This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / drivers / input / serio / hp_sdc.c
diff --git a/drivers/input/serio/hp_sdc.c b/drivers/input/serio/hp_sdc.c
new file mode 100644 (file)
index 0000000..7629452
--- /dev/null
@@ -0,0 +1,1054 @@
+/*
+ * 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/sched.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/hil.h>
+#include <asm/io.h>
+#include <asm/system.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 <asm/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_dequeue_transaction);
+
+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;
+       do_gettimeofday(&hp_sdc.rtv);
+
+       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, struct pt_regs * regs) {
+       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, struct pt_regs * regs) {
+       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) {
+               struct timeval tv;
+               do_gettimeofday(&tv);
+               if (tv.tv_sec > hp_sdc.rtv.tv_sec) tv.tv_usec += 1000000;
+               if (tv.tv_usec - hp_sdc.rtv.tv_usec > 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 (%ius)!\n",
+                              tv.tv_usec - hp_sdc.rtv.tv_usec);
+                       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, 0, 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];
+                       do_gettimeofday(&hp_sdc.rtv);
+                       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(0,0,0,0);
+       }
+       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) {
+       unsigned long flags;
+       int i;
+
+       if (this == NULL) {
+               tasklet_schedule(&hp_sdc.task);
+               return -EINVAL;
+       };
+
+       write_lock_irqsave(&hp_sdc.lock, flags);
+
+       /* 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;
+                       write_unlock_irqrestore(&hp_sdc.lock, flags);
+                       tasklet_schedule(&hp_sdc.task);
+                       return 0;
+               }
+       }
+       write_unlock_irqrestore(&hp_sdc.lock, flags);
+       printk(KERN_WARNING PREFIX "No free slot to add transaction.\n");
+       return -EBUSY;
+
+ fail:
+       write_unlock_irqrestore(&hp_sdc.lock,flags);
+       printk(KERN_WARNING PREFIX "Transaction add failed: transaction already queued?\n");
+       return -EINVAL;
+}
+
+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 *********************/
+
+void hp_sdc_kicker (unsigned long data) {
+       tasklet_schedule(&hp_sdc.task);
+       /* Re-insert the periodic task. */
+       mod_timer(&hp_sdc.kicker, jiffies + HZ);
+}
+
+/************************** Module Initialization ***************************/
+
+#if defined(__hppa__)
+
+static struct parisc_device_id hp_sdc_tbl[] = {
+       {
+               .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 parisc_driver hp_sdc_driver = {
+       .name =         "HP SDC",
+       .id_table =     hp_sdc_tbl,
+       .probe =        hp_sdc_init_hppa,
+};
+
+#endif /* __hppa__ */
+
+static int __init hp_sdc_init(void)
+{
+       int i;
+       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;
+
+       for (i = 0; i < HP_SDC_QUEUE_LEN; i++) hp_sdc.tq[i] = NULL;
+       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, 0, "HP SDC",
+                      (void *) hp_sdc.base_io)) goto err1;
+
+       errstr = "NMI not available for";
+       if (request_irq(hp_sdc.nmi, &hp_sdc_nmisr, 0, "HP SDC NMI", 
+                       (void *) hp_sdc.base_io)) goto err2;
+
+       printk(KERN_INFO PREFIX "HP SDC at 0x%p, IRQ %d (NMI IRQ %d)\n", 
+              (void *)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;
+       init_MUTEX_LOCKED(&s_sync);
+       hp_sdc_enqueue_transaction(&t_sync);
+       down(&s_sync); /* Wait for t_sync to complete */
+
+       /* Create the keepalive task */
+       init_timer(&hp_sdc.kicker);
+       hp_sdc.kicker.expires = jiffies + HZ;
+       hp_sdc.kicker.function = &hp_sdc_kicker;
+       add_timer(&hp_sdc.kicker);
+
+       hp_sdc.dev_err = 0;
+       return 0;
+ err2:
+       free_irq(hp_sdc.irq, NULL);
+ 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 int __init hp_sdc_init_hppa(struct parisc_device *d)
+{
+       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;
+       hp_sdc.data_io          = d->hpa + 0x800;
+       hp_sdc.status_io        = d->hpa + 0x801;
+
+       return hp_sdc_init();
+}
+
+#endif /* __hppa__ */
+
+#if !defined(__mc68000__) /* Link error on m68k! */
+static void __exit hp_sdc_exit(void)
+#else
+static void hp_sdc_exit(void)
+#endif
+{
+       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, NULL);
+       free_irq(hp_sdc.irq, NULL);
+       write_unlock_irq(&hp_sdc.lock);
+
+       del_timer(&hp_sdc.kicker);
+
+       tasklet_kill(&hp_sdc.task);
+
+/*        release_region(hp_sdc.data_io, 2); */
+
+#if defined(__hppa__)
+       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__)
+       mm_segment_t fs;
+       unsigned char i;
+#endif
+       
+       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;
+       fs = get_fs();
+       set_fs(KERNEL_DS);
+       if (!get_user(i, (unsigned char *)hp_sdc.data_io))
+               hp_sdc.dev = (void *)1;
+       set_fs(fs);
+       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;
+       }
+
+       init_MUTEX_LOCKED(&tq_init_sem);
+
+       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) {
+               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)
+ *
+ */