From 176baefb2eb5d7a3ddebe3ff803db1fce44574b5 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 8 Jun 2022 22:56:37 -0700 Subject: cxl/hdm: Commit decoder state to hardware After all the soft validation of the region has completed, convey the region configuration to hardware while being careful to commit decoders in specification mandated order. In addition to programming the endpoint decoder base-address, interleave ways and granularity, the switch decoder target lists are also established. While the kernel can enforce spec-mandated commit order, it can not enforce spec-mandated reset order. For example, the kernel can't stop someone from removing an endpoint device that is occupying decoderN in a switch decoder where decoderN+1 is also committed. To reset decoderN, decoderN+1 must be torn down first. That "tear down the world" implementation is saved for a follow-on patch. Callback operations are provided for the 'commit' and 'reset' operations. While those callbacks may prove useful for CXL accelerators (Type-2 devices with memory) the primary motivation is to enable a simple way for cxl_test to intercept those operations. Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/165784338418.1758207.14659830845389904356.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams --- tools/testing/cxl/test/cxl.c | 46 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'tools/testing') diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c index 4dad0fa7ac4c..a072b2d3e726 100644 --- a/tools/testing/cxl/test/cxl.c +++ b/tools/testing/cxl/test/cxl.c @@ -429,6 +429,50 @@ static int map_targets(struct device *dev, void *data) return 0; } +static int mock_decoder_commit(struct cxl_decoder *cxld) +{ + struct cxl_port *port = to_cxl_port(cxld->dev.parent); + int id = cxld->id; + + if (cxld->flags & CXL_DECODER_F_ENABLE) + return 0; + + dev_dbg(&port->dev, "%s commit\n", dev_name(&cxld->dev)); + if (port->commit_end + 1 != id) { + dev_dbg(&port->dev, + "%s: out of order commit, expected decoder%d.%d\n", + dev_name(&cxld->dev), port->id, port->commit_end + 1); + return -EBUSY; + } + + port->commit_end++; + cxld->flags |= CXL_DECODER_F_ENABLE; + + return 0; +} + +static int mock_decoder_reset(struct cxl_decoder *cxld) +{ + struct cxl_port *port = to_cxl_port(cxld->dev.parent); + int id = cxld->id; + + if ((cxld->flags & CXL_DECODER_F_ENABLE) == 0) + return 0; + + dev_dbg(&port->dev, "%s reset\n", dev_name(&cxld->dev)); + if (port->commit_end != id) { + dev_dbg(&port->dev, + "%s: out of order reset, expected decoder%d.%d\n", + dev_name(&cxld->dev), port->id, port->commit_end); + return -EBUSY; + } + + port->commit_end--; + cxld->flags &= ~CXL_DECODER_F_ENABLE; + + return 0; +} + static int mock_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm) { struct cxl_port *port = cxlhdm->port; @@ -482,6 +526,8 @@ static int mock_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm) cxld->interleave_ways = min_not_zero(target_count, 1); cxld->interleave_granularity = SZ_4K; cxld->target_type = CXL_DECODER_EXPANDER; + cxld->commit = mock_decoder_commit; + cxld->reset = mock_decoder_reset; if (target_count) { rc = device_for_each_child(port->uport, &ctx, -- cgit v1.2.3