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>

6 files changed, 133 insertions, 1 deletions

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index e08d322d01d7..996d16c9c6e5 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -58,6 +58,19 @@ config ATA_ACPI
           You can disable this at kernel boot time by using the
           option libata.noacpi=1
 
+config SATA_ZPODD
+        bool "SATA Zero Power ODD Support"
+        depends on ATA_ACPI
+        default n
+        help
+          This option adds support for SATA ZPODD. It requires both
+          ODD and the platform support, and if enabled, will automatically
+          power on/off the ODD when certain condition is satisfied. This
+          does not impact user's experience of the ODD, only power is saved
+          when ODD is not in use(i.e. no disc inside).
+
+          If unsure, say N.
+
 config SATA_PMP
         bool "SATA Port Multiplier support"
         default y
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 9329dafba91b..85e3de463ed1 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -107,3 +107,4 @@ libata-y	:= libata-core.o libata-scsi.o libata-eh.o libata-transport.o
 libata-$(CONFIG_ATA_SFF)        += libata-sff.o
 libata-$(CONFIG_SATA_PMP)       += libata-pmp.o
 libata-$(CONFIG_ATA_ACPI)       += libata-acpi.o
+libata-$(CONFIG_SATA_ZPODD)     += libata-zpodd.o
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 275941b576a8..c7ecd8492f1e 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2401,8 +2401,10 @@ int ata_dev_configure(struct ata_device *dev)
                         dma_dir_string = ", DMADIR";
                 }
 
-                if (ata_id_has_da(dev->id))
+                if (ata_id_has_da(dev->id)) {
                         dev->flags |= ATA_DFLAG_DA;
+                        zpodd_init(dev);
+                }
 
                 /* print device info to dmesg */
                 if (ata_msg_drv(ap) && print_info)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7c337e754dab..1ff018525e3b 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3755,6 +3755,8 @@ static void ata_scsi_remove_dev(struct ata_device *dev)
         mutex_lock(&ap->scsi_host->scan_mutex);
         spin_lock_irqsave(ap->lock, flags);
 
+        if (zpodd_dev_enabled(dev))
+                zpodd_exit(dev);
         ata_acpi_unbind(dev);
 
         /* clearing dev->sdev is protected by host lock */
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;
+}
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 7148a58020b9..a21740b4ee11 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -230,4 +230,18 @@ static inline void ata_sff_exit(void)
 { }
 #endif /* CONFIG_ATA_SFF */
 
+/* libata-zpodd.c */
+#ifdef CONFIG_SATA_ZPODD
+void zpodd_init(struct ata_device *dev);
+void zpodd_exit(struct ata_device *dev);
+static inline bool zpodd_dev_enabled(struct ata_device *dev)
+{
+        return dev->zpodd != NULL;
+}
+#else /* CONFIG_SATA_ZPODD */
+static inline void zpodd_init(struct ata_device *dev) {}
+static inline void zpodd_exit(struct ata_device *dev) {}
+static inline bool zpodd_dev_enabled(struct ata_device *dev) { return false; }
+#endif /* CONFIG_SATA_ZPODD */
+
 #endif /* __LIBATA_H__ */