[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: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 3634279..f2e7e2f 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5311,7 +5311,6 @@
{
struct Scsi_Host *shost;
struct ata_port *ap;
- int rc;
DPRINTK("ENTER\n");
@@ -5333,15 +5332,7 @@
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 @@
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);
@@ -5941,6 +5948,39 @@
}
/*
+ * 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
* likely to change as new drivers are added and updated.
@@ -5950,6 +5990,7 @@
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);
