[PATCH v4 04/10] hw/mem/cxl_type3: Add support to create DC regions to type3 memory devices

[nifan.cxl@gmail.com]

From: Fan Ni <fan.ni@samsung.com>

With the change, when setting up memory for type3 memory device, we can
create DC regions.
A property 'num-dc-regions' is added to ct3_props to allow users to pass the
number of DC regions to create. To make it easier, other region parameters
like region base, length, and block size are hard coded. If needed,
these parameters can be added easily.

With the change, we can create DC regions with proper kernel side
support like below:

region=$(cat /sys/bus/cxl/devices/decoder0.0/create_dc_region)
echo $region > /sys/bus/cxl/devices/decoder0.0/create_dc_region
echo 256 > /sys/bus/cxl/devices/$region/interleave_granularity
echo 1 > /sys/bus/cxl/devices/$region/interleave_ways

echo "dc0" >/sys/bus/cxl/devices/decoder2.0/mode
echo 0x40000000 >/sys/bus/cxl/devices/decoder2.0/dpa_size

echo 0x40000000 > /sys/bus/cxl/devices/$region/size
echo  "decoder2.0" > /sys/bus/cxl/devices/$region/target0
echo 1 > /sys/bus/cxl/devices/$region/commit
echo $region > /sys/bus/cxl/drivers/cxl_region/bind

However, we cannot really read/write to the DC regions due to lack of
1. host backend and address space setup for DC regions;
2. mailbox command support for adding/releasing DC extents.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
---
 hw/mem/cxl_type3.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 244d2b5fd5..c61cd2b5ac 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -567,6 +567,40 @@ static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value,
     }
 }
 
+/*
+ * TODO: dc region configuration will be updated once host backend and address
+ * space support is added for DCD.
+ */
+static bool cxl_create_dc_regions(CXLType3Dev *ct3d, Error **errp)
+{
+    int i;
+    uint64_t region_base = 0;
+    uint64_t region_len =  2 * GiB;
+    uint64_t decode_len = 2 * GiB;
+    uint64_t blk_size = 2 * MiB;
+    CXLDCDRegion *region;
+
+    if (ct3d->hostvmem) {
+        region_base += ct3d->hostvmem->size;
+    }
+    if (ct3d->hostpmem) {
+        region_base += ct3d->hostpmem->size;
+    }
+    for (i = 0; i < ct3d->dc.num_regions; i++) {
+        region = &ct3d->dc.regions[i];
+        region->base = region_base;
+        region->decode_len = decode_len;
+        region->len = region_len;
+        region->block_size = blk_size;
+        /* dsmad_handle is set when creating cdat table entries */
+        region->flags = 0;
+
+        region_base += region->len;
+    }
+
+    return true;
+}
+
 static bool cxl_setup_memory(CXLType3Dev *ct3d, Error **errp)
 {
     DeviceState *ds = DEVICE(ct3d);
@@ -635,6 +669,11 @@ static bool cxl_setup_memory(CXLType3Dev *ct3d, Error **errp)
         g_free(p_name);
     }
 
+    if (!cxl_create_dc_regions(ct3d, errp)) {
+        error_setg(errp, "setup DC regions failed");
+        return false;
+    }
+
     return true;
 }
 
@@ -930,6 +969,7 @@ static Property ct3_props[] = {
                      HostMemoryBackend *),
     DEFINE_PROP_UINT64("sn", CXLType3Dev, sn, UI64_NULL),
     DEFINE_PROP_STRING("cdat", CXLType3Dev, cxl_cstate.cdat.filename),
+    DEFINE_PROP_UINT8("num-dc-regions", CXLType3Dev, dc.num_regions, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
-- 
2.43.0