sandbox: serial: Update to use membuff

Rather than implementing our own circular queue, use membuff. This allows
us to read multiple bytes at once into the serial input.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/drivers/serial/sandbox.c b/drivers/serial/sandbox.c
index 8c74c3a1b8c203067c988141ecf04d0897e56f91..8e269a205d7ff999a3f482a5e039ccfb2dfc6604 100644 (file)
--- a/drivers/serial/sandbox.c
+++ b/drivers/serial/sandbox.c
@@ -21,24 +21,18 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-/*
- *
- *   serial_buf: A buffer that holds keyboard characters for the
- *              Sandbox U-Boot.
- *
- * invariants:
- *   serial_buf_write           == serial_buf_read -> empty buffer
- *   (serial_buf_write + 1) % 16 == serial_buf_read -> full buffer
- */
-static unsigned char serial_buf[16];
-static unsigned int serial_buf_write;
-static unsigned int serial_buf_read;
-
 struct sandbox_serial_platdata {
        int colour;     /* Text colour to use for output, -1 for none */
 };
 
+/**
+ * struct sandbox_serial_priv - Private data for this driver
+ *
+ * @buf: holds input characters available to be read by this driver
+ */
 struct sandbox_serial_priv {
+       struct membuff buf;
+       char serial_buf[16];
        bool start_of_line;
 };
 
@@ -71,6 +65,7 @@ static int sandbox_serial_probe(struct udevice *dev)
 
        if (state->term_raw != STATE_TERM_RAW)
                disable_ctrlc(1);
+       membuff_init(&priv->buf, priv->serial_buf, sizeof(priv->serial_buf));
 
        return 0;
 }
@@ -104,16 +99,12 @@ static int sandbox_serial_putc(struct udevice *dev, const char ch)
        return 0;
 }
 
-static unsigned int increment_buffer_index(unsigned int index)
-{
-       return (index + 1) % ARRAY_SIZE(serial_buf);
-}
-
 static int sandbox_serial_pending(struct udevice *dev, bool input)
 {
-       const unsigned int next_index =
-               increment_buffer_index(serial_buf_write);
+       struct sandbox_serial_priv *priv = dev_get_priv(dev);
        ssize_t count;
+       char *data;
+       int avail;
 
        if (!input)
                return 0;
@@ -121,26 +112,25 @@ static int sandbox_serial_pending(struct udevice *dev, bool input)
        os_usleep(100);
        if (!IS_ENABLED(CONFIG_SPL_BUILD))
                video_sync_all();
-       if (next_index == serial_buf_read)
+       avail = membuff_putraw(&priv->buf, 100, false, &data);
+       if (!avail)
                return 1;       /* buffer full */
 
-       count = os_read(0, &serial_buf[serial_buf_write], 1);
-       if (count == 1)
-               serial_buf_write = next_index;
+       count = os_read(0, data, avail);
+       if (count > 0)
+               membuff_putraw(&priv->buf, count, true, &data);
 
-       return serial_buf_write != serial_buf_read;
+       return membuff_avail(&priv->buf);
 }
 
 static int sandbox_serial_getc(struct udevice *dev)
 {
-       int result;
+       struct sandbox_serial_priv *priv = dev_get_priv(dev);
 
        if (!sandbox_serial_pending(dev, true))
                return -EAGAIN; /* buffer empty */
 
-       result = serial_buf[serial_buf_read];
-       serial_buf_read = increment_buffer_index(serial_buf_read);
-       return result;
+       return membuff_getbyte(&priv->buf);
 }
 
 #ifdef CONFIG_DEBUG_UART_SANDBOX