patch-2.1.126 linux/include/asm-mips/dma.h

• Lines: 55
• Date: Tue Oct 20 13:52:53 1998
• Orig file: v2.1.125/linux/include/asm-mips/dma.h
• Orig date: Wed Dec 10 10:31:10 1997

diff -u --recursive --new-file v2.1.125/linux/include/asm-mips/dma.h linux/include/asm-mips/dma.h
@@ -1,4 +1,4 @@
-/* $Id: dma.h,v 1.1.1.1 1997/06/01 03:17:12 ralf Exp $
+/* $Id: dma.h,v 1.2 1998/10/19 21:29:10 ralf Exp $
  * linux/include/asm/dma.h: Defines for using and allocating dma channels.
  * Written by Hennus Bergman, 1992.
  * High DMA channel support & info by Hannu Savolainen
@@ -14,6 +14,8 @@
 
 #include <linux/config.h>
 #include <asm/io.h>			/* need byte IO */
+#include <asm/spinlock.h>		/* And spinlocks */
+#include <linux/delay.h>
 
 
 #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
@@ -143,6 +145,21 @@
 #define DMA_MODE_WRITE	0x48	/* memory to I/O, no autoinit, increment, single mode */
 #define DMA_MODE_CASCADE 0xC0   /* pass thru DREQ->HRQ, DACK<-HLDA only */
 
+
+extern spinlock_t  dma_spin_lock;
+
+static __inline__ unsigned long claim_dma_lock(void)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&dma_spin_lock, flags);
+	return flags;
+}
+
+static __inline__ void release_dma_lock(unsigned long flags)
+{
+	spin_unlock_irqrestore(&dma_spin_lock, flags);
+}
+
 /* enable/disable a specific DMA channel */
 static __inline__ void enable_dma(unsigned int dmanr)
 {
@@ -158,6 +175,8 @@
 		dma_outb(dmanr | 4,  DMA1_MASK_REG);
 	else
 		dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
+	/* I hate voodoo programming but .. */
+	udelay(20);
 }
 
 /* Clear the 'DMA Pointer Flip Flop'.
@@ -165,7 +184,7 @@
  * Use this once to initialize the FF to a known state.
  * After that, keep track of it. :-)
  * --- In order to do that, the DMA routines below should ---
- * --- only be used while interrupts are disabled! ---
+ * --- only be used while holding the DMA lock ! ---
  */
 static __inline__ void clear_dma_ff(unsigned int dmanr)
 {