MIPS: reserve space for exception vectors

In order to set own exception handlers, a table with the exception
vectors must be built in DRAM and the CPU EBase register must be
set to the base address of this table.

Reserve the space above the stack and use gd->irq_sp as storage
for the exception base address.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index b7ce5df..02607f7 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -7,6 +7,7 @@
 
 obj-y	+= cache.o
 obj-y	+= cache_init.o
+obj-y	+= stack.o
 
 obj-$(CONFIG_CMD_BOOTM) += bootm.o
 
diff --git a/arch/mips/lib/stack.c b/arch/mips/lib/stack.c
new file mode 100644
index 0000000..c80f5fe
--- /dev/null
+++ b/arch/mips/lib/stack.c
@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int arch_reserve_stacks(void)
+{
+	/* reserve space for exception vector table */
+	gd->start_addr_sp -= 0x500;
+	gd->start_addr_sp &= ~0xFFF;
+	gd->irq_sp = gd->start_addr_sp;
+	debug("Reserving %d Bytes for exception vector at: %08lx\n",
+	      0x500, gd->start_addr_sp);
+
+	return 0;
+}