1 #include "devices/disk.h"
6 #include "devices/timer.h"
7 #include "threads/io.h"
8 #include "threads/interrupt.h"
9 #include "threads/synch.h"
11 /* ATA command block port addresses. */
12 #define reg_data(CHANNEL) ((CHANNEL)->reg_base + 0) /* Data. */
13 #define reg_error(CHANNEL) ((CHANNEL)->reg_base + 1) /* Error. */
14 #define reg_nsect(CHANNEL) ((CHANNEL)->reg_base + 2) /* Sector Count. */
15 #define reg_lbal(CHANNEL) ((CHANNEL)->reg_base + 3) /* LBA 0:7. */
16 #define reg_lbam(CHANNEL) ((CHANNEL)->reg_base + 4) /* LBA 15:8. */
17 #define reg_lbah(CHANNEL) ((CHANNEL)->reg_base + 5) /* LBA 23:16. */
18 #define reg_device(CHANNEL) ((CHANNEL)->reg_base + 6) /* Device/LBA 27:24. */
19 #define reg_status(CHANNEL) ((CHANNEL)->reg_base + 7) /* Status (r/o). */
20 #define reg_command(CHANNEL) reg_status (CHANNEL) /* Command (w/o). */
22 /* ATA control block port addresses.
23 (If we supported non-legacy ATA controllers this would not be
24 flexible enough, but it's fine for what we do.) */
25 #define reg_ctl(CHANNEL) ((CHANNEL)->reg_base + 0x206) /* Control (w/o). */
26 #define reg_alt_status(CHANNEL) reg_ctl (CHANNEL) /* Alt Status (r/o). */
28 /* Alternate Status Register bits. */
29 #define STA_BSY 0x80 /* Busy. */
30 #define STA_DRQ 0x08 /* Data Request. */
32 /* Control Register bits. */
33 #define CTL_SRST 0x04 /* Software Reset. */
35 /* Device Register bits. */
36 #define DEV_MBS 0xa0 /* Must be set. */
37 #define DEV_LBA 0x40 /* Linear based addressing. */
38 #define DEV_DEV 0x10 /* Select device: 0=master, 1=slave. */
41 Many more are defined but this is the small subset that we
43 #define CMD_IDENTIFY_DEVICE 0xec /* IDENTIFY DEVICE. */
44 #define CMD_READ_SECTOR_RETRY 0x20 /* READ SECTOR with retries. */
45 #define CMD_WRITE_SECTOR_RETRY 0x30 /* WRITE SECTOR with retries. */
50 char name[8]; /* Name, e.g. "hd0:1". */
51 struct channel *channel; /* Channel disk is on. */
52 int dev_no; /* Device 0 or 1 for master or slave. */
54 bool is_ata; /* 1=This device is an ATA disk. */
55 disk_sector_t capacity; /* Capacity in sectors (if is_ata is true). */
58 /* An ATA channel (aka controller).
59 Each channel can control up to two disks. */
62 char name[8]; /* Name, e.g. "hd0". */
63 uint16_t reg_base; /* Base I/O port. */
64 uint8_t irq; /* Interrupt in use. */
66 struct lock lock; /* Must acquire to access the controller. */
67 bool expecting_interrupt; /* True if an interrupt is expected, false if
68 any interrupt would be spurious. */
69 struct semaphore completion_wait; /* Up'd by interrupt handler. */
71 struct disk devices[2]; /* The devices on this channel. */
74 /* We support the two "legacy" ATA channels found in a standard PC. */
76 static struct channel channels[CHANNEL_CNT];
78 static void reset_channel (struct channel *);
79 static bool check_device_type (struct disk *);
80 static void identify_ata_device (struct disk *);
82 static void select_sector (struct disk *, disk_sector_t);
83 static void issue_pio_command (struct channel *, uint8_t command);
84 static void input_sector (struct channel *, void *);
85 static void output_sector (struct channel *, const void *);
87 static void wait_until_idle (const struct disk *);
88 static bool wait_while_busy (const struct disk *);
89 static void select_device (const struct disk *);
90 static void select_device_wait (const struct disk *);
92 static void interrupt_handler (struct intr_frame *);
94 /* Initialize the disk subsystem and detect disks. */
100 for (chan_no = 0; chan_no < CHANNEL_CNT; chan_no++)
102 struct channel *c = &channels[chan_no];
105 /* Initialize channel. */
106 snprintf (c->name, sizeof c->name, "hd%zd", chan_no);
120 lock_init (&c->lock, c->name);
121 c->expecting_interrupt = false;
122 sema_init (&c->completion_wait, 0, c->name);
124 /* Initialize devices. */
125 for (dev_no = 0; dev_no < 2; dev_no++)
127 struct disk *d = &c->devices[dev_no];
128 snprintf (d->name, sizeof d->name, "%s:%d", c->name, dev_no);
136 /* Register interrupt handler. */
137 intr_register (c->irq, 0, INTR_OFF, interrupt_handler, c->name);
139 /* Reset hardware. */
142 /* Distinguish ATA hard disks from other devices. */
143 if (check_device_type (&c->devices[0]))
144 check_device_type (&c->devices[1]);
146 /* Read hard disk identity information. */
147 for (dev_no = 0; dev_no < 2; dev_no++)
148 if (c->devices[dev_no].is_ata)
149 identify_ata_device (&c->devices[dev_no]);
153 /* Returns the disk numbered DEV_NO--either 0 or 1 for master or
154 slave, respectively--within the channel numbered CHAN_NO. */
156 disk_get (int chan_no, int dev_no)
158 ASSERT (dev_no == 0 || dev_no == 1);
160 if (chan_no < (int) CHANNEL_CNT)
162 struct disk *d = &channels[chan_no].devices[dev_no];
169 /* Returns the size of disk D, measured in DISK_SECTOR_SIZE-byte
172 disk_size (struct disk *d)
179 /* Reads sector SEC_NO from disk D into BUFFER, which must have
180 room for DISK_SECTOR_SIZE bytes. */
182 disk_read (struct disk *d, disk_sector_t sec_no, void *buffer)
187 ASSERT (buffer != NULL);
190 lock_acquire (&c->lock);
191 select_sector (d, sec_no);
192 issue_pio_command (c, CMD_READ_SECTOR_RETRY);
193 sema_down (&c->completion_wait);
194 if (!wait_while_busy (d))
195 PANIC ("%s: disk read failed, sector=%"PRDSNu, d->name, sec_no);
196 input_sector (c, buffer);
197 lock_release (&c->lock);
200 /* Write sector SEC_NO to disk D from BUFFER, which must contain
201 DISK_SECTOR_SIZE bytes. Returns after the disk has
202 acknowledged receiving the data. */
204 disk_write (struct disk *d, disk_sector_t sec_no, const void *buffer)
209 ASSERT (buffer != NULL);
212 lock_acquire (&c->lock);
213 select_sector (d, sec_no);
214 issue_pio_command (c, CMD_WRITE_SECTOR_RETRY);
215 if (!wait_while_busy (d))
216 PANIC ("%s: disk write failed, sector=%"PRDSNu, d->name, sec_no);
217 output_sector (c, buffer);
218 sema_down (&c->completion_wait);
219 lock_release (&c->lock);
222 /* Disk detection and identification. */
224 static void print_ata_string (char *string, size_t size);
226 /* Resets an ATA channel and waits for any devices present on it
227 to finish the reset. */
229 reset_channel (struct channel *c)
234 /* The ATA reset sequence depends on which devices are present,
235 so we start by detecting device presence. */
236 for (dev_no = 0; dev_no < 2; dev_no++)
238 struct disk *d = &c->devices[dev_no];
242 outb (reg_nsect (c), 0x55);
243 outb (reg_lbal (c), 0xaa);
245 outb (reg_nsect (c), 0xaa);
246 outb (reg_lbal (c), 0x55);
248 outb (reg_nsect (c), 0x55);
249 outb (reg_lbal (c), 0xaa);
251 present[dev_no] = (inb (reg_nsect (c)) == 0x55
252 && inb (reg_lbal (c)) == 0xaa);
255 /* Issue soft reset sequence, which selects device 0 as a side effect.
256 Also enable interrupts. */
257 outb (reg_ctl (c), 0);
258 timer_sleep (timer_us2ticks (10));
259 outb (reg_ctl (c), CTL_SRST);
260 timer_sleep (timer_us2ticks (10));
261 outb (reg_ctl (c), 0);
263 timer_sleep (timer_ms2ticks (150));
265 /* Wait for device 0 to clear BSY. */
268 select_device (&c->devices[0]);
269 wait_while_busy (&c->devices[0]);
272 /* Wait for device 1 to clear BSY. */
277 select_device (&c->devices[1]);
278 for (i = 0; i < 3000; i++)
280 if (inb (reg_nsect (c)) == 1 && inb (reg_lbal (c)) == 1)
282 timer_sleep (timer_ms2ticks (10));
284 wait_while_busy (&c->devices[1]);
288 /* Checks whether device D is an ATA disk and sets D's is_ata
289 member appropriately. If D is device 0 (master), returns true
290 if it's possible that a slave (device 1) exists on this
291 channel. If D is device 1 (slave), the return value is not
294 check_device_type (struct disk *d)
296 struct channel *c = d->channel;
297 uint8_t error, lbam, lbah;
301 error = inb (reg_error (c));
302 lbam = inb (reg_lbam (c));
303 lbah = inb (reg_lbah (c));
305 if (error != 1 && (error != 0x81 || d->dev_no == 1))
308 return error != 0x81;
312 d->is_ata = (lbam == 0 && lbah == 0) || (lbam == 0x3c && lbah == 0xc3);
317 /* Sends an IDENTIFY DEVICE command to disk D and reads the
318 response. Initializes D's capacity member based on the result
319 and prints a message describing the disk to the console. */
321 identify_ata_device (struct disk *d)
323 struct channel *c = d->channel;
324 uint16_t id[DISK_SECTOR_SIZE / 2];
328 /* Send the IDENTIFY DEVICE command, wait for an interrupt
329 indicating the device's response is ready, and read the data
331 select_device_wait (d);
332 issue_pio_command (c, CMD_IDENTIFY_DEVICE);
333 sema_down (&c->completion_wait);
334 if (!wait_while_busy (d))
339 input_sector (c, id);
341 /* Calculate capacity. */
342 d->capacity = id[60] | ((uint32_t) id[61] << 16);
344 /* Print identification message. */
345 printf ("%s: detected %'"PRDSNu" sector (", d->name, d->capacity);
346 if (d->capacity > 1024 / DISK_SECTOR_SIZE * 1024 * 1024)
347 printf ("%"PRDSNu" GB",
348 d->capacity / (1024 / DISK_SECTOR_SIZE * 1024 * 1024));
349 else if (d->capacity > 1024 / DISK_SECTOR_SIZE * 1024)
350 printf ("%"PRDSNu" MB", d->capacity / (1024 / DISK_SECTOR_SIZE * 1024));
351 else if (d->capacity > 1024 / DISK_SECTOR_SIZE)
352 printf ("%"PRDSNu" kB", d->capacity / (1024 / DISK_SECTOR_SIZE));
354 printf ("%"PRDSNu" byte", d->capacity * DISK_SECTOR_SIZE);
355 printf (") disk, model \"");
356 print_ata_string ((char *) &id[27], 40);
357 printf ("\", serial \"");
358 print_ata_string ((char *) &id[10], 20);
362 /* Prints STRING, which consists of SIZE bytes in a funky format:
363 each pair of bytes is in reverse order. Does not print
364 trailing whitespace and/or nulls. */
366 print_ata_string (char *string, size_t size)
370 /* Find the last non-white, non-null character. */
371 for (; size > 0; size--)
373 int c = string[(size - 1) ^ 1];
374 if (c != '\0' && !isspace (c))
379 for (i = 0; i < size; i++)
380 printf ("%c", string[i ^ 1]);
383 /* Selects device D, waiting for it to become ready, and then
384 writes SEC_NO to the disk's sector selection registers. (We
387 select_sector (struct disk *d, disk_sector_t sec_no)
389 struct channel *c = d->channel;
391 ASSERT (sec_no < d->capacity);
392 ASSERT (sec_no < (1UL << 28));
394 select_device_wait (d);
395 outb (reg_nsect (c), 1);
396 outb (reg_lbal (c), sec_no);
397 outb (reg_lbam (c), sec_no >> 8);
398 outb (reg_lbah (c), (sec_no >> 16));
399 outb (reg_device (c),
400 DEV_MBS | DEV_LBA | (d->dev_no == 1 ? DEV_DEV : 0) | (sec_no >> 24));
403 /* Writes COMMAND to channel C and prepares for receiving a
404 completion interrupt. */
406 issue_pio_command (struct channel *c, uint8_t command)
408 /* Interrupts must be enabled or our semaphore will never be
409 up'd by the completion handler. */
410 ASSERT (intr_get_level () == INTR_ON);
412 c->expecting_interrupt = true;
413 outb (reg_command (c), command);
416 /* Reads a sector from channel C's data register in PIO mode into
417 SECTOR, which must have room for DISK_SECTOR_SIZE bytes. */
419 input_sector (struct channel *c, void *sector)
421 insw (reg_data (c), sector, DISK_SECTOR_SIZE / 2);
424 /* Writes SECTOR to channel C's data register in PIO mode.
425 SECTOR must contain DISK_SECTOR_SIZE bytes. */
427 output_sector (struct channel *c, const void *sector)
429 outsw (reg_data (c), sector, DISK_SECTOR_SIZE / 2);
432 /* Low-level ATA primitives. */
434 /* Wait up to 10 seconds for the controller to become idle, that
435 is, for the BSY and DRQ bits to clear in the status register.
437 As a side effect, reading the status register clears any
438 pending interrupt. */
440 wait_until_idle (const struct disk *d)
444 for (i = 0; i < 1000; i++)
446 if ((inb (reg_status (d->channel)) & (STA_BSY | STA_DRQ)) == 0)
448 timer_sleep (timer_us2ticks (10));
451 printf ("%s: idle timeout\n", d->name);
454 /* Wait up to 30 seconds for disk D to clear BSY,
455 and then return the status of the DRQ bit.
456 The ATA standards say that a disk may take as long as that to
457 complete its reset. */
459 wait_while_busy (const struct disk *d)
461 struct channel *c = d->channel;
464 for (i = 0; i < 3000; i++)
467 printf ("%s: busy, waiting...", d->name);
468 if (!(inb (reg_alt_status (c)) & STA_BSY))
472 return (inb (reg_alt_status (c)) & STA_DRQ) != 0;
474 timer_sleep (timer_ms2ticks (10));
481 /* Program D's channel so that D is now the selected disk. */
483 select_device (const struct disk *d)
485 struct channel *c = d->channel;
486 uint8_t dev = DEV_MBS;
489 outb (reg_device (c), dev);
490 inb (reg_alt_status (c));
491 timer_sleep (timer_ns2ticks (400));
494 /* Select disk D in its channel, as select_device(), but wait for
495 the channel to become idle before and after. */
497 select_device_wait (const struct disk *d)
504 /* ATA interrupt handler. */
506 interrupt_handler (struct intr_frame *f)
510 for (c = channels; c < channels + CHANNEL_CNT; c++)
511 if (f->vec_no == c->irq)
513 if (c->expecting_interrupt)
515 inb (reg_status (c)); /* Acknowledge interrupt. */
516 sema_up (&c->completion_wait); /* Wake up waiter. */
519 printf ("%s: unexpected interrupt\n", c->name);