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linux-next/arch/cris/arch-v32/mach-fs/dram_init.S
Jesper Nilsson 035e111f9a CRIS v32: Add new machine dependent files for Etrax-FS and Artpec-3.
The two chips are somewhat different, and needs different handling.
Adds handing of the dma, dram initialization, hardware settings, io,
memory arbiter and pinmux

Also moves the dma, dram initialization and io from CRIS v32 common files.
2008-02-08 11:06:23 +01:00

117 lines
3.4 KiB
ArmAsm

/*
* 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: