On 4/14/23 11:54 AM, Dan Williams wrote:
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: d17d0540a0db ("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 Signed-off-by: Dan Williams dan.j.williams@intel.com
Reviewed-by: Dave Jiang dave.jiang@intel.com
drivers/cxl/core/hdm.c | 5 +++-- drivers/cxl/port.c | 18 +++++++++++++----- 2 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c index 6fdf7981ddc7..abe3877cfa63 100644 --- a/drivers/cxl/core/hdm.c +++ b/drivers/cxl/core/hdm.c @@ -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, diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c index 22a7ab2bae7c..eb57324c4ad4 100644 --- a/drivers/cxl/port.c +++ b/drivers/cxl/port.c @@ -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))
- if (!IS_ERR(cxlhdm))
return devm_cxl_enumerate_decoders(cxlhdm, NULL);- if (PTR_ERR(cxlhdm) != -ENODEV) {
dev_err(&port->dev, "Failed to map HDM decoder capability\n");- }
- if (rc == 1) {
dev_dbg(&port->dev, "Fallback to passthrough decoder\n");return devm_cxl_add_passthrough_decoder(port);- }
- return devm_cxl_enumerate_decoders(cxlhdm, NULL);
- dev_err(&port->dev, "HDM decoder capability not found\n");
- return -ENXIO; }
static int cxl_endpoint_port_probe(struct cxl_port *port)