From dba61cf8bb9bb96cde8dcf2c9a2dcc663074698b Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 5 Aug 2022 13:38:08 -0700
Subject: [PATCH 203/217] cxl/list: Add region to decoder listings

While decoders can be matched with regions by physical address, or filtered
by region, it is also useful to get a plain listing of the association.

Link: https://lore.kernel.org/r/165973188860.1528532.17427805440366364536.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 Documentation/cxl/lib/libcxl.txt |  7 +++++++
 cxl/json.c                       |  8 ++++++++
 cxl/lib/libcxl.c                 | 34 ++++++++++++++++++++++++++++++++
 cxl/lib/libcxl.sym               |  1 +
 cxl/libcxl.h                     |  1 +
 5 files changed, 51 insertions(+)

diff --git a/Documentation/cxl/lib/libcxl.txt b/Documentation/cxl/lib/libcxl.txt
index 50b0c9c..6756d2f 100644
--- a/Documentation/cxl/lib/libcxl.txt
+++ b/Documentation/cxl/lib/libcxl.txt
@@ -398,6 +398,7 @@ int cxl_decoder_set_dpa_size(struct cxl_decoder *decoder, unsigned long long siz
 const char *cxl_decoder_get_devname(struct cxl_decoder *decoder);
 int cxl_decoder_get_id(struct cxl_decoder *decoder);
 int cxl_decoder_get_nr_targets(struct cxl_decoder *decoder);
+struct cxl_region *cxl_decoder_get_region(struct cxl_decoder *decoder);
 
 enum cxl_decoder_target_type {
        CXL_DECODER_TTYPE_UNKNOWN,
@@ -446,6 +447,12 @@ Platform firmware may setup the CXL decode hierarchy before the OS
 boots, and may additionally require that the OS not change the decode
 settings. This property is indicated by the cxl_decoder_is_locked() API.
 
+When a decoder is associated with a region cxl_decoder_get_region()
+returns that region object. Note that it is only applicable to switch
+and endpoint decoders as root decoders have a 1:N relationship with
+regions.  Use cxl_region_foreach() for the similar functionality for
+root decoders.
+
 ==== TARGETS
 A root or switch level decoder takes an SPA (system-physical-address) as
 input and routes it to a downstream port. Which downstream port depends
diff --git a/cxl/json.c b/cxl/json.c
index ada1dbe..c3d9299 100644
--- a/cxl/json.c
+++ b/cxl/json.c
@@ -442,6 +442,7 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,
 	const char *devname = cxl_decoder_get_devname(decoder);
 	struct cxl_port *port = cxl_decoder_get_port(decoder);
 	struct json_object *jdecoder, *jobj;
+	struct cxl_region *region;
 	u64 val, size;
 
 	jdecoder = json_object_new_object();
@@ -486,6 +487,13 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,
 		}
 	}
 
+	region = cxl_decoder_get_region(decoder);
+	if (region) {
+		jobj = json_object_new_string(cxl_region_get_devname(region));
+		if (jobj)
+			json_object_object_add(jdecoder, "region", jobj);
+	}
+
 	if (size == 0) {
 		jobj = json_object_new_string("disabled");
 		if (jobj)
diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
index c7dc2b0..ff85b23 100644
--- a/cxl/lib/libcxl.c
+++ b/cxl/lib/libcxl.c
@@ -2124,6 +2124,40 @@ cxl_decoder_get_interleave_ways(struct cxl_decoder *decoder)
 	return decoder->interleave_ways;
 }
 
+CXL_EXPORT struct cxl_region *
+cxl_decoder_get_region(struct cxl_decoder *decoder)
+{
+	struct cxl_port *port = cxl_decoder_get_port(decoder);
+	struct cxl_ctx *ctx = cxl_decoder_get_ctx(decoder);
+	char *path = decoder->dev_buf;
+	char buf[SYSFS_ATTR_SIZE];
+	struct cxl_region *region;
+	struct cxl_decoder *iter;
+	int rc;
+
+	if (cxl_port_is_root(port))
+		return NULL;
+
+	sprintf(path, "%s/region", decoder->dev_path);
+	rc = sysfs_read_attr(ctx, path, buf);
+	if (rc < 0) {
+		err(ctx, "failed to read region name: %s\n", strerror(-rc));
+		return NULL;
+	}
+
+	if (strcmp(buf, "") == 0)
+		return NULL;
+
+	while (!cxl_port_is_root(port))
+		port = cxl_port_get_parent(port);
+
+	cxl_decoder_foreach(port, iter)
+		cxl_region_foreach(iter, region)
+			if (strcmp(cxl_region_get_devname(region), buf) == 0)
+				return region;
+	return NULL;
+}
+
 CXL_EXPORT struct cxl_region *
 cxl_decoder_create_pmem_region(struct cxl_decoder *decoder)
 {
diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym
index 549f88d..385a8f0 100644
--- a/cxl/lib/libcxl.sym
+++ b/cxl/lib/libcxl.sym
@@ -214,4 +214,5 @@ global:
 	cxl_decoder_get_interleave_granularity;
 	cxl_decoder_get_interleave_ways;
 	cxl_decoder_get_max_available_extent;
+	cxl_decoder_get_region;
 } LIBCXL_2;
diff --git a/cxl/libcxl.h b/cxl/libcxl.h
index 61c7fc4..2498fa1 100644
--- a/cxl/libcxl.h
+++ b/cxl/libcxl.h
@@ -201,6 +201,7 @@ bool cxl_decoder_is_locked(struct cxl_decoder *decoder);
 unsigned int
 cxl_decoder_get_interleave_granularity(struct cxl_decoder *decoder);
 unsigned int cxl_decoder_get_interleave_ways(struct cxl_decoder *decoder);
+struct cxl_region *cxl_decoder_get_region(struct cxl_decoder *decoder);
 struct cxl_region *cxl_decoder_create_pmem_region(struct cxl_decoder *decoder);
 struct cxl_decoder *cxl_decoder_get_by_name(struct cxl_ctx *ctx,
 					    const char *ident);
-- 
2.27.0