habanalabs: support clock gating enable/disable

In Gaudi there is a feature of clock gating certain engines.
Therefore, add this property to the device structure.

In addition, due to a limitation of this feature, the driver needs to
dynamically enable or disable this feature during run-time. Therefore, add
ASIC interface functions to enable/disable this function from the common
code.

Moreover, this feature must be turned off when the user wishes to debug the
ASIC by reading/writing registers and/or memory through the driver's
debugfs. Therefore, add an option to enable/disable clock gating via the
debugfs interface.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/debugfs-driver-habanalabs b/Documentation/ABI/testing/debugfs-driver-habanalabs
index 67e04f2d7e1d..f6d9c2a8d528 100644
--- a/Documentation/ABI/testing/debugfs-driver-habanalabs
+++ b/Documentation/ABI/testing/debugfs-driver-habanalabs
@@ -8,6 +8,16 @@ Description:    Sets the device address to be used for read or write through
                 only when the IOMMU is disabled.
                 The acceptable value is a string that starts with "0x"
 
+What:           /sys/kernel/debug/habanalabs/hl<n>/clk_gate
+Date:           May 2020
+KernelVersion:  5.8
+Contact:        oded.gabbay@gmail.com
+Description:    Allow the root user to disable/enable in runtime the clock
+                gating mechanism in Gaudi. Due to how Gaudi is built, the
+                clock gating needs to be disabled in order to access the
+                registers of the TPC and MME engines. This is sometimes needed
+                during debug by the user and hence the user needs this option
+
 What:           /sys/kernel/debug/habanalabs/hl<n>/command_buffers
 Date:           Jan 2019
 KernelVersion:  5.1