Register/deregister IRQ and DMA on direct FD driver open/close

elks/arch/i86/drivers/block/directfd.c

@@ -305,7 +305,8 @@ static void redo_fd_request(void);
 static void recal_interrupt(void);
 static void floppy_shutdown(void);
 static void motor_off_callback(int);
-static void floppy_setup(void);
+static int floppy_register(void);
+static void floppy_deregister(void);
 
 /*
  * These are global variables, as that's the easiest way to give
@@ -1478,7 +1479,7 @@ static int floppy_open(struct inode *inode, struct file *filp)
     drive = DEVICE_NR(inode->i_rdev);
     dev = drive & 3;
     if (++fd_ref[dev] == 1) {
-        floppy_setup();
+        floppy_register();
     }
     buffer_drive = buffer_track = -1;	/* FIXME: Don't invalidate buffer if
 					 * this is a reopen of the currently
@@ -1517,6 +1518,7 @@ static void floppy_release(struct inode *inode, struct file *filp)
         fsync_dev(dev);
         invalidate_inodes(dev);
         invalidate_buffers(dev);
+        floppy_deregister();
     }
 }
 
@@ -1557,22 +1559,38 @@ static void floppy_interrupt(int unused, struct pt_regs *unused1)
     handler();
 }
 
-static void floppy_setup(void)
+/* non-portable, should use int_vector_set and new function get_int_vector */
+#define FLOPPY_VEC      (_MK_FP(0, (FLOPPY_IRQ+8) << 2))
+static __u32 old_floppy_vec;
+
+static void floppy_deregister(void)
+{
+    outb(0x0c, FD_DOR);         /* all motors off, enable IRQ and DMA */
+    free_dma(FLOPPY_DMA);
+    clr_irq();
+    free_irq(FLOPPY_IRQ);
+    *(__u32 __far *)FLOPPY_VEC = old_floppy_vec;
+    enable_irq(FLOPPY_IRQ);
+    set_irq();
+}
+
+static int floppy_register(void)
 {
     int err;
-    static char once = 0;
 
-    if (once) return;           /* execute this routine only once for now */
-    once = 1;
-    outb(current_DOR, FD_DOR);	/* all motors off, DMA, /RST  (0x0c) */
+    current_DOR = 0x0c;
+    outb(0x0c, FD_DOR);         /* all motors off, enable IRQ and DMA */
+
+    old_floppy_vec = *((__u32 __far *)FLOPPY_VEC);
     err = request_irq(FLOPPY_IRQ, floppy_interrupt, INT_GENERIC);
     if (err) {
-	printk("Unable to grab IRQ%d for the floppy driver\n", FLOPPY_IRQ);
-	return;	/* should be able to signal failure back to the caller */
+	printk("df: IRQ %d busy\n", FLOPPY_IRQ);
+	return err;
+    }
+    if (request_dma(FLOPPY_DMA, DEVICE_NAME)) {
+	printk("df: DMA %d busy\n", FLOPPY_DMA);
+        return -EBUSY;
     }
-
-    if (request_dma(FLOPPY_DMA, (void *)DEVICE_NAME))
-	printk("Unable to grab DMA%d for the floppy driver\n", FLOPPY_DMA);
 
     /* Try to determine the floppy controller type */
     DEVICE_INTR = ignore_interrupt;	/* don't ask ... */
@@ -1599,6 +1617,7 @@ static void floppy_setup(void)
 	reset_floppy();
     }
 #endif
+    return 0;
 }
 
 void INITPROC floppy_init(void)

elks/arch/i86/drivers/block/dma.c

@@ -64,32 +64,15 @@ static struct dma_chan dma_chan_busy[MAX_DMA_CHANNELS] = {
 	__ret;		   \
 } )
 
-#ifdef ONE_DAY
-
-int get_dma_list(char *buf)
-{
-    int i, len = 0;
-
-    for (i = 0; i < MAX_DMA_CHANNELS; i++)
-	if (dma_chan_busy[i].lock)
-	    len += sprintf(buf + len, "%2d: %s\n",
-			   i, dma_chan_busy[i].device_id);
-    return len;
-}				/* get_dma_list */
-
-#endif
-
-int request_dma(unsigned char dma, void *device)
+int request_dma(unsigned char dma, const char *device)
 {
-    char *device_id = device;
-
     if (dma >= MAX_DMA_CHANNELS)
 	return -EINVAL;
 
     if (xchg(&dma_chan_busy[dma].lock, 1) != 0)
 	return -EBUSY;
 
-    dma_chan_busy[dma].device_id = device_id;
+    dma_chan_busy[dma].device_id = device;
 
     /* old flag was 0, now contains 1 to indicate busy */
     return 0;
@@ -225,6 +208,7 @@ void set_dma_count(unsigned char dma, unsigned int count)
     }
 }
 
+#if UNUSED
 /* Get DMA residue count. After a DMA transfer, this
  * should return zero. Reading this while a DMA transfer is
  * still in progress will return unpredictable results.
@@ -247,4 +231,16 @@ int get_dma_residue(unsigned char dma)
     return (dma <= 3) ? count : (count << 1);
 }
 
+int get_dma_list(char *buf)
+{
+    int i, len = 0;
+
+    for (i = 0; i < MAX_DMA_CHANNELS; i++)
+	if (dma_chan_busy[i].lock)
+	    len += sprintf(buf + len, "%2d: %s\n",
+			   i, dma_chan_busy[i].device_id);
+    return len;
+}				/* get_dma_list */
+#endif
+
 #endif

elks/include/arch/dma.h

@@ -137,7 +137,7 @@ extern void set_dma_page(unsigned char,unsigned char);
 extern void set_dma_addr(unsigned char,unsigned long);
 extern void set_dma_count(unsigned char,unsigned int);
 extern int get_dma_residue(unsigned char);
-extern int request_dma(unsigned char,void *);
+extern int request_dma(unsigned char,const char *);
 extern void free_dma(unsigned char);
 
 #endif

elks/include/arch/ports.h

@@ -121,5 +121,5 @@
 #define HD1_AT_IRQ	14		/* missing request_irq call*/
 #define HD2_AT_IRQ	15		/* missing request_irq call*/
 
-/* obsolete - experimental floppy drive, floppy.c (won't compile)*/
-#define FLOPPY_IRQ	6		/* missing request_irq call*/
+/* direct floppy driver, directfd.c */
+#define FLOPPY_IRQ	6