RE: [PATCH v5 02/26] cxl/rch: Prepare for caching the MMIO mapped PCIe AER capability

Dan Williams
2023-06-08T04:54:15Z

Terry Bowman wrote:
> From: Dan Williams <dan.j.williams@intel.com>
>
> Prepare cxl_probe_rcrb() for retrieving more than just the component
> register block. The RCH AER handling code wants to get back to the AER
> capability that happens to be MMIO mapped rather then configuration
> cycles.
>
> Move RCRB specific downstream port data, like the RCRB base and the
> AER capability offset, into its own data structure ('struct
> cxl_rcrb_info') for cxl_probe_rcrb() to fill. Extend 'struct
> cxl_dport' to include a 'struct cxl_rcrb_info' attribute.
>
> This centralizes all RCRB scanning in one routine.

With the addition of cxl_rcd_component_reg_phys() and
__rcrb_to_component() in the previous patch, this one becomes cleaner to
implement. Given the collisions it needed to be re-written. The
following is passing cxl_test:

-- >8 --
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index bd0a5788c696..b001669a5133 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -68,7 +68,9 @@ enum cxl_rcrb {
CXL_RCRB_DOWNSTREAM,
CXL_RCRB_UPSTREAM,
};
-resource_size_t __rcrb_to_component(struct device *dev, resource_size_t rcrb,
+struct cxl_rcrb_info;
+resource_size_t __rcrb_to_component(struct device *dev,
+ struct cxl_rcrb_info *ri,
enum cxl_rcrb which);

extern struct rw_semaphore cxl_dpa_rwsem;
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 45f5299af7a6..76888c75dae4 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -939,7 +939,8 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
return ERR_PTR(-ENOMEM);

if (rcrb != CXL_RESOURCE_NONE) {
- component_reg_phys = __rcrb_to_component(dport_dev, rcrb,
+ dport->rcrb.base = rcrb;
+ component_reg_phys = __rcrb_to_component(dport_dev, &dport->rcrb,
CXL_RCRB_DOWNSTREAM);
if (component_reg_phys == CXL_RESOURCE_NONE) {
dev_warn(dport_dev, "Invalid Component Registers in RCRB");
@@ -957,7 +958,6 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
dport->port_id = port_id;
dport->component_reg_phys = component_reg_phys;
dport->port = port;
- dport->rcrb = rcrb;

cond_cxl_root_lock(port);
rc = add_dport(port, dport);
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index 564dd430258a..6c4b33133918 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -332,10 +332,11 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
}
EXPORT_SYMBOL_NS_GPL(cxl_find_regblock, CXL);

-resource_size_t __rcrb_to_component(struct device *dev, resource_size_t rcrb,
+resource_size_t __rcrb_to_component(struct device *dev, struct cxl_rcrb_info *ri,
enum cxl_rcrb which)
{
resource_size_t component_reg_phys;
+ resource_size_t rcrb = ri->base;
void __iomem *addr;
u32 bar0, bar1;
u16 cmd;
@@ -400,6 +401,6 @@ resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
{
if (!dport->rch)
return CXL_RESOURCE_NONE;
- return __rcrb_to_component(dev, dport->rcrb, CXL_RCRB_UPSTREAM);
+ return __rcrb_to_component(dev, &dport->rcrb, CXL_RCRB_UPSTREAM);
}
EXPORT_SYMBOL_NS_GPL(cxl_rcd_component_reg_phys, CXL);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 28888bb0c088..7c8674079f1a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -582,12 +582,17 @@ cxl_find_dport_by_dev(struct cxl_port *port, const struct device *dport_dev)
return xa_load(&port->dports, (unsigned long)dport_dev);
}

+struct cxl_rcrb_info {
+ resource_size_t base;
+ u16 aer_cap;
+};
+
/**
* struct cxl_dport - CXL downstream port
* @dport: PCI bridge or firmware device representing the downstream link
* @port_id: unique hardware identifier for dport in decoder target list
* @component_reg_phys: downstream port component registers
- * @rcrb: base address for the Root Complex Register Block
+ * @rcrb: Data about the Root Complex Register Block layout
* @rch: Indicate whether this dport was enumerated in RCH or VH mode
* @port: reference to cxl_port that contains this downstream port
*/
@@ -595,7 +600,7 @@ struct cxl_dport {
struct device *dport;
int port_id;
resource_size_t component_reg_phys;
- resource_size_t rcrb;
+ struct cxl_rcrb_info rcrb;
bool rch;
struct cxl_port *port;
};
diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
index 30119a16ae85..dbeef5c6f606 100644
--- a/tools/testing/cxl/test/mock.c
+++ b/tools/testing/cxl/test/mock.c
@@ -271,8 +271,10 @@ struct cxl_dport *__wrap_devm_cxl_add_rch_dport(struct cxl_port *port,
if (ops && ops->is_mock_port(dport_dev)) {
dport = devm_cxl_add_dport(port, dport_dev, port_id,
CXL_RESOURCE_NONE);
- if (!IS_ERR(dport))
+ if (!IS_ERR(dport)) {
+ dport->rcrb.base = rcrb;
dport->rch = true;
+ }
} else
dport = devm_cxl_add_rch_dport(port, dport_dev, port_id, rcrb);
put_cxl_mock_ops(index);