ide.c File Reference

#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"

Include dependency graph for ide.c:

Go to the source code of this file.

Data Structures
struct	ata_disk
	An ATA device. More...
struct	channel
	An ATA channel (aka controller). More...

Macros
#define	reg_data(CHANNEL)   ((CHANNEL)->reg_base + 0)
	The code in this file is an interface to an ATA (IDE) controller. More...
#define	reg_error(CHANNEL)   ((CHANNEL)->reg_base + 1)
	Error. More...
#define	reg_nsect(CHANNEL)   ((CHANNEL)->reg_base + 2)
	Sector Count. More...
#define	reg_lbal(CHANNEL)   ((CHANNEL)->reg_base + 3)
	LBA 0:7. More...
#define	reg_lbam(CHANNEL)   ((CHANNEL)->reg_base + 4)
	LBA 15:8. More...
#define	reg_lbah(CHANNEL)   ((CHANNEL)->reg_base + 5)
	LBA 23:16. More...
#define	reg_device(CHANNEL)   ((CHANNEL)->reg_base + 6)
	Device/LBA 27:24. More...
#define	reg_status(CHANNEL)   ((CHANNEL)->reg_base + 7)
	Status (r/o). More...
#define	reg_command(CHANNEL)   reg_status (CHANNEL)
	Command (w/o). More...
#define	reg_ctl(CHANNEL)   ((CHANNEL)->reg_base + 0x206)
	ATA control block port addresses. More...
#define	reg_alt_status(CHANNEL)   reg_ctl (CHANNEL)
	Alt Status (r/o). More...
#define	STA_BSY   0x80
	Alternate Status Register bits. More...
#define	STA_DRDY   0x40
	Device Ready. More...
#define	STA_DRQ   0x08
	Data Request. More...
#define	CTL_SRST   0x04
	Control Register bits. More...
#define	DEV_MBS   0xa0
	Device Register bits. More...
#define	DEV_LBA   0x40
	Linear based addressing. More...
#define	DEV_DEV   0x10
	Select device: 0=master, 1=slave. More...
#define	CMD_IDENTIFY_DEVICE   0xec
	Commands. More...
#define	CMD_READ_SECTOR_RETRY   0x20
	READ SECTOR with retries. More...
#define	CMD_WRITE_SECTOR_RETRY   0x30
	WRITE SECTOR with retries. More...
#define	CHANNEL_CNT   2
	We support the two "legacy" ATA channels found in a standard PC. More...

Functions
static void	reset_channel (struct channel *c)
	Resets an ATA channel and waits for any devices present on it to finish the reset. More...
static bool	check_device_type (struct ata_disk *d)
	Checks whether device D is an ATA disk and sets D's is_ata member appropriately. More...
static void	identify_ata_device (struct ata_disk *d)
	Sends an IDENTIFY DEVICE command to disk D and reads the response. More...
static void	select_sector (struct ata_disk *d, block_sector_t sec_no)
	Selects device D, waiting for it to become ready, and then writes SEC_NO to the disk's sector selection registers. More...
static void	issue_pio_command (struct channel *c, uint8_t command)
	Writes COMMAND to channel C and prepares for receiving a completion interrupt. More...
static void	input_sector (struct channel *c, void *sector)
	Reads a sector from channel C's data register in PIO mode into SECTOR, which must have room for BLOCK_SECTOR_SIZE bytes. More...
static void	output_sector (struct channel *c, const void *sector)
	Writes SECTOR to channel C's data register in PIO mode. More...
static void	wait_until_idle (const struct ata_disk *d)
	Low-level ATA primitives. More...
static bool	wait_while_busy (const struct ata_disk *d)
	Wait up to 30 seconds for disk D to clear BSY, and then return the status of the DRQ bit. More...
static void	select_device (const struct ata_disk *d)
	Program D's channel so that D is now the selected disk. More...
static void	select_device_wait (const struct ata_disk *d)
	Select disk D in its channel, as select_device(), but wait for the channel to become idle before and after. More...
static void	interrupt_handler (struct intr_frame *f)
	ATA interrupt handler. More...
void	ide_init (void)
	Initialize the disk subsystem and detect disks. More...
static char *	descramble_ata_string (char *, int size)
	Disk detection and identification. More...
static void	ide_read (void *d_, block_sector_t sec_no, void *buffer)
	Reads sector SEC_NO from disk D into BUFFER, which must have room for BLOCK_SECTOR_SIZE bytes. More...
static void	ide_write (void *d_, block_sector_t sec_no, const void *buffer)
	Write sector SEC_NO to disk D from BUFFER, which must contain BLOCK_SECTOR_SIZE bytes. More...

Variables
static struct channel	channels [CHANNEL_CNT]
static struct block_operations	ide_operations

Macro Definition Documentation

CHANNEL_CNT

#define CHANNEL_CNT   2

We support the two "legacy" ATA channels found in a standard PC.

Definition at line 79 of file ide.c.

CMD_IDENTIFY_DEVICE

#define CMD_IDENTIFY_DEVICE   0xec

Commands.

Many more are defined but this is the small subset that we use. IDENTIFY DEVICE.

Definition at line 49 of file ide.c.

CMD_READ_SECTOR_RETRY

#define CMD_READ_SECTOR_RETRY   0x20

READ SECTOR with retries.

Definition at line 50 of file ide.c.

CMD_WRITE_SECTOR_RETRY

#define CMD_WRITE_SECTOR_RETRY   0x30

WRITE SECTOR with retries.

Definition at line 51 of file ide.c.

CTL_SRST

#define CTL_SRST   0x04

Control Register bits.

Software Reset.

Definition at line 39 of file ide.c.

DEV_DEV

#define DEV_DEV   0x10

Select device: 0=master, 1=slave.

Definition at line 44 of file ide.c.

DEV_LBA

#define DEV_LBA   0x40

Linear based addressing.

Definition at line 43 of file ide.c.

DEV_MBS

#define DEV_MBS   0xa0

Device Register bits.

Must be set.

Definition at line 42 of file ide.c.

reg_alt_status

#define reg_alt_status

(

CHANNEL

)

reg_ctl (CHANNEL)

Alt Status (r/o).

Definition at line 31 of file ide.c.

reg_command

#define reg_command

(

CHANNEL

)

reg_status (CHANNEL)

Command (w/o).

Definition at line 25 of file ide.c.

reg_ctl

#define reg_ctl

(

CHANNEL

)

((CHANNEL)->reg_base + 0x206)

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.) Control (w/o).

Definition at line 30 of file ide.c.

reg_data

#define reg_data

(

CHANNEL

)

((CHANNEL)->reg_base + 0)

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. Data.

Definition at line 17 of file ide.c.

reg_device

#define reg_device

(

CHANNEL

)

((CHANNEL)->reg_base + 6)

Device/LBA 27:24.

Definition at line 23 of file ide.c.

reg_error

#define reg_error

(

CHANNEL

)

((CHANNEL)->reg_base + 1)

Error.

Definition at line 18 of file ide.c.

reg_lbah

#define reg_lbah

(

CHANNEL

)

((CHANNEL)->reg_base + 5)

LBA 23:16.

Definition at line 22 of file ide.c.

reg_lbal

#define reg_lbal

(

CHANNEL

)

((CHANNEL)->reg_base + 3)

LBA 0:7.

Definition at line 20 of file ide.c.

reg_lbam

#define reg_lbam

(

CHANNEL

)

((CHANNEL)->reg_base + 4)

LBA 15:8.

Definition at line 21 of file ide.c.

reg_nsect

#define reg_nsect

(

CHANNEL

)

((CHANNEL)->reg_base + 2)

Sector Count.

Definition at line 19 of file ide.c.

reg_status

#define reg_status

(

CHANNEL

)

((CHANNEL)->reg_base + 7)

Status (r/o).

Definition at line 24 of file ide.c.

STA_BSY

#define STA_BSY   0x80

Alternate Status Register bits.

Busy.

Definition at line 34 of file ide.c.

STA_DRDY

#define STA_DRDY   0x40

Device Ready.

Definition at line 35 of file ide.c.

STA_DRQ

#define STA_DRQ   0x08

Data Request.

Definition at line 36 of file ide.c.

Function Documentation

check_device_type()

static bool check_device_type ( struct ata_disk *  d )

static

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.

Definition at line 230 of file ide.c.

References ata_disk::channel, ata_disk::dev_no, inb(), ata_disk::is_ata, reg_error, reg_lbah, reg_lbam, reg_status, select_device(), STA_BSY, and STA_DRDY.

Referenced by ide_init().

Here is the call graph for this function:

Here is the caller graph for this function:

descramble_ata_string()

static char * descramble_ata_string ( char *  string, int  size  )

static

Disk detection and identification.

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.

Definition at line 316 of file ide.c.

References isspace(), and block::size.

Referenced by identify_ata_device().

Here is the call graph for this function:

Here is the caller graph for this function:

ide_init()

void ide_init

(

void

)

Initialize the disk subsystem and detect disks.

devices/ide.h

Definition at line 102 of file ide.c.

References ata_disk::channel, CHANNEL_CNT, channels, check_device_type(), channel::completion_wait, ata_disk::dev_no, channel::devices, channel::expecting_interrupt, identify_ata_device(), interrupt_handler(), intr_register_ext(), channel::irq, ata_disk::is_ata, channel::lock, lock_init(), ata_disk::name, channel::name, NOT_REACHED, channel::reg_base, reset_channel(), sema_init(), and snprintf().

Referenced by pintos_init().

Here is the call graph for this function:

Here is the caller graph for this function:

ide_read()

static void ide_read ( void *  d_, block_sector_t  sec_no, void *  buffer  )

static

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.

Definition at line 345 of file ide.c.

References buffer, ata_disk::channel, CMD_READ_SECTOR_RETRY, channel::completion_wait, input_sector(), issue_pio_command(), channel::lock, lock_acquire(), lock_release(), ata_disk::name, PANIC, PRDSNu, select_sector(), sema_down(), and wait_while_busy().

Here is the call graph for this function:

ide_write()

static void ide_write ( void *  d_, block_sector_t  sec_no, const void *  buffer  )

static

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.

Definition at line 365 of file ide.c.

References buffer, ata_disk::channel, CMD_WRITE_SECTOR_RETRY, channel::completion_wait, issue_pio_command(), channel::lock, lock_acquire(), lock_release(), ata_disk::name, output_sector(), PANIC, PRDSNu, select_sector(), sema_down(), and wait_while_busy().

Here is the call graph for this function:

identify_ata_device()

static void identify_ata_device ( struct ata_disk *  d )

static

Sends an IDENTIFY DEVICE command to disk D and reads the response.

Registers the disk with the block device layer.

Definition at line 260 of file ide.c.

References ASSERT, BLOCK_RAW, block_register(), BLOCK_SECTOR_SIZE, ata_disk::channel, CMD_IDENTIFY_DEVICE, channel::completion_wait, descramble_ata_string(), ide_operations, input_sector(), ata_disk::is_ata, issue_pio_command(), ata_disk::name, partition_scan(), print_human_readable_size(), printf(), select_device_wait(), sema_down(), snprintf(), and wait_while_busy().

Referenced by ide_init().

Here is the call graph for this function:

Here is the caller graph for this function:

input_sector()

static void input_sector ( struct channel *  c, void *  sector  )

static

Reads a sector from channel C's data register in PIO mode into SECTOR, which must have room for BLOCK_SECTOR_SIZE bytes.

Definition at line 420 of file ide.c.

References BLOCK_SECTOR_SIZE, insw(), and reg_data.

Referenced by ide_read(), and identify_ata_device().

Here is the call graph for this function:

Here is the caller graph for this function:

interrupt_handler()

static void interrupt_handler ( struct intr_frame *  f )

static

ATA interrupt handler.

< Acknowledge interrupt.

< Wake up waiter.

Definition at line 507 of file ide.c.

References CHANNEL_CNT, channels, channel::completion_wait, channel::expecting_interrupt, inb(), channel::irq, channel::name, NOT_REACHED, printf(), reg_status, sema_up(), and intr_frame::vec_no.

Referenced by ide_init().

Here is the call graph for this function:

Here is the caller graph for this function:

issue_pio_command()

static void issue_pio_command ( struct channel *  c, uint8_t  command  )

static

Writes COMMAND to channel C and prepares for receiving a completion interrupt.

Definition at line 407 of file ide.c.

References ASSERT, channel::expecting_interrupt, intr_get_level(), INTR_ON, outb(), and reg_command.

Referenced by ide_read(), ide_write(), and identify_ata_device().

Here is the call graph for this function:

Here is the caller graph for this function:

output_sector()

static void output_sector ( struct channel *  c, const void *  sector  )

static

Writes SECTOR to channel C's data register in PIO mode.

SECTOR must contain BLOCK_SECTOR_SIZE bytes.

Definition at line 428 of file ide.c.

References BLOCK_SECTOR_SIZE, outsw(), and reg_data.

Referenced by ide_write().

Here is the call graph for this function:

Here is the caller graph for this function:

reset_channel()

static void reset_channel ( struct channel *  c )

static

Resets an ATA channel and waits for any devices present on it to finish the reset.

Definition at line 165 of file ide.c.

References CTL_SRST, ata_disk::dev_no, channel::devices, inb(), outb(), reg_ctl, reg_lbal, reg_nsect, select_device(), timer_msleep(), timer_usleep(), and wait_while_busy().

Referenced by ide_init().

Here is the call graph for this function:

Here is the caller graph for this function:

select_device()

static void select_device ( const struct ata_disk *  d )

static

Program D's channel so that D is now the selected disk.

Definition at line 484 of file ide.c.

References ata_disk::channel, DEV_DEV, DEV_MBS, ata_disk::dev_no, inb(), outb(), reg_alt_status, reg_device, and timer_nsleep().

Referenced by check_device_type(), reset_channel(), and select_device_wait().

Here is the call graph for this function:

Here is the caller graph for this function:

select_device_wait()

static void select_device_wait ( const struct ata_disk *  d )

static

Select disk D in its channel, as select_device(), but wait for the channel to become idle before and after.

Definition at line 498 of file ide.c.

References select_device(), and wait_until_idle().

Referenced by identify_ata_device(), and select_sector().

Here is the call graph for this function:

Here is the caller graph for this function:

select_sector()

static void select_sector ( struct ata_disk *  d, block_sector_t  sec_no  )

static

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.)

Definition at line 389 of file ide.c.

References ASSERT, ata_disk::channel, DEV_DEV, DEV_LBA, DEV_MBS, ata_disk::dev_no, outb(), reg_device, reg_lbah, reg_lbal, reg_lbam, reg_nsect, and select_device_wait().

Referenced by ide_read(), and ide_write().

Here is the call graph for this function:

Here is the caller graph for this function:

wait_until_idle()

static void wait_until_idle ( const struct ata_disk *  d )

static

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.

Definition at line 441 of file ide.c.

References ata_disk::channel, inb(), ata_disk::name, printf(), reg_status, STA_BSY, STA_DRQ, and timer_usleep().

Referenced by select_device_wait().

Here is the call graph for this function:

Here is the caller graph for this function:

wait_while_busy()

static bool wait_while_busy ( const struct ata_disk *  d )

static

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.

Definition at line 460 of file ide.c.

References ata_disk::channel, inb(), ata_disk::name, printf(), reg_alt_status, STA_BSY, STA_DRQ, and timer_msleep().

Referenced by ide_read(), ide_write(), identify_ata_device(), and reset_channel().

Here is the call graph for this function:

Here is the caller graph for this function:

Variable Documentation

channels

struct channel channels[CHANNEL_CNT]

static

Definition at line 80 of file ide.c.

Referenced by ide_init(), and interrupt_handler().

ide_operations

static struct block_operations ide_operations

static

Initial value:

=
  {
    ide_read,
    ide_write
  }

Definition at line 82 of file ide.c.

Referenced by identify_ata_device().