[PATCH] drivers/net/3c505.c

[Paul]

Alan Cox <[e-mail]>, on Thu Aug 02, 2001 [03:19:56 PM] said:
> > 	Well, I have tracked down my problem. We see a comparison
> > like this to  determine whether to use a bounce buffer:
> > 
> > if ( virt_to_bus(addr+buflen) >= MAX_DMA_ADDRESS) {
> > ...(use a bounce buffer 'cause that addr is not dma-able)...
> > 
> > 	This is not working, because MAX_DMA_ADDRESS is defined
> > so:
> > 
> > ./include/asm-i386/dma.h:
> > #define MAX_DMA_ADDRESS (PAGE_OFFSET+0x1000000)
> 
> MAX_DMA_ADDRESS is intended for checking virtual addresses not bus
> addresses. 
> 
> Alan

	Dear Alan;

	Here are two alternate patches to 3c505.c . They both
enable the card to 'work' on my 486 machine with > 16meg. Is
either a correct fix?

Paul
[e-mail]

--- 2.4.7/drivers/net/3c505.c	Wed Aug  1 23:48:44 2001
+++ 2.4.7.3c505.hack/drivers/net/3c505.c	Thu Aug  2 20:35:02 2001
@@ -607,7 +607,7 @@
 
 	skb_reserve(skb, 2);
 	target = skb_put(skb, rlen);
-	if (virt_to_bus(target + rlen) >= MAX_DMA_ADDRESS) {
+	if ((unsigned long)(target + rlen) >= MAX_DMA_ADDRESS) {
 		adapter->current_dma.target = target;
 		target = adapter->dma_buffer;
 	} else {
@@ -1027,11 +1027,13 @@
 	adapter->current_dma.direction = 1;
 	adapter->current_dma.start_time = jiffies;
 
-	target = virt_to_bus(skb->data);
-	if ((target + nlen) >= MAX_DMA_ADDRESS) {
+	if ((unsigned long)(skb->data + nlen) >= MAX_DMA_ADDRESS) {
 		memcpy(adapter->dma_buffer, skb->data, nlen);
 		target = virt_to_bus(adapter->dma_buffer);
 	}
+	else {
+		target = virt_to_bus(skb->data);
+	}
 	adapter->current_dma.skb = skb;
 
 	flags=claim_dma_lock();

-=-=-=-=-=-=-=-=-=- (as seen in some scsi drivers)

--- 2.4.7/drivers/net/3c505.c	Wed Aug  1 23:48:44 2001
+++ 2.4.7.3c505.hack/drivers/net/3c505.c	Thu Aug  2 20:45:16 2001
@@ -106,6 +106,7 @@
 #include <asm/bitops.h>
 #include <asm/io.h>
 #include <asm/dma.h>
+#include <asm/scatterlist.h>
 
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
@@ -607,7 +608,7 @@
 
 	skb_reserve(skb, 2);
 	target = skb_put(skb, rlen);
-	if (virt_to_bus(target + rlen) >= MAX_DMA_ADDRESS) {
+	if (virt_to_phys(target + rlen -1) > ISA_DMA_THRESHOLD) {
 		adapter->current_dma.target = target;
 		target = adapter->dma_buffer;
 	} else {
@@ -1027,11 +1028,13 @@
 	adapter->current_dma.direction = 1;
 	adapter->current_dma.start_time = jiffies;
 
-	target = virt_to_bus(skb->data);
-	if ((target + nlen) >= MAX_DMA_ADDRESS) {
+	if (virt_to_phys(skb->data + nlen -1) > ISA_DMA_THRESHOLD) {
 		memcpy(adapter->dma_buffer, skb->data, nlen);
 		target = virt_to_bus(adapter->dma_buffer);
 	}
+	else {
+		target = virt_to_bus(skb->data);
+	}
 	adapter->current_dma.skb = skb;
 
 	flags=claim_dma_lock();