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Commit 664faf09 authored by Tejun Heo's avatar Tejun Heo
Browse files

[PATCH] libata-hp-prep: implement followup softreset handling 



In some cases, hardreset must be followed by SRST.

* some controllers can't classify with hardreset
* some controllers can't wait for !BSY after hardreset (LLDD should
  explicitly request followup softreset by returning -EAGAIN)
* (later) PM needs SRST w/ PMP==15 to operate after hardreset

To handle above cases, this patch implements follow-up softreset.
After a hardreset, ata_eh_reset() checks whether any of above
conditions are met and do a follow-up softreset if necessary.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
parent f5914a46

drivers/scsi/libata-eh.c

+52 −6
Original line number Diff line number Diff line
@@ -1318,16 +1318,28 @@ static void ata_eh_report(struct ata_port *ap) 
	}

}



static int ata_eh_reset(struct ata_port *ap,

static int ata_eh_followup_srst_needed(int rc, int classify,

				       const unsigned int *classes)

{

	if (rc == -EAGAIN)

		return 1;

	if (rc != 0)

		return 0;

	if (classify && classes[0] == ATA_DEV_UNKNOWN)

		return 1;

	return 0;

}



static int ata_eh_reset(struct ata_port *ap, int classify,

			ata_prereset_fn_t prereset, ata_reset_fn_t softreset,

			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)

{

	struct ata_eh_context *ehc = &ap->eh_context;

	unsigned int classes[ATA_MAX_DEVICES];

	unsigned int *classes = ehc->classes;

	int tries = ATA_EH_RESET_TRIES;

	unsigned int action;

	ata_reset_fn_t reset;

	int i, rc;

	int i, did_followup_srst, rc;



	/* Determine which reset to use and record in ehc->i.action.

	 * prereset() may examine and modify it.
@@ -1381,10 +1393,44 @@ static int ata_eh_reset(struct ata_port *ap, 


	rc = ata_do_reset(ap, reset, classes);



	did_followup_srst = 0;

	if (reset == hardreset &&

	    ata_eh_followup_srst_needed(rc, classify, classes)) {

		/* okay, let's do follow-up softreset */

		did_followup_srst = 1;

		reset = softreset;



		if (!reset) {

			ata_port_printk(ap, KERN_ERR,

					"follow-up softreset required "

					"but no softreset avaliable\n");

			return -EINVAL;

		}



		ata_eh_about_to_do(ap, ATA_EH_RESET_MASK);

		rc = ata_do_reset(ap, reset, classes);



		if (rc == 0 && classify &&

		    classes[0] == ATA_DEV_UNKNOWN) {

			ata_port_printk(ap, KERN_ERR,

					"classification failed\n");

			return -EINVAL;

		}

	}



	if (rc && --tries) {

		const char *type;



		if (reset == softreset) {

			if (did_followup_srst)

				type = "follow-up soft";

			else

				type = "soft";

		} else

			type = "hard";



		ata_port_printk(ap, KERN_WARNING,

				"%sreset failed, retrying in 5 secs\n",

				reset == softreset ? "soft" : "hard");

				"%sreset failed, retrying in 5 secs\n", type);

		ssleep(5);



		if (reset == hardreset)
@@ -1508,7 +1554,7 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset, 
	if (ehc->i.action & ATA_EH_RESET_MASK) {

		ata_eh_freeze_port(ap);



		rc = ata_eh_reset(ap, prereset, softreset, hardreset,

		rc = ata_eh_reset(ap, 0, prereset, softreset, hardreset,

				  postreset);

		if (rc) {

			ata_port_printk(ap, KERN_ERR,