From: Eli Cohen Date: Sun, 26 Feb 2006 22:36:06 +0000 (-0800) Subject: IB/mthca: Write FW commands through doorbell page X-Git-Tag: v2.6.17-rc1~1180^2~24 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14abdffcc0a0ca9c5bb3274648d073e09a6fd2ba;p=pandora-kernel.git IB/mthca: Write FW commands through doorbell page 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 Signed-off-by: Roland Dreier --- Reading git-diff-tree failed