lib: sbi: Improve get_feature_str() implementation and usage

We do following improvements for get_feature_str():
1. We should return "none" from get_feature_str() no features
   available instead of sbi_boot_prints() explicitly handling
   failure.
2. We don't need to return failure (just like misa_xlen())
   because we are returning "none" for no features and we are
   truncating output when space is not available.
3. Based on 1 and 2, the sbi_boot_prints() can be further
   simplified.
4. No need for two char[] in sbi_boot_prints()

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

include/sbi/sbi_hart.h

@@ -43,7 +43,7 @@ int  sbi_hart_pmp_check_addr(struct sbi_scratch *scratch, unsigned long daddr,
 			     unsigned long attr);
 bool sbi_hart_has_feature(u32 hartid, unsigned long feature);
 unsigned long sbi_hart_get_features(u32 hartid);
-int sbi_hart_get_features_str(u32 hartid, char *features_str, int nfstr);
+void sbi_hart_get_features_str(u32 hartid, char *features_str, int nfstr);
 
 void __attribute__((noreturn)) sbi_hart_hang(void);
 

include/sbi/sbi_platform.h

@@ -244,10 +244,9 @@ u32 sbi_platform_hart_index(const struct sbi_platform *plat, u32 hartid);
  *		       updated
  * @param nfstr length of the features_str. The feature string will be truncated
  *		if nfstr is not long enough.
- * @return the features value currently set for the given platform
  */
-int sbi_platform_get_features_str(const struct sbi_platform *plat,
+void sbi_platform_get_features_str(const struct sbi_platform *plat,
-				  char *features_str, int nfstr);
+				   char *features_str, int nfstr);
 
 /**
  * Get name of the platform

lib/sbi/sbi_hart.c

@@ -270,18 +270,20 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
  *		       updated
  * @param nfstr length of the features_str. The feature string will be truncated
  *		if nfstr is not long enough.
- * @return the features value currently set for the given platform
  */
-int sbi_hart_get_features_str(u32 hartid, char *features_str, int nfstr)
+void sbi_hart_get_features_str(u32 hartid, char *features_str, int nfstr)
 {
 	unsigned long features, feat = 1UL;
 	char *temp;
 	int offset = 0;
 
-	if (!features_str || !nfstr)
+	if (!features_str || nfstr <= 0)
-		return SBI_EINVAL;
+		return;
+	sbi_memset(features_str, 0, nfstr);
 
 	features = sbi_hart_get_features(hartid);
+	if (!features)
+		goto done;
 
 	do {
 		if (features & feat) {
@@ -295,9 +297,11 @@ int sbi_hart_get_features_str(u32 hartid, char *features_str, int nfstr)
 		feat = feat << 1;
 	} while (feat <= SBI_HART_HAS_LAST_FEATURE);
 
-	features_str[offset - 1] = '\0';
+done:
-
+	if (offset)
-	return 0;
+		features_str[offset - 1] = '\0';
+	else
+		sbi_strncpy(features_str, "none", nfstr);
 }
 
 static void sbi_hart_set_feature(u32 hartid, unsigned long feature)

lib/sbi/sbi_init.c

@@ -35,10 +35,8 @@
 
 static void sbi_boot_prints(struct sbi_scratch *scratch, u32 hartid)
 {
-	int xlen, ret;
+	int xlen;
-	char str[64];
+	char str[128];
-	int max_fstr_len = 128;
-	char features[128];
 	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
 
 #ifdef OPENSBI_VERSION_GIT
@@ -56,35 +54,26 @@ static void sbi_boot_prints(struct sbi_scratch *scratch, u32 hartid)
 		sbi_printf("Error %d getting MISA XLEN\n", xlen);
 		sbi_hart_hang();
 	}
-	misa_string(xlen, str, sizeof(str));
 
 	/* Platform details */
 	sbi_printf("Platform Name          : %s\n", sbi_platform_name(plat));
 	sbi_printf("Platform HART Count    : %u\n",
 		   sbi_platform_hart_count(plat));
-
+	sbi_platform_get_features_str(plat, str, sizeof(str));
-	sbi_memset(features, 0, max_fstr_len);
+	sbi_printf("Platform Features      : %s\n", str);
-	ret = sbi_platform_get_features_str(plat, features, max_fstr_len);
-	if (!ret)
-		sbi_printf("Platform Features      : %s\n", features);
-	else
-		sbi_printf("Platform Features      : %s\n", "none");
 
 	/* Boot HART details */
 	sbi_printf("Boot HART ID           : %u\n", hartid);
+	misa_string(xlen, str, sizeof(str));
 	sbi_printf("Boot HART ISA          : %s\n", str);
-
+	sbi_hart_get_features_str(hartid, str, sizeof(str));
-	sbi_memset(features, 0, max_fstr_len);
+	sbi_printf("BOOT HART Features     : %s\n", str);
-	ret = sbi_hart_get_features_str(hartid, features, max_fstr_len);
-	if (!ret)
-		sbi_printf("BOOT HART Features     : %s\n", features);
-	else
-		sbi_printf("BOOT HART Features     : %s\n", "none");
 
 	/* Firmware details */
 	sbi_printf("Firmware Base          : 0x%lx\n", scratch->fw_start);
 	sbi_printf("Firmware Size          : %d KB\n",
 		   (u32)(scratch->fw_size / 1024));
+
 	/* Generic details */
 	sbi_printf("Runtime SBI Version    : %d.%d\n",
 		   sbi_ecall_version_major(), sbi_ecall_version_minor());

lib/sbi/sbi_platform.c

@@ -38,27 +38,20 @@ static inline char *sbi_platform_feature_id2string(unsigned long feature)
 	return fstr;
 }
 
-/**
+void sbi_platform_get_features_str(const struct sbi_platform *plat,
- * Get the platform features in string format
+				   char *features_str, int nfstr)
- *
- * @param plat pointer to struct sbi_platform
- * @param features_str pointer to a char array where the features string will be
- *		       updated
- * @param nfstr length of the features_str. The feature string will be truncated
- *		if nfstr is not long enough.
- * @return the features value currently set for the given platform
- */
-int sbi_platform_get_features_str(const struct sbi_platform *plat,
-						char *features_str, int nfstr)
 {
 	unsigned long features, feat = 1UL;
 	char *temp;
 	int offset = 0;
 
 	if (!plat || !features_str || !nfstr)
-		return SBI_EINVAL;
+		return;
+	sbi_memset(features_str, 0, nfstr);
 
 	features = sbi_platform_get_features(plat);
+	if (!features)
+		goto done;
 
 	do {
 		if (features & feat) {
@@ -72,21 +65,14 @@ int sbi_platform_get_features_str(const struct sbi_platform *plat,
 		feat = feat << 1;
 	} while (feat <= SBI_PLATFORM_HAS_LAST_FEATURE);
 
-	features_str[offset - 1] = '\0';
+done:
-
+	if (offset)
-	return 0;
+		features_str[offset - 1] = '\0';
+	else
+		sbi_strncpy(features_str, "none", nfstr);
 }
 
-/**
+u32 sbi_platform_hart_index(const struct sbi_platform *plat, u32 hartid)
- * Get HART index for the given HART
- *
- * @param plat pointer to struct sbi_platform
- * @param hartid HART ID
- *
- * @return 0 <= value < hart_count for valid HART otherwise -1U
- */
-u32 sbi_platform_hart_index(const struct sbi_platform *plat,
-					  u32 hartid)
 {
 	u32 i;