[PATCH] grub-core/term/i386/coreboot/cbmemc.c: Update console format

[Julius Werner <jwerner@chromium.org>]

Changed cbmemc to support updated console format from coreboot.
---
 grub-core/term/i386/coreboot/cbmemc.c | 44 +++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/grub-core/term/i386/coreboot/cbmemc.c b/grub-core/term/i386/coreboot/cbmemc.c
index 25e64a05c..9e20f52fb 100644
--- a/grub-core/term/i386/coreboot/cbmemc.c
+++ b/grub-core/term/i386/coreboot/cbmemc.c
@@ -29,11 +29,14 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
+#define CURSOR_MASK (1 << 28)
+#define OVERFLOW (1 << 31)
+
 struct grub_linuxbios_cbmemc
 {
   grub_uint32_t size;
-  grub_uint32_t pointer;
-  char data[0];
+  grub_uint32_t cursor;
+  char body[0];
 };
 
 static struct grub_linuxbios_cbmemc *cbmemc;
@@ -41,11 +44,20 @@ static struct grub_linuxbios_cbmemc *cbmemc;
 static void
 put (struct grub_term_output *term __attribute__ ((unused)), const int c)
 {
+  grub_uint32_t flags, cursor;
   if (!cbmemc)
     return;
-  if (cbmemc->pointer < cbmemc->size)
-    cbmemc->data[cbmemc->pointer] = c;
-  cbmemc->pointer++;
+  flags = cbmemc->cursor & ~CURSOR_MASK;
+  cursor = cbmemc->cursor & CURSOR_MASK;
+  if (cursor >= cbmemc->size)
+    return;
+  cbmemc->body[cursor++] = c;
+  if (cursor >= cbmemc->size)
+    {
+      cursor = 0;
+      flags |= OVERFLOW;
+    }
+  cbmemc->cursor = flags | cursor;
 }
 
 struct grub_terminfo_output_state grub_cbmemc_terminfo_output =
@@ -87,20 +99,28 @@ grub_cmd_cbmemc (struct grub_command *cmd __attribute__ ((unused)),
 		 int argc __attribute__ ((unused)),
 		 char *argv[] __attribute__ ((unused)))
 {
-  grub_size_t len;
-  char *str;
+  grub_size_t size, cursor;
   struct grub_linuxbios_cbmemc *cbmemc_saved;
 
   if (!cbmemc)
     return grub_error (GRUB_ERR_IO, "no CBMEM console found");
 
-  len = cbmemc->pointer;
-  if (len > cbmemc->size)
-    len = cbmemc->size;
-  str = cbmemc->data;
   cbmemc_saved = cbmemc;
   cbmemc = 0;
-  grub_xnputs (str, len);
+  cursor = cbmemc->cursor & CURSOR_MASK;
+  if (!(cbmemc->cursor & OVERFLOW) && cursor < cbmemc->size)
+    size = cursor;
+  else
+    size = cbmemc->size;
+  if (cbmemc->cursor & OVERFLOW)
+    {
+      if (cursor > size)
+        cursor = 0;
+      grub_xnputs(cbmemc->body + cursor, size - cursor);
+      grub_xnputs(cbmemc->body, cursor);
+    }
+  else
+    grub_xnputs(cbmemc->body, size);
   cbmemc = cbmemc_saved;
   return 0;
 }
-- 
2.12.2