[U-Boot] [PATCH v1 10/12] dm: video: Add basic ANSI escape sequence support

Rob Clark
2017-09-10T13:22:31Z

Really just the subset that is needed by efi_console. Perhaps more will
be added later, for example color support would be useful to implement
efi_cout_set_attribute().

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
drivers/video/vidconsole-uclass.c | 112 ++++++++++++++++++++++++++++++++++++++
drivers/video/video-uclass.c | 4 +-
include/video.h | 7 +++
include/video_console.h | 11 ++++
4 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/drivers/video/vidconsole-uclass.c b/drivers/video/vidconsole-uclass.c
index e081d5a0ee..7998b4cf5f 100644
--- a/drivers/video/vidconsole-uclass.c
+++ b/drivers/video/vidconsole-uclass.c
@@ -9,6 +9,7 @@
*/

#include <common.h>
+#include <linux/ctype.h>
#include <dm.h>
#include <video.h>
#include <video_console.h>
@@ -107,12 +108,123 @@ static void vidconsole_newline(struct udevice *dev)
video_sync(dev->parent);
}

+/*
+ * Parse a number from string that ends in a non-numeric character..
+ * sscanf() would be nice. This is just enough for parsing ANSI escape
+ * sequences.
+ */
+static char *parsenum(char *s, int *num)
+{
+ int n = 0;
+
+ while (isdigit(*s)) {
+ n = (10 * n) + (*s - '0');
+ s++;
+ }
+
+ *num = n;
+ return s;
+}
+
+static void vidconsole_escape_char(struct udevice *dev, char ch)
+{
+ struct vidconsole_priv *priv = dev_get_uclass_priv(dev);
+
+ /* Sanity checking for bogus ESC sequences: */
+ if (priv->escape_len >= sizeof(priv->escape_buf))
+ goto error;
+ if (priv->escape_len == 0 && ch != '[')
+ goto error;
+
+ priv->escape_buf[priv->escape_len++] = ch;
+
+ /*
+ * Escape sequences are terminated by a letter, so keep
+ * accumulating until we get one:
+ */
+ if (!isalpha(ch))
+ return;
+
+ /*
+ * clear escape mode first, otherwise things will get highly
+ * surprising if you hit any debug prints that come back to
+ * this console.
+ */
+ priv->escape = 0;
+
+ switch (ch) {
+ case 'H':
+ case 'f': {
+ int row, col;
+ char *s = priv->escape_buf;
+
+ /*
+ * Set cursor position: [%d;%df or [%d;%dH
+ */
+ s++; /* [ */
+ s = parsenum(s, &row);
+ s++; /* ; */
+ s = parsenum(s, &col);
+
+ priv->ycur = row * priv->y_charsize;
+ priv->xcur_frac = priv->xstart_frac +
+ VID_TO_POS(col * priv->x_charsize);
+
+ break;
+ }
+ case 'J': {
+ int mode;
+
+ /*
+ * Clear part/all screen:
+ * [J or [0J - clear screen from cursor down
+ * [1J - clear screen from cursor up
+ * [2J - clear entire screen
+ *
+ * TODO we really only handle entire-screen case, others
+ * probably require some additions to video-uclass (and
+ * are not really needed yet by efi_console)
+ */
+ parsenum(priv->escape_buf + 1, &mode);
+
+ if (mode == 2) {
+ video_clear(dev->parent);
+ video_sync(dev->parent);
+ priv->ycur = 0;
+ priv->xcur_frac = priv->xstart_frac;
+ } else {
+ debug("unsupported clear mode: %d\n", mode);
+ }
+ break;
+ }
+ default:
+ debug("unrecognized escape sequence: %*s\n",
+ priv->escape_len, priv->escape_buf);
+ }
+
+ return;
+
+error:
+ /* something went wrong, just revert to normal mode: */
+ priv->escape = 0;
+ return;
+}
+
int vidconsole_put_char(struct udevice *dev, char ch)
{
struct vidconsole_priv *priv = dev_get_uclass_priv(dev);
int ret;

+ if (priv->escape) {
+ vidconsole_escape_char(dev, ch);
+ return 0;
+ }
+
switch (ch) {
+ case '\x1b':
+ priv->escape_len = 0;
+ priv->escape = 1;
+ break;
case '\a':
/* beep */
break;
diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
index 3036e3a1f2..0163039821 100644
--- a/drivers/video/video-uclass.c
+++ b/drivers/video/video-uclass.c
@@ -87,7 +87,7 @@ int video_reserve(ulong *addrp)
return 0;
}

-static int video_clear(struct udevice *dev)
+void video_clear(struct udevice *dev)
{
struct video_priv *priv = dev_get_uclass_priv(dev);

@@ -100,8 +100,6 @@ static int video_clear(struct udevice *dev)
} else {
memset(priv->fb, priv->colour_bg, priv->fb_size);
}
-
- return 0;
}

/* Flush video activity to the caches */
diff --git a/include/video.h b/include/video.h
index 5b4e78b182..61ff653121 100644
--- a/include/video.h
+++ b/include/video.h
@@ -115,6 +115,13 @@ struct video_ops {
int video_reserve(ulong *addrp);

/**
+ * video_clear() - Clear a device's frame buffer to background color.
+ *
+ * @dev: Device to clear
+ */
+void video_clear(struct udevice *dev);
+
+/**
* video_sync() - Sync a device's frame buffer with its hardware
*
* Some frame buffers are cached or have a secondary frame buffer. This
diff --git a/include/video_console.h b/include/video_console.h
index 26047934da..9dce234bd9 100644
--- a/include/video_console.h
+++ b/include/video_console.h
@@ -29,6 +29,9 @@
* @xsize_frac: Width of the display in fractional units
* @xstart_frac: Left margin for the text console in fractional units
* @last_ch: Last character written to the text console on this line
+ * @escape: TRUE if currently accumulating an ANSI escape sequence
+ * @escape_len: Length of accumulated escape sequence so far
+ * @escape_buf: Buffer to accumulate escape sequence
*/
struct vidconsole_priv {
struct stdio_dev sdev;
@@ -42,6 +45,14 @@ struct vidconsole_priv {
int xsize_frac;
int xstart_frac;
int last_ch;
+ /*
+ * ANSI escape sequences are accumulated character by character,
+ * starting after the ESC char (0x1b) until the entire sequence
+ * is consumed at which point it is acted upon.
+ */
+ int escape;
+ int escape_len;
+ char escape_buf[32];
};

/**
--
2.13.5