path: root/drivers/ata/libata-pmp.c

/*
 * libata-pmp.c - libata port multiplier support
 *
 * Copyright (c) 2007  SUSE Linux Products GmbH
 * Copyright (c) 2007  Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 */

#include <linux/kernel.h>
#include <linux/libata.h>
#include "libata.h"

/**
 *	sata_pmp_read - read PMP register
 *	@link: link to read PMP register for
 *	@reg: register to read
 *	@r_val: resulting value
 *
 *	Wrapper around ap->ops->pmp_read to make it easier to call and
 *	nomarlize error return value.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pmp_dev = ap->link.device;
	int rc;

	might_sleep();

	rc = ap->ops->pmp_read(pmp_dev, link->pmp, reg, r_val);
	if (rc)
		rc = -EIO;
	return rc;
}

/**
 *	sata_pmp_write - write PMP register
 *	@link: link to write PMP register for
 *	@reg: register to write
 *	@r_val: value to write
 *
 *	Wrapper around ap->ops->pmp_write to make it easier to call
 *	and nomarlize error return value.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sata_pmp_write(struct ata_link *link, int reg, u32 val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pmp_dev = ap->link.device;
	int rc;

	might_sleep();

	rc = ap->ops->pmp_write(pmp_dev, link->pmp, reg, val);
	if (rc)
		rc = -EIO;
	return rc;
}

/**
 *	sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
 *	@qc: ATA command in question
 *
 *	A host which has command switching PMP support cannot issue
 *	commands to multiple links simultaneously.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host lock)
 *
 *	RETURNS:
 *	ATA_DEFER_* if deferring is needed, 0 otherwise.
 */
int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
{
	struct ata_link *link = qc->dev->link;
	struct ata_port *ap = link->ap;

	if (ap->excl_link == NULL || ap->excl_link == link) {
		if (ap->nr_active_links == 0 || ata_link_active(link)) {
			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
			return ata_std_qc_defer(qc);
		}

		ap->excl_link = link;
	}

	return ATA_DEFER_PORT;
}

/**
 *	sata_pmp_read_init_tf - initialize TF for PMP read
 *	@tf: taskfile to initialize
 *	@dev: PMP dev
 *	@pmp: port multiplier port number
 *	@reg: register to read
 *
 *	Initialize @tf for PMP read command.
 *
 *	LOCKING:
 *	None.
 */
void sata_pmp_read_init_tf(struct ata_taskfile *tf,
			   struct ata_device *dev, int pmp, int reg)
{
	ata_tf_init(dev, tf);
	tf->command = ATA_CMD_PMP_READ;
	tf->protocol = ATA_PROT_NODATA;
	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->feature = reg;
	tf->device = pmp;
}

/**
 *	sata_pmp_read_val - extract PMP read result from TF
 *	@tf: target TF
 *
 *	Determine PMP read result from @tf.
 *
 *	LOCKING:
 *	None.
 */
u32 sata_pmp_read_val(const struct ata_taskfile *tf)
{
	return tf->nsect