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From 5a8ccd79b6bad32e52620a94199bf1af2e19708e Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@bootlin.com>
Date: Wed, 19 Jun 2019 12:17:51 +0200
Subject: [PATCH] drm/modes: Allow to specify rotation and reflection
 on the commandline
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Commit 1bf4e09227c345e246062285eba4b8fe660e512e upstream.
Minor conflict resolution as upstream has moved functions
from drm_fb_helper.c to a new drm_client_modeset.c

Rotations and reflections setup are needed in some scenarios to initialise
properly the initial framebuffer. Some drivers already had a bunch of
quirks to deal with this, such as either a private kernel command line
parameter (omapdss) or on the device tree (various panels).

In order to accomodate this, let's create a video mode parameter to deal
with the rotation and reflexion.

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/777da16e42db757c1f5b414b5ca34507097fed5c.1560783090.git-series.maxime.ripard@bootlin.com
---
 Documentation/fb/modedb.txt     |  12 ++++
 drivers/gpu/drm/drm_fb_helper.c |  30 +++++++++
 drivers/gpu/drm/drm_modes.c     | 114 ++++++++++++++++++++++++++------
 include/drm/drm_connector.h     |  10 +++
 4 files changed, 146 insertions(+), 20 deletions(-)

--- a/Documentation/fb/modedb.txt
+++ b/Documentation/fb/modedb.txt
@@ -51,6 +51,18 @@ To force the VGA output to be enabled an
 Specifying the option multiple times for different ports is possible, e.g.:
     video=LVDS-1:d video=HDMI-1:D
 
+Options can also be passed after the mode, using commas as separator.
+
+       Sample usage: 720x480,rotate=180 - 720x480 mode, rotated by 180 degrees
+
+Valid options are:
+
+  - reflect_x (boolean): Perform an axial symmetry on the X axis
+  - reflect_y (boolean): Perform an axial symmetry on the Y axis
+  - rotate (integer): Rotate the initial framebuffer by x
+    degrees. Valid values are 0, 90, 180 and 270.
+
+
 ***** oOo ***** oOo ***** oOo ***** oOo ***** oOo ***** oOo ***** oOo *****
 
 What is the VESA(TM) Coordinated Video Timings (CVT)?
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2464,6 +2464,7 @@ static void drm_setup_crtc_rotation(stru
                                    struct drm_connector *connector)
 {
        struct drm_plane *plane = fb_crtc->mode_set.crtc->primary;
+       struct drm_cmdline_mode *cmdline;
        uint64_t valid_mask = 0;
        int i, rotation;
 
@@ -2483,6 +2484,35 @@ static void drm_setup_crtc_rotation(stru
                rotation = DRM_MODE_ROTATE_0;
        }
 
+       /**
+        * The panel already defined the default rotation
+        * through its orientation. Whatever has been provided
+        * on the command line needs to be added to that.
+        *
+        * Unfortunately, the rotations are at different bit
+        * indices, so the math to add them up are not as
+        * trivial as they could.
+        *
+        * Reflections on the other hand are pretty trivial to deal with, a
+        * simple XOR between the two handle the addition nicely.
+        */
+       cmdline = &connector->cmdline_mode;
+       if (cmdline->specified) {
+               unsigned int cmdline_rest, panel_rest;
+               unsigned int cmdline_rot, panel_rot;
+               unsigned int sum_rot, sum_rest;
+
+               panel_rot = ilog2(rotation & DRM_MODE_ROTATE_MASK);
+               cmdline_rot = ilog2(cmdline->rotation_reflection & DRM_MODE_ROTATE_MASK);
+               sum_rot = (panel_rot + cmdline_rot) % 4;
+
+               panel_rest = rotation & ~DRM_MODE_ROTATE_MASK;
+               cmdline_rest = cmdline->rotation_reflection & ~DRM_MODE_ROTATE_MASK;
+               sum_rest = panel_rest ^ cmdline_rest;
+
+               rotation = (1 << sum_rot) | sum_rest;
+       }
+
        /*
         * TODO: support 90 / 270 degree hardware rotation,
         * depending on the hardware this may require the framebuffer
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1560,6 +1560,71 @@ static int drm_mode_parse_cmdline_res_mo
        return 0;
 }
 
+static int drm_mode_parse_cmdline_options(char *str, size_t len,
+                                         struct drm_connector *connector,
+                                         struct drm_cmdline_mode *mode)
+{
+       unsigned int rotation = 0;
+       char *sep = str;
+
+       while ((sep = strchr(sep, ','))) {
+               char *delim, *option;
+
+               option = sep + 1;
+               delim = strchr(option, '=');
+               if (!delim) {
+                       delim = strchr(option, ',');
+
+                       if (!delim)
+                               delim = str + len;
+               }
+
+               if (!strncmp(option, "rotate", delim - option)) {
+                       const char *value = delim + 1;
+                       unsigned int deg;
+
+                       deg = simple_strtol(value, &sep, 10);
+
+                       /* Make sure we have parsed something */
+                       if (sep == value)
+                               return -EINVAL;
+
+                       switch (deg) {
+                       case 0:
+                               rotation |= DRM_MODE_ROTATE_0;
+                               break;
+
+                       case 90:
+                               rotation |= DRM_MODE_ROTATE_90;
+                               break;
+
+                       case 180:
+                               rotation |= DRM_MODE_ROTATE_180;
+                               break;
+
+                       case 270:
+                               rotation |= DRM_MODE_ROTATE_270;
+                               break;
+
+                       default:
+                               return -EINVAL;
+                       }
+               } else if (!strncmp(option, "reflect_x", delim - option)) {
+                       rotation |= DRM_MODE_REFLECT_X;
+                       sep = delim;
+               } else if (!strncmp(option, "reflect_y", delim - option)) {
+                       rotation |= DRM_MODE_REFLECT_Y;
+                       sep = delim;
+               } else {
+                       return -EINVAL;
+               }
+       }
+
+       mode->rotation_reflection = rotation;
+
+       return 0;
+}
+
 /**
  * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
  * @mode_option: optional per connector mode option
@@ -1575,6 +1640,10 @@ static int drm_mode_parse_cmdline_res_mo
  *
  *     <xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]
  *
+ * Additionals options can be provided following the mode, using a comma to
+ * separate each option. Valid options can be found in
+ * Documentation/fb/modedb.txt.
+ *
  * The intermediate drm_cmdline_mode structure is required to store additional
  * options from the command line modline like the force-enable/disable flag.
  *
@@ -1587,9 +1656,10 @@ bool drm_mode_parse_command_line_for_con
 {
        const char *name;
        bool named_mode = false, parse_extras = false;
-       unsigned int bpp_off = 0, refresh_off = 0;
+       unsigned int bpp_off = 0, refresh_off = 0, options_off = 0;
        unsigned int mode_end = 0;
        char *bpp_ptr = NULL, *refresh_ptr = NULL, *extra_ptr = NULL;
+       char *options_ptr = NULL;
        char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
        int ret;
 
@@ -1638,13 +1708,18 @@ bool drm_mode_parse_command_line_for_con
                mode->refresh_specified = true;
        }
 
+       /* Locate the start of named options */
+       options_ptr = strchr(name, ',');
+       if (options_ptr)
+               options_off = options_ptr - name;
+
        /* Locate the end of the name / resolution, and parse it */
-       if (bpp_ptr && refresh_ptr) {
-               mode_end = min(bpp_off, refresh_off);
-       } else if (bpp_ptr) {
+       if (bpp_ptr) {
                mode_end = bpp_off;
        } else if (refresh_ptr) {
                mode_end = refresh_off;
+       } else if (options_ptr) {
+               mode_end = options_off;
        } else {
                mode_end = strlen(name);
                parse_extras = true;
@@ -1686,24 +1761,23 @@ bool drm_mode_parse_command_line_for_con
        else if (refresh_ptr)
                extra_ptr = refresh_end_ptr;
 
-       if (extra_ptr) {
-               if (!named_mode) {
-                       int len = strlen(name) - (extra_ptr - name);
-
-                       ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
-                                                          connector, mode);
-                       if (ret)
-                               return false;
-               } else {
-                       int remaining = strlen(name) - (extra_ptr - name);
+       if (extra_ptr &&
+           extra_ptr != options_ptr) {
+               int len = strlen(name) - (extra_ptr - name);
 
-                       /*
-                        * We still have characters to process, while
-                        * we shouldn't have any
-                        */
-                       if (remaining > 0)
-                               return false;
-               }
+               ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
+                                                  connector, mode);
+               if (ret)
+                       return false;
+       }
+
+       if (options_ptr) {
+               int len = strlen(name) - (options_ptr - name);
+
+               ret = drm_mode_parse_cmdline_options(options_ptr, len,
+                                                    connector, mode);
+               if (ret)
+                       return false;
        }
 
        return true;
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -857,6 +857,16 @@ struct drm_cmdline_mode {
         * state to one of the DRM_FORCE_* values.
         */
        enum drm_connector_force force;
+
+       /**
+        * @rotation_reflection:
+        *
+        * Initial rotation and reflection of the mode setup from the
+        * command line. See DRM_MODE_ROTATE_* and
+        * DRM_MODE_REFLECT_*. The only rotations supported are
+        * DRM_MODE_ROTATE_0 and DRM_MODE_ROTATE_180.
+        */
+       unsigned int rotation_reflection;
 };
 
 /**