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