MIPS: add support for pre-relocation malloc

Implement MIPS specific setup of the gd_t structure to support
pre-relocation malloc. If CONFIG_SYS_MALLOC_F_LEN is specified,
a memory area will be reserved after the initial stack area and
the gd->malloc_base pointer will be initialized.

After this patch the new driver model can be used on MIPS.

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

arch/mips/cpu/mips32/start.S

@@ -140,9 +140,31 @@ reset:
 #endif
 
 	/* Set up temporary stack */
-	li	sp, CONFIG_SYS_INIT_SP_ADDR
+	li	t0, -16
+	li	t1, CONFIG_SYS_INIT_SP_ADDR
+	and	sp, t1, t0		# force 16 byte alignment
+	sub	sp, sp, GD_SIZE		# reserve space for gd
+	and	sp, sp, t0		# force 16 byte alignment
+	move	k0, sp			# save gd pointer
+#ifdef CONFIG_SYS_MALLOC_F_LEN
+	li	t2, CONFIG_SYS_MALLOC_F_LEN
+	sub	sp, sp, t2		# reserve space for early malloc
+	and	sp, sp, t0		# force 16 byte alignment
+#endif
 	move	fp, sp
 
+	/* Clear gd */
+	move	t0, k0
+1:
+	sw	zero, 0(t0)
+	blt	t0, t1, 1b
+	 addi	t0, 4
+
+#ifdef CONFIG_SYS_MALLOC_F_LEN
+	addu	t0, k0, GD_MALLOC_BASE	# gd->malloc_base offset
+	sw	sp, 0(t0)
+#endif
+
 	la	t9, board_init_f
 	jr	t9
 	 move	ra, zero

arch/mips/cpu/mips64/start.S

@@ -134,9 +134,31 @@ reset:
 #endif
 
 	/* Set up temporary stack */
-	dli	sp, CONFIG_SYS_INIT_SP_ADDR
+	dli	t0, -16
+	dli	t1, CONFIG_SYS_INIT_SP_ADDR
+	and	sp, t1, t0		# force 16 byte alignment
+	dsub	sp, sp, GD_SIZE		# reserve space for gd
+	and	sp, sp, t0		# force 16 byte alignment
+	move	k0, sp			# save gd pointer
+#ifdef CONFIG_SYS_MALLOC_F_LEN
+	dli	t2, CONFIG_SYS_MALLOC_F_LEN
+	dsub	sp, sp, t2		# reserve space for early malloc
+	and	sp, sp, t0		# force 16 byte alignment
+#endif
 	move	fp, sp
 
+	/* Clear gd */
+	move	t0, k0
+1:
+	sw	zero, 0(t0)
+	blt	t0, t1, 1b
+	 daddi	t0, 4
+
+#ifdef CONFIG_SYS_MALLOC_F_LEN
+	daddu	t0, k0, GD_MALLOC_BASE	# gd->malloc_base offset
+	sw	sp, 0(t0)
+#endif
+
 	dla	t9, board_init_f
 	jr	t9
 	 move	ra, zero

arch/mips/include/asm/config.h

@@ -7,8 +7,6 @@
 #ifndef _ASM_CONFIG_H_
 #define _ASM_CONFIG_H_
 
-#define CONFIG_SYS_GENERIC_GLOBAL_DATA
-
 #define CONFIG_LMB
 #define CONFIG_SYS_BOOT_RAMDISK_HIGH