RE: [PATCH v10 04/15] cxl/hdm: Use stored Component Register mappings to map HDM decoder capability

[Dan Williams]

Dan Williams wrote:
> Terry Bowman wrote:
> > From: Robert Richter <rrichter@xxxxxxx>
> > 
> > Now, that the Component Register mappings are stored, use them to
> > enable and map the HDM decoder capabilities. The Component Registers
> > do not need to be probed again for this, remove probing code.
> > 
> > The HDM capability applies to Endpoints, USPs and VH Host Bridges. The
> > Endpoint's component register mappings are located in the cxlds and
> > else in the port's structure. Provide a helper function
> > cxl_port_get_comp_map() to locate the mappings depending on the
> > component's type.
> > 
> > Signed-off-by: Robert Richter <rrichter@xxxxxxx>
> > Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> > ---
> >  drivers/cxl/core/hdm.c | 65 +++++++++++++++++++++++-------------------
> >  1 file changed, 35 insertions(+), 30 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> > index 17c8ba8c75e0..892a1fb5e4c6 100644
> > --- a/drivers/cxl/core/hdm.c
> > +++ b/drivers/cxl/core/hdm.c
> > @@ -81,27 +81,6 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
> >  		cxlhdm->interleave_mask |= GENMASK(14, 12);
> >  }
> >  
> > -static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
> > -				struct cxl_component_regs *regs)
> > -{
> > -	struct cxl_register_map map = {
> > -		.dev = &port->dev,
> > -		.resource = port->component_reg_phys,
> > -		.base = crb,
> > -		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
> > -	};
> > -
> > -	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
> > -	if (!map.component_map.hdm_decoder.valid) {
> > -		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(&map, &port->dev, regs,
> > -				      BIT(CXL_CM_CAP_CAP_ID_HDM));
> > -}
> > -
> >  static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> >  {
> >  	struct cxl_hdm *cxlhdm;
> > @@ -146,6 +125,22 @@ static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> >  	return true;
> >  }
> >  
> > +static struct cxl_register_map *cxl_port_get_comp_map(struct cxl_port *port)
> > +{
> > +	/*
> > +	 * HDM capability applies to Endpoints, USPs and VH Host
> > +	 * Bridges. The Endpoint's component register mappings are
> > +	 * located in the cxlds.
> > +	 */
> > +	if (is_cxl_endpoint(port)) {
> > +		struct cxl_memdev *memdev = to_cxl_memdev(port->uport_dev);
> > +
> > +		return &memdev->cxlds->comp_map;
> > +	}
> > +
> > +	return &port->comp_map;
> > +}
> 
> This was the function I was hoping would disappear in the new version.
> cxl_pci and cxl_port care about different register blocks and have
> different mapping lifetimes. I think that justifies having the
> endpoint->comp_map be valid for everything that the cxl_port driver
> cares about even though it duplicates some informatiom from
> cxlds->comp_map.

In the interest of time I went ahead and reflowed this patch to the
below and it is passing my tests. I also noticed some other @dev vs
@host confusion in some of the previous register conversion so perhaps I
should just send out v11 with this all rolled together...

-- >8 --
Subject: cxl/hdm: Use stored Component Register mappings to map HDM decoder capability

From: Robert Richter <rrichter@xxxxxxx>

Now, that the Component Register mappings are stored, use them to
enable and map the HDM decoder capabilities. The Component Registers
do not need to be probed again for this, remove probing code.

The HDM capability applies to Endpoints, USPs and VH Host Bridges. The
Endpoint's component register mappings are located in the cxlds and
else in the port's structure. Duplicate the cxlds->comp_map in
port->comp_map for endpoint ports.

Signed-off-by: Robert Richter <rrichter@xxxxxxx>
Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
[rework to drop cxl_port_get_comp_map()]
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/cxl/core/hdm.c  |   48 +++++++++++++++++++----------------------------
 drivers/cxl/core/port.c |   29 ++++++++++++++++++++++------
 drivers/cxl/mem.c       |    5 ++---
 3 files changed, 43 insertions(+), 39 deletions(-)

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 11d9971f3e8c..ced7801516d2 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -81,26 +81,6 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
 		cxlhdm->interleave_mask |= GENMASK(14, 12);
 }
 
-static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
-				struct cxl_component_regs *regs)
-{
-	struct cxl_register_map map = {
-		.host = &port->dev,
-		.resource = port->component_reg_phys,
-		.base = crb,
-		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
-	};
-
-	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
-	if (!map.component_map.hdm_decoder.valid) {
-		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(&map, regs, BIT(CXL_CM_CAP_CAP_ID_HDM));
-}
-
 static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
 {
 	struct cxl_hdm *cxlhdm;
@@ -155,7 +135,7 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
 {
 	struct device *dev = &port->dev;
 	struct cxl_hdm *cxlhdm;
-	void __iomem *crb;
+	struct cxl_register_map *comp_map;
 	int rc;
 
 	cxlhdm = devm_kzalloc(dev, sizeof(*cxlhdm), GFP_KERNEL);
@@ -164,19 +144,29 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
 	cxlhdm->port = port;
 	dev_set_drvdata(dev, cxlhdm);
 
-	crb = ioremap(port->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);
-	if (!crb && info && info->mem_enabled) {
-		cxlhdm->decoder_count = info->ranges;
-		return cxlhdm;
-	} else if (!crb) {
+	comp_map = &port->comp_map;
+	if (comp_map->resource == CXL_RESOURCE_NONE) {
+		if (info && info->mem_enabled) {
+			cxlhdm->decoder_count = info->ranges;
+			return cxlhdm;
+		}
+		WARN_ON(1);
 		dev_err(dev, "No component registers mapped\n");
 		return ERR_PTR(-ENXIO);
 	}
 
-	rc = map_hdm_decoder_regs(port, crb, &cxlhdm->regs);
-	iounmap(crb);
-	if (rc)
+	if (!comp_map->component_map.hdm_decoder.valid) {
+		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
+		/* unique error code to indicate no HDM decoder capability */
+		return ERR_PTR(-ENODEV);
+	}
+
+	rc = cxl_map_component_regs(comp_map, &cxlhdm->regs,
+				    BIT(CXL_CM_CAP_CAP_ID_HDM));
+	if (rc) {
+		dev_dbg(dev, "Failed to map HDM capability.\n");
 		return ERR_PTR(rc);
+	}
 
 	parse_hdm_decoder_caps(cxlhdm);
 	if (cxlhdm->decoder_count == 0) {
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 3732925162e4..64fcb5b22372 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -741,16 +741,31 @@ static struct cxl_port *__devm_cxl_add_port(struct device *host,
 		return port;
 
 	dev = &port->dev;
-	if (is_cxl_memdev(uport_dev))
+	if (is_cxl_memdev(uport_dev)) {
+		struct cxl_memdev *cxlmd = to_cxl_memdev(uport_dev);
+		struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
 		rc = dev_set_name(dev, "endpoint%d", port->id);
-	else if (parent_dport)
+		if (rc)
+			goto err;
+
+		/*
+		 * The endpoint driver already enumerated the component and RAS
+		 * registers. Reuse that enumeration while prepping them to be
+		 * mapped by the cxl_port driver.
+		 */
+		port->comp_map = cxlds->comp_map;
+		port->comp_map.host = &port->dev;
+	} else if (parent_dport) {
 		rc = dev_set_name(dev, "port%d", port->id);
-	else
-		rc = dev_set_name(dev, "root%d", port->id);
-	if (rc)
-		goto err;
+		if (rc)
+			goto err;
 
-	rc = cxl_port_setup_regs(port, component_reg_phys);
+		rc = cxl_port_setup_regs(port, component_reg_phys);
+		if (rc)
+			goto err;
+	} else
+		rc = dev_set_name(dev, "root%d", port->id);
 	if (rc)
 		goto err;
 
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 317c7548e4e9..04107058739b 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -49,7 +49,6 @@ static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
 				 struct cxl_dport *parent_dport)
 {
 	struct cxl_port *parent_port = parent_dport->port;
-	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_port *endpoint, *iter, *down;
 	int rc;
 
@@ -65,8 +64,8 @@ static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
 		ep->next = down;
 	}
 
-	endpoint = devm_cxl_add_port(host, &cxlmd->dev,
-				     cxlds->component_reg_phys,
+	/* Note: endpoint port component registers are derived from @cxlds */
+	endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE,
 				     parent_dport);
 	if (IS_ERR(endpoint))
 		return PTR_ERR(endpoint);