Initial revision

contrib/smc9462tx-flash/dp83820flash.c

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+/*
+   Kernel module for the dp83820 flash write utility. This code was written
+   by Dave Ashley for NXTV, Inc.
+   Copyright 2004 by NXTV, Inc.
+   Written 20040219 by Dave Ashley.
+
+   This code is released under the terms of the GPL. No warranty.
+
+   THEORY: The dp83820 bootrom interface is flawed in that you can't
+   read or write a single byte at a time, and this is required in order
+   to write to flash devices like the AT29C512. So the workaround is
+   to use the chips ability to map into memory the bootrom, then the cpu
+   can directly do byte accesses.
+
+   The problem is that a "feature" of the dp83820 is that when you map
+   in the bootrom, you conveniently lose access to the PCI registers.
+   So we need to do this in kernel space and wrap every access to the
+   bootrom within interrupt_disable/restore, in case a network interrupt
+   were to come in.
+
+   This kernel module is very simple, it just creates a proc file
+   /proc/dp83820
+   If you write 3 bytes to this file you are doing a write to the flashrom:
+
+Byte 1   2    3
+   ALOW AHIGH DATA
+
+   If you write 2 bytes to this file you are doing a read from the flashrom:
+Byte 1   2
+   ALOW AHIGH
+   Then the next read from the file will return a single byte of what
+   was at that location.
+
+   You only get one shot at accessing the proc file, you need to then
+   close/open if you want to do another access. This could probably be
+   cleaned up pretty easily so more accesses can be done without having
+   to close/open the file.     
+
+*/
+
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/proc_fs.h>
+#include <linux/module.h>
+
+
+#define PROCNAME "dp83820"
+
+struct pci_dev *mydev=0;
+unsigned long loc;
+unsigned char *addr=0;
+
+unsigned char lastread;
+
+
+int my_read_proc(char *buf, char **start,off_t offset,int count, int *eof,void *data)
+{
+int retval=0;
+
+	if(count>0)
+	{
+		buf[0]=lastread;
+		retval=1;
+	}
+
+	*eof=1;
+
+	return retval;
+}
+
+int my_write_proc(struct file *file, const char *buffer, unsigned long count,
+		void *data)
+{
+unsigned char *msg;
+
+unsigned long flags;
+
+	msg=(void *)buffer;
+	save_flags(flags);
+	cli();
+	pci_write_config_dword(mydev, 0x30, loc | 1);
+
+	switch(count)
+	{
+		case 2:
+			lastread=addr[msg[0] | (msg[1]<<8)];
+			break;
+		case 3:
+			addr[msg[0] | (msg[1]<<8)] = msg[2];
+			break;
+	}
+	pci_write_config_dword(mydev, 0x30, loc);
+	restore_flags(flags);
+	return count;
+}
+
+
+struct proc_dir_entry *de=0;
+
+int __init init_module(void)
+{
+int found=0;
+	mydev=0;
+	pci_for_each_dev(mydev)
+	{
+		if(mydev->vendor==0x100b && mydev->device==0x0022)
+		{
+			found=1;
+			break;
+		}
+	}
+	if(!found)
+	{
+		printk("Could not find DP83820 network device\n");
+		return ENODEV;
+	}
+
+	de=create_proc_entry(PROCNAME,0,0);
+	if(!de)
+		return -1;
+	de->data=0;
+	de->read_proc=my_read_proc;
+	de->write_proc=my_write_proc;
+
+	loc=mydev->resource[PCI_ROM_RESOURCE].start;
+	addr=ioremap_nocache(loc,0x10000);
+
+
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	if(de)
+	{
+		remove_proc_entry(PROCNAME,0);
+		de=0;
+	}
+	if(addr)
+	{
+		iounmap(addr);
+		addr=0;
+	}
+}
+