[PATCH 2/5] libata: Bind the Linux device tree to the ACPI device tree

[Matthew Garrett <mjg@redhat.com>]

We want to be able to express the dependencies between ACPI dock
devices and their children. This requires us to be able to associate
the ACPI device tree and libata devices. This patch uses the generic
ACPI glue framework to do so.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/ata/libata-acpi.c |  118 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/ata/libata-core.c |    3 +
 drivers/ata/libata.h      |    4 ++
 3 files changed, 125 insertions(+), 0 deletions(-)

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 8b5ea39..277f102 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -47,6 +47,31 @@ static void ata_acpi_clear_gtf(struct ata_device *dev)
 	dev->gtf_cache = NULL;
 }
 
+static acpi_handle ap_acpi_handle(struct ata_port *ap)
+{
+	if (ap->flags & ATA_FLAG_ACPI_SATA)
+		return NULL;
+	return DEVICE_ACPI_HANDLE(&ap->scsi_host->shost_gendev);
+}
+
+static acpi_handle dev_acpi_handle(struct ata_device *dev)
+{
+	acpi_integer adr;
+	struct ata_port *ap = dev->link->ap;
+
+	if (dev->sdev)
+		return DEVICE_ACPI_HANDLE(&dev->sdev->sdev_gendev);
+
+	if (ap->flags & ATA_FLAG_ACPI_SATA) {
+		if (!sata_pmp_attached(ap))
+			adr = SATA_ADR(ap->port_no, NO_PORT_MULT);
+		else
+			adr = SATA_ADR(ap->port_no, dev->link->pmp);
+		return acpi_get_child(DEVICE_ACPI_HANDLE(ap->host->dev), adr);
+	} else
+		return acpi_get_child(ap_acpi_handle(ap), dev->devno);
+}
+
 /**
  * ata_acpi_associate_sata_port - associate SATA port with ACPI objects
  * @ap: target SATA port
@@ -1029,3 +1054,96 @@ void ata_acpi_on_disable(struct ata_device *dev)
 {
 	ata_acpi_clear_gtf(dev);
 }
+
+static int is_pci_ata(struct device *dev)
+{
+	struct pci_dev *pdev;
+
+	if (!is_pci_dev(dev))
+		return 0;
+
+	pdev = to_pci_dev(dev);
+
+	if ((pdev->class >> 8) != PCI_CLASS_STORAGE_SATA &&
+	    (pdev->class >> 8) != PCI_CLASS_STORAGE_IDE)
+		return 0;
+
+	return 1;
+}
+
+static int ata_acpi_bind_host(struct device *dev, int host, acpi_handle *handle)
+{
+	struct Scsi_Host *shost = dev_to_shost(dev);
+	struct ata_port *ap = ata_shost_to_port(shost);
+
+	if (ap->flags & ATA_FLAG_ACPI_SATA)
+		return -ENODEV;
+
+	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), ap->port_no);
+
+	if (!*handle)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int ata_acpi_bind_device(struct device *dev, int channel, int id,
+				acpi_handle *handle)
+{
+	struct device *host = dev->parent->parent;
+	struct Scsi_Host *shost = dev_to_shost(host);
+	struct ata_port *ap = ata_shost_to_port(shost);
+	struct ata_device *ata_dev;
+
+	if (ap->flags & ATA_FLAG_ACPI_SATA)
+		ata_dev = &ap->link.device[channel];
+	else
+		ata_dev = &ap->link.device[id];
+
+	*handle = dev_acpi_handle(ata_dev);
+
+	if (!*handle)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int ata_acpi_find_device(struct device *dev, acpi_handle *handle)
+{
+	unsigned int host, channel, id, lun;
+
+	if (sscanf(dev_name(dev), "host%u", &host) == 1) {
+		if (!is_pci_ata(dev->parent))
+			return -ENODEV;
+
+		return ata_acpi_bind_host(dev, host, handle);
+	} else if (sscanf(dev_name(dev), "%d:%d:%d:%d",
+			&host, &channel, &id, &lun) == 4) {
+		if (!is_pci_ata(dev->parent->parent->parent))
+			return -ENODEV;
+
+		return ata_acpi_bind_device(dev, channel, id, handle);
+	} else
+		return -ENODEV;
+}
+
+static int ata_acpi_find_dummy(struct device *dev, acpi_handle *handle)
+{
+	return -ENODEV;
+}
+
+static struct acpi_bus_type ata_acpi_bus = {
+	.bus = &scsi_bus_type,
+	.find_bridge = ata_acpi_find_dummy,
+	.find_device = ata_acpi_find_device,
+};
+
+int ata_acpi_register(void)
+{
+	return register_acpi_bus_type(&ata_acpi_bus);
+}
+
+void ata_acpi_unregister(void)
+{
+	unregister_acpi_bus_type(&ata_acpi_bus);
+}
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 932eaee..4978b7a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6546,6 +6546,8 @@ static int __init ata_init(void)
 
 	ata_parse_force_param();
 
+	ata_acpi_register();
+
 	rc = ata_sff_init();
 	if (rc) {
 		kfree(ata_force_tbl);
@@ -6559,6 +6561,7 @@ static int __init ata_init(void)
 static void __exit ata_exit(void)
 {
 	ata_sff_exit();
+	ata_acpi_unregister();
 	kfree(ata_force_tbl);
 }
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 9ce1ecc..16061fb 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -115,6 +115,8 @@ extern void ata_acpi_on_resume(struct ata_port *ap);
 extern int ata_acpi_on_devcfg(struct ata_device *dev);
 extern void ata_acpi_on_disable(struct ata_device *dev);
 extern void ata_acpi_set_state(struct ata_port *ap, pm_message_t state);
+extern int ata_acpi_register(void);
+extern void ata_acpi_unregister(void);
 #else
 static inline void ata_acpi_associate_sata_port(struct ata_port *ap) { }
 static inline void ata_acpi_associate(struct ata_host *host) { }
@@ -125,6 +127,8 @@ static inline int ata_acpi_on_devcfg(struct ata_device *dev) { return 0; }
 static inline void ata_acpi_on_disable(struct ata_device *dev) { }
 static inline void ata_acpi_set_state(struct ata_port *ap,
 				      pm_message_t state) { }
+static inline int ata_acpi_register(void) { return 0; }
+static void ata_acpi_unregister(void) { }
 #endif
 
 /* libata-scsi.c */
-- 
1.7.1