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

From: Dan Williams
Date: Mon Apr 17 2023 - 18:45:50 EST

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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 dport 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. Introduce 'struct cxl_rch_dport' to wrap a
'struct cxl_dport' with a 'struct cxl_rcrb_info' attribute.

This centralizes all RCRB scanning in one routine.

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/cxl/acpi.c | 16 ++++++++--------
drivers/cxl/core/port.c | 33 +++++++++++++++++++++------------
drivers/cxl/core/regs.c | 12 ++++++++----
drivers/cxl/cxl.h | 21 +++++++++++++++------
drivers/cxl/mem.c | 15 ++++++++++-----
tools/testing/cxl/Kbuild | 2 +-
tools/testing/cxl/test/cxl.c | 10 ++++++----
tools/testing/cxl/test/mock.c | 12 ++++++------
tools/testing/cxl/test/mock.h | 7 ++++---
9 files changed, 79 insertions(+), 49 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 4e66483f1fd3..2647eb04fcdb 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -375,7 +375,7 @@ static int add_host_bridge_uport(struct device *match, void *arg)
struct cxl_chbs_context {
struct device *dev;
unsigned long long uid;
- resource_size_t rcrb;
+ struct cxl_rcrb_info rcrb;
resource_size_t chbcr;
u32 cxl_version;
};
@@ -395,7 +395,7 @@ static int cxl_get_chbcr(union acpi_subtable_headers *header, void *arg,
return 0;

ctx->cxl_version = chbs->cxl_version;
- ctx->rcrb = CXL_RESOURCE_NONE;
+ ctx->rcrb.base = CXL_RESOURCE_NONE;
ctx->chbcr = CXL_RESOURCE_NONE;

if (!chbs->base)
@@ -409,9 +409,8 @@ static int cxl_get_chbcr(union acpi_subtable_headers *header, void *arg,
if (chbs->length != CXL_RCRB_SIZE)
return 0;

- ctx->rcrb = chbs->base;
- ctx->chbcr = cxl_rcrb_to_component(ctx->dev, chbs->base,
- CXL_RCRB_DOWNSTREAM);
+ ctx->chbcr = cxl_probe_rcrb(ctx->dev, chbs->base, &ctx->rcrb,
+ CXL_RCRB_DOWNSTREAM);

return 0;
}
@@ -451,8 +450,9 @@ static int add_host_bridge_dport(struct device *match, void *arg)
return 0;
}

- if (ctx.rcrb != CXL_RESOURCE_NONE)
- dev_dbg(match, "RCRB found for UID %lld: %pa\n", uid, &ctx.rcrb);
+ if (ctx.rcrb.base != CXL_RESOURCE_NONE)
+ dev_dbg(match, "RCRB found for UID %lld: %pa\n", uid,
+ &ctx.rcrb.base);

if (ctx.chbcr == CXL_RESOURCE_NONE) {
dev_warn(match, "CHBCR invalid for Host Bridge (UID %lld)\n",
@@ -466,7 +466,7 @@ static int add_host_bridge_dport(struct device *match, void *arg)
bridge = pci_root->bus->bridge;
if (ctx.cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11)
dport = devm_cxl_add_rch_dport(root_port, bridge, uid,
- ctx.chbcr, ctx.rcrb);
+ ctx.chbcr, &ctx.rcrb);
else
dport = devm_cxl_add_dport(root_port, bridge, uid,
ctx.chbcr);
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 4003f445320c..d194f48259ff 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -920,7 +920,7 @@ static void cxl_dport_unlink(void *data)
static struct cxl_dport *
__devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
int port_id, resource_size_t component_reg_phys,
- resource_size_t rcrb)
+ struct cxl_rcrb_info *ri)
{
char link_name[CXL_TARGET_STRLEN];
struct cxl_dport *dport;
@@ -942,17 +942,26 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
CXL_TARGET_STRLEN)
return ERR_PTR(-EINVAL);

- dport = devm_kzalloc(host, sizeof(*dport), GFP_KERNEL);
- if (!dport)
- return ERR_PTR(-ENOMEM);
+ if (ri && ri->base != CXL_RESOURCE_NONE) {
+ struct cxl_rch_dport *rdport;
+
+ rdport = devm_kzalloc(host, sizeof(*rdport), GFP_KERNEL);
+ if (!rdport)
+ return ERR_PTR(-ENOMEM);
+
+ rdport->rcrb.base = ri->base;
+ dport = &rdport->dport;
+ dport->rch = true;
+ } else {
+ dport = devm_kzalloc(host, sizeof(*dport), GFP_KERNEL);
+ if (!dport)
+ return ERR_PTR(-ENOMEM);
+ }

dport->dport = dport_dev;
dport->port_id = port_id;
dport->component_reg_phys = component_reg_phys;
dport->port = port;
- if (rcrb != CXL_RESOURCE_NONE)
- dport->rch = true;
- dport->rcrb = rcrb;

cond_cxl_root_lock(port);
rc = add_dport(port, dport);
@@ -994,7 +1003,7 @@ struct cxl_dport *devm_cxl_add_dport(struct cxl_port *port,
struct cxl_dport *dport;

dport = __devm_cxl_add_dport(port, dport_dev, port_id,
- component_reg_phys, CXL_RESOURCE_NONE);
+ component_reg_phys, NULL);
if (IS_ERR(dport)) {
dev_dbg(dport_dev, "failed to add dport to %s: %ld\n",
dev_name(&port->dev), PTR_ERR(dport));
@@ -1013,24 +1022,24 @@ EXPORT_SYMBOL_NS_GPL(devm_cxl_add_dport, CXL);
* @dport_dev: firmware or PCI device representing the dport
* @port_id: identifier for this dport in a decoder's target list
* @component_reg_phys: optional location of CXL component registers
- * @rcrb: mandatory location of a Root Complex Register Block
+ * @ri: mandatory data about the Root Complex Register Block layout
*
* See CXL 3.0 9.11.8 CXL Devices Attached to an RCH
*/
struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
struct device *dport_dev, int port_id,
resource_size_t component_reg_phys,
- resource_size_t rcrb)
+ struct cxl_rcrb_info *ri)
{
struct cxl_dport *dport;

- if (rcrb == CXL_RESOURCE_NONE) {
+ if (!ri || ri->base == CXL_RESOURCE_NONE) {
dev_dbg(&port->dev, "failed to add RCH dport, missing RCRB\n");
return ERR_PTR(-EINVAL);
}

dport = __devm_cxl_add_dport(port, dport_dev, port_id,
- component_reg_phys, rcrb);
+ component_reg_phys, ri);
if (IS_ERR(dport)) {
dev_dbg(dport_dev, "failed to add RCH dport to %s: %ld\n",
dev_name(&port->dev), PTR_ERR(dport));
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index 52d1dbeda527..b1c0db898a50 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -332,9 +332,8 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
}
EXPORT_SYMBOL_NS_GPL(cxl_find_regblock, CXL);

-resource_size_t cxl_rcrb_to_component(struct device *dev,
- resource_size_t rcrb,
- enum cxl_rcrb which)
+resource_size_t cxl_probe_rcrb(struct device *dev, resource_size_t rcrb,
+ struct cxl_rcrb_info *ri, enum cxl_rcrb which)
{
resource_size_t component_reg_phys;
void __iomem *addr;
@@ -344,6 +343,8 @@ resource_size_t cxl_rcrb_to_component(struct device *dev,

if (which == CXL_RCRB_UPSTREAM)
rcrb += SZ_4K;
+ else
+ ri->base = rcrb;

/*
* RCRB's BAR[0..1] point to component block containing CXL
@@ -364,6 +365,9 @@ resource_size_t cxl_rcrb_to_component(struct device *dev,
cmd = readw(addr + PCI_COMMAND);
bar0 = readl(addr + PCI_BASE_ADDRESS_0);
bar1 = readl(addr + PCI_BASE_ADDRESS_1);
+
+ /* TODO: retrieve rcrb->aer_cap here */
+
iounmap(addr);
release_mem_region(rcrb, SZ_4K);

@@ -395,4 +399,4 @@ resource_size_t cxl_rcrb_to_component(struct device *dev,

return component_reg_phys;
}
-EXPORT_SYMBOL_NS_GPL(cxl_rcrb_to_component, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_probe_rcrb, CXL);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 1503ccec9a84..b0807f54e9fd 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -267,9 +267,9 @@ enum cxl_rcrb {
CXL_RCRB_DOWNSTREAM,
CXL_RCRB_UPSTREAM,
};
-resource_size_t cxl_rcrb_to_component(struct device *dev,
- resource_size_t rcrb,
- enum cxl_rcrb which);
+struct cxl_rcrb_info;
+resource_size_t cxl_probe_rcrb(struct device *dev, resource_size_t rcrb,
+ struct cxl_rcrb_info *ri, enum cxl_rcrb which);

#define CXL_RESOURCE_NONE ((resource_size_t) -1)
#define CXL_TARGET_STRLEN 20
@@ -589,12 +589,12 @@ 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_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
* @rch: Indicate whether this dport was enumerated in RCH or VH mode
* @port: reference to cxl_port that contains this downstream port
*/
@@ -602,11 +602,20 @@ struct cxl_dport {
struct device *dport;
int port_id;
resource_size_t component_reg_phys;
- resource_size_t rcrb;
bool rch;
struct cxl_port *port;
};

+struct cxl_rcrb_info {
+ resource_size_t base;
+ u16 aer_cap;
+};
+
+struct cxl_rch_dport {
+ struct cxl_dport dport;
+ struct cxl_rcrb_info rcrb;
+};
+
/**
* struct cxl_ep - track an endpoint's interest in a port
* @ep: device that hosts a generic CXL endpoint (expander or accelerator)
@@ -674,7 +683,7 @@ struct cxl_dport *devm_cxl_add_dport(struct cxl_port *port,
struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
struct device *dport_dev, int port_id,
resource_size_t component_reg_phys,
- resource_size_t rcrb);
+ struct cxl_rcrb_info *ri);

struct cxl_decoder *to_cxl_decoder(struct device *dev);
struct cxl_root_decoder *to_cxl_root_decoder(struct device *dev);
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 097d86dd2a8e..7da6135e0b17 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -71,10 +71,15 @@ static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
* host-bridge RCRB if they are not already mapped via the
* typical register locator mechanism.
*/
- if (parent_dport->rch && cxlds->component_reg_phys == CXL_RESOURCE_NONE)
- component_reg_phys = cxl_rcrb_to_component(
- &cxlmd->dev, parent_dport->rcrb, CXL_RCRB_UPSTREAM);
- else
+ if (parent_dport->rch &&
+ cxlds->component_reg_phys == CXL_RESOURCE_NONE) {
+ struct cxl_rch_dport *rdport =
+ container_of(parent_dport, typeof(*rdport), dport);
+
+ component_reg_phys =
+ cxl_probe_rcrb(&cxlmd->dev, rdport->rcrb.base,
+ &rdport->rcrb, CXL_RCRB_UPSTREAM);
+ } else
component_reg_phys = cxlds->component_reg_phys;
endpoint = devm_cxl_add_port(host, &cxlmd->dev, component_reg_phys,
parent_dport);
@@ -92,7 +97,7 @@ static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd,
}

return 0;
-}
+ }

static int cxl_mem_probe(struct device *dev)
{
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index fba7bec96acd..bef1bc3bd912 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -11,7 +11,7 @@ ldflags-y += --wrap=devm_cxl_enumerate_decoders
ldflags-y += --wrap=cxl_await_media_ready
ldflags-y += --wrap=cxl_hdm_decode_init
ldflags-y += --wrap=cxl_dvsec_rr_decode
-ldflags-y += --wrap=cxl_rcrb_to_component
+ldflags-y += --wrap=cxl_probe_rcrb

DRIVERS := ../../../drivers
CXL_SRC := $(DRIVERS)/cxl
diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 385cdeeab22c..805c79491485 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -983,12 +983,14 @@ static int mock_cxl_port_enumerate_dports(struct cxl_port *port)
return 0;
}

-resource_size_t mock_cxl_rcrb_to_component(struct device *dev,
- resource_size_t rcrb,
- enum cxl_rcrb which)
+resource_size_t mock_cxl_probe_rcrb(struct device *dev, resource_size_t rcrb,
+ struct cxl_rcrb_info *ri, enum cxl_rcrb which)
{
dev_dbg(dev, "rcrb: %pa which: %d\n", &rcrb, which);

+ if (which == CXL_RCRB_DOWNSTREAM)
+ ri->base = rcrb;
+
return (resource_size_t) which + 1;
}

@@ -1000,7 +1002,7 @@ static struct cxl_mock_ops cxl_mock_ops = {
.is_mock_dev = is_mock_dev,
.acpi_table_parse_cedt = mock_acpi_table_parse_cedt,
.acpi_evaluate_integer = mock_acpi_evaluate_integer,
- .cxl_rcrb_to_component = mock_cxl_rcrb_to_component,
+ .cxl_probe_rcrb = mock_cxl_probe_rcrb,
.acpi_pci_find_root = mock_acpi_pci_find_root,
.devm_cxl_port_enumerate_dports = mock_cxl_port_enumerate_dports,
.devm_cxl_setup_hdm = mock_cxl_setup_hdm,
diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
index c4e53f22e421..148bd4f184f5 100644
--- a/tools/testing/cxl/test/mock.c
+++ b/tools/testing/cxl/test/mock.c
@@ -244,9 +244,9 @@ int __wrap_cxl_dvsec_rr_decode(struct device *dev, int dvsec,
}
EXPORT_SYMBOL_NS_GPL(__wrap_cxl_dvsec_rr_decode, CXL);

-resource_size_t __wrap_cxl_rcrb_to_component(struct device *dev,
- resource_size_t rcrb,
- enum cxl_rcrb which)
+resource_size_t __wrap_cxl_probe_rcrb(struct device *dev, resource_size_t rcrb,
+ struct cxl_rcrb_info *ri,
+ enum cxl_rcrb which)
{
int index;
resource_size_t component_reg_phys;
@@ -254,14 +254,14 @@ resource_size_t __wrap_cxl_rcrb_to_component(struct device *dev,

if (ops && ops->is_mock_port(dev))
component_reg_phys =
- ops->cxl_rcrb_to_component(dev, rcrb, which);
+ ops->cxl_probe_rcrb(dev, rcrb, ri, which);
else
- component_reg_phys = cxl_rcrb_to_component(dev, rcrb, which);
+ component_reg_phys = cxl_probe_rcrb(dev, rcrb, ri, which);
put_cxl_mock_ops(index);

return component_reg_phys;
}
-EXPORT_SYMBOL_NS_GPL(__wrap_cxl_rcrb_to_component, CXL);
+EXPORT_SYMBOL_NS_GPL(__wrap_cxl_probe_rcrb, CXL);

MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(ACPI);
diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
index bef8817b01f2..7ef21356d052 100644
--- a/tools/testing/cxl/test/mock.h
+++ b/tools/testing/cxl/test/mock.h
@@ -15,9 +15,10 @@ struct cxl_mock_ops {
acpi_string pathname,
struct acpi_object_list *arguments,
unsigned long long *data);
- resource_size_t (*cxl_rcrb_to_component)(struct device *dev,
- resource_size_t rcrb,
- enum cxl_rcrb which);
+ resource_size_t (*cxl_probe_rcrb)(struct device *dev,
+ resource_size_t rcrb,
+ struct cxl_rcrb_info *ri,
+ enum cxl_rcrb which);
struct acpi_pci_root *(*acpi_pci_find_root)(acpi_handle handle);
bool (*is_mock_bus)(struct pci_bus *bus);
bool (*is_mock_port)(struct device *dev);
--
2.39.2
-- >8 --

> +
> + parent_dport->ras_cap = cxl_component_to_ras(parent_dport->dport,
> + parent_dport->component_reg_phys);

Since this is component register offset based can it not be shared with
the VH case? I have been expecting that RCH RAS capability and VH RAS
capability scanning would need to be unified in the cxl_port driver.

Next message: Suren Baghdasaryan: "Re: [PATCH v2 1/1] mm: do not increment pgfault stats when page fault handler retries"
Previous message: Elliot Berman: "Re: [PATCH v11 22/26] virt: gunyah: Add proxy-scheduled vCPUs"
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