Regions are carved out of an addresses space which is claimed by top
level decoders, and subsequently their children decoders. Regions are
created with a size and therefore must fit, with proper alignment, in
that address space. The support for doing this fitting is handled by the
driver automatically.
As an example, a platform might configure a top level decoder to claim
1TB of address space @ 0x800000000 -> 0x10800000000; it would be
possible to create M regions with appropriate alignment to occupy that
address space. Each of those regions would have a host physical address
somewhere in the range between 32G and 1.3TB, and the location will be
determined by the logic added here.
The request_region() usage is not strictly mandatory at this point as
the actual handling of the address space is done with genpools. It is
highly likely however that the resource/region APIs will become useful
in the not too distant future.
All decoders manage a host physical address space while active. Only the
root decoder has constraints on location and size. As a result, it makes
most sense for the root decoder to be responsible for managing the
entire address space, and mid-level decoders and endpoints can ask the
root decoder for suballocations.
Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
---
drivers/cxl/acpi.c | 30 ++++++++++++++++++++++++++++++
drivers/cxl/cxl.h | 2 ++
drivers/cxl/region.c | 12 ++++++------
3 files changed, 38 insertions(+), 6 deletions(-)
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 4c746a6ef48c..a7ce0d660b34 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
#include <linux/platform_device.h>
+#include <linux/genalloc.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
@@ -73,6 +74,27 @@ static int cxl_acpi_cfmws_verify(struct device *dev,
return 0;
}
+/*
+ * Every decoder while active has an address space that it is decoding. However,
+ * only the root level decoders have fixed host physical address space ranges.
+ */
+static int cxl_create_cfmws_address_space(struct cxl_decoder *cxld,
+ struct acpi_cedt_cfmws *cfmws)
+{
+ const int order = ilog2(SZ_256M * cxld->interleave_ways);
+ struct device *dev = &cxld->dev;
+ struct gen_pool *pool;
+
+ pool = devm_gen_pool_create(dev, order, NUMA_NO_NODE, dev_name(dev));
+ if (IS_ERR(pool))
+ return PTR_ERR(pool);
+
+ cxld->address_space = pool;
+
+ return gen_pool_add(cxld->address_space, cfmws->base_hpa,
+ cfmws->window_size, NUMA_NO_NODE);
+}
+
struct cxl_cfmws_context {
struct device *dev;
struct cxl_port *root_port;
@@ -113,6 +135,14 @@ static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
cxld->interleave_ways = CFMWS_INTERLEAVE_WAYS(cfmws);
cxld->interleave_granularity = CFMWS_INTERLEAVE_GRANULARITY(cfmws);
+ rc = cxl_create_cfmws_address_space(cxld, cfmws);
+ if (rc) {
+ dev_err(dev,
+ "Failed to create CFMWS address space for decoder\n");
+ put_device(&cxld->dev);
+ return 0;
+ }
+
rc = cxl_decoder_add(cxld, target_map);
if (rc)
put_device(&cxld->dev);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index b318cabfc4a2..19e65ed35796 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -207,6 +207,7 @@ enum cxl_decoder_type {
* @target_type: accelerator vs expander (type2 vs type3) selector
* @flags: memory type capabilities and locking
* @region_ida: allocator for region ids.
+ * @address_space: Used/free address space for regions.
* @nr_targets: number of elements in @target
* @target: active ordered target list in current decoder configuration
*/
@@ -222,6 +223,7 @@ struct cxl_decoder {
enum cxl_decoder_type target_type;
unsigned long flags;
struct ida region_ida;
+ struct gen_pool *address_space;
const int nr_targets;
struct cxl_dport *target[];
};
diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c
index 9174925b67e3..b458d7b97120 100644
--- a/drivers/cxl/region.c
+++ b/drivers/cxl/region.c
@@ -126,7 +126,7 @@ static bool find_cdat_dsmas(const struct cxl_region *region)
/**
* qtg_match() - Does this CFMWS have desirable QTG for the endpoint
- * @cfmws: The CFMWS for the region
+ * @rootd: The root decoder for the region
* @endpoint: Endpoint whose QTG is being compared
*
* Prior to calling this function, the caller should verify that all endpoints
@@ -134,7 +134,7 @@ static bool find_cdat_dsmas(const struct cxl_region *region)
*
* Returns true if the QTG ID of the CFMWS matches the endpoint
*/
-static bool qtg_match(const struct cxl_decoder *cfmws,
+static bool qtg_match(const struct cxl_decoder *rootd,
const struct cxl_memdev *endpoint)
{
/* TODO: */
@@ -143,7 +143,7 @@ static bool qtg_match(const struct cxl_decoder *cfmws,
/**
* region_xhb_config_valid() - determine cross host bridge validity
- * @cfmws: The CFMWS to check against
+ * @rootd: The root decoder to check against
* @region: The region being programmed
*
* The algorithm is outlined in 2.13.14 "Verify XHB configuration sequence" of
@@ -152,7 +152,7 @@ static bool qtg_match(const struct cxl_decoder *cfmws,
* Returns true if the configuration is valid.
*/
static bool region_xhb_config_valid(const struct cxl_region *region,
- const struct cxl_decoder *cfmws)
+ const struct cxl_decoder *rootd)
{
/* TODO: */
return true;
@@ -160,7 +160,7 @@ static bool region_xhb_config_valid(const struct cxl_region *region,
/**
* region_hb_rp_config_valid() - determine root port ordering is correct
- * @cfmws: CFMWS decoder for this @region
+ * @rootd: root decoder for this @region
* @region: Region to validate
*
* The algorithm is outlined in 2.13.15 "Verify HB root port configuration
@@ -169,7 +169,7 @@ static bool region_xhb_config_valid(const struct cxl_region *region,
* Returns true if the configuration is valid.
*/
static bool region_hb_rp_config_valid(const struct cxl_region *region,
- const struct cxl_decoder *cfmws)
+ const struct cxl_decoder *rootd)
{
/* TODO: */
return true;
--
2.34.1
