sd.c

linux 内核源代码

			start_lba >>= 3;
			break;
		default:
			/* Print something here with limiting frequency. */
			goto out;
			break;
		}
		/* This computation should always be done in terms of
		 * the resolution of the device's medium.
		 */
		good_bytes = (bad_lba - start_lba)*SCpnt->device->sector_size;
		break;
	case RECOVERED_ERROR:
	case NO_SENSE:
		/* Inform the user, but make sure that it's not treated
		 * as a hard error.
		 */
		scsi_print_sense("sd", SCpnt);
		SCpnt->result = 0;
		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
		good_bytes = xfer_size;
		break;
	case ILLEGAL_REQUEST:
		if (SCpnt->device->use_10_for_rw &&
		    (SCpnt->cmnd[0] == READ_10 ||
		     SCpnt->cmnd[0] == WRITE_10))
			SCpnt->device->use_10_for_rw = 0;
		if (SCpnt->device->use_10_for_ms &&
		    (SCpnt->cmnd[0] == MODE_SENSE_10 ||
		     SCpnt->cmnd[0] == MODE_SELECT_10))
			SCpnt->device->use_10_for_ms = 0;
		break;
	default:
		break;
	}
 out:
	return good_bytes;
}

static int media_not_present(struct scsi_disk *sdkp,
			     struct scsi_sense_hdr *sshdr)
{

	if (!scsi_sense_valid(sshdr))
		return 0;
	/* not invoked for commands that could return deferred errors */
	if (sshdr->sense_key != NOT_READY &&
	    sshdr->sense_key != UNIT_ATTENTION)
		return 0;
	if (sshdr->asc != 0x3A) /* medium not present */
		return 0;

	set_media_not_present(sdkp);
	return 1;
}

/*
 * spinup disk - called only in sd_revalidate_disk()
 */
static void
sd_spinup_disk(struct scsi_disk *sdkp)
{
	unsigned char cmd[10];
	unsigned long spintime_expire = 0;
	int retries, spintime;
	unsigned int the_result;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;

	spintime = 0;

	/* Spin up drives, as required.  Only do this at boot time */
	/* Spinup needs to be done for module loads too. */
	do {
		retries = 0;

		do {
			cmd[0] = TEST_UNIT_READY;
			memset((void *) &cmd[1], 0, 9);

			the_result = scsi_execute_req(sdkp->device, cmd,
						      DMA_NONE, NULL, 0,
						      &sshdr, SD_TIMEOUT,
						      SD_MAX_RETRIES);

			/*
			 * If the drive has indicated to us that it
			 * doesn't have any media in it, don't bother
			 * with any more polling.
			 */
			if (media_not_present(sdkp, &sshdr))
				return;

			if (the_result)
				sense_valid = scsi_sense_valid(&sshdr);
			retries++;
		} while (retries < 3 && 
			 (!scsi_status_is_good(the_result) ||
			  ((driver_byte(the_result) & DRIVER_SENSE) &&
			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));

		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
			/* no sense, TUR either succeeded or failed
			 * with a status error */
			if(!spintime && !scsi_status_is_good(the_result)) {
				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
				sd_print_result(sdkp, the_result);
			}
			break;
		}
					
		/*
		 * The device does not want the automatic start to be issued.
		 */
		if (sdkp->device->no_start_on_add) {
			break;
		}

		/*
		 * If manual intervention is required, or this is an
		 * absent USB storage device, a spinup is meaningless.
		 */
		if (sense_valid &&
		    sshdr.sense_key == NOT_READY &&
		    sshdr.asc == 4 && sshdr.ascq == 3) {
			break;		/* manual intervention required */

		/*
		 * Issue command to spin up drive when not ready
		 */
		} else if (sense_valid && sshdr.sense_key == NOT_READY) {
			if (!spintime) {
				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");
				cmd[0] = START_STOP;
				cmd[1] = 1;	/* Return immediately */
				memset((void *) &cmd[2], 0, 8);
				cmd[4] = 1;	/* Start spin cycle */
				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
						 NULL, 0, &sshdr,
						 SD_TIMEOUT, SD_MAX_RETRIES);
				spintime_expire = jiffies + 100 * HZ;
				spintime = 1;
			}
			/* Wait 1 second for next try */
			msleep(1000);
			printk(".");

		/*
		 * Wait for USB flash devices with slow firmware.
		 * Yes, this sense key/ASC combination shouldn't
		 * occur here.  It's characteristic of these devices.
		 */
		} else if (sense_valid &&
				sshdr.sense_key == UNIT_ATTENTION &&
				sshdr.asc == 0x28) {
			if (!spintime) {
				spintime_expire = jiffies + 5 * HZ;
				spintime = 1;
			}
			/* Wait 1 second for next try */
			msleep(1000);
		} else {
			/* we don't understand the sense code, so it's
			 * probably pointless to loop */
			if(!spintime) {
				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
				sd_print_sense_hdr(sdkp, &sshdr);
			}
			break;
		}
				
	} while (spintime && time_before_eq(jiffies, spintime_expire));

	if (spintime) {
		if (scsi_status_is_good(the_result))
			printk("ready\n");
		else
			printk("not responding...\n");
	}
}

/*
 * read disk capacity
 */
static void
sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
{
	unsigned char cmd[16];
	int the_result, retries;
	int sector_size = 0;
	int longrc = 0;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;
	struct scsi_device *sdp = sdkp->device;

repeat:
	retries = 3;
	do {
		if (longrc) {
			memset((void *) cmd, 0, 16);
			cmd[0] = SERVICE_ACTION_IN;
			cmd[1] = SAI_READ_CAPACITY_16;
			cmd[13] = 12;
			memset((void *) buffer, 0, 12);
		} else {
			cmd[0] = READ_CAPACITY;
			memset((void *) &cmd[1], 0, 9);
			memset((void *) buffer, 0, 8);
		}
		
		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
					      buffer, longrc ? 12 : 8, &sshdr,
					      SD_TIMEOUT, SD_MAX_RETRIES);

		if (media_not_present(sdkp, &sshdr))
			return;

		if (the_result)
			sense_valid = scsi_sense_valid(&sshdr);
		retries--;

	} while (the_result && retries);

	if (the_result && !longrc) {
		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed\n");
		sd_print_result(sdkp, the_result);
		if (driver_byte(the_result) & DRIVER_SENSE)
			sd_print_sense_hdr(sdkp, &sshdr);
		else
			sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");

		/* Set dirty bit for removable devices if not ready -
		 * sometimes drives will not report this properly. */
		if (sdp->removable &&
		    sense_valid && sshdr.sense_key == NOT_READY)
			sdp->changed = 1;

		/* Either no media are present but the drive didn't tell us,
		   or they are present but the read capacity command fails */
		/* sdkp->media_present = 0; -- not always correct */
		sdkp->capacity = 0; /* unknown mapped to zero - as usual */

		return;
	} else if (the_result && longrc) {
		/* READ CAPACITY(16) has been failed */
		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
		sd_print_result(sdkp, the_result);
		sd_printk(KERN_NOTICE, sdkp, "Use 0xffffffff as device size\n");

		sdkp->capacity = 1 + (sector_t) 0xffffffff;		
		goto got_data;
	}	
	
	if (!longrc) {
		sector_size = (buffer[4] << 24) |
			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
		if (buffer[0] == 0xff && buffer[1] == 0xff &&
		    buffer[2] == 0xff && buffer[3] == 0xff) {
			if(sizeof(sdkp->capacity) > 4) {
				sd_printk(KERN_NOTICE, sdkp, "Very big device. "
					  "Trying to use READ CAPACITY(16).\n");
				longrc = 1;
				goto repeat;
			}
			sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use "
				  "a kernel compiled with support for large "
				  "block devices.\n");
			sdkp->capacity = 0;
			goto got_data;
		}
		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
			(buffer[1] << 16) |
			(buffer[2] << 8) |
			buffer[3]);			
	} else {
		sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
			((u64)buffer[1] << 48) |
			((u64)buffer[2] << 40) |
			((u64)buffer[3] << 32) |
			((sector_t)buffer[4] << 24) |
			((sector_t)buffer[5] << 16) |
			((sector_t)buffer[6] << 8)  |
			(sector_t)buffer[7]);
			
		sector_size = (buffer[8] << 24) |
			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
	}	

	/* Some devices return the total number of sectors, not the
	 * highest sector number.  Make the necessary adjustment. */
	if (sdp->fix_capacity) {
		--sdkp->capacity;

	/* Some devices have version which report the correct sizes
	 * and others which do not. We guess size according to a heuristic
	 * and err on the side of lowering the capacity. */
	} else {
		if (sdp->guess_capacity)
			if (sdkp->capacity & 0x01) /* odd sizes are odd */
				--sdkp->capacity;
	}

got_data:
	if (sector_size == 0) {
		sector_size = 512;
		sd_printk(KERN_NOTICE, sdkp, "Sector size 0 reported, "
			  "assuming 512.\n");
	}

	if (sector_size != 512 &&
	    sector_size != 1024 &&
	    sector_size != 2048 &&
	    sector_size != 4096 &&
	    sector_size != 256) {
		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.\n",
			  sector_size);
		/*
		 * The user might want to re-format the drive with
		 * a supported sectorsize.  Once this happens, it
		 * would be relatively trivial to set the thing up.
		 * For this reason, we leave the thing in the table.
		 */
		sdkp->capacity = 0;
		/*
		 * set a bogus sector size so the normal read/write
		 * logic in the block layer will eventually refuse any
		 * request on this device without tripping over power
		 * of two sector size assumptions
		 */
		sector_size = 512;
	}
	{
		/*
		 * The msdos fs needs to know the hardware sector size
		 * So I have created this table. See ll_rw_blk.c
		 * Jacques Gelinas ([e-mail])
		 */
		int hard_sector = sector_size;
		sector_t sz = (sdkp->capacity/2) * (hard_sector/256);
		struct request_queue *queue = sdp->request_queue;
		sector_t mb = sz;

		blk_queue_hardsect_size(queue, hard_sector);
		/* avoid 64-bit division on 32-bit platforms */
		sector_div(sz, 625);
		mb -= sz - 974;
		sector_div(mb, 1950);

		sd_printk(KERN_NOTICE, sdkp,
			  "%llu %d-byte hardware sectors (%llu MB)\n",
			  (unsigned long long)sdkp->capacity,
			  hard_sector, (unsigned long long)mb);
	}

	/* Rescale capacity to 512-byte units */
	if (sector_size == 4096)
		sdkp->capacity <<= 3;
	else if (sector_size == 2048)
		sdkp->capacity <<= 2;
	else if (sector_size == 1024)
		sdkp->capacity <<= 1;
	else if (sector_size == 256)
		sdkp->capacity >>= 1;

	sdkp->device->sector_size = sector_size;
}

/* called with buffer of length 512 */
static inline int
sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
		 unsigned char *buffer, int len, struct scsi_mode_data *data,
		 struct scsi_sense_hdr *sshdr)
{
	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
			       SD_TIMEOUT, SD_MAX_RETRIES, data,
			       sshdr);
}

/*
 * read write protect setting, if possible - called only in sd_revalidate_disk()
 * called with buffer of length SD_BUF_SIZE
 */
static void
sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)
{
	int res;
	struct scsi_device *sdp = sdkp->device;
	struct scsi_mode_data data;

	set_disk_ro(sdkp->disk, 0);
	if (sdp->skip_ms_page_3f) {
		sd_printk(KERN_NOTICE, sdkp, "Assuming Write Enabled\n");
		return;
	}

	if (sdp->use_192_bytes_for_3f) {
		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
	} else {
		/*
		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
		 * We have to start carefully: some devices hang if we ask
		 * for more than is available.
		 */
		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);

		/*
		 * Second attempt: ask for page 0 When only page 0 is
		 * implemented, a request for page 3F may return Sense Key
		 * 5: Illegal Request, Sense Code 24: Invalid field in
		 * CDB.
		 */
		if (!scsi_status_is_good(res))
			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);

		/*
		 * Third attempt: ask 255 bytes, as we did earlier.
		 */
		if (!scsi_status_is_good(res))
			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
					       &data, NULL);
	}

	if (!scsi_status_is_good(res)) {
		sd_printk(KERN_WARNING, sdkp,
			  "Test WP failed, assume Write Enabled\n");
	} else {
		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
		set_disk_ro(sdkp->disk, sdkp->write_prot);
		sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
			  sdkp->write_prot ? "on" : "off");
		sd_printk(KERN_DEBUG, sdkp,
			  "Mode Sense: %02x %02x %02x %02x\n",
			  buffer[0], buffer[1], buffer[2], buffer[3]);
	}
}

/*
 * sd_read_cache_type - called only from sd_revalidate_disk()
 * called with buffer of length SD_BUF_SIZE
 */
static void
sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
{
	int len = 0, res;
	struct scsi_device *sdp = sdkp->device;

	int dbd;
	int modepage;
	struct scsi_mode_data data;
	struct scsi_sense_hdr sshdr;

	if (sdp->skip_ms_page_8)
		goto defaults;

	if (sdp->type == TYPE_RBC) {
		modepage = 6;
		dbd = 8;
	} else {
		modepage = 8;
		dbd = 0;
	}

	/* cautiously ask */
	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);

	if (!scsi_status_is_good(res))
		goto bad_sense;

	if (!data.header_length) {
		modepage = 6;
		sd_printk(KERN_ERR, sdkp, "Missing header in MODE_SENSE response\n");
	}

	/* that went OK, now ask for the proper length */
	len = data.length;

	/*
	 * We're only interested in the first three bytes, actually.
	 * But the data cache page is defined for the first 20.
	 */