14abdffcc0
This patch is checks whether the HCA supports posting FW commands through a doorbell page (user access region 0, or "UAR0"). If this is supported, the driver maps UAR0 and uses it for FW commands. This can be controlled by the value of a writable module parameter fw_cmd_doorbell. When the parameter is 0, the commands are posted through HCR using the old method; otherwise if HCA is capable commands go through UAR0. This use of UAR0 to post commands eliminates the need for polling the "go" bit prior to posting a new command. Since reading from a PCI device is much more expensive then issuing a posted write, it is expected that issuing FW commands this way will provide better CPU utilization. Signed-off-by: Eli Cohen <eli@mellanox.co.il> Signed-off-by: Roland Dreier <rolandd@cisco.com> |
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