1 files changed, 196 insertions, 0 deletions

diff --git a/arch/m68k/atari/stdma.c b/arch/m68k/atari/stdma.c
new file mode 100644
index 000000000000..288f5e6a124e
--- /dev/null
+++ b/arch/m68k/atari/stdma.c
@@ -0,0 +1,196 @@
+/*
+ *  linux/arch/m68k/atari/stmda.c
+ *
+ *  Copyright (C) 1994 Roman Hodek
+ *
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+
+/* This file contains some function for controlling the access to the  */
+/* ST-DMA chip that may be shared between devices. Currently we have:  */
+/*   TT:     Floppy and ACSI bus                                       */
+/*   Falcon: Floppy and SCSI                                           */
+/*                                                                     */
+/* The controlling functions set up a wait queue for access to the     */
+/* ST-DMA chip. Callers to stdma_lock() that cannot granted access are */
+/* put onto a queue and waked up later if the owner calls              */
+/* stdma_release(). Additionally, the caller gives his interrupt       */
+/* service routine to stdma_lock().                                    */
+/*                                                                     */
+/* On the Falcon, the IDE bus uses just the ACSI/Floppy interrupt, but */
+/* not the ST-DMA chip itself. So falhd.c needs not to lock the        */
+/* chip. The interrupt is routed to falhd.c if IDE is configured, the  */
+/* model is a Falcon and the interrupt was caused by the HD controller */
+/* (can be determined by looking at its status register).              */
+
+
+#include <linux/types.h>
+#include <linux/kdev_t.h>
+#include <linux/genhd.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+
+#include <asm/atari_stdma.h>
+#include <asm/atariints.h>
+#include <asm/atarihw.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+
+static int stdma_locked;                        /* the semaphore */
+                                                /* int func to be called */
+static irqreturn_t (*stdma_isr)(int, void *, struct pt_regs *);
+static void *stdma_isr_data;                    /* data passed to isr */
+static DECLARE_WAIT_QUEUE_HEAD(stdma_wait);     /* wait queue for ST-DMA */
+
+
+
+
+/***************************** Prototypes *****************************/
+
+static irqreturn_t stdma_int (int irq, void *dummy, struct pt_regs *fp);
+
+/************************* End of Prototypes **************************/
+
+
+
+/*
+ * Function: void stdma_lock( isrfunc isr, void *data )
+ *
+ * Purpose: Tries to get a lock on the ST-DMA chip that is used by more
+ *   then one device driver. Waits on stdma_wait until lock is free.
+ *   stdma_lock() may not be called from an interrupt! You have to
+ *   get the lock in your main routine and release it when your
+ *   request is finished.
+ *
+ * Inputs: A interrupt function that is called until the lock is
+ *   released.
+ *
+ * Returns: nothing
+ *
+ */
+
+void stdma_lock(irqreturn_t (*handler)(int, void *, struct pt_regs *),
+                void *data)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);          /* protect lock */
+
+        /* Since the DMA is used for file system purposes, we
+         have to sleep uninterruptible (there may be locked
+         buffers) */
+        wait_event(stdma_wait, !stdma_locked);
+
+        stdma_locked   = 1;
+        stdma_isr      = handler;
+        stdma_isr_data = data;
+        local_irq_restore(flags);
+}
+
+
+/*
+ * Function: void stdma_release( void )
+ *
+ * Purpose: Releases the lock on the ST-DMA chip.
+ *
+ * Inputs: none
+ *
+ * Returns: nothing
+ *
+ */
+
+void stdma_release(void)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        stdma_locked   = 0;
+        stdma_isr      = NULL;
+        stdma_isr_data = NULL;
+        wake_up(&stdma_wait);
+
+        local_irq_restore(flags);
+}
+
+
+/*
+ * Function: int stdma_others_waiting( void )
+ *
+ * Purpose: Check if someone waits for the ST-DMA lock.
+ *
+ * Inputs: none
+ *
+ * Returns: 0 if no one is waiting, != 0 otherwise
+ *
+ */
+
+int stdma_others_waiting(void)
+{
+        return waitqueue_active(&stdma_wait);
+}
+
+
+/*
+ * Function: int stdma_islocked( void )
+ *
+ * Purpose: Check if the ST-DMA is currently locked.
+ * Note: Returned status is only valid if ints are disabled while calling and
+ *       as long as they remain disabled.
+ *       If called with ints enabled, status can change only from locked to
+ *       unlocked, because ints may not lock the ST-DMA.
+ *
+ * Inputs: none
+ *
+ * Returns: != 0 if locked, 0 otherwise
+ *
+ */
+
+int stdma_islocked(void)
+{
+        return stdma_locked;
+}
+
+
+/*
+ * Function: void stdma_init( void )
+ *
+ * Purpose: Initialize the ST-DMA chip access controlling.
+ *   It sets up the interrupt and its service routine. The int is registered
+ *   as slow int, client devices have to live with that (no problem
+ *   currently).
+ *
+ * Inputs: none
+ *
+ * Return: nothing
+ *
+ */
+
+void __init stdma_init(void)
+{
+        stdma_isr = NULL;
+        request_irq(IRQ_MFP_FDC, stdma_int, IRQ_TYPE_SLOW,
+                    "ST-DMA: floppy/ACSI/IDE/Falcon-SCSI", stdma_int);
+}
+
+
+/*
+ * Function: void stdma_int()
+ *
+ * Purpose: The interrupt routine for the ST-DMA. It calls the isr
+ *   registered by stdma_lock().
+ *
+ */
+
+static irqreturn_t stdma_int(int irq, void *dummy, struct pt_regs *fp)
+{
+  if (stdma_isr)
+      (*stdma_isr)(irq, stdma_isr_data, fp);
+  return IRQ_HANDLED;
+}