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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);
195: outb_p(0xA0|(drive<<4)|head,++port);
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");
224: if((i = inb(ERR_STAT)) != 1)
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: }
259: port_read(HD_DATA,this_request->bh->b_data+
260: 512*(this_request->nsector&1),256);
261: this_request->errors = 0;
262: if (--this_request->nsector)
263: return;
264: this_request->bh->b_uptodate = 1;
265: this_request->bh->b_dirt = 0;
266: wake_up(&wait_for_request);
267: unlock_buffer(this_request->bh);
268: this_request->hd = -1;
269: this_request=this_request->next;
270: do_request();
271: }
272:
273: static void write_intr(void)
274: {
275: if (win_result()) {
276: bad_rw_intr();
277: return;
278: }
279: if (--this_request->nsector) {
280: port_write(HD_DATA,this_request->bh->b_data+512,256);
281: return;
282: }
283: this_request->bh->b_uptodate = 1;
284: this_request->bh->b_dirt = 0;
285: wake_up(&wait_for_request);
286: unlock_buffer(this_request->bh);
287: this_request->hd = -1;
288: this_request=this_request->next;
289: do_request();
290: }
291:
292: static void do_request(void)
293: {
294: int i,r;
295:
296: if (sorting)
297: return;
298: if (!this_request) {
299: do_hd=NULL;
300: return;
301: }
302: if (this_request->cmd == WIN_WRITE) {
303: hd_out(this_request->hd,this_request->nsector,this_request->
304: sector,this_request->head,this_request->cyl,
305: this_request->cmd,&write_intr);
306: for(i=0 ; i<3000 && !(r=inb_p(HD_STATUS)&DRQ_STAT) ; i++)
307: /* nothing */ ;
308: if (!r) {
309: reset_hd(this_request->hd);
310: return;
311: }
312: port_write(HD_DATA,this_request->bh->b_data+
313: 512*(this_request->nsector&1),256);
314: } else if (this_request->cmd == WIN_READ) {
315: hd_out(this_request->hd,this_request->nsector,this_request->
316: sector,this_request->head,this_request->cyl,
317: this_request->cmd,&read_intr);
318: } else
319: panic("unknown hd-command");
320: }
321:
322: /*
323: * add-request adds a request to the linked list.
324: * It sets the 'sorting'-variable when doing something
325: * that interrupts shouldn't touch.
326: */
327: static void add_request(struct hd_request * req)
328: {
329: struct hd_request * tmp;
330:
331: if (req->nsector != 2)
332: panic("nsector!=2 not implemented");
333: /*
334: * Not to mess up the linked lists, we never touch the two first
335: * entries (not this_request, as it is used by current interrups,
336: * and not this_request->next, as it can be assigned to this_request).
337: * This is not too high a price to pay for the ability of not
338: * disabling interrupts.
339: */
340: sorting=1;
341: if (!(tmp=this_request))
342: this_request=req;
343: else {
344: if (!(tmp->next))
345: tmp->next=req;
346: else {
347: tmp=tmp->next;
348: for ( ; tmp->next ; tmp=tmp->next)
349: if ((IN_ORDER(tmp,req) ||
350: !IN_ORDER(tmp,tmp->next)) &&
351: IN_ORDER(req,tmp->next))
352: break;
353: req->next=tmp->next;
354: tmp->next=req;
355: }
356: }
357: sorting=0;
358: /*
359: * NOTE! As a result of sorting, the interrupts may have died down,
360: * as they aren't redone due to locking with sorting=1. They might
361: * also never have started, if this is the first request in the queue,
362: * so we restart them if necessary.
363: */
364: if (!do_hd)
365: do_request();
366: }
367:
368: void rw_abs_hd(int rw,unsigned int nr,unsigned int sec,unsigned int head,
369: unsigned int cyl,struct buffer_head * bh)
370: {
371: struct hd_request * req;
372:
373: if (rw!=READ && rw!=WRITE)
374: panic("Bad hd command, must be R/W");
375: lock_buffer(bh);
376: repeat:
377: for (req=0+request ; req<NR_REQUEST+request ; req++)
378: if (req->hd<0)
379: break;
380: if (req==NR_REQUEST+request) {
381: sleep_on(&wait_for_request);
382: goto repeat;
383: }
384: req->hd=nr;
385: req->nsector=2;
386: req->sector=sec;
387: req->head=head;
388: req->cyl=cyl;
389: req->cmd = ((rw==READ)?WIN_READ:WIN_WRITE);
390: req->bh=bh;
391: req->errors=0;
392: req->next=NULL;
393: add_request(req);
394: wait_on_buffer(bh);
395: }
396:
397: void hd_init(void)
398: {
399: int i;
400:
401: for (i=0 ; i<NR_REQUEST ; i++) {
402: request[i].hd = -1;
403: request[i].next = NULL;
404: }
405: for (i=0 ; i<NR_HD ; i++) {
406: hd[i*5].start_sect = 0;
407: hd[i*5].nr_sects = hd_info[i].head*
408: hd_info[i].sect*hd_info[i].cyl;
409: }
410: set_trap_gate(0x2E,&hd_interrupt);
411: outb_p(inb_p(0x21)&0xfb,0x21);
412: outb(inb_p(0xA1)&0xbf,0xA1);
413: }
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