--- /dev/null
+#include "devices/ide.h"
+#include <ctype.h>
+#include <debug.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include "devices/block.h"
+#include "devices/partition.h"
+#include "devices/timer.h"
+#include "threads/io.h"
+#include "threads/interrupt.h"
+#include "threads/synch.h"
+
+/* The code in this file is an interface to an ATA (IDE)
+ controller. It attempts to comply to [ATA-3]. */
+
+/* ATA command block port addresses. */
+#define reg_data(CHANNEL) ((CHANNEL)->reg_base + 0) /* Data. */
+#define reg_error(CHANNEL) ((CHANNEL)->reg_base + 1) /* Error. */
+#define reg_nsect(CHANNEL) ((CHANNEL)->reg_base + 2) /* Sector Count. */
+#define reg_lbal(CHANNEL) ((CHANNEL)->reg_base + 3) /* LBA 0:7. */
+#define reg_lbam(CHANNEL) ((CHANNEL)->reg_base + 4) /* LBA 15:8. */
+#define reg_lbah(CHANNEL) ((CHANNEL)->reg_base + 5) /* LBA 23:16. */
+#define reg_device(CHANNEL) ((CHANNEL)->reg_base + 6) /* Device/LBA 27:24. */
+#define reg_status(CHANNEL) ((CHANNEL)->reg_base + 7) /* Status (r/o). */
+#define reg_command(CHANNEL) reg_status (CHANNEL) /* Command (w/o). */
+
+/* ATA control block port addresses.
+ (If we supported non-legacy ATA controllers this would not be
+ flexible enough, but it's fine for what we do.) */
+#define reg_ctl(CHANNEL) ((CHANNEL)->reg_base + 0x206) /* Control (w/o). */
+#define reg_alt_status(CHANNEL) reg_ctl (CHANNEL) /* Alt Status (r/o). */
+
+/* Alternate Status Register bits. */
+#define STA_BSY 0x80 /* Busy. */
+#define STA_DRDY 0x40 /* Device Ready. */
+#define STA_DRQ 0x08 /* Data Request. */
+
+/* Control Register bits. */
+#define CTL_SRST 0x04 /* Software Reset. */
+
+/* Device Register bits. */
+#define DEV_MBS 0xa0 /* Must be set. */
+#define DEV_LBA 0x40 /* Linear based addressing. */
+#define DEV_DEV 0x10 /* Select device: 0=master, 1=slave. */
+
+/* Commands.
+ Many more are defined but this is the small subset that we
+ use. */
+#define CMD_IDENTIFY_DEVICE 0xec /* IDENTIFY DEVICE. */
+#define CMD_READ_SECTOR_RETRY 0x20 /* READ SECTOR with retries. */
+#define CMD_WRITE_SECTOR_RETRY 0x30 /* WRITE SECTOR with retries. */
+
+/* An ATA device. */
+struct ata_disk
+ {
+ char name[8]; /* Name, e.g. "hda". */
+ struct channel *channel; /* Channel that disk is attached to. */
+ int dev_no; /* Device 0 or 1 for master or slave. */
+ bool is_ata; /* Is device an ATA disk? */
+ };
+
+/* An ATA channel (aka controller).
+ Each channel can control up to two disks. */
+struct channel
+ {
+ char name[8]; /* Name, e.g. "ide0". */
+ uint16_t reg_base; /* Base I/O port. */
+ uint8_t irq; /* Interrupt in use. */
+
+ struct lock lock; /* Must acquire to access the controller. */
+ bool expecting_interrupt; /* True if an interrupt is expected, false if
+ any interrupt would be spurious. */
+ struct semaphore completion_wait; /* Up'd by interrupt handler. */
+
+ struct ata_disk devices[2]; /* The devices on this channel. */
+ };
+
+/* We support the two "legacy" ATA channels found in a standard PC. */
+#define CHANNEL_CNT 2
+static struct channel channels[CHANNEL_CNT];
+
+static struct block_operations ide_operations;
+
+static void reset_channel (struct channel *);
+static bool check_device_type (struct ata_disk *);
+static void identify_ata_device (struct ata_disk *);
+
+static void select_sector (struct ata_disk *, block_sector_t);
+static void issue_pio_command (struct channel *, uint8_t command);
+static void input_sector (struct channel *, void *);
+static void output_sector (struct channel *, const void *);
+
+static void wait_until_idle (const struct ata_disk *);
+static bool wait_while_busy (const struct ata_disk *);
+static void select_device (const struct ata_disk *);
+static void select_device_wait (const struct ata_disk *);
+
+static void interrupt_handler (struct intr_frame *);
+
+/* Initialize the disk subsystem and detect disks. */
+void
+ide_init (void)
+{
+ size_t chan_no;
+
+ for (chan_no = 0; chan_no < CHANNEL_CNT; chan_no++)
+ {
+ struct channel *c = &channels[chan_no];
+ int dev_no;
+
+ /* Initialize channel. */
+ snprintf (c->name, sizeof c->name, "ide%zu", chan_no);
+ switch (chan_no)
+ {
+ case 0:
+ c->reg_base = 0x1f0;
+ c->irq = 14 + 0x20;
+ break;
+ case 1:
+ c->reg_base = 0x170;
+ c->irq = 15 + 0x20;
+ break;
+ default:
+ NOT_REACHED ();
+ }
+ lock_init (&c->lock);
+ c->expecting_interrupt = false;
+ sema_init (&c->completion_wait, 0);
+
+ /* Initialize devices. */
+ for (dev_no = 0; dev_no < 2; dev_no++)
+ {
+ struct ata_disk *d = &c->devices[dev_no];
+ snprintf (d->name, sizeof d->name,
+ "hd%c", 'a' + chan_no * 2 + dev_no);
+ d->channel = c;
+ d->dev_no = dev_no;
+ d->is_ata = false;
+ }
+
+ /* Register interrupt handler. */
+ intr_register_ext (c->irq, interrupt_handler, c->name);
+
+ /* Reset hardware. */
+ reset_channel (c);
+
+ /* Distinguish ATA hard disks from other devices. */
+ if (check_device_type (&c->devices[0]))
+ check_device_type (&c->devices[1]);
+
+ /* Read hard disk identity information. */
+ for (dev_no = 0; dev_no < 2; dev_no++)
+ if (c->devices[dev_no].is_ata)
+ identify_ata_device (&c->devices[dev_no]);
+ }
+}
+\f
+/* Disk detection and identification. */
+
+static char *descramble_ata_string (char *, int size);
+
+/* Resets an ATA channel and waits for any devices present on it
+ to finish the reset. */
+static void
+reset_channel (struct channel *c)
+{
+ bool present[2];
+ int dev_no;
+
+ /* The ATA reset sequence depends on which devices are present,
+ so we start by detecting device presence. */
+ for (dev_no = 0; dev_no < 2; dev_no++)
+ {
+ struct ata_disk *d = &c->devices[dev_no];
+
+ select_device (d);
+
+ outb (reg_nsect (c), 0x55);
+ outb (reg_lbal (c), 0xaa);
+
+ outb (reg_nsect (c), 0xaa);
+ outb (reg_lbal (c), 0x55);
+
+ outb (reg_nsect (c), 0x55);
+ outb (reg_lbal (c), 0xaa);
+
+ present[dev_no] = (inb (reg_nsect (c)) == 0x55
+ && inb (reg_lbal (c)) == 0xaa);
+ }
+
+ /* Issue soft reset sequence, which selects device 0 as a side effect.
+ Also enable interrupts. */
+ outb (reg_ctl (c), 0);
+ timer_usleep (10);
+ outb (reg_ctl (c), CTL_SRST);
+ timer_usleep (10);
+ outb (reg_ctl (c), 0);
+
+ timer_msleep (150);
+
+ /* Wait for device 0 to clear BSY. */
+ if (present[0])
+ {
+ select_device (&c->devices[0]);
+ wait_while_busy (&c->devices[0]);
+ }
+
+ /* Wait for device 1 to clear BSY. */
+ if (present[1])
+ {
+ int i;
+
+ select_device (&c->devices[1]);
+ for (i = 0; i < 3000; i++)
+ {
+ if (inb (reg_nsect (c)) == 1 && inb (reg_lbal (c)) == 1)
+ break;
+ timer_msleep (10);
+ }
+ wait_while_busy (&c->devices[1]);
+ }
+}
+
+/* Checks whether device D is an ATA disk and sets D's is_ata
+ member appropriately. If D is device 0 (master), returns true
+ if it's possible that a slave (device 1) exists on this
+ channel. If D is device 1 (slave), the return value is not
+ meaningful. */
+static bool
+check_device_type (struct ata_disk *d)
+{
+ struct channel *c = d->channel;
+ uint8_t error, lbam, lbah, status;
+
+ select_device (d);
+
+ error = inb (reg_error (c));
+ lbam = inb (reg_lbam (c));
+ lbah = inb (reg_lbah (c));
+ status = inb (reg_status (c));
+
+ if ((error != 1 && (error != 0x81 || d->dev_no == 1))
+ || (status & STA_DRDY) == 0
+ || (status & STA_BSY) != 0)
+ {
+ d->is_ata = false;
+ return error != 0x81;
+ }
+ else
+ {
+ d->is_ata = (lbam == 0 && lbah == 0) || (lbam == 0x3c && lbah == 0xc3);
+ return true;
+ }
+}
+
+/* Sends an IDENTIFY DEVICE command to disk D and reads the
+ response. Registers the disk with the block device
+ layer. */
+static void
+identify_ata_device (struct ata_disk *d)
+{
+ struct channel *c = d->channel;
+ char id[BLOCK_SECTOR_SIZE];
+ block_sector_t capacity;
+ char *model, *serial;
+ char extra_info[128];
+ struct block *block;
+
+ ASSERT (d->is_ata);
+
+ /* Send the IDENTIFY DEVICE command, wait for an interrupt
+ indicating the device's response is ready, and read the data
+ into our buffer. */
+ select_device_wait (d);
+ issue_pio_command (c, CMD_IDENTIFY_DEVICE);
+ sema_down (&c->completion_wait);
+ if (!wait_while_busy (d))
+ {
+ d->is_ata = false;
+ return;
+ }
+ input_sector (c, id);
+
+ /* Calculate capacity.
+ Read model name and serial number. */
+ capacity = *(uint32_t *) &id[60 * 2];
+ model = descramble_ata_string (&id[10 * 2], 20);
+ serial = descramble_ata_string (&id[27 * 2], 40);
+ snprintf (extra_info, sizeof extra_info,
+ "model \"%s\", serial \"%s\"", model, serial);
+
+ /* Disable access to IDE disks over 1 GB, which are likely
+ physical IDE disks rather than virtual ones. If we don't
+ allow access to those, we're less likely to scribble on
+ someone's important data. You can disable this check by
+ hand if you really want to do so. */
+ if (capacity >= 1024 * 1024 * 1024 / BLOCK_SECTOR_SIZE)
+ {
+ printf ("%s: ignoring ", d->name);
+ print_human_readable_size (capacity * 512);
+ printf ("disk for safety\n");
+ d->is_ata = false;
+ return;
+ }
+
+ /* Register. */
+ block = block_register (d->name, BLOCK_RAW, extra_info, capacity,
+ &ide_operations, d);
+ partition_scan (block);
+}
+
+/* Translates STRING, which consists of SIZE bytes in a funky
+ format, into a null-terminated string in-place. Drops
+ trailing whitespace and null bytes. Returns STRING. */
+static char *
+descramble_ata_string (char *string, int size)
+{
+ int i;
+
+ /* Swap all pairs of bytes. */
+ for (i = 0; i + 1 < size; i += 2)
+ {
+ char tmp = string[i];
+ string[i] = string[i + 1];
+ string[i + 1] = tmp;
+ }
+
+ /* Find the last non-white, non-null character. */
+ for (size--; size > 0; size--)
+ {
+ int c = string[size - 1];
+ if (c != '\0' && !isspace (c))
+ break;
+ }
+ string[size] = '\0';
+
+ return string;
+}
+\f
+/* Reads sector SEC_NO from disk D into BUFFER, which must have
+ room for BLOCK_SECTOR_SIZE bytes.
+ Internally synchronizes accesses to disks, so external
+ per-disk locking is unneeded. */
+static void
+ide_read (void *d_, block_sector_t sec_no, void *buffer)
+{
+ struct ata_disk *d = d_;
+ struct channel *c = d->channel;
+ lock_acquire (&c->lock);
+ select_sector (d, sec_no);
+ issue_pio_command (c, CMD_READ_SECTOR_RETRY);
+ sema_down (&c->completion_wait);
+ if (!wait_while_busy (d))
+ PANIC ("%s: disk read failed, sector=%"PRDSNu, d->name, sec_no);
+ input_sector (c, buffer);
+ lock_release (&c->lock);
+}
+
+/* Write sector SEC_NO to disk D from BUFFER, which must contain
+ BLOCK_SECTOR_SIZE bytes. Returns after the disk has
+ acknowledged receiving the data.
+ Internally synchronizes accesses to disks, so external
+ per-disk locking is unneeded. */
+static void
+ide_write (void *d_, block_sector_t sec_no, const void *buffer)
+{
+ struct ata_disk *d = d_;
+ struct channel *c = d->channel;
+ lock_acquire (&c->lock);
+ select_sector (d, sec_no);
+ issue_pio_command (c, CMD_WRITE_SECTOR_RETRY);
+ if (!wait_while_busy (d))
+ PANIC ("%s: disk write failed, sector=%"PRDSNu, d->name, sec_no);
+ output_sector (c, buffer);
+ sema_down (&c->completion_wait);
+ lock_release (&c->lock);
+}
+
+static struct block_operations ide_operations =
+ {
+ ide_read,
+ ide_write
+ };
+\f
+/* Selects device D, waiting for it to become ready, and then
+ writes SEC_NO to the disk's sector selection registers. (We
+ use LBA mode.) */
+static void
+select_sector (struct ata_disk *d, block_sector_t sec_no)
+{
+ struct channel *c = d->channel;
+
+ ASSERT (sec_no < (1UL << 28));
+
+ select_device_wait (d);
+ outb (reg_nsect (c), 1);
+ outb (reg_lbal (c), sec_no);
+ outb (reg_lbam (c), sec_no >> 8);
+ outb (reg_lbah (c), (sec_no >> 16));
+ outb (reg_device (c),
+ DEV_MBS | DEV_LBA | (d->dev_no == 1 ? DEV_DEV : 0) | (sec_no >> 24));
+}
+
+/* Writes COMMAND to channel C and prepares for receiving a
+ completion interrupt. */
+static void
+issue_pio_command (struct channel *c, uint8_t command)
+{
+ /* Interrupts must be enabled or our semaphore will never be
+ up'd by the completion handler. */
+ ASSERT (intr_get_level () == INTR_ON);
+
+ c->expecting_interrupt = true;
+ outb (reg_command (c), command);
+}
+
+/* Reads a sector from channel C's data register in PIO mode into
+ SECTOR, which must have room for BLOCK_SECTOR_SIZE bytes. */
+static void
+input_sector (struct channel *c, void *sector)
+{
+ insw (reg_data (c), sector, BLOCK_SECTOR_SIZE / 2);
+}
+
+/* Writes SECTOR to channel C's data register in PIO mode.
+ SECTOR must contain BLOCK_SECTOR_SIZE bytes. */
+static void
+output_sector (struct channel *c, const void *sector)
+{
+ outsw (reg_data (c), sector, BLOCK_SECTOR_SIZE / 2);
+}
+\f
+/* Low-level ATA primitives. */
+
+/* Wait up to 10 seconds for the controller to become idle, that
+ is, for the BSY and DRQ bits to clear in the status register.
+
+ As a side effect, reading the status register clears any
+ pending interrupt. */
+static void
+wait_until_idle (const struct ata_disk *d)
+{
+ int i;
+
+ for (i = 0; i < 1000; i++)
+ {
+ if ((inb (reg_status (d->channel)) & (STA_BSY | STA_DRQ)) == 0)
+ return;
+ timer_usleep (10);
+ }
+
+ printf ("%s: idle timeout\n", d->name);
+}
+
+/* Wait up to 30 seconds for disk D to clear BSY,
+ and then return the status of the DRQ bit.
+ The ATA standards say that a disk may take as long as that to
+ complete its reset. */
+static bool
+wait_while_busy (const struct ata_disk *d)
+{
+ struct channel *c = d->channel;
+ int i;
+
+ for (i = 0; i < 3000; i++)
+ {
+ if (i == 700)
+ printf ("%s: busy, waiting...", d->name);
+ if (!(inb (reg_alt_status (c)) & STA_BSY))
+ {
+ if (i >= 700)
+ printf ("ok\n");
+ return (inb (reg_alt_status (c)) & STA_DRQ) != 0;
+ }
+ timer_msleep (10);
+ }
+
+ printf ("failed\n");
+ return false;
+}
+
+/* Program D's channel so that D is now the selected disk. */
+static void
+select_device (const struct ata_disk *d)
+{
+ struct channel *c = d->channel;
+ uint8_t dev = DEV_MBS;
+ if (d->dev_no == 1)
+ dev |= DEV_DEV;
+ outb (reg_device (c), dev);
+ inb (reg_alt_status (c));
+ timer_nsleep (400);
+}
+
+/* Select disk D in its channel, as select_device(), but wait for
+ the channel to become idle before and after. */
+static void
+select_device_wait (const struct ata_disk *d)
+{
+ wait_until_idle (d);
+ select_device (d);
+ wait_until_idle (d);
+}
+\f
+/* ATA interrupt handler. */
+static void
+interrupt_handler (struct intr_frame *f)
+{
+ struct channel *c;
+
+ for (c = channels; c < channels + CHANNEL_CNT; c++)
+ if (f->vec_no == c->irq)
+ {
+ if (c->expecting_interrupt)
+ {
+ inb (reg_status (c)); /* Acknowledge interrupt. */
+ sema_up (&c->completion_wait); /* Wake up waiter. */
+ }
+ else
+ printf ("%s: unexpected interrupt\n", c->name);
+ return;
+ }
+
+ NOT_REACHED ();
+}
+
+
projects / pintos-anon / blobdiff