1 files changed, 99 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-ata b/Documentation/ABI/testing/sysfs-ata
new file mode 100644
index 000000000000..0a932155cbba
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-ata
@@ -0,0 +1,99 @@
+What:           /sys/class/ata_...
+Date:           August 2008
+Contact:        Gwendal Grignou<gwendal@google.com>
+Description:
+
+Provide a place in sysfs for storing the ATA topology of the system.  This allows
+retrieving various information about ATA objects.
+
+Files under /sys/class/ata_port
+-------------------------------
+
+        For each port, a directory ataX is created where X is the ata_port_id of
+        the port. The device parent is the ata host device.
+
+idle_irq (read)
+
+        Number of IRQ received by the port while idle [some ata HBA only].
+
+nr_pmp_links (read)
+
+        If a SATA Port Multiplier (PM) is connected, number of link behind it.
+
+Files under /sys/class/ata_link
+-------------------------------
+
+        Behind each port, there is a ata_link. If there is a SATA PM in the
+        topology, 15 ata_link objects are created.
+
+        If a link is behind a port, the directory name is linkX, where X is
+        ata_port_id of the port.
+        If a link is behind a PM, its name is linkX.Y where X is ata_port_id
+        of the parent port and Y the PM port.
+
+hw_sata_spd_limit
+
+        Maximum speed supported by the connected SATA device.
+
+sata_spd_limit
+
+        Maximum speed imposed by libata.
+
+sata_spd
+
+        Current speed of the link [1.5, 3Gps,...].
+
+Files under /sys/class/ata_device
+---------------------------------
+
+        Behind each link, up to two ata device are created.
+        The name of the directory is devX[.Y].Z where:
+        - X is ata_port_id of the port where the device is connected,
+        - Y the port of the PM if any, and
+        - Z the device id: for PATA, there is usually 2 devices [0,1],
+        only 1 for SATA.
+
+class
+        Device class. Can be "ata" for disk, "atapi" for packet device,
+        "pmp" for PM, or "none" if no device was found behind the link.
+
+dma_mode
+
+        Transfer modes supported by the device when in DMA mode.
+        Mostly used by PATA device.
+
+pio_mode
+
+        Transfer modes supported by the device when in PIO mode.
+        Mostly used by PATA device.
+
+xfer_mode
+
+        Current transfer mode.
+
+id
+
+        Cached result of IDENTIFY command, as described in ATA8 7.16 and 7.17.
+        Only valid if the device is not a PM.
+
+gscr
+
+        Cached result of the dump of PM GSCR register.
+        Valid registers are:
+        0:      SATA_PMP_GSCR_PROD_ID,
+        1:      SATA_PMP_GSCR_REV,
+        2:      SATA_PMP_GSCR_PORT_INFO,
+        32:     SATA_PMP_GSCR_ERROR,
+        33:     SATA_PMP_GSCR_ERROR_EN,
+        64:     SATA_PMP_GSCR_FEAT,
+        96:     SATA_PMP_GSCR_FEAT_EN,
+        130:    SATA_PMP_GSCR_SII_GPIO
+        Only valid if the device is a PM.
+
+spdn_cnt
+
+        Number of time libata decided to lower the speed of link due to errors.
+
+ering
+
+        Formatted output of the error ring of the device.