Changeset 949 for trunk/softs/tsar_boot/src/reset_elf_loader.c

Timestamp:

Feb 18, 2015, 4:18:43 PM (9 years ago)

Author:

cfuguet

Message:

preloader: when loading LINUX, copy the DTB in low memory addresses

File:

• trunk/softs/tsar_boot/src/reset_elf_loader.c (modified) (3 diffs)

trunk/softs/tsar_boot/src/reset_elf_loader.c

@@ -17 +17 @@
 
 extern int blk_buf_idx;
+extern int dtb_start, dtb_end;
+
+addr_t dtb_addr;
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -56 +59 @@
      */
     int pseg;
-    for (pseg = 0; pseg < elf_header.e_phnum; pseg++)
-    {
+    for (pseg = 0; pseg < elf_header.e_phnum; pseg++) {
         if(elf_pht[pseg].p_type != PT_LOAD) continue;
 
@@ -91 +93 @@
     }
 
+    if (pseg == 0) {
+        reset_puts("\n[RESET ERROR] No loadable segments");
+        goto error;
+    }
+
+    /* By default, the used device tree is the one in the ROM */
+    dtb_addr = (addr_t)&dtb_start;
+
+#if OS_LINUX
+    /* When loading a Linux kernel, the device tree should be located in low
+     * memory addresses before the kernel itself.
+     * - When the ROM-contained DTB is located before the kernel no need to copy
+     *   the DTB elsewhere.
+     * - When the ROM-contained DTB is located after the kernel the DTB is
+     *   copied before the kernel. */
+    const int copy_dtb = ((addr_t)&dtb_start > elf_pht[0].p_paddr);
+    if (copy_dtb) {
+        size_t dtb_size = (size_t)&dtb_end - (size_t)&dtb_start;
+        dtb_addr = SEG_RAM_BASE;
+        if ((dtb_addr + (addr_t)dtb_size) >= elf_pht[0].p_paddr) {
+            reset_puts("\n[RESET ERROR] Insufficient space to copy the DTB");
+            goto error;
+        }
+
+        memcpy((void*)dtb_addr, (void*)&dtb_start, dtb_size);
+        reset_puts("\n[RESET] Device tree blob copied / address = ");
+        reset_putx(dtb_addr);
+        reset_puts(" / size = ");
+        reset_putx(dtb_size);
+    }
+#endif
+
     reset_puts("\n[RESET] Complete reset_elf_loader at cycle ");
-    reset_putd( proctime() );
+    reset_putd(proctime());
     reset_puts(" / boot entry = ");
-    reset_putx( (addr_t)(elf_header.e_entry) );
+    reset_putx((addr_t)elf_header.e_entry);
     reset_puts("\n");
 
-    return ((void *) elf_header.e_entry);
+    return ((void*)elf_header.e_entry);
 
 error: