From: Dan Williams Date: Fri, 5 Aug 2022 20:27:45 +0000 (-0700) Subject: cxl/region: Fix x1 interleave to greater than x1 interleave routing X-Git-Tag: v6.0-rc1~42^2~2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=298d44d04b2ba97824c3dadd1dbf7c154a2a86e2;p=linux-2.6-block.git cxl/region: Fix x1 interleave to greater than x1 interleave routing In cases where the decode fans out as it traverses downstream, the interleave granularity needs to increment to identify the port selector bits out of the remaining address bits. For example, recall that with an x2 parent port intereleave (IW == 1), the downstream decode for children of those ports will either see address bit IG+8 always set, or address bit IG+8 always clear. So if the child port needs to select a downstream port it can only use address bits starting at IG+9 (where IG and IW are the CXL encoded values for interleave granularity (ilog2(ig) - 8) and ways (ilog2(iw))). When the parent port interleave is x1 no such masking occurs and the child port can maintain the granularity that was routed to the parent port. Reported-by: Jonathan Cameron Reviewed-by: Vishal Verma Reviewed-by: Ira Weiny Link: https://lore.kernel.org/r/165973126583.1526540.657948655360009242.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams --- diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index e71077beb021..641bc6344a4a 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -1025,7 +1025,11 @@ static int cxl_port_setup_targets(struct cxl_port *port, return rc; } - if (cxl_rr->nr_targets > 1) { + /* + * If @parent_port is masking address bits, pick the next unused address + * bit to route @port's targets. + */ + if (parent_iw > 1 && cxl_rr->nr_targets > 1) { u32 address_bit = max(peig + peiw, eiw + peig); eig = address_bit - eiw + 1;