Endpoint decoder mode is used to represent the partition the decoder
points to such as ram or pmem.

Expand the mode to allow a decoder to point to a specific DC partition
(Region).

Based on an original patch by Navneet Singh.

Reviewed-by: Dave Jiang <dave.ji...@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com>
Signed-off-by: Ira Weiny <ira.we...@intel.com>

---
Changes:
[Carpenter/smatch: fix cxl_decoder_mode_names array]
---
 Documentation/ABI/testing/sysfs-bus-cxl | 25 ++++++++++++------------
 drivers/cxl/core/hdm.c                  | 16 ++++++++++++++++
 drivers/cxl/core/port.c                 | 16 +++++++++++-----
 drivers/cxl/cxl.h                       | 34 +++++++++++++++++----------------
 4 files changed, 58 insertions(+), 33 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl 
b/Documentation/ABI/testing/sysfs-bus-cxl
index 
ff3ae83477f0876c0ee2d3955d27a11fa9d16d83..8d990d702f63363879150cf523c0be6229f315e0
 100644
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -361,23 +361,24 @@ Description:
 
 
 What:          /sys/bus/cxl/devices/decoderX.Y/mode
-Date:          May, 2022
-KernelVersion: v6.0
+Date:          May, 2022, October 2024
+KernelVersion: v6.0, v6.13 (dcY)
 Contact:       linux-...@vger.kernel.org
 Description:
                (RW) When a CXL decoder is of devtype "cxl_decoder_endpoint" it
-               translates from a host physical address range, to a device local
-               address range. Device-local address ranges are further split
-               into a 'ram' (volatile memory) range and 'pmem' (persistent
-               memory) range. The 'mode' attribute emits one of 'ram', 'pmem',
-               'mixed', or 'none'. The 'mixed' indication is for error cases
-               when a decoder straddles the volatile/persistent partition
-               boundary, and 'none' indicates the decoder is not actively
-               decoding, or no DPA allocation policy has been set.
+               translates from a host physical address range, to a device
+               local address range. Device-local address ranges are further
+               split into a 'ram' (volatile memory) range, 'pmem' (persistent
+               memory) range, and Dynamic Capacity (DC) ranges. The 'mode'
+               attribute emits one of 'ram', 'pmem', 'dcY', 'mixed', or
+               'none'. The 'mixed' indication is for error cases when a
+               decoder straddles partition boundaries, and 'none' indicates
+               the decoder is not actively decoding, or no DPA allocation
+               policy has been set.
 
                'mode' can be written, when the decoder is in the 'disabled'
-               state, with either 'ram' or 'pmem' to set the boundaries for the
-               next allocation.
+               state, with 'ram', 'pmem', or 'dcY' to set the boundaries for
+               the next allocation.
 
 
 What:          /sys/bus/cxl/devices/decoderX.Y/dpa_resource
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 
e15241f94d17b774aa5befb37fb453af637a17ce..d0c32c3c6564df869d41030144c6d2a7c063747d
 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -548,6 +548,7 @@ int cxl_dpa_set_mode(struct cxl_endpoint_decoder *cxled,
        switch (mode) {
        case CXL_DECODER_RAM:
        case CXL_DECODER_PMEM:
+       case CXL_DECODER_DC0 ... CXL_DECODER_DC7:
                break;
        default:
                dev_dbg(dev, "unsupported mode: %d\n", mode);
@@ -571,6 +572,21 @@ int cxl_dpa_set_mode(struct cxl_endpoint_decoder *cxled,
                return -ENXIO;
        }
 
+       if (mode >= CXL_DECODER_DC0 && mode <= CXL_DECODER_DC7) {
+               struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
+               int index;
+
+               index = dc_mode_to_region_index(mode);
+               if (!resource_size(&cxlds->dc_res[index])) {
+                       dev_dbg(dev, "no available dynamic capacity\n");
+                       return -ENXIO;
+               }
+               if (mds->dc_region[index].shareable) {
+                       dev_err(dev, "DC region %d is shareable\n", index);
+                       return -EINVAL;
+               }
+       }
+
        cxled->mode = mode;
        return 0;
 }
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 
5c0b8ead315f41c4df14918ad4dcdb269990c5dd..7459ca8eae002727405bf1077d0187bcfb579144
 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -205,11 +205,17 @@ static ssize_t mode_store(struct device *dev, struct 
device_attribute *attr,
        enum cxl_decoder_mode mode;
        ssize_t rc;
 
-       if (sysfs_streq(buf, "pmem"))
-               mode = CXL_DECODER_PMEM;
-       else if (sysfs_streq(buf, "ram"))
-               mode = CXL_DECODER_RAM;
-       else
+       for (mode = 0; mode < CXL_DECODER_MODE_MAX; mode++)
+               if (sysfs_streq(buf, cxl_decoder_mode_names[mode]))
+                       break;
+
+       if (mode == CXL_DECODER_NONE ||
+           mode == CXL_DECODER_DEAD ||
+           mode == CXL_DECODER_MODE_MAX)
+               return -EINVAL;
+
+       /* Not yet supported */
+       if (mode >= CXL_DECODER_MIXED)
                return -EINVAL;
 
        rc = cxl_dpa_set_mode(cxled, mode);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 
055c840b6c2856ec77162c3c5f87293f00f8d8ec..79660c87e6be533a1d55311896f9a3c5514648f8
 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -389,27 +389,29 @@ enum cxl_decoder_mode {
        CXL_DECODER_DC7,
        CXL_DECODER_MIXED,
        CXL_DECODER_DEAD,
+       CXL_DECODER_MODE_MAX,
+};
+
+static const char * const cxl_decoder_mode_names[] = {
+       [CXL_DECODER_NONE] = "none",
+       [CXL_DECODER_RAM] = "ram",
+       [CXL_DECODER_PMEM] = "pmem",
+       [CXL_DECODER_DC0] = "dc0",
+       [CXL_DECODER_DC1] = "dc1",
+       [CXL_DECODER_DC2] = "dc2",
+       [CXL_DECODER_DC3] = "dc3",
+       [CXL_DECODER_DC4] = "dc4",
+       [CXL_DECODER_DC5] = "dc5",
+       [CXL_DECODER_DC6] = "dc6",
+       [CXL_DECODER_DC7] = "dc7",
+       [CXL_DECODER_MIXED] = "mixed",
+       [CXL_DECODER_DEAD] = "dead",
 };
 
 static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
 {
-       static const char * const names[] = {
-               [CXL_DECODER_NONE] = "none",
-               [CXL_DECODER_RAM] = "ram",
-               [CXL_DECODER_PMEM] = "pmem",
-               [CXL_DECODER_DC0] = "dc0",
-               [CXL_DECODER_DC1] = "dc1",
-               [CXL_DECODER_DC2] = "dc2",
-               [CXL_DECODER_DC3] = "dc3",
-               [CXL_DECODER_DC4] = "dc4",
-               [CXL_DECODER_DC5] = "dc5",
-               [CXL_DECODER_DC6] = "dc6",
-               [CXL_DECODER_DC7] = "dc7",
-               [CXL_DECODER_MIXED] = "mixed",
-       };
-
        if (mode >= CXL_DECODER_NONE && mode <= CXL_DECODER_MIXED)
-               return names[mode];
+               return cxl_decoder_mode_names[mode];
        return "mixed";
 }
 

-- 
2.47.1


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