libata: identify and init ZPODD devices

The ODD can be enabled for ZPODD if the following three conditions are
satisfied:
1 The ODD supports device attention;
2 The platform can runtime power off the ODD through ACPI;
3 The ODD is either slot type or drawer type.
For such ODDs, zpodd_init is called and a new structure is allocated for
it to store ZPODD related stuffs.

And the zpodd_dev_enabled function is used to test if ZPODD is currently
enabled for this ODD.

A new config CONFIG_SATA_ZPODD is added to selectively build ZPODD code.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/ata/libata-zpodd.c b/drivers/ata/libata-zpodd.c
new file mode 100644
index 000000000000..27eed2f09a8a
--- /dev/null
+++ b/drivers/ata/libata-zpodd.c
@@ -0,0 +1,100 @@
+#include <linux/libata.h>
+#include <linux/cdrom.h>
+
+#include "libata.h"
+
+enum odd_mech_type {
+	ODD_MECH_TYPE_SLOT,
+	ODD_MECH_TYPE_DRAWER,
+	ODD_MECH_TYPE_UNSUPPORTED,
+};
+
+struct zpodd {
+	enum odd_mech_type	mech_type; /* init during probe, RO afterwards */
+	struct ata_device	*dev;
+};
+
+/* Per the spec, only slot type and drawer type ODD can be supported */
+static enum odd_mech_type zpodd_get_mech_type(struct ata_device *dev)
+{
+	char buf[16];
+	unsigned int ret;
+	struct rm_feature_desc *desc = (void *)(buf + 8);
+	struct ata_taskfile tf = {};
+
+	char cdb[] = {  GPCMD_GET_CONFIGURATION,
+			2,      /* only 1 feature descriptor requested */
+			0, 3,   /* 3, removable medium feature */
+			0, 0, 0,/* reserved */
+			0, sizeof(buf),
+			0, 0, 0,
+	};
+
+	tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf.command = ATA_CMD_PACKET;
+	tf.protocol = ATAPI_PROT_PIO;
+	tf.lbam = sizeof(buf);
+
+	ret = ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
+				buf, sizeof(buf), 0);
+	if (ret)
+		return ODD_MECH_TYPE_UNSUPPORTED;
+
+	if (be16_to_cpu(desc->feature_code) != 3)
+		return ODD_MECH_TYPE_UNSUPPORTED;
+
+	if (desc->mech_type == 0 && desc->load == 0 && desc->eject == 1)
+		return ODD_MECH_TYPE_SLOT;
+	else if (desc->mech_type == 1 && desc->load == 0 && desc->eject == 1)
+		return ODD_MECH_TYPE_DRAWER;
+	else
+		return ODD_MECH_TYPE_UNSUPPORTED;
+}
+
+static bool odd_can_poweroff(struct ata_device *ata_dev)
+{
+	acpi_handle handle;
+	acpi_status status;
+	struct acpi_device *acpi_dev;
+
+	handle = ata_dev_acpi_handle(ata_dev);
+	if (!handle)
+		return false;
+
+	status = acpi_bus_get_device(handle, &acpi_dev);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	return acpi_device_can_poweroff(acpi_dev);
+}
+
+void zpodd_init(struct ata_device *dev)
+{
+	enum odd_mech_type mech_type;
+	struct zpodd *zpodd;
+
+	if (dev->zpodd)
+		return;
+
+	if (!odd_can_poweroff(dev))
+		return;
+
+	mech_type = zpodd_get_mech_type(dev);
+	if (mech_type == ODD_MECH_TYPE_UNSUPPORTED)
+		return;
+
+	zpodd = kzalloc(sizeof(struct zpodd), GFP_KERNEL);
+	if (!zpodd)
+		return;
+
+	zpodd->mech_type = mech_type;
+
+	zpodd->dev = dev;
+	dev->zpodd = zpodd;
+}
+
+void zpodd_exit(struct ata_device *dev)
+{
+	kfree(dev->zpodd);
+	dev->zpodd = NULL;
+}