semihosting: Expand qemu_semihosting_console_inc to read

Allow more than one character to be read at one time.
Will be used by m68k and nios2 semihosting for stdio.

Reviewed-by: Luc Michel <lmichel@kalray.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

2 files changed, 21 insertions, 6 deletions

diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index 40f3730778..fdb143ace8 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -428,8 +428,15 @@ void do_common_semihosting(CPUState *cs)
         break;
 
     case TARGET_SYS_READC:
-        ret = qemu_semihosting_console_inc(cs);
-        common_semi_set_ret(cs, ret);
+        {
+            uint8_t ch;
+            int ret = qemu_semihosting_console_read(cs, &ch, 1);
+            if (ret == 1) {
+                common_semi_cb(cs, ch, 0);
+            } else {
+                common_semi_cb(cs, -1, EIO);
+            }
+        }
         break;
 
     case TARGET_SYS_ISERROR:
diff --git a/semihosting/console.c b/semihosting/console.c
index 17ece6bdca..e5ac3f20ba 100644
--- a/semihosting/console.c
+++ b/semihosting/console.c
@@ -144,12 +144,14 @@ static void console_read(void *opaque, const uint8_t *buf, int size)
     c->sleeping_cpus = NULL;
 }
 
-target_ulong qemu_semihosting_console_inc(CPUState *cs)
+int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
 {
-    uint8_t ch;
     SemihostingConsole *c = &console;
+    int ret = 0;
 
     g_assert(qemu_mutex_iothread_locked());
+
+    /* Block if the fifo is completely empty. */
     if (fifo8_is_empty(&c->fifo)) {
         c->sleeping_cpus = g_slist_prepend(c->sleeping_cpus, cs);
         cs->halted = 1;
@@ -157,8 +159,14 @@ target_ulong qemu_semihosting_console_inc(CPUState *cs)
         cpu_loop_exit(cs);
         /* never returns */
     }
-    ch = fifo8_pop(&c->fifo);
-    return (target_ulong) ch;
+
+    /* Read until buffer full or fifo exhausted. */
+    do {
+        *(char *)(buf + ret) = fifo8_pop(&c->fifo);
+        ret++;
+    } while (ret < len && !fifo8_is_empty(&c->fifo));
+
+    return ret;
 }
 
 void qemu_semihosting_console_init(void)