patch-1.3.45 linux/include/asm-ppc/dma.h

• Lines: 272
• Date: Sat Nov 25 19:49:06 1995
• Orig file: v1.3.44/linux/include/asm-ppc/dma.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.44/linux/include/asm-ppc/dma.h linux/include/asm-ppc/dma.h
@@ -0,0 +1,271 @@
+/* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $
+ * 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
+ * and John Boyd, Nov. 1992.
+ */
+
+#ifndef _ASM_DMA_H
+#define _ASM_DMA_H
+
+#include <asm/io.h>		/* need byte IO */
+
+
+#ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER
+#define dma_outb	outb_p
+#else
+#define dma_outb	outb
+#endif
+
+#define dma_inb		inb
+
+/*
+ * NOTES about DMA transfers:
+ *
+ *  controller 1: channels 0-3, byte operations, ports 00-1F
+ *  controller 2: channels 4-7, word operations, ports C0-DF
+ *
+ *  - ALL registers are 8 bits only, regardless of transfer size
+ *  - channel 4 is not used - cascades 1 into 2.
+ *  - channels 0-3 are byte - addresses/counts are for physical bytes
+ *  - channels 5-7 are word - addresses/counts are for physical words
+ *  - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries
+ *  - transfer count loaded to registers is 1 less than actual count
+ *  - controller 2 offsets are all even (2x offsets for controller 1)
+ *  - page registers for 5-7 don't use data bit 0, represent 128K pages
+ *  - page registers for 0-3 use bit 0, represent 64K pages
+ *
+ * DMA transfers are limited to the lower 16MB of _physical_ memory.  
+ * Note that addresses loaded into registers must be _physical_ addresses,
+ * not logical addresses (which may differ if paging is active).
+ *
+ *  Address mapping for channels 0-3:
+ *
+ *   A23 ... A16 A15 ... A8  A7 ... A0    (Physical addresses)
+ *    |  ...  |   |  ... |   |  ... |
+ *    |  ...  |   |  ... |   |  ... |
+ *    |  ...  |   |  ... |   |  ... |
+ *   P7  ...  P0  A7 ... A0  A7 ... A0   
+ * |    Page    | Addr MSB | Addr LSB |   (DMA registers)
+ *
+ *  Address mapping for channels 5-7:
+ *
+ *   A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0    (Physical addresses)
+ *    |  ...  |   \   \   ... \  \  \  ... \  \
+ *    |  ...  |    \   \   ... \  \  \  ... \  (not used)
+ *    |  ...  |     \   \   ... \  \  \  ... \
+ *   P7  ...  P1 (0) A7 A6  ... A0 A7 A6 ... A0   
+ * |      Page      |  Addr MSB   |  Addr LSB  |   (DMA registers)
+ *
+ * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses
+ * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at
+ * the hardware level, so odd-byte transfers aren't possible).
+ *
+ * Transfer count (_not # bytes_) is limited to 64K, represented as actual
+ * count - 1 : 64K => 0xFFFF, 1 => 0x0000.  Thus, count is always 1 or more,
+ * and up to 128K bytes may be transferred on channels 5-7 in one operation. 
+ *
+ */
+
+#define MAX_DMA_CHANNELS	8
+
+/* The maximum address that we can perform a DMA transfer to on this platform */
+#define MAX_DMA_ADDRESS      0x1000000
+
+/* 8237 DMA controllers */
+#define IO_DMA1_BASE	0x00	/* 8 bit slave DMA, channels 0..3 */
+#define IO_DMA2_BASE	0xC0	/* 16 bit master DMA, ch 4(=slave input)..7 */
+
+/* DMA controller registers */
+#define DMA1_CMD_REG		0x08	/* command register (w) */
+#define DMA1_STAT_REG		0x08	/* status register (r) */
+#define DMA1_REQ_REG            0x09    /* request register (w) */
+#define DMA1_MASK_REG		0x0A	/* single-channel mask (w) */
+#define DMA1_MODE_REG		0x0B	/* mode register (w) */
+#define DMA1_CLEAR_FF_REG	0x0C	/* clear pointer flip-flop (w) */
+#define DMA1_TEMP_REG           0x0D    /* Temporary Register (r) */
+#define DMA1_RESET_REG		0x0D	/* Master Clear (w) */
+#define DMA1_CLR_MASK_REG       0x0E    /* Clear Mask */
+#define DMA1_MASK_ALL_REG       0x0F    /* all-channels mask (w) */
+
+#define DMA2_CMD_REG		0xD0	/* command register (w) */
+#define DMA2_STAT_REG		0xD0	/* status register (r) */
+#define DMA2_REQ_REG            0xD2    /* request register (w) */
+#define DMA2_MASK_REG		0xD4	/* single-channel mask (w) */
+#define DMA2_MODE_REG		0xD6	/* mode register (w) */
+#define DMA2_CLEAR_FF_REG	0xD8	/* clear pointer flip-flop (w) */
+#define DMA2_TEMP_REG           0xDA    /* Temporary Register (r) */
+#define DMA2_RESET_REG		0xDA	/* Master Clear (w) */
+#define DMA2_CLR_MASK_REG       0xDC    /* Clear Mask */
+#define DMA2_MASK_ALL_REG       0xDE    /* all-channels mask (w) */
+
+#define DMA_ADDR_0              0x00    /* DMA address registers */
+#define DMA_ADDR_1              0x02
+#define DMA_ADDR_2              0x04
+#define DMA_ADDR_3              0x06
+#define DMA_ADDR_4              0xC0
+#define DMA_ADDR_5              0xC4
+#define DMA_ADDR_6              0xC8
+#define DMA_ADDR_7              0xCC
+
+#define DMA_CNT_0               0x01    /* DMA count registers */
+#define DMA_CNT_1               0x03
+#define DMA_CNT_2               0x05
+#define DMA_CNT_3               0x07
+#define DMA_CNT_4               0xC2
+#define DMA_CNT_5               0xC6
+#define DMA_CNT_6               0xCA
+#define DMA_CNT_7               0xCE
+
+#define DMA_PAGE_0              0x87    /* DMA page registers */
+#define DMA_PAGE_1              0x83
+#define DMA_PAGE_2              0x81
+#define DMA_PAGE_3              0x82
+#define DMA_PAGE_5              0x8B
+#define DMA_PAGE_6              0x89
+#define DMA_PAGE_7              0x8A
+
+#define DMA_MODE_READ	0x44	/* I/O to memory, no autoinit, increment, single mode */
+#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 */
+
+/* enable/disable a specific DMA channel */
+static __inline__ void enable_dma(unsigned int dmanr)
+{
+	if (dmanr<=3)
+		dma_outb(dmanr,  DMA1_MASK_REG);
+	else
+		dma_outb(dmanr & 3,  DMA2_MASK_REG);
+}
+
+static __inline__ void disable_dma(unsigned int dmanr)
+{
+	if (dmanr<=3)
+		dma_outb(dmanr | 4,  DMA1_MASK_REG);
+	else
+		dma_outb((dmanr & 3) | 4,  DMA2_MASK_REG);
+}
+
+/* Clear the 'DMA Pointer Flip Flop'.
+ * Write 0 for LSB/MSB, 1 for MSB/LSB access.
+ * 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! ---
+ */
+static __inline__ void clear_dma_ff(unsigned int dmanr)
+{
+	if (dmanr<=3)
+		dma_outb(0,  DMA1_CLEAR_FF_REG);
+	else
+		dma_outb(0,  DMA2_CLEAR_FF_REG);
+}
+
+/* set mode (above) for a specific DMA channel */
+static __inline__ void set_dma_mode(unsigned int dmanr, char mode)
+{
+	if (dmanr<=3)
+		dma_outb(mode | dmanr,  DMA1_MODE_REG);
+	else
+		dma_outb(mode | (dmanr&3),  DMA2_MODE_REG);
+}
+
+/* Set only the page register bits of the transfer address.
+ * This is used for successive transfers when we know the contents of
+ * the lower 16 bits of the DMA current address register, but a 64k boundary
+ * may have been crossed.
+ */
+static __inline__ void set_dma_page(unsigned int dmanr, char pagenr)
+{
+	switch(dmanr) {
+		case 0:
+			dma_outb(pagenr, DMA_PAGE_0);
+			break;
+		case 1:
+			dma_outb(pagenr, DMA_PAGE_1);
+			break;
+		case 2:
+			dma_outb(pagenr, DMA_PAGE_2);
+			break;
+		case 3:
+			dma_outb(pagenr, DMA_PAGE_3);
+			break;
+		case 5:
+			dma_outb(pagenr & 0xfe, DMA_PAGE_5);
+			break;
+		case 6:
+			dma_outb(pagenr & 0xfe, DMA_PAGE_6);
+			break;
+		case 7:
+			dma_outb(pagenr & 0xfe, DMA_PAGE_7);
+			break;
+	}
+}
+
+
+/* Set transfer address & page bits for specific DMA channel.
+ * Assumes dma flipflop is clear.
+ */
+static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a)
+{
+	set_dma_page(dmanr, a>>16);
+	if (dmanr <= 3)  {
+	    dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
+            dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE );
+	}  else  {
+	    dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
+	    dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE );
+	}
+}
+
+
+/* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for
+ * a specific DMA channel.
+ * You must ensure the parameters are valid.
+ * NOTE: from a manual: "the number of transfers is one more
+ * than the initial word count"! This is taken into account.
+ * Assumes dma flip-flop is clear.
+ * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7.
+ */
+static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count)
+{
+        count--;
+	if (dmanr <= 3)  {
+	    dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
+	    dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE );
+        } else {
+	    dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
+	    dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE );
+        }
+}
+
+
+/* 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.
+ * If called before the channel has been used, it may return 1.
+ * Otherwise, it returns the number of _bytes_ left to transfer.
+ *
+ * Assumes DMA flip-flop is clear.
+ */
+static __inline__ int get_dma_residue(unsigned int dmanr)
+{
+	unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE
+					 : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE;
+
+	/* using short to get 16-bit wrap around */
+	unsigned short count;
+
+	count = 1 + dma_inb(io_port);
+	count += dma_inb(io_port) << 8;
+	
+	return (dmanr<=3)? count : (count<<1);
+}
+
+
+/* These are in kernel/dma.c: */
+/*extern int request_dma(unsigned int dmanr, char * device_id);*/	/* reserve a DMA channel */
+extern void free_dma(unsigned int dmanr);	/* release it again */
+
+
+#endif /* _ASM_DMA_H */