xref: /xv6-public/memide.c (revision c24ac5d7)
14fa8614dSRuss Cox // Fake IDE disk; stores blocks in memory.
24fa8614dSRuss Cox // Useful for running kernel without scratch disk.
34fa8614dSRuss Cox 
44fa8614dSRuss Cox #include "types.h"
54fa8614dSRuss Cox #include "defs.h"
64fa8614dSRuss Cox #include "param.h"
74fa8614dSRuss Cox #include "mmu.h"
84fa8614dSRuss Cox #include "proc.h"
94fa8614dSRuss Cox #include "x86.h"
104fa8614dSRuss Cox #include "traps.h"
114fa8614dSRuss Cox #include "spinlock.h"
124fa8614dSRuss Cox #include "buf.h"
134fa8614dSRuss Cox 
144fa8614dSRuss Cox extern uchar _binary_fs_img_start[], _binary_fs_img_size[];
154fa8614dSRuss Cox 
164fa8614dSRuss Cox static int disksize;
174fa8614dSRuss Cox static uchar *memdisk;
184fa8614dSRuss Cox 
194fa8614dSRuss Cox void
204fa8614dSRuss Cox ideinit(void)
214fa8614dSRuss Cox {
224fa8614dSRuss Cox   memdisk = _binary_fs_img_start;
23*c24ac5d7SFrans Kaashoek   disksize = (uint)_binary_fs_img_size/BSIZE;
244fa8614dSRuss Cox }
254fa8614dSRuss Cox 
264fa8614dSRuss Cox // Interrupt handler.
274fa8614dSRuss Cox void
284fa8614dSRuss Cox ideintr(void)
294fa8614dSRuss Cox {
304fa8614dSRuss Cox   // no-op
314fa8614dSRuss Cox }
324fa8614dSRuss Cox 
334fa8614dSRuss Cox // Sync buf with disk.
344fa8614dSRuss Cox // If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID.
354fa8614dSRuss Cox // Else if B_VALID is not set, read buf from disk, set B_VALID.
364fa8614dSRuss Cox void
374fa8614dSRuss Cox iderw(struct buf *b)
384fa8614dSRuss Cox {
394fa8614dSRuss Cox   uchar *p;
404fa8614dSRuss Cox 
414fa8614dSRuss Cox   if(!(b->flags & B_BUSY))
424fa8614dSRuss Cox     panic("iderw: buf not busy");
434fa8614dSRuss Cox   if((b->flags & (B_VALID|B_DIRTY)) == B_VALID)
444fa8614dSRuss Cox     panic("iderw: nothing to do");
454fa8614dSRuss Cox   if(b->dev != 1)
464fa8614dSRuss Cox     panic("iderw: request not for disk 1");
47*c24ac5d7SFrans Kaashoek   if(b->block >= disksize)
48*c24ac5d7SFrans Kaashoek     panic("iderw: block out of range");
494fa8614dSRuss Cox 
50*c24ac5d7SFrans Kaashoek   p = memdisk + b->block*BSIZE;
514fa8614dSRuss Cox 
524fa8614dSRuss Cox   if(b->flags & B_DIRTY){
534fa8614dSRuss Cox     b->flags &= ~B_DIRTY;
54*c24ac5d7SFrans Kaashoek     memmove(p, b->data, BSIZE);
554fa8614dSRuss Cox   } else
56*c24ac5d7SFrans Kaashoek     memmove(b->data, p, BSIZE);
574fa8614dSRuss Cox   b->flags |= B_VALID;
584fa8614dSRuss Cox }
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