[259] in linux-net channel archive
3c503 --- memory saver
daemon@ATHENA.MIT.EDU (Paul Gortmaker)
Sun Apr 30 06:51:34 1995
From: Paul Gortmaker <gpg109@rsphy1.anu.edu.au>
To: linux-net@vger.rutgers.edu
Date: Sun, 30 Apr 1995 19:57:17 +1000 (EST)
Here is a patch I have had kicking around for a while. As you may
or may not know, the 3c503 has the ability to support PIO transfers
to the card (akin to a ne2000) instead of the standard (read faster/better)
shared memory implementation.
However, since it is slower, and the 8390 is buggy for PIO usage,
you shouldn't use a 3c503 in PIO mode. If you do, the linux driver will
print a message like "REJUMPER FOR SHARED MEMORY" at boot, and then still
try and use it in the crippled PIO mode.
This patch just #ifdef's out all the PIO code based on whether you have
defined CONFIG_EL2_PIO, for a 20% reduction in the driver size, as
seen below. This may be useful for 2 and 4MB machines.
=========================================
with PIO support
text data bss dec hex
3576 44 0 3620 e24
-rw------- 1 root root 4964 Apr 13 19:50 3c503.o
without PIO support
text data bss dec hex
2700 44 0 2744 ab8
-rw------- 1 root root 4005 Apr 15 15:33 3c503.o
=========================================
This doesn't change the driver behaviour in any other way, so I
wouldn't expect it to fix any problems you might already have.
However, it means two less "if (dev->mem_start)" per Rx packet,
and one less per Tx, so you may see a 0.0001% performance increase. ;-)
Have fun with it.
Paul.
--- 3c503.c.old Sun Apr 30 17:06:31 1995
+++ 3c503.c Sun Apr 30 17:07:24 1995
@@ -12,8 +12,8 @@
Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
This driver should work with the 3c503 and 3c503/16. It should be used
- in shared memory mode for best performance, although it may also work
- in programmed-I/O mode.
+ in shared memory mode for best performance, although it can be
+ configured to work in programmed-I/O mode.
Sources:
EtherLink II Technical Reference Guide,
@@ -25,6 +25,12 @@
static char *version =
"3c503.c:v1.10 9/23/93 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";
+/* Do we support the slower, bug-ridden PIO mode of the 8390? */
+/* #define CONFIG_EL2_PIO */
+
+/* Do we do a quick test on the card's memory at boot? */
+/* #define CONFIG_EL2_MEMTEST */
+
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
@@ -56,9 +62,11 @@
the other for the typical I/O probe. */
struct netdev_entry el2_drv =
{"3c503", el2_probe, EL1_IO_EXTENT, 0};
+#ifdef CONFIG_EL2_PIO
struct netdev_entry el2pio_drv =
{"3c503pio", el2_pioprobe1, EL1_IO_EXTENT, netcard_portlist};
#endif
+#endif
static int el2_open(struct device *dev);
static int el2_close(struct device *dev);
@@ -102,14 +110,14 @@
if (el2_probe1(dev, netcard_portlist[i]) == 0)
return 0;
}
-#if ! defined(no_probe_nonshared_memory) && ! defined (HAVE_DEVLIST)
+#if defined(CONFIG_EL2_PIO) && ! defined (HAVE_DEVLIST)
return el2_pio_probe(dev);
#else
return ENODEV;
#endif
}
-#ifndef HAVE_DEVLIST
+#if defined(CONFIG_EL2_PIO) && ! defined (HAVE_DEVLIST)
/* Try all of the locations that aren't obviously empty. This touches
a lot of locations, and is much riskier than the code above. */
int
@@ -172,6 +180,13 @@
return ENODEV;
}
+#ifndef CONFIG_EL2_PIO
+ if ((membase_reg & 0xf0) == 0) {
+ printk("3c503 in PIO mode ignored - rejumper for shared memory.\n");
+ return ENODEV;
+ }
+#endif
+
request_region(ioaddr, EL2_IO_EXTENT,"3c503");
if (dev == NULL)
@@ -206,14 +221,18 @@
ei_status.interface_num = dev->mem_end & 0xf;
#endif
+#ifdef CONFIG_EL2_PIO
if ((membase_reg & 0xf0) == 0) {
dev->mem_start = 0;
} else {
+#else
+ {
+#endif
dev->mem_start = ((membase_reg & 0xc0) ? 0xD8000 : 0xC8000) +
((membase_reg & 0xA0) ? 0x4000 : 0);
#define EL2_MEMSIZE (EL2SM_STOP_PG - EL2SM_START_PG)*256
-#ifdef EL2MEMTEST
+#ifdef CONFIG_EL2_MEMTEST
/* This has never found an error, but someone might care. */
{ /* Check the card's memory. */
int *mem_base = (int *)dev->mem_start;
@@ -224,14 +243,16 @@
if (mem_base[0] != 0xba5eba5e
|| mem_base[i] != memtest_value) {
printk(" memory failure or memory address conflict.\n");
+#ifdef CONFIG_EL2_PIO
dev->mem_start = 0;
+#endif
break;
}
memtest_value += 0x55555555;
mem_base[i] = 0;
}
}
-#endif /* EL2MEMTEST */
+#endif /* EL2_MEMTEST */
/* Divide the on-board memory into a single maximum-sized transmit
(double-sized for ping-pong transmit) buffer at the base, and
use the rest as a receive ring. */
@@ -262,12 +283,14 @@
dev->open = &el2_open;
dev->stop = &el2_close;
- if (dev->mem_start)
- printk("\n%s: %s with shared memory at %#6lx-%#6lx,\n",
- dev->name, ei_status.name, dev->mem_start, dev->mem_end-1);
- else
+#ifdef CONFIG_EL2_PIO
+ if (dev->mem_start == 0)
printk("\n%s: %s using programmed I/O (REJUMPER for SHARED MEMORY).\n",
dev->name, ei_status.name);
+ else
+#endif
+ printk("\n%s: %s with shared memory at %#6lx-%#6lx,\n",
+ dev->name, ei_status.name, dev->mem_start, dev->mem_end-1);
if (ei_debug > 1)
printk(version);
@@ -376,20 +399,26 @@
el2_block_output(struct device *dev, int count,
const unsigned char *buf, const start_page)
{
- int i; /* Buffer index */
+#ifdef CONFIG_EL2_PIO
+ int i; /* Buffer index */
int boguscount = 0; /* timeout counter */
+#endif
+ void *dest_addr;
/* This should really be set with during an open(). */
outb(EGACFR_NORM, E33G_GACFR); /* Enable RAM and interrupts. */
+#ifdef CONFIG_EL2_PIO
if (dev->mem_start) { /* Shared memory transfer */
- void *dest_addr = (void *)(dev->mem_start +
+#endif
+ dest_addr = (void *)(dev->mem_start +
((start_page - ei_status.tx_start_page) << 8));
memcpy(dest_addr, buf, count);
if (ei_debug > 2 && memcmp(dest_addr, buf, count))
printk("%s: 3c503 send_packet() bad memory copy @ %#5x.\n",
dev->name, (int) dest_addr);
return;
+#ifdef CONFIG_EL2_PIO
}
/* No shared memory, put the packet out the slow way. */
/* Set up then start the internal memory transfer to Tx Start Page */
@@ -413,18 +442,23 @@
}
outb_p(ei_status.interface_num==0 ? ECNTRL_THIN : ECNTRL_AUI, E33G_CNTRL);
return;
+#endif
}
/* Returns the new ring pointer. */
static int
el2_block_input(struct device *dev, int count, char *buf, int ring_offset)
{
+#ifdef CONFIG_EL2_PIO
int boguscount = 0;
- int end_of_ring = dev->rmem_end;
unsigned int i;
+#endif
+ int end_of_ring = dev->rmem_end;
/* Maybe enable shared memory just be to be safe... nahh.*/
+#ifdef CONFIG_EL2_PIO
if (dev->mem_start) { /* Use the shared memory. */
+#endif
ring_offset -= (EL2SM_START_PG<<8);
if (dev->mem_start + ring_offset + count > end_of_ring) {
/* We must wrap the input move. */
@@ -436,6 +470,7 @@
}
memcpy(buf, (char *)dev->mem_start + ring_offset, count);
return ring_offset + count;
+#ifdef CONFIG_EL2_PIO
}
/* No shared memory, use programmed I/O. */
outb(ring_offset & 0xff, E33G_DMAAL);
@@ -458,6 +493,7 @@
}
outb_p(ei_status.interface_num == 0 ? ECNTRL_THIN : ECNTRL_AUI, E33G_CNTRL);
return 0;
+#endif
}
/*
