Re: [PATCH] cxl: Move port register setup to when first dport appear

[Ira Weiny <ira.weiny@intel.com>]

Dave Jiang wrote:
> 
> 
> On 9/18/25 12:30 PM, Ira Weiny wrote:
> > Dave Jiang wrote:
> > 
> > [snip]
> > 
> >>
> >> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> >> index 76dd06d282df..416d45516d82 100644
> >> --- a/drivers/cxl/core/port.c
> >> +++ b/drivers/cxl/core/port.c
> >> @@ -867,9 +867,7 @@ static int cxl_port_add(struct cxl_port *port,
> >>  		if (rc)
> >>  			return rc;
> >>  
> >> -		rc = cxl_port_setup_regs(port, component_reg_phys);
> >> -		if (rc)
> >> -			return rc;
> >> +		port->component_reg_phys = component_reg_phys;
> >>  	} else {
> >>  		rc = dev_set_name(dev, "root%d", port->id);
> >>  		if (rc)
> >> @@ -1200,6 +1198,18 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
> >>  
> >>  	cxl_debugfs_create_dport_dir(dport);
> >>  
> >> +	/*
> >> +	 * Setup port register if this is the first dport showed up. Having
> >> +	 * a dport also means that there is at least 1 active link.
> >> +	 */
> >> +	if (port->nr_dports == 1 &&
> >> +	    port->component_reg_phys != CXL_RESOURCE_NONE) {
> > 
> > Should this be
> > 	    port->component_reg_phys == CXL_RESOURCE_NONE) {
> > 	                             ^^
> > ?
> > 
> > to match with 
> > 
> >         /* Note: endpoint port component registers are derived from @cxlds */
> >         endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE,
> >                                      parent_dport);
> > 
> > in the memdev probe path?
> 
> 
> No. port->component_reg_phys gets set in cxl_port_add(). So by the time the first dport shows up, we are using it to setup the register and then setting that back to CXL_RESOURCE_NONE. So therefore the port probe happens when it's the first dport and port->component_reg_phys is a valid address. 
>  

Ok I see it now.  yes I was not thinking correctly in that the acpi path
is setting the component_reg_phys and it is being saved for later...

All is good now.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>


[snip]