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1.1 root 1: #include <linux/config.h>
2: #include <linux/sched.h>
3: #include <linux/fs.h>
4: #include <linux/kernel.h>
5: #include <linux/hdreg.h>
6: #include <asm/system.h>
7: #include <asm/io.h>
8: #include <asm/segment.h>
9:
10: /*
11: * This code handles all hd-interrupts, and read/write requests to
12: * the hard-disk. It is relatively straigthforward (not obvious maybe,
13: * but interrupts never are), while still being efficient, and never
14: * disabling interrupts (except to overcome possible race-condition).
15: * The elevator block-seek algorithm doesn't need to disable interrupts
16: * due to clever programming.
17: */
18:
19: /* Max read/write errors/sector */
20: #define MAX_ERRORS 5
21: #define MAX_HD 2
22: #define NR_REQUEST 32
23:
24: /*
25: * This struct defines the HD's and their types.
26: * Currently defined for CP3044's, ie a modified
27: * type 17.
28: */
29: static struct hd_i_struct{
30: int head,sect,cyl,wpcom,lzone,ctl;
31: } hd_info[]= { HD_TYPE };
32:
33: #define NR_HD ((sizeof (hd_info))/(sizeof (struct hd_i_struct)))
34:
35: static struct hd_struct {
36: long start_sect;
37: long nr_sects;
38: } hd[5*MAX_HD]={{0,0},};
39:
40: static struct hd_request {
41: int hd; /* -1 if no request */
42: int nsector;
43: int sector;
44: int head;
45: int cyl;
46: int cmd;
47: int errors;
48: struct buffer_head * bh;
49: struct hd_request * next;
50: } request[NR_REQUEST];
51:
52: #define IN_ORDER(s1,s2) \
53: ((s1)->hd<(s2)->hd || (s1)->hd==(s2)->hd && \
54: ((s1)->cyl<(s2)->cyl || (s1)->cyl==(s2)->cyl && \
55: ((s1)->head<(s2)->head || (s1)->head==(s2)->head && \
56: ((s1)->sector<(s2)->sector))))
57:
58: static struct hd_request * this_request = NULL;
59:
60: static int sorting=0;
61:
62: static void do_request(void);
63: static void reset_controller(void);
64: static void rw_abs_hd(int rw,unsigned int nr,unsigned int sec,unsigned int head,
65: unsigned int cyl,struct buffer_head * bh);
66: void hd_init(void);
67:
68: #define port_read(port,buf,nr) \
69: __asm__("cld;rep;insw"::"d" (port),"D" (buf),"c" (nr):"cx","di")
70:
71: #define port_write(port,buf,nr) \
72: __asm__("cld;rep;outsw"::"d" (port),"S" (buf),"c" (nr):"cx","si")
73:
74: extern void hd_interrupt(void);
75:
76: static struct task_struct * wait_for_request=NULL;
77:
78: static inline void lock_buffer(struct buffer_head * bh)
79: {
80: if (bh->b_lock)
81: printk("hd.c: buffer multiply locked\n");
82: bh->b_lock=1;
83: }
84:
85: static inline void unlock_buffer(struct buffer_head * bh)
86: {
87: if (!bh->b_lock)
88: printk("hd.c: free buffer being unlocked\n");
89: bh->b_lock=0;
90: wake_up(&bh->b_wait);
91: }
92:
93: static inline void wait_on_buffer(struct buffer_head * bh)
94: {
95: cli();
96: while (bh->b_lock)
97: sleep_on(&bh->b_wait);
98: sti();
99: }
100:
101: void rw_hd(int rw, struct buffer_head * bh)
102: {
103: unsigned int block,dev;
104: unsigned int sec,head,cyl;
105:
106: block = bh->b_blocknr << 1;
107: dev = MINOR(bh->b_dev);
108: if (dev >= 5*NR_HD || block+2 > hd[dev].nr_sects)
109: return;
110: block += hd[dev].start_sect;
111: dev /= 5;
112: __asm__("divl %4":"=a" (block),"=d" (sec):"0" (block),"1" (0),
113: "r" (hd_info[dev].sect));
114: __asm__("divl %4":"=a" (cyl),"=d" (head):"0" (block),"1" (0),
115: "r" (hd_info[dev].head));
116: rw_abs_hd(rw,dev,sec+1,head,cyl,bh);
117: }
118:
119: /* This may be used only once, enforced by 'static int callable' */
120: int sys_setup(void)
121: {
122: static int callable = 1;
123: int i,drive;
124: struct partition *p;
125:
126: if (!callable)
127: return -1;
128: callable = 0;
129: for (drive=0 ; drive<NR_HD ; drive++) {
130: rw_abs_hd(READ,drive,1,0,0,(struct buffer_head *) start_buffer);
131: if (!start_buffer->b_uptodate) {
132: printk("Unable to read partition table of drive %d\n\r",
133: drive);
134: panic("");
135: }
136: if (start_buffer->b_data[510] != 0x55 || (unsigned char)
137: start_buffer->b_data[511] != 0xAA) {
138: printk("Bad partition table on drive %d\n\r",drive);
139: panic("");
140: }
141: p = 0x1BE + (void *)start_buffer->b_data;
142: for (i=1;i<5;i++,p++) {
143: hd[i+5*drive].start_sect = p->start_sect;
144: hd[i+5*drive].nr_sects = p->nr_sects;
145: }
146: }
147: printk("Partition table%s ok.\n\r",(NR_HD>1)?"s":"");
148: mount_root();
149: return (0);
150: }
151:
152: /*
153: * This is the pointer to a routine to be executed at every hd-interrupt.
154: * Interesting way of doing things, but should be rather practical.
155: */
156: void (*do_hd)(void) = NULL;
157:
158: static int controller_ready(void)
159: {
160: int retries=1000;
161:
162: while (--retries && (inb(HD_STATUS)&0xc0)!=0x40);
163: return (retries);
164: }
165:
166: static int win_result(void)
167: {
168: int i=inb(HD_STATUS);
169:
170: if ((i & (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT))
171: == (READY_STAT | SEEK_STAT))
172: return(0); /* ok */
173: if (i&1) i=inb(HD_ERROR);
174: return (1);
175: }
176:
177: static void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,
178: unsigned int head,unsigned int cyl,unsigned int cmd,
179: void (*intr_addr)(void))
180: {
181: register int port asm("dx");
182:
183: if (drive>1 || head>15)
184: panic("Trying to write bad sector");
185: if (!controller_ready())
186: panic("HD controller not ready");
187: do_hd = intr_addr;
188: outb(_CTL,HD_CMD);
189: port=HD_DATA;
190: outb_p(_WPCOM,++port);
191: outb_p(nsect,++port);
192: outb_p(sect,++port);
193: outb_p(cyl,++port);
194: outb_p(cyl>>8,++port);
1.1.1.2 ! root 195: outb_p(0xB0|(drive<<4)|head,++port);
1.1 root 196: outb(cmd,++port);
197: }
198:
199: static int drive_busy(void)
200: {
201: unsigned int i;
202:
203: for (i = 0; i < 100000; i++)
204: if (READY_STAT == (inb(HD_STATUS) & (BUSY_STAT | READY_STAT)))
205: break;
206: i = inb(HD_STATUS);
207: i &= BUSY_STAT | READY_STAT | SEEK_STAT;
208: if (i == READY_STAT | SEEK_STAT)
209: return(0);
210: printk("HD controller times out\n\r");
211: return(1);
212: }
213:
214: static void reset_controller(void)
215: {
216: int i;
217:
218: outb(4,HD_CMD);
219: for(i = 0; i < 1000; i++) nop();
220: outb(0,HD_CMD);
221: for(i = 0; i < 10000 && drive_busy(); i++) /* nothing */;
222: if (drive_busy())
223: printk("HD-controller still busy\n\r");
1.1.1.2 ! root 224: if((i = inb(HD_STATUS)) & ERR_STAT)
1.1 root 225: printk("HD-controller reset failed: %02x\n\r",i);
226: }
227:
228: static void reset_hd(int nr)
229: {
230: reset_controller();
231: hd_out(nr,_SECT,_SECT,_HEAD-1,_CYL,WIN_SPECIFY,&do_request);
232: }
233:
234: void unexpected_hd_interrupt(void)
235: {
236: panic("Unexpected HD interrupt\n\r");
237: }
238:
239: static void bad_rw_intr(void)
240: {
241: int i = this_request->hd;
242:
243: if (this_request->errors++ >= MAX_ERRORS) {
244: this_request->bh->b_uptodate = 0;
245: unlock_buffer(this_request->bh);
246: wake_up(&wait_for_request);
247: this_request->hd = -1;
248: this_request=this_request->next;
249: }
250: reset_hd(i);
251: }
252:
253: static void read_intr(void)
254: {
255: if (win_result()) {
256: bad_rw_intr();
257: return;
258: }
1.1.1.2 ! root 259:
! 260: if (this_request->nsector==2){
! 261: this_request->nsector--;
! 262: port_read(HD_DATA,this_request->bh->b_data,256);
! 263: }
! 264: else{
! 265: port_read(HD_DATA,this_request->bh->b_data+512,256);
1.1 root 266: return;
1.1.1.2 ! root 267: }
! 268:
! 269: this_request->errors = 0;
! 270:
1.1 root 271: this_request->bh->b_uptodate = 1;
272: this_request->bh->b_dirt = 0;
273: wake_up(&wait_for_request);
274: unlock_buffer(this_request->bh);
275: this_request->hd = -1;
276: this_request=this_request->next;
277: do_request();
278: }
279:
280: static void write_intr(void)
281: {
282: if (win_result()) {
283: bad_rw_intr();
284: return;
285: }
286: if (--this_request->nsector) {
287: port_write(HD_DATA,this_request->bh->b_data+512,256);
288: return;
289: }
290: this_request->bh->b_uptodate = 1;
291: this_request->bh->b_dirt = 0;
292: wake_up(&wait_for_request);
293: unlock_buffer(this_request->bh);
294: this_request->hd = -1;
295: this_request=this_request->next;
296: do_request();
297: }
298:
299: static void do_request(void)
300: {
301: int i,r;
302:
303: if (sorting)
304: return;
305: if (!this_request) {
306: do_hd=NULL;
307: return;
308: }
309: if (this_request->cmd == WIN_WRITE) {
310: hd_out(this_request->hd,this_request->nsector,this_request->
311: sector,this_request->head,this_request->cyl,
312: this_request->cmd,&write_intr);
313: for(i=0 ; i<3000 && !(r=inb_p(HD_STATUS)&DRQ_STAT) ; i++)
314: /* nothing */ ;
315: if (!r) {
316: reset_hd(this_request->hd);
317: return;
318: }
319: port_write(HD_DATA,this_request->bh->b_data+
320: 512*(this_request->nsector&1),256);
321: } else if (this_request->cmd == WIN_READ) {
322: hd_out(this_request->hd,this_request->nsector,this_request->
323: sector,this_request->head,this_request->cyl,
324: this_request->cmd,&read_intr);
325: } else
326: panic("unknown hd-command");
327: }
328:
329: /*
330: * add-request adds a request to the linked list.
331: * It sets the 'sorting'-variable when doing something
332: * that interrupts shouldn't touch.
333: */
334: static void add_request(struct hd_request * req)
335: {
336: struct hd_request * tmp;
337:
338: if (req->nsector != 2)
339: panic("nsector!=2 not implemented");
340: /*
341: * Not to mess up the linked lists, we never touch the two first
342: * entries (not this_request, as it is used by current interrups,
343: * and not this_request->next, as it can be assigned to this_request).
344: * This is not too high a price to pay for the ability of not
345: * disabling interrupts.
346: */
347: sorting=1;
348: if (!(tmp=this_request))
349: this_request=req;
350: else {
351: if (!(tmp->next))
352: tmp->next=req;
353: else {
354: tmp=tmp->next;
355: for ( ; tmp->next ; tmp=tmp->next)
356: if ((IN_ORDER(tmp,req) ||
357: !IN_ORDER(tmp,tmp->next)) &&
358: IN_ORDER(req,tmp->next))
359: break;
360: req->next=tmp->next;
361: tmp->next=req;
362: }
363: }
364: sorting=0;
365: /*
366: * NOTE! As a result of sorting, the interrupts may have died down,
367: * as they aren't redone due to locking with sorting=1. They might
368: * also never have started, if this is the first request in the queue,
369: * so we restart them if necessary.
370: */
371: if (!do_hd)
372: do_request();
373: }
374:
375: void rw_abs_hd(int rw,unsigned int nr,unsigned int sec,unsigned int head,
376: unsigned int cyl,struct buffer_head * bh)
377: {
378: struct hd_request * req;
379:
380: if (rw!=READ && rw!=WRITE)
381: panic("Bad hd command, must be R/W");
382: lock_buffer(bh);
383: repeat:
384: for (req=0+request ; req<NR_REQUEST+request ; req++)
385: if (req->hd<0)
386: break;
387: if (req==NR_REQUEST+request) {
388: sleep_on(&wait_for_request);
389: goto repeat;
390: }
391: req->hd=nr;
392: req->nsector=2;
393: req->sector=sec;
394: req->head=head;
395: req->cyl=cyl;
396: req->cmd = ((rw==READ)?WIN_READ:WIN_WRITE);
397: req->bh=bh;
398: req->errors=0;
399: req->next=NULL;
400: add_request(req);
401: wait_on_buffer(bh);
402: }
403:
404: void hd_init(void)
405: {
406: int i;
407:
408: for (i=0 ; i<NR_REQUEST ; i++) {
409: request[i].hd = -1;
410: request[i].next = NULL;
411: }
412: for (i=0 ; i<NR_HD ; i++) {
413: hd[i*5].start_sect = 0;
414: hd[i*5].nr_sects = hd_info[i].head*
415: hd_info[i].sect*hd_info[i].cyl;
416: }
417: set_trap_gate(0x2E,&hd_interrupt);
418: outb_p(inb_p(0x21)&0xfb,0x21);
419: outb(inb_p(0xA1)&0xbf,0xA1);
420: }
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