Fixed MTP to work with TWRP

arch/cris/arch-v32/mach-fs/dram_init.S

@@ -0,0 +1,116 @@
+/*
+ * DRAM/SDRAM initialization - alter with care
+ * This file is intended to be included from other assembler files
+ *
+ * Note: This file may not modify r8 or r9 because they are used to
+ * carry information from the decompresser to the kernel
+ *
+ * Copyright (C) 2000-2007 Axis Communications AB
+ *
+ * Authors:  Mikael Starvik <starvik@axis.com>
+ */
+
+/* Just to be certain the config file is included, we include it here
+ * explicitely instead of depending on it being included in the file that
+ * uses this code.
+ */
+
+#include <hwregs/asm/reg_map_asm.h>
+#include <hwregs/asm/bif_core_defs_asm.h>
+
+	;; WARNING! The registers r8 and r9 are used as parameters carrying
+	;; information from the decompressor (if the kernel was compressed).
+	;; They should not be used in the code below.
+
+	; Refer to BIF MDS for a description of SDRAM initialization
+
+	; Bank configuration
+	move.d   REG_ADDR(bif_core, regi_bif_core, rw_sdram_cfg_grp0), $r0
+	move.d   CONFIG_ETRAX_SDRAM_GRP0_CONFIG, $r1
+	move.d   $r1, [$r0]
+	move.d   REG_ADDR(bif_core, regi_bif_core, rw_sdram_cfg_grp1), $r0
+	move.d   CONFIG_ETRAX_SDRAM_GRP1_CONFIG, $r1
+	move.d   $r1, [$r0]
+
+	; Calculate value of mrs_data
+	; CAS latency = 2 && bus_width = 32 => 0x40
+	; CAS latency = 3 && bus_width = 32 => 0x60
+	; CAS latency = 2 && bus_width = 16 => 0x20
+	; CAS latency = 3 && bus_width = 16 => 0x30
+
+	; Check if value is already supplied in kernel config
+	move.d   CONFIG_ETRAX_SDRAM_COMMAND, $r2
+	bne	 _set_timing
+	nop
+
+	move.d   0x40, $r4       ; Assume 32 bits and CAS latency = 2
+	move.d   CONFIG_ETRAX_SDRAM_TIMING, $r1
+	and.d    0x07, $r1       ; Get CAS latency
+	cmpq	 2, $r1		 ; CL = 2 ?
+	beq	 _bw_check
+	nop
+	move.d   0x60, $r4
+
+_bw_check:
+	; Assume that group 0 width is equal to group 1. This assumption
+	; is wrong for a group 1 only hardware (such as the grand old
+	; StorPoint+).
+	move.d   CONFIG_ETRAX_SDRAM_GRP0_CONFIG, $r1
+	and.d    0x200, $r1	; DRAM width is bit 9
+	beq      _set_timing
+	lslq	 2, $r4		;  mrs_data starts at bit 2
+	lsrq     1, $r4		;  16 bits. Shift down value.
+
+	; Set timing parameters (refresh off to avoid Guinness TR 83)
+_set_timing:
+	move.d   CONFIG_ETRAX_SDRAM_TIMING, $r1
+	and.d    ~(3 << reg_bif_core_rw_sdram_timing___ref___lsb), $r1
+	move.d   REG_ADDR(bif_core, regi_bif_core, rw_sdram_timing), $r0
+	move.d   $r1, [$r0]
+
+	; Issue NOP command
+	move.d REG_ADDR(bif_core, regi_bif_core, rw_sdram_cmd), $r5
+	moveq regk_bif_core_nop, $r1
+	move.d $r1, [$r5]
+
+	; Wait 200us
+	move.d   10000, $r2
+1:	bne      1b
+	subq     1, $r2
+
+	; Issue initialization command sequence
+	lapc     _sdram_commands_start, $r2
+	lapc     _sdram_commands_end,  $r3
+1:	clear.d  $r6
+	move.b   [$r2+], $r6	; Load command
+	or.d     $r4, $r6	; Add calculated mrs
+	move.d   $r6, [$r5]	; Write rw_sdram_cmd
+	; Wait 80 ns between each command
+	move.d	 4000, $r7
+2:	bne	 2b
+	subq	 1, $r7
+	cmp.d    $r2, $r3	; Last command?
+	bne      1b
+	nop
+
+	; Start refresh
+	move.d   CONFIG_ETRAX_SDRAM_TIMING, $r1
+	move.d   REG_ADDR(bif_core, regi_bif_core, rw_sdram_timing), $r0
+	move.d   $r1, [$r0]
+
+	; Initialization finished
+	ba       _sdram_commands_end
+	nop
+
+_sdram_commands_start:
+	.byte   regk_bif_core_pre ; Precharge
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_ref ; refresh
+	.byte   regk_bif_core_mrs ; mrs
+_sdram_commands_end: