Reuse the already existing xserver framebuffer mapping for sunxi_disp_t

Avoid creating a new mapping because that's a waste of the virtual address
space. Also we are going to use this xserver framebuffer mapping address
for testing whether window backing pixmaps are allocated in the framebuffer
and can be accelerated by G2D.
Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

src/fbdev.c

@@ -930,7 +930,8 @@ FBDevScreenInit(SCREEN_INIT_ARGS_DECL)
 #endif
 
 	fPtr->sunxi_disp_private = sunxi_disp_init(xf86FindOptionValue(
-	                                fPtr->pEnt->device->options,"fbdev"));
+	                                fPtr->pEnt->device->options,"fbdev"),
+	                                fPtr->fbmem);
 
 	if (!fPtr->sunxi_disp_private)
 		xf86DrvMsg(pScrn->scrnIndex, X_INFO,

src/sunxi_disp.c

@@ -36,7 +36,7 @@
 
 /*****************************************************************************/
 
-sunxi_disp_t *sunxi_disp_init(const char *device)
+sunxi_disp_t *sunxi_disp_init(const char *device, void *xserver_fbmem)
 {
     sunxi_disp_t *ctx = calloc(sizeof(sunxi_disp_t), 1);
     struct fb_var_screeninfo fb_var;
@@ -58,6 +58,9 @@ sunxi_disp_t *sunxi_disp_init(const char *device)
         return NULL;
     }
 
+    /* store the already existing mapping done by xserver */
+    ctx->xserver_fbmem = xserver_fbmem;
+
     ctx->fd_disp = open("/dev/disp", O_RDWR);
 
     /* maybe it's even not a sunxi hardware */
@@ -107,15 +110,21 @@ sunxi_disp_t *sunxi_disp_init(const char *device)
         return NULL;
     }
 
-    /* mmap framebuffer memory */
-    ctx->framebuffer_addr = (uint8_t *)mmap(0, ctx->framebuffer_size,
-                                            PROT_READ | PROT_WRITE,
-                                            MAP_SHARED, ctx->fd_fb, 0);
-    if (ctx->framebuffer_addr == MAP_FAILED) {
-        close(ctx->fd_fb);
-        close(ctx->fd_disp);
-        free(ctx);
-        return NULL;
+    if (ctx->xserver_fbmem) {
+        /* use already existing mapping */
+        ctx->framebuffer_addr = ctx->xserver_fbmem;
+    }
+    else {
+        /* mmap framebuffer memory */
+        ctx->framebuffer_addr = (uint8_t *)mmap(0, ctx->framebuffer_size,
+                                                PROT_READ | PROT_WRITE,
+                                                MAP_SHARED, ctx->fd_fb, 0);
+        if (ctx->framebuffer_addr == MAP_FAILED) {
+            close(ctx->fd_fb);
+            close(ctx->fd_disp);
+            free(ctx);
+            return NULL;
+        }
     }
 
     ctx->cursor_enabled = 0;
@@ -147,7 +156,8 @@ int sunxi_disp_close(sunxi_disp_t *ctx)
         if (ctx->cursor_enabled)
             sunxi_hw_cursor_hide(ctx);
         /* close descriptors */
-        munmap(ctx->framebuffer_addr, ctx->framebuffer_size);
+        if (!ctx->xserver_fbmem)
+            munmap(ctx->framebuffer_addr, ctx->framebuffer_size);
         close(ctx->fd_fb);
         close(ctx->fd_disp);
         ctx->fd_disp = -1;

src/sunxi_disp.h

@@ -43,6 +43,8 @@ typedef struct {
     int                 framebuffer_height;/* virtual vertical resolution */
     uint32_t            gfx_layer_size;    /* the size of the primary layer */
 
+    uint8_t            *xserver_fbmem; /* framebuffer mapping done by xserver */
+
     /* Hardware cursor support */
     int                 cursor_enabled;
     int                 cursor_x, cursor_y;
@@ -52,7 +54,7 @@ typedef struct {
     int                 layer_has_scaler;
 } sunxi_disp_t;
 
-sunxi_disp_t *sunxi_disp_init(const char *fb_device);
+sunxi_disp_t *sunxi_disp_init(const char *fb_device, void *xserver_fbmem);
 int sunxi_disp_close(sunxi_disp_t *ctx);
 
 /*

test/sunxi_disp_vsync_demo.c

@@ -81,7 +81,7 @@ int main(int argc, char *argv[])
 {
     int pos = 0, framenum = 0, yoffs, color;
 
-    disp = sunxi_disp_init("/dev/fb0");
+    disp = sunxi_disp_init("/dev/fb0", NULL);
     /*
      * setup the signal handler to catch Ctrl-C in order to prevent leaking
      * the layer on process termination (that's a kernel bug).