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Commit dd5b06c4 authored by Tejun Heo's avatar Tejun Heo
Browse files

[PATCH] libata: implement dummy port 



Implement dummy port which can be requested by setting appropriate bit
in probe_ent->dummy_port_mask.  The dummy port is used as placeholder
for stolen legacy port.  This allows libata to guarantee that
index_of(ap) == ap->port_no == actual_device_port_no, and thus to
remove error-prone ap->hard_port_no.

As it's used only when one port of a legacy controller is reserved by
some other entity (e.g. IDE), the focus is on keeping the added *code*
complexity at minimum, so dummy port allocates all libata core
resources and acts as a normal port.  It just has all dummy port_ops.

This patch only implements dummy port.  The following patch will make
libata use it for stolen legacy ports.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
parent 2ec7df04

drivers/scsi/libata-core.c

+51 −10
Original line number Diff line number Diff line
@@ -5311,7 +5311,6 @@ static struct ata_port * ata_port_add(const struct ata_probe_ent *ent, 
{

	struct Scsi_Host *shost;

	struct ata_port *ap;

	int rc;



	DPRINTK("ENTER\n");
@@ -5333,15 +5332,7 @@ static struct ata_port * ata_port_add(const struct ata_probe_ent *ent, 
	ata_port_init(ap, host_set, ent, port_no);

	ata_port_init_shost(ap, shost);



	rc = ap->ops->port_start(ap);

	if (rc)

		goto err_out;



	return ap;



err_out:

	scsi_host_put(shost);

	return NULL;

}



/**
@@ -5415,11 +5406,27 @@ int ata_device_add(const struct ata_probe_ent *ent) 
		if (!ap)

			goto err_out;



		host_set->ports[i] = ap;



		/* dummy? */

		if (ent->dummy_port_mask & (1 << i)) {

			ata_port_printk(ap, KERN_INFO, "DUMMY\n");

			ap->ops = &ata_dummy_port_ops;

			continue;

		}



		/* start port */

		rc = ap->ops->port_start(ap);

		if (rc) {

			host_set->ports[i] = NULL;

			scsi_host_put(ap->host);

			goto err_out;

		}



		/* Report the secondary IRQ for second channel legacy */

		if (i == 1 && ent->irq2)

			irq_line = ent->irq2;



		host_set->ports[i] = ap;

		xfer_mode_mask =(ap->udma_mask << ATA_SHIFT_UDMA) |

				(ap->mwdma_mask << ATA_SHIFT_MWDMA) |

				(ap->pio_mask << ATA_SHIFT_PIO);
@@ -5940,6 +5947,39 @@ u32 ata_wait_register(void __iomem *reg, u32 mask, u32 val, 
	return tmp;

}



/*

 * Dummy port_ops

 */

static void ata_dummy_noret(struct ata_port *ap)	{ }

static int ata_dummy_ret0(struct ata_port *ap)		{ return 0; }

static void ata_dummy_qc_noret(struct ata_queued_cmd *qc) { }



static u8 ata_dummy_check_status(struct ata_port *ap)

{

	return ATA_DRDY;

}



static unsigned int ata_dummy_qc_issue(struct ata_queued_cmd *qc)

{

	return AC_ERR_SYSTEM;

}



const struct ata_port_operations ata_dummy_port_ops = {

	.port_disable		= ata_port_disable,

	.check_status		= ata_dummy_check_status,

	.check_altstatus	= ata_dummy_check_status,

	.dev_select		= ata_noop_dev_select,

	.qc_prep		= ata_noop_qc_prep,

	.qc_issue		= ata_dummy_qc_issue,

	.freeze			= ata_dummy_noret,

	.thaw			= ata_dummy_noret,

	.error_handler		= ata_dummy_noret,

	.post_internal_cmd	= ata_dummy_qc_noret,

	.irq_clear		= ata_dummy_noret,

	.port_start		= ata_dummy_ret0,

	.port_stop		= ata_dummy_noret,

};



/*

 * libata is essentially a library of internal helper functions for

 * low-level ATA host controller drivers.  As such, the API/ABI is
@@ -5950,6 +5990,7 @@ u32 ata_wait_register(void __iomem *reg, u32 mask, u32 val, 
EXPORT_SYMBOL_GPL(sata_deb_timing_normal);

EXPORT_SYMBOL_GPL(sata_deb_timing_hotplug);

EXPORT_SYMBOL_GPL(sata_deb_timing_long);

EXPORT_SYMBOL_GPL(ata_dummy_port_ops);

EXPORT_SYMBOL_GPL(ata_std_bios_param);

EXPORT_SYMBOL_GPL(ata_std_ports);

EXPORT_SYMBOL_GPL(ata_host_set_init);

include/linux/libata.h

+8 −0
Original line number Diff line number Diff line
@@ -353,6 +353,7 @@ struct ata_probe_ent { 
	struct ata_ioports	port[ATA_MAX_PORTS];

	unsigned int		n_ports;

	unsigned int		hard_port_no;

	unsigned int		dummy_port_mask;

	unsigned int		pio_mask;

	unsigned int		mwdma_mask;

	unsigned int		udma_mask;
@@ -652,6 +653,8 @@ extern const unsigned long sata_deb_timing_normal[]; 
extern const unsigned long sata_deb_timing_hotplug[];

extern const unsigned long sata_deb_timing_long[];



extern const struct ata_port_operations ata_dummy_port_ops;



static inline const unsigned long *

sata_ehc_deb_timing(struct ata_eh_context *ehc)

{
@@ -661,6 +664,11 @@ sata_ehc_deb_timing(struct ata_eh_context *ehc) 
		return sata_deb_timing_normal;

}



static inline int ata_port_is_dummy(struct ata_port *ap)

{

	return ap->ops == &ata_dummy_port_ops;

}



extern void ata_port_probe(struct ata_port *);

extern void __sata_phy_reset(struct ata_port *ap);

extern void sata_phy_reset(struct ata_port *ap);