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cxl/port: Scan single-target ports for decoders

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Do not assume that a single-target port falls back to a passthrough
decoder configuration. Scan for decoders and only fallback after probing
that the HDM decoder capability is not present.

One user visible affect of this bug is the inability to enumerate
present CXL regions as the decoder settings for the present decoders are
skipped.

Fixes: d17d0540a0 ("cxl/core/hdm: Add CXL standard decoder enumeration to the core")
Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: http://lore.kernel.org/r/20230227153128.8164-1-Jonathan.Cameron@huawei.com
Cc: <stable@vger.kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://lore.kernel.org/r/168149845130.792294.3210421233937427962.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2023-04-14 11:54:11 -07:00
parent 104087a8aa
commit 7bba261e0a
2 changed files with 17 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/cxl/core/hdm.c
View file

@ -92,8 +92,9 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
cxl_probe_component_regs(&port->dev, crb, &map.component_map);
if (!map.component_map.hdm_decoder.valid) {
dev_err(&port->dev, "HDM decoder registers invalid\n");
return -ENXIO;
dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
/* unique error code to indicate no HDM decoder capability */
return -ENODEV;
}
return cxl_map_component_regs(&port->dev, regs, &map,

20
drivers/cxl/port.c
View file

@ -66,14 +66,22 @@ static int cxl_switch_port_probe(struct cxl_port *port)
if (rc < 0)
return rc;
if (rc == 1)
return devm_cxl_add_passthrough_decoder(port);
cxlhdm = devm_cxl_setup_hdm(port, NULL);
if (IS_ERR(cxlhdm))
return PTR_ERR(cxlhdm);
if (!IS_ERR(cxlhdm))
return devm_cxl_enumerate_decoders(cxlhdm, NULL);
return devm_cxl_enumerate_decoders(cxlhdm, NULL);
if (PTR_ERR(cxlhdm) != -ENODEV) {
dev_err(&port->dev, "Failed to map HDM decoder capability\n");
return PTR_ERR(cxlhdm);
}
if (rc == 1) {
dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
return devm_cxl_add_passthrough_decoder(port);
}
dev_err(&port->dev, "HDM decoder capability not found\n");
return -ENXIO;
}
static int cxl_endpoint_port_probe(struct cxl_port *port)