Beispiel #1
0
/*
 * Stop the OS-specific port helper thread and kill the per-port lock.
 */
void
ahci_os_stop_port(struct ahci_port *ap)
{
	if (ap->sysctl_tree) {
		sysctl_ctx_free(&ap->sysctl_ctx);
		ap->sysctl_tree = NULL;
	}

	if (ap->ap_thread) {
		ahci_os_signal_port_thread(ap, AP_SIGF_STOP);
		ahci_os_sleep(10);
		if (ap->ap_thread) {
			kprintf("%s: Waiting for thread to terminate\n",
				PORTNAME(ap));
			while (ap->ap_thread)
				ahci_os_sleep(100);
			kprintf("%s: thread terminated\n",
				PORTNAME(ap));
		}
	}
	lockuninit(&ap->ap_lock);
}
Beispiel #2
0
/*
 * AHCI soft reset through port multiplier.
 *
 * This function keeps port communications intact and attempts to generate
 * a reset to the connected device using device commands.  Unlike
 * hard-port operations we can't do fancy stop/starts or stuff like
 * that without messing up other commands that might be running or
 * queued.
 */
int
ahci_pm_softreset(struct ahci_port *ap, int target)
{
	struct ata_port		*at;
	struct ahci_ccb		*ccb;
	struct ahci_cmd_hdr	*cmd_slot;
	u_int8_t		*fis;
	int			count;
	int			error;
	u_int32_t		data;

	error = EIO;
	at = ap->ap_ata[target];

	DPRINTF(AHCI_D_VERBOSE, "%s: soft reset\n", PORTNAME(ap));

	count = 2;
retry:
	/*
	 * Try to clear the phy so we get a good signature, otherwise
	 * the PM may not latch a new signature.
	 *
	 * NOTE: This cannot be safely done between the first and second
	 *	 softreset FISs.  It's now or never.
	 */
	if (ahci_pm_phy_status(ap, target, &data)) {
		kprintf("%s: (B)Cannot clear phy status\n",
			ATANAME(ap ,at));
	}
	ahci_pm_write(ap, target, SATA_PMREG_SERR, -1);

	/*
	 * Prep first D2H command with SRST feature & clear busy/reset flags
	 *
	 * It is unclear which other fields in the FIS are used.  Just zero
	 * everything.
	 *
	 * When soft-resetting a port behind a multiplier at will be
	 * non-NULL, assigning it to the ccb prevents the port interrupt
	 * from hard-resetting the port if a problem crops up.
	 */
	ccb = ahci_get_err_ccb(ap);
	ccb->ccb_xa.flags = ATA_F_POLL | ATA_F_EXCLUSIVE | ATA_F_AUTOSENSE;
	ccb->ccb_xa.complete = ahci_pm_dummy_done;
	ccb->ccb_xa.at = at;

	fis = ccb->ccb_cmd_table->cfis;
	bzero(fis, sizeof(ccb->ccb_cmd_table->cfis));
	fis[0] = ATA_FIS_TYPE_H2D;
	fis[1] = at->at_target;
	fis[15] = ATA_FIS_CONTROL_SRST|ATA_FIS_CONTROL_4BIT;

	cmd_slot = ccb->ccb_cmd_hdr;
	cmd_slot->prdtl = 0;
	cmd_slot->flags = htole16(5);	/* FIS length: 5 DWORDS */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_C); /* Clear busy on OK */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_R); /* Reset */
	cmd_slot->flags |= htole16(at->at_target <<
				   AHCI_CMD_LIST_FLAG_PMP_SHIFT);

	ccb->ccb_xa.state = ATA_S_PENDING;

	/*
	 * This soft reset of the AP target can cause a stream of IFS
	 * errors to occur.  Setting AP_F_IGNORE_IFS prevents the port
	 * from being hard reset (because its the target behind the
	 * port that isn't happy).
	 *
	 * The act of sending the soft reset can cause the target to
	 * blow the port up and generate IFS errors.
	 */
	ap->ap_flags |= AP_F_IGNORE_IFS;
	ap->ap_flags &= ~AP_F_IFS_IGNORED;

	if (ahci_poll(ccb, 1000, ahci_ata_cmd_timeout) != ATA_S_COMPLETE) {
		kprintf("%s: Soft-reset through PM failed, %s\n",
			ATANAME(ap, at),
			(count > 1 ? "retrying" : "giving up"));
		ahci_put_err_ccb(ccb);
		if (--count) {
			if (ap->ap_flags & AP_F_IFS_IGNORED)
				ahci_os_sleep(5000);
			else
				ahci_os_sleep(1000);
			ahci_pwrite(ap, AHCI_PREG_SERR, -1);
			ahci_pwrite(ap, AHCI_PREG_IS, AHCI_PREG_IS_IFS);
			goto retry;
		}
		goto err;
	}

	/*
	 * WARNING!  SENSITIVE TIME PERIOD!  WARNING!
	 *
	 * The first and second FISes are supposed to be back-to-back,
	 * I think the idea is to get the second sent and then after
	 * the device resets it will send a signature.  Do not delay
	 * here and most definitely do not issue any commands to other
	 * targets!
	 */

	/*
	 * Prep second D2H command to read status and complete reset sequence
	 * AHCI 10.4.1 and "Serial ATA Revision 2.6".  I can't find the ATA
	 * Rev 2.6 and it is unclear how the second FIS should be set up
	 * from the AHCI document.
	 *
	 * Give the device 3ms before sending the second FIS.
	 *
	 * It is unclear which other fields in the FIS are used.  Just zero
	 * everything.
	 */
	bzero(fis, sizeof(ccb->ccb_cmd_table->cfis));
	fis[0] = ATA_FIS_TYPE_H2D;
	fis[1] = at->at_target;
	fis[15] = ATA_FIS_CONTROL_4BIT;

	cmd_slot->prdtl = 0;
	cmd_slot->flags = htole16(5);	/* FIS length: 5 DWORDS */
	cmd_slot->flags |= htole16(at->at_target <<
				   AHCI_CMD_LIST_FLAG_PMP_SHIFT);

	ccb->ccb_xa.state = ATA_S_PENDING;
	ccb->ccb_xa.flags = ATA_F_POLL | ATA_F_EXCLUSIVE | ATA_F_AUTOSENSE;

	ap->ap_flags &= ~AP_F_IFS_IGNORED;

	if (ahci_poll(ccb, 1000, ahci_ata_cmd_timeout) != ATA_S_COMPLETE) {
		kprintf("%s: Soft-reset(2) through PM failed, %s\n",
			ATANAME(ap, at),
			(count > 1 ? "retrying" : "giving up"));
		if (--count) {
			ahci_os_sleep(1000);
			ahci_put_err_ccb(ccb);
			ahci_pwrite(ap, AHCI_PREG_SERR, -1);
			ahci_pwrite(ap, AHCI_PREG_IS, AHCI_PREG_IS_IFS);
			goto retry;
		}
		goto err;
	}

	ahci_put_err_ccb(ccb);
	ahci_os_sleep(100);
	ahci_pwrite(ap, AHCI_PREG_SERR, -1);
	ahci_pwrite(ap, AHCI_PREG_IS, AHCI_PREG_IS_IFS);

	ahci_pm_write(ap, target, SATA_PMREG_SERR, -1);
	if (ahci_pm_phy_status(ap, target, &data)) {
		kprintf("%s: (C)Cannot clear phy status\n",
			ATANAME(ap ,at));
	}
	ahci_pm_write(ap, target, SATA_PMREG_SERR, -1);

	/*
	 * Do it again, even if we think we got a good result
	 */
	if (--count) {
		fis[15] = 0;
		goto retry;
	}

	/*
	 * If the softreset is trying to clear a BSY condition after a
	 * normal portreset we assign the port type.
	 *
	 * If the softreset is being run first as part of the ccb error
	 * processing code then report if the device signature changed
	 * unexpectedly.
	 */
	if (at->at_type == ATA_PORT_T_NONE) {
		at->at_type = ahci_port_signature_detect(ap, at);
	} else {
		if (ahci_port_signature_detect(ap, at) != at->at_type) {
			kprintf("%s: device signature unexpectedly "
				"changed\n", ATANAME(ap, at));
			error = EBUSY; /* XXX */
		}
	}
	error = 0;

	/*
	 * Who knows what kind of mess occured.  We have exclusive access
	 * to the port so try to clean up potential problems.
	 */
err:
	ahci_os_sleep(100);

	/*
	 * Clear error status so we can detect removal.
	 */
	if (ahci_pm_write(ap, target, SATA_PMREG_SERR, -1)) {
		kprintf("%s: ahci_pm_softreset unable to clear SERR\n",
			ATANAME(ap, at));
	}
	ahci_pwrite(ap, AHCI_PREG_SERR, -1);
	ahci_pwrite(ap, AHCI_PREG_IS, AHCI_PREG_IS_IFS);
	ap->ap_flags &= ~(AP_F_IGNORE_IFS | AP_F_IFS_IGNORED);

	at->at_probe = error ? ATA_PROBE_FAILED : ATA_PROBE_NEED_IDENT;
	return (error);
}
Beispiel #3
0
/*
 * AHCI port multiplier probe.  This routine is run by the hardreset code
 * if it gets past the device detect, whether or not BSY is found to be
 * stuck.
 *
 * We MUST use CLO to properly probe whether the port multiplier exists
 * or not.
 *
 * Return 0 on success, non-zero on failure.
 */
int
ahci_pm_port_probe(struct ahci_port *ap, int orig_error)
{
	struct ahci_cmd_hdr *cmd_slot;
	struct ata_port	*at;
	struct ahci_ccb	*ccb = NULL;
	u_int8_t	*fis = NULL;
	int		error;
	u_int32_t	cmd;
	u_int32_t	fbs;
	int		count;
	int		rstcount;
	int		i;
	int		fbsmode;
	int		sig;

	count = 2;
	rstcount = 2;
retry:
	fbsmode = 0;

	/*
	 * This code is only called from hardreset, which does not
	 * high level command processing.  The port should be stopped.
	 *
	 * Set PMA mode while the port is stopped.
	 *
	 * NOTE: On retry the port might be running, stopped, or failed.
	 */
	ahci_port_stop(ap, 0);
	ap->ap_state = AP_S_NORMAL;
	cmd = ahci_pread(ap, AHCI_PREG_CMD) & ~AHCI_PREG_CMD_ICC;
#if 1
	if ((cmd & AHCI_PREG_CMD_PMA) == 0) {
		cmd |= AHCI_PREG_CMD_PMA;
		ahci_pwrite(ap, AHCI_PREG_CMD, cmd);
	}
#endif

	/*
	 * Check to see if FBS is supported by checking the cap and the
	 * support bit in the port CMD register.  If it looks good, try
	 * to write to the FBS register.
	 */
	if (ap->ap_sc->sc_cap & AHCI_REG_CAP_FBSS) {
		const char *str1 = "";
		const char *str2 = "";
		const char *str3 = "";

		if (cmd & AHCI_PREG_CMD_FBSCP) {
			str1 = "HW indicates support";
		} else if (ap->ap_sc->sc_flags & AHCI_F_FORCE_FBSS) {
			cmd |= AHCI_PREG_CMD_FBSCP;	/* Force on */
			str1 = "HW indicates no-support, force";
		} else {
			str1 = "HW indicates no-support";
		}
		if (cmd & AHCI_PREG_CMD_FBSCP) {
			fbs = ahci_pread(ap, AHCI_PREG_FBS);
			ahci_pwrite(ap, AHCI_PREG_FBS, fbs | AHCI_PREG_FBS_EN);
			fbs = ahci_pread(ap, AHCI_PREG_FBS);
			if (fbs & AHCI_PREG_FBS_EN) {
				str2 = ", enable succeeded";
				fbsmode = 1;
			} else {
				str2 = ", enable failed";
			}

			/*
			 * Must be off during the PM probe, we will enable
			 * it at the end.
			 */
			ahci_pwrite(ap, AHCI_PREG_FBS, fbs & ~AHCI_PREG_FBS_EN);
		}
		kprintf("%s: FBS Cap detected: %s%s%s\n",
			PORTNAME(ap), str1, str2, str3);
	}

	/*
	 * If the probe fails, cleanup any previous state.
	 */
	if (fbsmode == 0 && (ap->ap_flags & AP_F_FBSS_ENABLED)) {
		ap->ap_flags &= ~AP_F_FBSS_ENABLED;
		ahci_pwrite(ap, AHCI_PREG_FBS, 0);
	}

	/*
	 * Flush any errors and request CLO unconditionally, then start
	 * the port.
	 */
	ahci_flush_tfd(ap);
	ahci_port_clo(ap);
	if (ahci_port_start(ap)) {
		kprintf("%s: PMPROBE cannot start port\n",
		        PORTNAME(ap));
		error = EIO;
		goto err;
	}

	/*
	 * When a PM is present and the cable or driver cycles, the PM may
	 * hang in BSY and require another COMRESET sequence to clean it up.
	 * The CLO above didn't work (for example, if there is no CLO
	 * support), so do another hard COMRESET to try to clear the busy
	 * condition.
	 */
	if (ahci_pwait_clr(ap, AHCI_PREG_TFD,
			       AHCI_PREG_TFD_STS_BSY | AHCI_PREG_TFD_STS_DRQ)) {
		if (--rstcount) {
			int pmdetect;

			kprintf("%s: PMPROBE BUSY, comreset and retry\n",
				PORTNAME(ap));
			ahci_comreset(ap, &pmdetect);
			if (pmdetect)
				goto retry;
		}
		kprintf("%s: PMPROBE BUSY, giving up\n",
			PORTNAME(ap));
		error = EBUSY;
		goto err;
	}

	/*
	 * Use the error CCB for all commands
	 *
	 * NOTE!  This CCB is used for both the first and second commands.
	 *	  The second command must use CCB slot 1 to properly load
	 *	  the signature.
	 */
	ccb = ahci_get_err_ccb(ap);
	ccb->ccb_xa.flags = ATA_F_POLL | ATA_F_SILENT;
	ccb->ccb_xa.complete = ahci_pm_dummy_done;
	ccb->ccb_xa.at = ap->ap_ata[15];
	cmd_slot = ccb->ccb_cmd_hdr;
	KKASSERT(ccb->ccb_slot == 1);

	/*
	 * Prep the first H2D command with SRST feature & clear busy/reset
	 * flags.
	 */
	fis = ccb->ccb_cmd_table->cfis;
	bzero(fis, sizeof(ccb->ccb_cmd_table->cfis));
	fis[0] = ATA_FIS_TYPE_H2D;
	fis[1] = 0x0F;			/* Target 15 */
	fis[15] = ATA_FIS_CONTROL_SRST | ATA_FIS_CONTROL_4BIT;

	cmd_slot->prdtl = 0;
	cmd_slot->flags = htole16(5);	/* FIS length: 5 DWORDS */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_C); /* Clear busy on OK */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_R); /* Reset */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_PMP); /* port 0xF */

	ccb->ccb_xa.state = ATA_S_PENDING;

	if (bootverbose) {
		kprintf("%s: PMPROBE PreStatus 0x%pb%i\n", PORTNAME(ap),
			AHCI_PFMT_TFD_STS, ahci_pread(ap, AHCI_PREG_TFD));
	}

	/*
	 * The only way one can determine if a port multiplier is on the
	 * port is to probe target 15, and of course this will fail if
	 * there is no port multiplier.
	 *
	 * The probing has to be done whether or not a device is probed on
	 * target 0, because when a PM is attached target 0 represents
	 * slot #0 behind the PM.
	 *
	 * Port multipliers are expected to answer more quickly than normal
	 * devices, use a shorter timeout than normal.
	 *
	 * If there is no PM here this command can still succeed due to
	 * the _C_
	 */
	if (ahci_poll(ccb, 1000, ahci_quick_timeout) != ATA_S_COMPLETE) {
		kprintf("%s: PMPROBE(1) No Port Multiplier was found.\n",
			PORTNAME(ap));
		if (--count) {
			rstcount = 2;
			ahci_put_err_ccb(ccb);
			goto retry;
		}
		error = EBUSY;
		goto err;
	}

	if (bootverbose) {
		kprintf("%s: PMPROBE PosStatus 0x%pb%i\n", PORTNAME(ap),
			AHCI_PFMT_TFD_STS, ahci_pread(ap, AHCI_PREG_TFD));
	}
#if 0
	/*
	 * REMOVED - Ignore a BSY condition between the first and second
	 *	     FIS in the PM probe.  Seems to work better.
	 */
	if (ahci_pwait_clr(ap, AHCI_PREG_TFD,
			       AHCI_PREG_TFD_STS_BSY | AHCI_PREG_TFD_STS_DRQ)) {
		kprintf("%s: PMPROBE Busy after first FIS\n", PORTNAME(ap));
	} else if (bootverbose) {
		kprintf("%s: PMPROBE Clean after first FIS\n", PORTNAME(ap));
	}
#endif

	/*
	 * The device may have muffed up the PHY when it reset.
	 */
	ahci_flush_tfd(ap);
	ahci_pwrite(ap, AHCI_PREG_SERR, -1);
	/* ahci_pm_phy_status(ap, 15, &cmd); */

	/*
	 * Prep second D2H command to read status and complete reset sequence
	 * AHCI 10.4.1 and "Serial ATA Revision 2.6".  I can't find the ATA
	 * Rev 2.6 and it is unclear how the second FIS should be set up
	 * from the AHCI document.
	 *
	 * Give the device 3ms before sending the second FIS.
	 *
	 * It is unclear which other fields in the FIS are used.  Just zero
	 * everything.
	 */
	ccb->ccb_xa.flags = ATA_F_POLL | ATA_F_SILENT;

	bzero(fis, sizeof(ccb->ccb_cmd_table->cfis));
	fis[0] = ATA_FIS_TYPE_H2D;
	fis[1] = 0x0F;
	fis[15] = ATA_FIS_CONTROL_4BIT;

	cmd_slot->prdtl = 0;
	cmd_slot->flags = htole16(5);	/* FIS length: 5 DWORDS */
	cmd_slot->flags |= htole16(AHCI_CMD_LIST_FLAG_PMP); /* port 0xF */

	ccb->ccb_xa.state = ATA_S_PENDING;

	/*
	 * The only way one can determine if a port multiplier is on the
	 * port is to probe target 15, and of course this will fail if
	 * there is no port multiplier.
	 *
	 * The probing has to be done whether or not a device is probed on
	 * target 0, because when a PM is attached target 0 represents
	 * slot #0 behind the PM.
	 */
	if (ahci_poll(ccb, 5000, ahci_quick_timeout) != ATA_S_COMPLETE) {
		kprintf("%s: PMPROBE(2) No Port Multiplier was found.\n",
			PORTNAME(ap));
		if (--count) {
			rstcount = 2;
			ahci_put_err_ccb(ccb);
			goto retry;
		}
		error = EBUSY;
		goto err;
	}

	/*
	 * Some controllers return completion for the second FIS before
	 * updating the signature register.  Sleep a bit to allow for it.
	 */
	ahci_os_sleep(500);

	/*
	 * What? We succeeded?  Yup, but for some reason the signature
	 * is still latched from the original detect (that saw target 0
	 * behind the PM), and I don't know how to clear the condition
	 * other then by retrying the whole reset sequence.
	 */
	sig = ahci_port_signature_detect(ap, NULL);
	if (sig == ATA_PORT_T_PM) {
		kprintf("%s: PMPROBE PM Signature detected\n",
			PORTNAME(ap));
		ap->ap_ata[15]->at_probe = ATA_PROBE_GOOD;
		error = 0;
	} else if (--count == 0) {
		kprintf("%s: PMPROBE PM Signature not detected\n",
			PORTNAME(ap));
		error = EBUSY;
	} else {
		rstcount = 2;
		fis[15] = 0;
		ahci_put_err_ccb(ccb);
		if (bootverbose) {
			kprintf("%s: PMPROBE retry on count\n",
				PORTNAME(ap));
		}
		goto retry;
	}

	/*
	 * Fall through / clean up the CCB and perform error processing.
	 */
err:
	if (ccb != NULL)
		ahci_put_err_ccb(ccb);

	if (error == 0 && ahci_pm_identify(ap)) {
		ahci_os_sleep(500);
		if (ahci_pm_identify(ap)) {
			kprintf("%s: PM - cannot identify port multiplier\n",
				PORTNAME(ap));
			error = EBUSY;
		} else {
			kprintf("%s: PM - Had to identify twice\n",
				PORTNAME(ap));
		}
	}

	/*
	 * Turn on FBS mode, clear any stale error.  Enforce a 1/10 second
	 * delay primarily for the IGN_CR quirk.
	 */
	if (error == 0 && fbsmode) {
		ahci_port_stop(ap, 0);
		ap->ap_flags |= AP_F_FBSS_ENABLED;
		fbs = ahci_pread(ap, AHCI_PREG_FBS);
		fbs &= ~AHCI_PREG_FBS_DEV;
		fbs |= AHCI_PREG_FBS_DEC;
		ahci_pwrite(ap, AHCI_PREG_FBS, fbs | AHCI_PREG_FBS_EN);
		ahci_os_sleep(100);
		if (ahci_port_start(ap)) {
			kprintf("%s: PMPROBE failed to restart port "
				"after FBS enable\n",
				PORTNAME(ap));
			ahci_pwrite(ap, AHCI_PREG_FBS, fbs & ~AHCI_PREG_FBS_EN);
			ap->ap_flags &= ~AP_F_FBSS_ENABLED;
		}
	}


	/*
	 * If we probed the PM reset the state for the targets behind
	 * it so they get probed by the state machine.
	 */
	if (error == 0) {
		for (i = 0; i < AHCI_MAX_PMPORTS; ++i) {
			at = ap->ap_ata[i];
			at->at_probe = ATA_PROBE_NEED_INIT;
			at->at_features |= ATA_PORT_F_RESCAN;
		}
		ap->ap_type = ATA_PORT_T_PM;
		return (0);
	}

	/*
	 * If we failed turn off PMA, otherwise identify the port multiplier.
	 * CAM will iterate the devices.
	 */
	ahci_port_stop(ap, 0);
	ahci_port_clo(ap);
#if 1
	cmd = ahci_pread(ap, AHCI_PREG_CMD) & ~AHCI_PREG_CMD_ICC;
	cmd &= ~AHCI_PREG_CMD_PMA;
	ahci_pwrite(ap, AHCI_PREG_CMD, cmd);
#endif
	if (orig_error == 0) {
		if (ahci_pwait_clr(ap, AHCI_PREG_TFD,
			    AHCI_PREG_TFD_STS_BSY | AHCI_PREG_TFD_STS_DRQ)) {
			kprintf("%s: PM probe: port will not come ready\n",
				PORTNAME(ap));
			orig_error = EBUSY;
			ahci_port_init(ap);
		}
	}
	return(orig_error);
}
Beispiel #4
0
/*
 * Do a COMRESET sequence on the target behind a port multiplier.
 *
 * If hard is 2 we also cycle the phy on the target.
 *
 * This must be done prior to any softreset or probe attempts on
 * targets behind the port multiplier.
 *
 * Returns 0 on success or an error.
 */
int
ahci_pm_hardreset(struct ahci_port *ap, int target, int hard)
{
	struct ata_port *at;
	u_int32_t data;
	int loop;
	int error = EIO;

	at = ap->ap_ata[target];

	/*
	 * Turn off power management and kill the phy on the target
	 * if requested.  Hold state for 10ms.
	 */
	data = ap->ap_sc->sc_ipm_disable;
	if (hard == 2)
		data |= AHCI_PREG_SCTL_DET_DISABLE;
	if (ahci_pm_write(ap, target, SATA_PMREG_SERR, -1))
		goto err;
	if (ahci_pm_write(ap, target, SATA_PMREG_SCTL, data))
		goto err;
	ahci_os_sleep(10);

	/*
	 * Start transmitting COMRESET.  COMRESET must be sent for at
	 * least 1ms.
	 */
	at->at_probe = ATA_PROBE_FAILED;
	at->at_type = ATA_PORT_T_NONE;
	data = ap->ap_sc->sc_ipm_disable | AHCI_PREG_SCTL_DET_INIT;
	switch(AhciForceGen) {
	case 0:
		data |= AHCI_PREG_SCTL_SPD_ANY;
		break;
	case 1:
		data |= AHCI_PREG_SCTL_SPD_GEN1;
		break;
	case 2:
		data |= AHCI_PREG_SCTL_SPD_GEN2;
		break;
	case 3:
		data |= AHCI_PREG_SCTL_SPD_GEN3;
		break;
	default:
		data |= AHCI_PREG_SCTL_SPD_GEN3;
		break;
	}
	if (ahci_pm_write(ap, target, SATA_PMREG_SCTL, data))
		goto err;

	/*
	 * It takes about 100ms for the DET logic to settle down,
	 * from trial and error testing.  If this is too short
	 * the softreset code will fail.
	 */
	ahci_os_sleep(100);

	if (ahci_pm_phy_status(ap, target, &data)) {
		kprintf("%s: (A)Cannot clear phy status\n",
			ATANAME(ap ,at));
	}

	/*
	 * Flush any status, then clear DET to initiate negotiation.
	 */
	ahci_pm_write(ap, target, SATA_PMREG_SERR, -1);
	data = ap->ap_sc->sc_ipm_disable | AHCI_PREG_SCTL_DET_NONE;
	if (ahci_pm_write(ap, target, SATA_PMREG_SCTL, data))
		goto err;

	/*
	 * Try to determine if there is a device on the port.  This
	 * operation usually runs sequentially on the PM, use a short
	 * 3/10 second timeout.  The disks should already be sufficiently
	 * powered.
	 *
	 * If we fail clear any pending status since we may have
	 * cycled the phy and probably caused another PRCS interrupt.
	 */
	for (loop = 3; loop; --loop) {
		if (ahci_pm_read(ap, target, SATA_PMREG_SSTS, &data))
			goto err;
		if (data & AHCI_PREG_SSTS_DET)
			break;
		ahci_os_sleep(100);
	}
	if (loop == 0) {
		kprintf("%s.%d: Port appears to be unplugged\n",
			PORTNAME(ap), target);
		error = ENODEV;
		goto err;
	}

	/*
	 * There is something on the port.  Give the device 3 seconds
	 * to fully negotiate.
	 */
	for (loop = 30; loop; --loop) {
		if (ahci_pm_read(ap, target, SATA_PMREG_SSTS, &data))
			goto err;
		if ((data & AHCI_PREG_SSTS_DET) == AHCI_PREG_SSTS_DET_DEV)
			break;
		ahci_os_sleep(100);
	}

	/*
	 * Device not detected
	 */
	if (loop == 0) {
		kprintf("%s: Device may be powered down\n",
			PORTNAME(ap));
		error = ENODEV;
		goto err;
	}

	/*
	 * Device detected
	 */
	kprintf("%s.%d: Device detected data=%08x\n",
		PORTNAME(ap), target, data);
	/*
	 * Clear SERR on the target so we get a new NOTIFY event if a hot-plug
	 * or hot-unplug occurs.  Clear any spurious IFS that may have
	 * occured during the probe.
	 *
	 * WARNING!  100ms seems to work in most cases but
	 */
	ahci_os_sleep(100);
	ahci_pm_write(ap, target, SATA_PMREG_SERR, -1);
	ahci_pwrite(ap, AHCI_PREG_SERR, -1);
	ahci_pwrite(ap, AHCI_PREG_IS, AHCI_PREG_IS_IFS);

	error = 0;
err:
	at->at_probe = error ? ATA_PROBE_FAILED : ATA_PROBE_NEED_SOFT_RESET;
	return (error);
}