util/spd_tools: Support comments in json

Allow comments in json file for better documentation. Comments must be
on seperate line.

BUG=none
TEST=Injest global_ddr4_mem_parts.json.txt with comments

Change-Id: I51295408d4f916708e4ed5bc42d5468ccdc68a6b
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44834
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/spd_tools/ddr4/gen_spd.go

@@ -12,6 +12,7 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
+	"regexp"
 )
 
 /*
@@ -998,6 +999,10 @@ func readMemoryParts(memParts *memParts, memPartsFileName string) error {
 		return err
 	}
 
+	// Strip comments from json file
+	re := regexp.MustCompile(`(?m)^\s*//.*`)
+	databytes = re.ReplaceAll(databytes, []byte(""))
+
 	return json.Unmarshal(databytes, memParts)
 }
 

util/spd_tools/ddr4/global_ddr4_mem_parts.json.txt

@@ -1,3 +1,6 @@
+// Global list of ddr4 memory part attributes.
+// These attributes match the part specifications and are independent
+// of any SoC expectations.
 {
     "parts": [
         {