[PATCH] lib: sbi: sbi_ecall: Improve return SBI error

[Yu Chien Peter Lin]

We should also check if the return error code is greater than 0
(SBI_SUCCESS), as this is an invalid error.

Also rename the variable returned via a0 to 'out_err' and use
SBI_ERR_NOT_SUPPORTED when the extension does not have a handler
for consistency with the standard SBI errors defined in Table 1
of the SBI specification.

Signed-off-by: Yu Chien Peter Lin <peterlin at andestech.com>
---
 lib/sbi/sbi_ecall.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/lib/sbi/sbi_ecall.c b/lib/sbi/sbi_ecall.c
index 27ce5d49..8accf675 100644
--- a/lib/sbi/sbi_ecall.c
+++ b/lib/sbi/sbi_ecall.c
@@ -97,34 +97,34 @@ void sbi_ecall_unregister_extension(struct sbi_ecall_extension *ext)
 
 int sbi_ecall_handler(struct sbi_trap_regs *regs)
 {
-	int ret = 0;
+	int out_err = 0;
+	unsigned long out_val = 0;
 	struct sbi_ecall_extension *ext;
 	unsigned long extension_id = regs->a7;
 	unsigned long func_id = regs->a6;
 	struct sbi_trap_info trap = {0};
-	unsigned long out_val = 0;
 	bool is_0_1_spec = 0;
 
 	ext = sbi_ecall_find_extension(extension_id);
 	if (ext && ext->handle) {
-		ret = ext->handle(extension_id, func_id,
+		out_err = ext->handle(extension_id, func_id,
 				  regs, &out_val, &trap);
 		if (extension_id >= SBI_EXT_0_1_SET_TIMER &&
 		    extension_id <= SBI_EXT_0_1_SHUTDOWN)
 			is_0_1_spec = 1;
 	} else {
-		ret = SBI_ENOTSUPP;
+		out_err = SBI_ERR_NOT_SUPPORTED;
 	}
 
-	if (ret == SBI_ETRAP) {
+	if (out_err == SBI_ETRAP) {
 		trap.epc = regs->mepc;
 		sbi_trap_redirect(regs, &trap);
 	} else {
-		if (ret < SBI_LAST_ERR) {
+		if (out_err < SBI_LAST_ERR || SBI_SUCCESS < out_err) {
 			sbi_printf("%s: Invalid error %d for ext=0x%lx "
-				   "func=0x%lx\n", __func__, ret,
+				   "func=0x%lx\n", __func__, out_err,
 				   extension_id, func_id);
-			ret = SBI_ERR_FAILED;
+			out_err = SBI_ERR_FAILED;
 		}
 
 		/*
@@ -136,7 +136,7 @@ int sbi_ecall_handler(struct sbi_trap_regs *regs)
 		 * case should be handled differently.
 		 */
 		regs->mepc += 4;
-		regs->a0 = ret;
+		regs->a0 = out_err;
 		if (!is_0_1_spec)
 			regs->a1 = out_val;
 	}
-- 
2.34.1