From: Navneet Singh <navneet.si...@intel.com>

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).

Signed-off-by: Navneet Singh <navneet.si...@intel.com>
Co-developed-by: Ira Weiny <ira.we...@intel.com>
Signed-off-by: Ira Weiny <ira.we...@intel.com>

---
Changes:
[Fan: change mode range logic]
[Fan: use !resource_size()]
[djiang: use the static mode name string array in mode_store()]
[Jonathan: remove rc check from mode to region index]
[Jonathan: clarify decoder mode 'mixed']
[djbw: drop cleanup patch and just follow the convention in cxl_dpa_set_mode()]
[fan: make dcd resource size check similar to other partitions]
[djbw, jonathan, fan: remove mode range check from dc_mode_to_region_index]
[iweiny: push sysfs versions to 6.12]
---
 Documentation/ABI/testing/sysfs-bus-cxl | 21 ++++++++++----------
 drivers/cxl/core/hdm.c                  | 10 ++++++++++
 drivers/cxl/core/port.c                 | 10 +++++-----
 drivers/cxl/cxl.h                       | 35 ++++++++++++++++++---------------
 4 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl 
b/Documentation/ABI/testing/sysfs-bus-cxl
index 3f5627a1210a..957717264709 100644
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -316,23 +316,24 @@ Description:
 
 
 What:          /sys/bus/cxl/devices/decoderX.Y/mode
-Date:          May, 2022
-KernelVersion: v6.0
+Date:          May, 2022, October 2024
+KernelVersion: v6.0, v6.12 (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.
+               into a 'ram' (volatile memory) range, 'pmem' (persistent
+               memory) range, or Dynamic Capacity (DC) range. 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 b4a517c6d283..ceca0b3d3e5c 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -551,6 +551,7 @@ 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);
@@ -578,6 +579,15 @@ int cxl_dpa_set_mode(struct cxl_endpoint_decoder *cxled,
                goto out;
        }
 
+       if (mode >= CXL_DECODER_DC0 && mode <= CXL_DECODER_DC7) {
+               rc = dc_mode_to_region_index(mode);
+               if (!resource_size(&cxlds->dc_res[rc])) {
+                       dev_dbg(dev, "no available dynamic capacity\n");
+                       rc = -ENXIO;
+                       goto out;
+               }
+       }
+
        cxled->mode = mode;
        rc = 0;
 out:
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 8054cbaac9f6..222aa0aeeef7 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -205,11 +205,11 @@ 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 = CXL_DECODER_RAM; mode < CXL_DECODER_MIXED; mode++)
+               if (sysfs_streq(buf, cxl_decoder_mode_names[mode]))
+                       break;
+
+       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 53b666ef4097..16861c867537 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -365,6 +365,9 @@ struct cxl_decoder {
 /*
  * CXL_DECODER_DEAD prevents endpoints from being reattached to regions
  * while cxld_unregister() is running
+ *
+ * NOTE: CXL_DECODER_RAM must be second and CXL_DECODER_MIXED must be last.
+ *      See mode_store()
  */
 enum cxl_decoder_mode {
        CXL_DECODER_NONE,
@@ -382,25 +385,25 @@ enum cxl_decoder_mode {
        CXL_DECODER_DEAD,
 };
 
+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",
+};
+
 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";
 }
 

-- 
2.45.2


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