[syntacore] support for platform extensions in syntacore_target.cfg

Add `platform_extension` that allows to specify a key to be used with
`::scr_info::expose_custom_string` function.

Change-Id: Ib0b4e5a5a2e2a6f1eb0ab950e4e60e800e27f474
Signed-off-by: Parshintsev Anatoly <[email protected]>

Author: aap-sc

tcl/target/syntacore_target.cfg

@@ -53,6 +53,7 @@ set __sc_target_defaults(chipname) riscv
 set __sc_target_defaults(expose_csrs) ""
 set __sc_target_defaults(disable_EQ_triggers) 1
 set __sc_target_defaults(disable_ebreak) 0
+set __sc_target_defaults(platform_extension) ""
 
 set __sc_target_defaults(smp_configuration) 0
 set __sc_target_defaults(gdb_report_data_abort) 1
@@ -75,6 +76,13 @@ proc proc_exists p {
 	# return uplevel 1 [expr {[llength [info procs $p]] > 0}]
 }
 
+proc check_and_call {msg proc_name args} {
+	if {![proc_exists $proc_name]} {
+		error $msg
+	}
+	tailcall $proc_name {*}$args
+}
+
 proc sc_pre_tap_hook {} {
 }
 
@@ -274,6 +282,14 @@ proc init_targets {} {
 		jtag newtap [dict get $tap_item prefix] [dict get $tap_item suffix] -irlen [dict get $tap_item irlen]
 	}
 
+	set _PLATFORM_EXT [sc_target_config_get platform_extension]
+	set _EXPOSED_REGISTERS ""
+	if {$_PLATFORM_EXT ne "" } {
+		set errmsg "incorrect version of scr_info platform extension plugin"
+		set platform_name [check_and_call $errmsg ::scr_info::type_name $_PLATFORM_EXT]
+		set _EXPOSED_REGISTERS [check_and_call $errmsg ::scr_info::expose_custom_string ${platform_name}]
+		sc_target_config_log "new registers from scr_info platform: $_EXPOSED_REGISTERS"
+	}
 	foreach tgt_item [lindex $tapmap 1] {
 		if {[sc_target_config_get no_ocd_targets] == 1} {
 			continue
@@ -303,6 +319,10 @@ proc init_targets {} {
 			$_TARGETNAME riscv hide_csrs $HIDE_CSRS
 		}
 
+		if {$_EXPOSED_REGISTERS ne ""} {
+			$_TARGETNAME riscv expose_csrs $_EXPOSED_REGISTERS
+		}
+
 		if {[sc_target_config_get expose_csrs] ne ""} {
 			$_TARGETNAME riscv expose_csrs [sc_target_config_get expose_csrs]
 		}