command: Prefer uint8_t* for buffers; prefer uint8_fast_t for lengths

Prefer using 'uint8_t' buffers as it is too easy to run into C sign
extension problems with 'char' buffers.  Prefer using 'uint_fast8_t'
for buffer lengths as gcc does a better job compiling them on 32bit
mcus.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

2 files changed, 12 insertions, 12 deletions

diff --git a/src/pru/internal.h b/src/pru/internal.h
index abbc9e40..dc125cd3 100644
--- a/src/pru/internal.h
+++ b/src/pru/internal.h
@@ -25,7 +25,7 @@
 // Layout of shared memory
 struct shared_response_buffer {
     uint32_t count;
-    char data[MESSAGE_MAX];
+    uint8_t data[MESSAGE_MAX];
 };
 struct shared_mem {
     uint32_t signal;
@@ -36,7 +36,7 @@ struct shared_mem {
     const struct command_parser *command_index;
     uint32_t command_index_size;
     const struct command_parser *shutdown_handler;
-    char read_data[512];
+    uint8_t read_data[512];
 };
 
 #define SIGNAL_PRU0_WAITING 0xefefefef
diff --git a/src/pru/pru0.c b/src/pru/pru0.c
index 58f15175..2a136e9e 100644
--- a/src/pru/pru0.c
+++ b/src/pru/pru0.c
@@ -32,7 +32,7 @@ static uint16_t transport_dst;
 #define CHAN_PORT                                       30
 
 #define RPMSG_HDR_SIZE 16
-static char transmit_buf[RPMSG_BUF_SIZE - RPMSG_HDR_SIZE];
+static uint8_t transmit_buf[RPMSG_BUF_SIZE - RPMSG_HDR_SIZE];
 static int transmit_pos;
 
 // Transmit all pending message blocks
@@ -48,7 +48,7 @@ flush_messages(void)
 
 // Generate a message block and queue it for transmission
 static void
-build_message(char *msg, int msglen)
+build_message(uint8_t *msg, int msglen)
 {
     if (transmit_pos + msglen > sizeof(transmit_buf))
         flush_messages();
@@ -105,13 +105,13 @@ send_pru1_shutdown(void)
 
 // Dispatch all the commands in a message block
 static void
-do_dispatch(char *buf, uint32_t msglen)
+do_dispatch(uint8_t *buf, uint32_t msglen)
 {
-    char *p = &buf[MESSAGE_HEADER_SIZE];
-    char *msgend = &buf[msglen-MESSAGE_TRAILER_SIZE];
+    uint8_t *p = &buf[MESSAGE_HEADER_SIZE];
+    uint8_t *msgend = &buf[msglen-MESSAGE_TRAILER_SIZE];
     while (p < msgend) {
         // Parse command
-        uint8_t cmdid = *p++;
+        uint_fast8_t cmdid = *p++;
         const struct command_parser *cp = &SHARED_MEM->command_index[cmdid];
         if (!cmdid || cmdid >= SHARED_MEM->command_index_size
             || cp->num_args > ARRAY_SIZE(SHARED_MEM->next_command_args)) {
@@ -131,7 +131,7 @@ check_can_read(void)
 {
     // Read data
     uint16_t dst, len;
-    char *p = SHARED_MEM->read_data;
+    uint8_t *p = SHARED_MEM->read_data;
     int16_t ret = pru_rpmsg_receive(&transport, &transport_dst, &dst, p, &len);
     if (ret)
         return ret == PRU_RPMSG_NO_BUF_AVAILABLE;
@@ -144,8 +144,8 @@ check_can_read(void)
 
     // Parse data into message blocks
     for (;;) {
-        uint8_t pop_count, msglen = len > MESSAGE_MAX ? MESSAGE_MAX : len;
-        int8_t ret = command_find_block(p, msglen, &pop_count);
+        uint_fast8_t pop_count, msglen = len > MESSAGE_MAX ? MESSAGE_MAX : len;
+        int_fast8_t ret = command_find_block(p, msglen, &pop_count);
         if (!ret)
             break;
         if (ret > 0)
@@ -210,7 +210,7 @@ sched_shutdown(uint_fast8_t reason)
 void
 console_sendf(const struct command_encoder *ce, va_list args)
 {
-    char buf[MESSAGE_MIN];
+    uint8_t buf[MESSAGE_MIN];
     build_message(buf, sizeof(buf));
 }