Add MAIL_T macro; read framebuffer allocation response

1 files changed, 19 insertions, 2 deletions

diff --git a/src/framebuffer.c b/src/framebuffer.c
index e3303b6..c3845b1 100644
--- a/src/framebuffer.c
+++ b/src/framebuffer.c
@@ -2,6 +2,7 @@
 
 #include <mailbox.h>
 
+#include <stddef.h>
 #include <stdint.h>
 
 #define WIDTH     640
@@ -9,8 +10,15 @@
 #define DEPTH      32
 #define ALIGNMENT  16 // Framebuffer byte alignment.
 
+typedef struct Framebuffer {
+  volatile void* pixels;
+  size_t         size;
+} Framebuffer;
+
+static Framebuffer framebuffer = {};
+
 bool framebuffer_init(uint32_t* error) {
-  volatile __attribute__((aligned(MAIL_ALIGN))) uint32_t ConfigureScreen[20] = {
+  MAIL_T uint32_t ConfigureScreen[20] = {
     80, // Size in bytes, aligned to MAIL_ALIGN.
     MAILBOX_REQUEST,
     TAG_FRAMEBUFFER_SET_PHYSICAL_SCREEN_SIZE, 8, MAILBOX_REQUEST, WIDTH, HEIGHT,
@@ -25,7 +33,7 @@ bool framebuffer_init(uint32_t* error) {
     goto end;
   }
   
-  volatile __attribute__((aligned(MAIL_ALIGN))) uint32_t InitFramebuffer[8] = {
+  MAIL_T uint32_t InitFramebuffer[8] = {
     32, // Size in bytes, aligned to MAIL_ALIGN.
     MAILBOX_REQUEST,
     TAG_FRAMEBUFFER_ALLOCATE, 8, MAILBOX_REQUEST, ALIGNMENT, 0,
@@ -33,6 +41,15 @@ bool framebuffer_init(uint32_t* error) {
   };
   mbox_write(PROPERTY_CHANNEL, InitFramebuffer);
   response = mbox_read(PROPERTY_CHANNEL);
+  if (response->code != MAILBOX_SUCCESS) {
+    goto end;
+  }
+  
+  // The input mail is overwritten with the response.
+  //   u32 fb base address
+  //   u32 fb size
+  framebuffer.pixels = (void*)(uintptr_t)InitFramebuffer[5];
+  framebuffer.size   = InitFramebuffer[6];
   
 end:
   *error = response->code;