scripts/dtc: Add support for floating-point literals

Signed-off-by: Asahi Lina <lina@asahilina.net>
AsahiLinux · Mar 28, 2023 · a636217 · a636217
1 parent 5ee7556
commit a636217
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Showing 4 changed files with 66 additions and 0 deletions.
diff --git a/scripts/dtc/data.c b/scripts/dtc/data.c
@@ -184,6 +184,33 @@ struct data data_append_integer(struct data d, uint64_t value, int bits)
 	}
 }
 
+struct data data_append_float(struct data d, double value, int bits)
+{
+	float f32;
+	uint32_t u32;
+	double f64;
+	uint64_t u64;
+	fdt32_t value_32;
+	fdt64_t value_64;
+
+	switch (bits) {
+	case 32:
+		f32 = value;
+		memcpy(&u32, &f32, sizeof(u32));
+		value_32 = cpu_to_fdt32(u32);
+		return data_append_data(d, &value_32, 4);
+
+	case 64:
+		f64 = value;
+		memcpy(&u64, &f64, sizeof(u64));
+		value_64 = cpu_to_fdt64(u64);
+		return data_append_data(d, &value_64, 8);
+
+	default:
+		die("Invalid literal size (%d)\n", bits);
+	}
+}
+
 struct data data_append_re(struct data d, uint64_t address, uint64_t size)
 {
 	struct fdt_reserve_entry re;

diff --git a/scripts/dtc/dtc-lexer.l b/scripts/dtc/dtc-lexer.l
@@ -151,6 +151,28 @@ static void PRINTF(1, 2) lexical_error(const char *fmt, ...);
 			return DT_LABEL;
 		}
 
+<V1>[-+]?(([0-9]+\.[0-9]*)|([0-9]*\.[0-9]+))(e[-+]?[0-9]+)?f? {
+			char *e;
+			DPRINT("Floating-point Literal: '%s'\n", yytext);
+
+			errno = 0;
+			yylval.floating = strtod(yytext, &e);
+
+			if (*e && (*e != 'f' || e[1])) {
+				lexical_error("Bad floating-point literal '%s'",
+					      yytext);
+			}
+
+			if (errno == ERANGE)
+				lexical_error("Floating-point literal '%s' out of range",
+					      yytext);
+			else
+				/* ERANGE is the only strtod error triggerable
+				 *  by strings matching the pattern */
+				assert(errno == 0);
+			return DT_FP_LITERAL;
+		}
+
 <V1>([0-9]+|0[xX][0-9a-fA-F]+)(U|L|UL|LL|ULL)? {
 			char *e;
 			DPRINT("Integer Literal: '%s'\n", yytext);

diff --git a/scripts/dtc/dtc-parser.y b/scripts/dtc/dtc-parser.y
@@ -48,6 +48,7 @@ static bool is_ref_relative(const char *ref)
 	struct node *nodelist;
 	struct reserve_info *re;
 	uint64_t integer;
+	double floating;
 	unsigned int flags;
 }
 
@@ -61,6 +62,7 @@ static bool is_ref_relative(const char *ref)
 %token DT_OMIT_NO_REF
 %token <propnodename> DT_PROPNODENAME
 %token <integer> DT_LITERAL
+%token <floating> DT_FP_LITERAL
 %token <integer> DT_CHAR_LITERAL
 %token <byte> DT_BYTE
 %token <data> DT_STRING
@@ -86,6 +88,7 @@ static bool is_ref_relative(const char *ref)
 %type <node> subnode
 %type <nodelist> subnodes
 
+%type <floating> floating_prim
 %type <integer> integer_prim
 %type <integer> integer_unary
 %type <integer> integer_mul
@@ -392,6 +395,15 @@ arrayprefix:
 			$$.data = data_add_marker(empty_data, TYPE_UINT32, NULL);
 			$$.bits = 32;
 		}
+	| arrayprefix floating_prim
+		{
+			if ($1.bits < 32) {
+				ERROR(&@2, "Floating-point values must be"
+				      " 32-bit or 64-bit");
+			}
+
+			$$.data = data_append_float($1.data, $2, $1.bits);
+		}
 	| arrayprefix integer_prim
 		{
 			if ($1.bits < 64) {
@@ -436,6 +448,10 @@ arrayprefix:
 		}
 	;
 
+floating_prim:
+	DT_FP_LITERAL
+	;
+
 integer_prim:
 	  DT_LITERAL
 	| DT_CHAR_LITERAL

diff --git a/scripts/dtc/dtc.h b/scripts/dtc/dtc.h
@@ -177,6 +177,7 @@ struct data data_insert_at_marker(struct data d, struct marker *m,
 struct data data_merge(struct data d1, struct data d2);
 struct data data_append_cell(struct data d, cell_t word);
 struct data data_append_integer(struct data d, uint64_t word, int bits);
+struct data data_append_float(struct data d, double value, int bits);
 struct data data_append_re(struct data d, uint64_t address, uint64_t size);
 struct data data_append_addr(struct data d, uint64_t addr);
 struct data data_append_byte(struct data d, uint8_t byte);