_irq(&hp_sdc.rtq_lock);
+		if (hp_sdc.rcurr == curridx) {
+			read_unlock_irq(&hp_sdc.rtq_lock);
+			continue;
+		}
+		read_unlock_irq(&hp_sdc.rtq_lock);
+		if (hp_sdc.tq[curridx] != NULL)
+			break; /* Found one. */
+	}
+	if (curridx == hp_sdc.wcurr) { /* There's nothing queued to do. */
+		curridx = -1;
+	}
+	hp_sdc.wcurr = curridx;
+
+ start:
+
+	/* Check to see if the interrupt mask needs to be set. */
+	if (hp_sdc.set_im) {
+		hp_sdc_status_out8(hp_sdc.im | HP_SDC_CMD_SET_IM);
+		hp_sdc.set_im = 0;
+		goto finish;
+	}
+
+	if (hp_sdc.wcurr == -1)
+		goto done;
+
+	curr = hp_sdc.tq[curridx];
+	idx = curr->actidx;
+
+	if (curr->actidx >= curr->endidx) {
+		hp_sdc.tq[curridx] = NULL;
+		/* Interleave outbound data between the transactions. */
+		hp_sdc.wcurr++;
+		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
+			hp_sdc.wcurr = 0;
+		goto finish;
+	}
+
+	act = curr->seq[idx];
+	idx++;
+
+	if (curr->idx >= curr->endidx) {
+		if (act & HP_SDC_ACT_DEALLOC)
+			kfree(curr);
+		hp_sdc.tq[curridx] = NULL;
+		/* Interleave outbound data between the transactions. */
+		hp_sdc.wcurr++;
+		if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
+			hp_sdc.wcurr = 0;
+		goto finish;
+	}
+
+	while (act & HP_SDC_ACT_PRECMD) {
+		if (curr->idx != idx) {
+			idx++;
+			act &= ~HP_SDC_ACT_PRECMD;
+			break;
+		}
+		hp_sdc_status_out8(curr->seq[idx]);
+		curr->idx++;
+		/* act finished? */
+		if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_PRECMD)
+			goto actdone;
+		/* skip quantity field if data-out sequence follows. */
+		if (act & HP_SDC_ACT_DATAOUT)
+			curr->idx++;
+		goto finish;
+	}
+	if (act & HP_SDC_ACT_DATAOUT) {
+		int qty;
+
+		qty = curr->seq[idx];
+		idx++;
+		if (curr->idx - idx < qty) {
+			hp_sdc_data_out8(curr->seq[curr->idx]);
+			curr->idx++;
+			/* act finished? */
+			if (curr->idx - idx >= qty &&
+			    (act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAOUT)
+				goto actdone;
+			goto finish;
+		}
+		idx += qty;
+		act &= ~HP_SDC_ACT_DATAOUT;
+	} else
+	    while (act & HP_SDC_ACT_DATAREG) {
+		int mask;
+		uint8_t w7[4];
+
+		mask = curr->seq[idx];
+		if (idx != curr->idx) {
+			idx++;
+			idx += !!(mask & 1);
+			idx += !!(mask & 2);
+			idx += !!(mask & 4);
+			idx += !!(mask & 8);
+			act &= ~HP_SDC_ACT_DATAREG;
+			break;
+		}
+
+		w7[0] = (mask & 1) ? curr->seq[++idx] : hp_sdc.r7[0];
+		w7[1] = (mask & 2) ? curr->seq[++idx] : hp_sdc.r7[1];
+		w7[2] = (mask & 4) ? curr->seq[++idx] : hp_sdc.r7[2];
+		w7[3] = (mask & 8) ? curr->seq[++idx] : hp_sdc.r7[3];
+
+		if (hp_sdc.wi > 0x73 || hp_sdc.wi < 0x70 ||
+		    w7[hp_sdc.wi - 0x70] == hp_sdc.r7[hp_sdc.wi - 0x70]) {
+			int i = 0;
+
+			/* Need to point the write index register */
+			while (i < 4 && w7[i] == hp_sdc.r7[i])
+				i++;
+
+			if (i < 4) {
+				hp_sdc_status_out8(HP_SDC_CMD_SET_D0 + i);
+				hp_sdc.wi = 0x70 + i;
+				goto finish;
+			}
+
+			idx++;
+			if ((act & HP_SDC_ACT_DURING) == HP_SDC_ACT_DATAREG)
+				goto actdone;
+
+			curr->idx = idx;
+			act &= ~HP_SDC_ACT_DATAREG;
+			break;
+		}
+
+		hp_sdc_data_out8(w7[hp_sdc.wi - 0x70]);
+		hp_sdc.r7[hp_sdc.wi - 0x70] = w7[hp_sdc.wi - 0x70];
+		hp_sdc.wi++; /* write index register autoincrements */
+		{
+			int i = 0;
+
+			while ((i < 4) && w7[i] == hp_sdc.r7[i])
+				i++;
+			if (i >= 4) {
+				curr->idx = idx + 1;
+				if ((act & HP_SDC_ACT_DURING) ==
+				    HP_SDC_ACT_DATAREG)
+					goto actdone;
+			}
+		}
+		goto finish;
+	}
+	/* We don't go any further in the command if there is a pending read,
+	   because we don't want interleaved results. */
+	read_lock_irq(&hp_sdc.rtq_lock);
+	if (hp_sdc.rcurr >= 0) {
+		read_unlock_irq(&hp_sdc.rtq_lock);
+		goto finish;
+	}
+	read_unlock_irq(&hp_sdc.rtq_lock);
+
+
+	if (act & HP_SDC_ACT_POSTCMD) {
+		uint8_t postcmd;
+
+		/* curr->idx should == idx at this point. */
+		postcmd = curr->seq[idx];
+		curr->idx++;
+		if (act & HP_SDC_ACT_DATAIN) {
+
+			/* Start a new read */
+			hp_sdc.rqty = curr->seq[curr->idx];
+			hp_sdc.rtime = ktime_get();
+			curr->idx++;
+			/* Still need to lock here in case of spurious irq. */
+			write_lock_irq(&hp_sdc.rtq_lock);
+			hp_sdc.rcurr = curridx;
+			write_unlock_irq(&hp_sdc.rtq_lock);
+			hp_sdc_status_out8(postcmd);
+			goto finish;
+		}
+		hp_sdc_status_out8(postcmd);
+		goto actdone;
+	}
+
+ actdone:
+	if (act & HP_SDC_ACT_SEMAPHORE)
+		up(curr->act.semaphore);
+	else if (act & HP_SDC_ACT_CALLBACK)
+		curr->act.irqhook(0,NULL,0,0);
+
+	if (curr->idx >= curr->endidx) { /* This transaction is over. */
+		if (act & HP_SDC_ACT_DEALLOC)
+			kfree(curr);
+		hp_sdc.tq[curridx] = NULL;
+	} else {
+		curr->actidx = idx + 1;
+		curr->idx = idx + 2;
+	}
+	/* Interleave outbound data between the transactions. */
+	hp_sdc.wcurr++;
+	if (hp_sdc.wcurr >= HP_SDC_QUEUE_LEN)
+		hp_sdc.wcurr = 0;
+
+ finish:
+	/* If by some quirk IBF has cleared and our ISR has run to
+	   see that that has happened, do it all again. */
+	if (!hp_sdc.ibf && limit++ < 20)
+		goto anew;
+
+ done:
+	if (hp_sdc.wcurr >= 0)
+		tasklet_schedule(&hp_sdc.task);
+	write_unlock(&hp_sdc.lock);
+
+	return 0;
+}
+
+/******* Functions called in either user or kernel context ****/
+int __hp_sdc_enqueue_transaction(hp_sdc_transaction *this)
+{
+	int i;
+
+	if (this == NULL) {
+		BUG();
+		return -EINVAL;
+	}
+
+	/* Can't have same transaction on queue twice */
+	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
+		if (hp_sdc.tq[i] == this)
+			goto fail;
+
+	this->actidx = 0;
+	this->idx = 1;
+
+	/* Search for empty slot */
+	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
+		if (hp_sdc.tq[i] == NULL) {
+			hp_sdc.tq[i] = this;
+			tasklet_schedule(&hp_sdc.task);
+			return 0;
+		}
+
+	printk(KERN_WARNING PREFIX "No free slot to add transaction.\n");
+	return -EBUSY;
+
+ fail:
+	printk(KERN_WARNING PREFIX "Transaction add failed: transaction already queued?\n");
+	return -EINVAL;
+}
+
+int hp_sdc_enqueue_transaction(hp_sdc_transaction *this) {
+	unsigned long flags;
+	int ret;
+
+	write_lock_irqsave(&hp_sdc.lock, flags);
+	ret = __hp_sdc_enqueue_transaction(this);
+	write_unlock_irqrestore(&hp_sdc.lock,flags);
+
+	return ret;
+}
+
+int hp_sdc_dequeue_transaction(hp_sdc_transaction *this)
+{
+	unsigned long flags;
+	int i;
+
+	write_lock_irqsave(&hp_sdc.lock, flags);
+
+	/* TODO: don't remove it if it's not done. */
+
+	for (i = 0; i < HP_SDC_QUEUE_LEN; i++)
+		if (hp_sdc.tq[i] == this)
+			hp_sdc.tq[i] = NULL;
+
+	write_unlock_irqrestore(&hp_sdc.lock, flags);
+	return 0;
+}
+
+
+
+/********************** User context functions **************************/
+int hp_sdc_request_timer_irq(hp_sdc_irqhook *callback)
+{
+	if (callback == NULL || hp_sdc.dev == NULL)
+		return -EINVAL;
+
+	write_lock_irq(&hp_sdc.hook_lock);
+	if (hp_sdc.timer != NULL) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EBUSY;
+	}
+
+	hp_sdc.timer = callback;
+	/* Enable interrupts from the timers */
+	hp_sdc.im &= ~HP_SDC_IM_FH;
+        hp_sdc.im &= ~HP_SDC_IM_PT;
+	hp_sdc.im &= ~HP_SDC_IM_TIMERS;
+	hp_sdc.set_im = 1;
+	write_unlock_irq(&hp_sdc.hook_lock);
+
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+int hp_sdc_request_hil_irq(hp_sdc_irqhook *callback)
+{
+	if (callback == NULL || hp_sdc.dev == NULL)
+		return -EINVAL;
+
+	write_lock_irq(&hp_sdc.hook_lock);
+	if (hp_sdc.hil != NULL) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EBUSY;
+	}
+
+	hp_sdc.hil = callback;
+	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
+	hp_sdc.set_im = 1;
+	write_unlock_irq(&hp_sdc.hook_lock);
+
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+int hp_sdc_request_cooked_irq(hp_sdc_irqhook *callback)
+{
+	if (callback == NULL || hp_sdc.dev == NULL)
+		return -EINVAL;
+
+	write_lock_irq(&hp_sdc.hook_lock);
+	if (hp_sdc.cooked != NULL) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EBUSY;
+	}
+
+	/* Enable interrupts from the HIL MLC */
+	hp_sdc.cooked = callback;
+	hp_sdc.im &= ~(HP_SDC_IM_HIL | HP_SDC_IM_RESET);
+	hp_sdc.set_im = 1;
+	write_unlock_irq(&hp_sdc.hook_lock);
+
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+int hp_sdc_release_timer_irq(hp_sdc_irqhook *callback)
+{
+	write_lock_irq(&hp_sdc.hook_lock);
+	if ((callback != hp_sdc.timer) ||
+	    (hp_sdc.timer == NULL)) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EINVAL;
+	}
+
+	/* Disable interrupts from the timers */
+	hp_sdc.timer = NULL;
+	hp_sdc.im |= HP_SDC_IM_TIMERS;
+	hp_sdc.im |= HP_SDC_IM_FH;
+	hp_sdc.im |= HP_SDC_IM_PT;
+	hp_sdc.set_im = 1;
+	write_unlock_irq(&hp_sdc.hook_lock);
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+int hp_sdc_release_hil_irq(hp_sdc_irqhook *callback)
+{
+	write_lock_irq(&hp_sdc.hook_lock);
+	if ((callback != hp_sdc.hil) ||
+	    (hp_sdc.hil == NULL)) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EINVAL;
+	}
+
+	hp_sdc.hil = NULL;
+	/* Disable interrupts from HIL only if there is no cooked driver. */
+	if(hp_sdc.cooked == NULL) {
+		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
+		hp_sdc.set_im = 1;
+	}
+	write_unlock_irq(&hp_sdc.hook_lock);
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+int hp_sdc_release_cooked_irq(hp_sdc_irqhook *callback)
+{
+	write_lock_irq(&hp_sdc.hook_lock);
+	if ((callback != hp_sdc.cooked) ||
+	    (hp_sdc.cooked == NULL)) {
+		write_unlock_irq(&hp_sdc.hook_lock);
+		return -EINVAL;
+	}
+
+	hp_sdc.cooked = NULL;
+	/* Disable interrupts from HIL only if there is no raw HIL driver. */
+	if(hp_sdc.hil == NULL) {
+		hp_sdc.im |= (HP_SDC_IM_HIL | HP_SDC_IM_RESET);
+		hp_sdc.set_im = 1;
+	}
+	write_unlock_irq(&hp_sdc.hook_lock);
+	tasklet_schedule(&hp_sdc.task);
+
+	return 0;
+}
+
+/************************* Keepalive timer task *********************/
+
+static void hp_sdc_kicker(struct timer_list *unused)
+{
+	tasklet_schedule(&hp_sdc.task);
+	/* Re-insert the periodic task. */
+	mod_timer(&hp_sdc.kicker, jiffies + HZ);
+}
+
+/************************** Module Initialization ***************************/
+
+#if defined(__hppa__)
+
+static const struct parisc_device_id hp_sdc_tbl[] __initconst = {
+	{
+		.hw_type =	HPHW_FIO,
+		.hversion_rev =	HVERSION_REV_ANY_ID,
+		.hversion =	HVERSION_ANY_ID,
+		.sversion =	0x73,
+	 },
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(parisc, hp_sdc_tbl);
+
+static int __init hp_sdc_init_hppa(struct parisc_device *d);
+static struct delayed_work moduleloader_work;
+
+static struct parisc_driver hp_sdc_driver __refdata = {
+	.name =		"hp_sdc",
+	.id_table =	hp_sdc_tbl,
+	.probe =	hp_sdc_init_hppa,
+};
+
+#endif /* __hppa__ */
+
+static int __init hp_sdc_init(void)
+{
+	char *errstr;
+	hp_sdc_transaction t_sync;
+	uint8_t ts_sync[6];
+	struct semaphore s_sync;
+
+	rwlock_init(&hp_sdc.lock);
+	rwlock_init(&hp_sdc.ibf_lock);
+	rwlock_init(&hp_sdc.rtq_lock);
+	rwlock_init(&hp_sdc.hook_lock);
+
+	hp_sdc.timer		= NULL;
+	hp_sdc.hil		= NULL;
+	hp_sdc.pup		= NULL;
+	hp_sdc.cooked		= NULL;
+	hp_sdc.im		= HP_SDC_IM_MASK;  /* Mask maskable irqs */
+	hp_sdc.set_im		= 1;
+	hp_sdc.wi		= 0xff;
+	hp_sdc.r7[0]		= 0xff;
+	hp_sdc.r7[1]		= 0xff;
+	hp_sdc.r7[2]		= 0xff;
+	hp_sdc.r7[3]		= 0xff;
+	hp_sdc.ibf		= 1;
+
+	memset(&hp_sdc.tq, 0, sizeof(hp_sdc.tq));
+
+	hp_sdc.wcurr		= -1;
+        hp_sdc.rcurr		= -1;
+	hp_sdc.rqty		= 0;
+
+	hp_sdc.dev_err = -ENODEV;
+
+	errstr = "IO not found for";
+	if (!hp_sdc.base_io)
+		goto err0;
+
+	errstr = "IRQ not found for";
+	if (!hp_sdc.irq)
+		goto err0;
+
+	hp_sdc.dev_err = -EBUSY;
+
+#if defined(__hppa__)
+	errstr = "IO not available for";
+        if (request_region(hp_sdc.data_io, 2, hp_sdc_driver.name))
+		goto err0;
+#endif
+
+	errstr = "IRQ not available for";
+	if (request_irq(hp_sdc.irq, &hp_sdc_isr, IRQF_SHARED,
+			"HP SDC", &hp_sdc))
+		goto err1;
+
+	errstr = "NMI not available for";
+	if (request_irq(hp_sdc.nmi, &hp_sdc_nmisr, IRQF_SHARED,
+			"HP SDC NMI", &hp_sdc))
+		goto err2;
+
+	pr_info(PREFIX "HP SDC at 0x%08lx, IRQ %d (NMI IRQ %d)\n",
+	       hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
+
+	hp_sdc_status_in8();
+	hp_sdc_data_in8();
+
+	tasklet_init(&hp_sdc.task, hp_sdc_tasklet, 0);
+
+	/* Sync the output buffer registers, thus scheduling hp_sdc_tasklet. */
+	t_sync.actidx	= 0;
+	t_sync.idx	= 1;
+	t_sync.endidx	= 6;
+	t_sync.seq	= ts_sync;
+	ts_sync[0]	= HP_SDC_ACT_DATAREG | HP_SDC_ACT_SEMAPHORE;
+	ts_sync[1]	= 0x0f;
+	ts_sync[2] = ts_sync[3]	= ts_sync[4] = ts_sync[5] = 0;
+	t_sync.act.semaphore = &s_sync;
+	sema_init(&s_sync, 0);
+	hp_sdc_enqueue_transaction(&t_sync);
+	down(&s_sync); /* Wait for t_sync to complete */
+
+	/* Create the keepalive task */
+	timer_setup(&hp_sdc.kicker, hp_sdc_kicker, 0);
+	hp_sdc.kicker.expires = jiffies + HZ;
+	add_timer(&hp_sdc.kicker);
+
+	hp_sdc.dev_err = 0;
+	return 0;
+ err2:
+	free_irq(hp_sdc.irq, &hp_sdc);
+ err1:
+	release_region(hp_sdc.data_io, 2);
+ err0:
+	printk(KERN_WARNING PREFIX ": %s SDC IO=0x%p IRQ=0x%x NMI=0x%x\n",
+		errstr, (void *)hp_sdc.base_io, hp_sdc.irq, hp_sdc.nmi);
+	hp_sdc.dev = NULL;
+
+	return hp_sdc.dev_err;
+}
+
+#if defined(__hppa__)
+
+static void request_module_delayed(struct work_struct *work)
+{
+	request_module("hp_sdc_mlc");
+}
+
+static int __init hp_sdc_init_hppa(struct parisc_device *d)
+{
+	int ret;
+
+	if (!d)
+		return 1;
+	if (hp_sdc.dev != NULL)
+		return 1;	/* We only expect one SDC */
+
+	hp_sdc.dev		= d;
+	hp_sdc.irq		= d->irq;
+	hp_sdc.nmi		= d->aux_irq;
+	hp_sdc.base_io		= d->hpa.start;
+	hp_sdc.data_io		= d->hpa.start + 0x800;
+	hp_sdc.status_io	= d->hpa.start + 0x801;
+
+	INIT_DELAYED_WORK(&moduleloader_work, request_module_delayed);
+
+	ret = hp_sdc_init();
+	/* after successful initialization give SDC some time to settle
+	 * and then load the hp_sdc_mlc upper layer driver */
+	if (!ret)
+		schedule_delayed_work(&moduleloader_work,
+			msecs_to_jiffies(2000));
+
+	return ret;
+}
+
+#endif /* __hppa__ */
+
+static void hp_sdc_exit(void)
+{
+	/* do nothing if we don't have a SDC */
+	if (!hp_sdc.dev)
+		return;
+
+	write_lock_irq(&hp_sdc.lock);
+
+	/* Turn off all maskable "sub-function" irq's. */
+	hp_sdc_spin_ibf();
+	sdc_writeb(HP_SDC_CMD_SET_IM | HP_SDC_IM_MASK, hp_sdc.status_io);
+
+	/* Wait until we know this has been processed by the i8042 */
+	hp_sdc_spin_ibf();
+
+	free_irq(hp_sdc.nmi, &hp_sdc);
+	free_irq(hp_sdc.irq, &hp_sdc);
+	write_unlock_irq(&hp_sdc.lock);
+
+	del_timer_sync(&hp_sdc.kicker);
+
+	tasklet_kill(&hp_sdc.task);
+
+#if defined(__hppa__)
+	cancel_delayed_work_sync(&moduleloader_work);
+	if (unregister_parisc_driver(&hp_sdc_driver))
+		printk(KERN_WARNING PREFIX "Error unregistering HP SDC");
+#endif
+}
+
+static int __init hp_sdc_register(void)
+{
+	hp_sdc_transaction tq_init;
+	uint8_t tq_init_seq[5];
+	struct semaphore tq_init_sem;
+#if defined(__mc68000__)
+	unsigned char i;
+#endif
+
+	if (hp_sdc_disabled) {
+		printk(KERN_WARNING PREFIX "HP SDC driver disabled by no_hpsdc=1.\n");
+		return -ENODEV;
+	}
+
+	hp_sdc.dev = NULL;
+	hp_sdc.dev_err = 0;
+#if defined(__hppa__)
+	if (register_parisc_driver(&hp_sdc_driver)) {
+		printk(KERN_WARNING PREFIX "Error registering SDC with system bus tree.\n");
+		return -ENODEV;
+	}
+#elif defined(__mc68000__)
+	if (!MACH_IS_HP300)
+	    return -ENODEV;
+
+	hp_sdc.irq	 = 1;
+	hp_sdc.nmi	 = 7;
+	hp_sdc.base_io	 = (unsigned long) 0xf0428000;
+	hp_sdc.data_io	 = (unsigned long) hp_sdc.base_io + 1;
+	hp_sdc.status_io = (unsigned long) hp_sdc.base_io + 3;
+	if (!copy_from_kernel_nofault(&i, (unsigned char *)hp_sdc.data_io, 1))
+		hp_sdc.dev = (void *)1;
+	hp_sdc.dev_err   = hp_sdc_init();
+#endif
+	if (hp_sdc.dev == NULL) {
+		printk(KERN_WARNING PREFIX "No SDC found.\n");
+		return hp_sdc.dev_err;
+	}
+
+	sema_init(&tq_init_sem, 0);
+
+	tq_init.actidx		= 0;
+	tq_init.idx		= 1;
+	tq_init.endidx		= 5;
+	tq_init.seq		= tq_init_seq;
+	tq_init.act.semaphore	= &tq_init_sem;
+
+	tq_init_seq[0] =
+		HP_SDC_ACT_POSTCMD | HP_SDC_ACT_DATAIN | HP_SDC_ACT_SEMAPHORE;
+	tq_init_seq[1] = HP_SDC_CMD_READ_KCC;
+	tq_init_seq[2] = 1;
+	tq_init_seq[3] = 0;
+	tq_init_seq[4] = 0;
+
+	hp_sdc_enqueue_transaction(&tq_init);
+
+	down(&tq_init_sem);
+	up(&tq_init_sem);
+
+	if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
+		printk(KERN_WARNING PREFIX "Error reading config byte.\n");
+		hp_sdc_exit();
+		return -ENODEV;
+	}
+	hp_sdc.r11 = tq_init_seq[4];
+	if (hp_sdc.r11 & HP_SDC_CFG_NEW) {
+		const char *str;
+		printk(KERN_INFO PREFIX "New style SDC\n");
+		tq_init_seq[1] = HP_SDC_CMD_READ_XTD;
+		tq_init.actidx		= 0;
+		tq_init.idx		= 1;
+		down(&tq_init_sem);
+		hp_sdc_enqueue_transaction(&tq_init);
+		down(&tq_init_sem);
+		up(&tq_init_sem);
+		if ((tq_init_seq[0] & HP_SDC_ACT_DEAD) == HP_SDC_ACT_DEAD) {
+			printk(KERN_WARNING PREFIX "Error reading extended config byte.\n");
+			return -ENODEV;
+		}
+		hp_sdc.r7e = tq_init_seq[4];
+		HP_SDC_XTD_REV_STRINGS(hp_sdc.r7e & HP_SDC_XTD_REV, str)
+		printk(KERN_INFO PREFIX "Revision: %s\n", str);
+		if (hp_sdc.r7e & HP_SDC_XTD_BEEPER)
+			printk(KERN_INFO PREFIX "TI SN76494 beeper present\n");
+		if (hp_sdc.r7e & HP_SDC_XTD_BBRTC)
+			printk(KERN_INFO PREFIX "OKI MSM-58321 BBRTC present\n");
+		printk(KERN_INFO PREFIX "Spunking the self test register to force PUP "
+		       "on next firmware reset.\n");
+		tq_init_seq[0] = HP_SDC_ACT_PRECMD |
+			HP_SDC_ACT_DATAOUT | HP_SDC_ACT_SEMAPHORE;
+		tq_init_seq[1] = HP_SDC_CMD_SET_STR;
+		tq_init_seq[2] = 1;
+		tq_init_seq[3] = 0;
+		tq_init.actidx		= 0;
+		tq_init.idx		= 1;
+		tq_init.endidx		= 4;
+		down(&tq_init_sem);
+		hp_sdc_enqueue_transaction(&tq_init);
+		down(&tq_init_sem);
+		up(&tq_init_sem);
+	} else
+		printk(KERN_INFO PREFIX "Old style SDC (1820-%s).\n",
+		       (hp_sdc.r11 & HP_SDC_CFG_REV) ? "3300" : "2564/3087");
+
+        return 0;
+}
+
+module_init(hp_sdc_register);
+module_exit(hp_sdc_exit);
+
+/* Timing notes:  These measurements taken on my 64MHz 7100-LC (715/64)
+ *                                              cycles cycles-adj    time
+ * between two consecutive mfctl(16)'s:              4        n/a    63ns
+ * hp_sdc_spin_ibf when idle:                      119        115   1.7us
+ * gsc_writeb status register:                      83         79   1.2us
+ * IBF to clear after sending SET_IM:             6204       6006    93us
+ * IBF to clear after sending LOAD_RT:            4467       4352    68us
+ * IBF to clear after sending two LOAD_RTs:      18974      18859   295us
+ * READ_T1, read status/data, IRQ, call handler: 35564        n/a   556us
+ * cmd to ~IBF READ_T1 2nd time right after:   5158403        n/a    81ms
+ * between IRQ received and ~IBF for above:    2578877        n/a    40ms
+ *
+ * Performance stats after a run of this module configuring HIL and
+ * receiving a few mouse events:
+ *
+ * status in8  282508 cycles 7128 calls
+ * status out8   8404 cycles  341 calls
+ * data out8     1734 cycles   78 calls
+ * isr         174324 cycles  617 calls (includes take)
+ * take          1241 cycles    2 calls
+ * put        1411504 cycles 6937 calls
+ * task       1655209 cycles 6937 calls (includes put)
+ *
+ */