汇编初始化SDRAM详解1~2

《朱老师物联网大讲堂》学习笔记

学习地址:www.zhulaoshi.org


汇编初始化SDRAM


在这里,我们的那个链接脚本中想要重定位的地址修改了,这个地址是SDRAM中的地址,

修改为0x20000000


在我们那个start.S文件中,我们在开关icache和重定位代码之间,增加了初始化SDRAM的代码,

是通过函数sdram_asm_init来实现的,

在正式讲解这个函数之前,先说明一下,

汇编实现的函数,返回要手动去做,

比如可以这样:mov pc, lr


DDR的初始化和SOC(里面的DDR控制器)有关,比如寄存器,

也和开发板使用的DDR芯片有关,不过这个问题不大,因为芯片标准比较一致,而且一般都是原厂给设置参数,

和开发板设计时的连接方式也有关,比如我们这里是4片内存芯片,不过连接方式和对内存需要会有所不同。


初始化步骤在数据手册里面,

有27个步骤,见P598.


在我们这个S5PV210开发板上,初始化分DRAM0 和DRAM1


下面的图就是设置步骤,步骤还是挺多的,不过里面涉及时序等的计算,其实已经不是我们这里的主题了。

汇编初始化SDRAM详解1~2_第1张图片


汇编初始化SDRAM详解1~2_第2张图片


下面是DRAM初始化的代码,很多,而且由于很多参数,我们难以去计算,

都是参考原厂提供的代码,因此能看多少是多少,

#include "s5pv210.h"

#if 1
#define DMC0_MEMCONTROL		0x00202400 	// MemControl	BL=4, 1Chip, DDR2 Type, dynamic self refresh, force precharge, dynamic power down off

#define DMC0_MEMCONFIG_0	0x20F01323	// MemConfig0	256MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
#define DMC0_MEMCONFIG_1	0x30F00312	// MemConfig1		默认值

#define DMC0_TIMINGA_REF	0x00000618	// TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4E)
#define DMC0_TIMING_ROW		0x28233287	// TimingRow	for @200MHz
#define DMC0_TIMING_DATA	0x23240304	// TimingData	CL=3
#define	DMC0_TIMING_PWR		0x09C80232	// TimingPower

#define	DMC1_MEMCONTROL		0x00202400	// MemControl	BL=4, 2 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off

#define DMC1_MEMCONFIG_0	0x40F01323	// MemConfig0	512MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
#define DMC1_MEMCONFIG_1	0x60E00312	// MemConfig1

#define DMC1_TIMINGA_REF	0x00000618	// TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4
#define DMC1_TIMING_ROW		0x28233289	// TimingRow	for @200MHz
#define DMC1_TIMING_DATA	0x23240304	// TimingData	CL=3
#define	DMC1_TIMING_PWR		0x08280232	// TimingPower

#endif

#if 0

#define DMC0_MEMCONTROL		0x00212400 	// MemControl	BL=4, 1Chip, DDR2 Type, dynamic self refresh, force precharge, dynamic power down off

#define DMC0_MEMCONFIG_0	0x20E01323	// MemConfig0	512MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
#define DMC0_MEMCONFIG_1	0x40F01323	// MemConfig1

#define DMC0_TIMINGA_REF	0x00000618	// TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4E)
#define DMC0_TIMING_ROW		0x28233287	// TimingRow	for @200MHz
#define DMC0_TIMING_DATA	0x23240304	// TimingData	CL=3
#define	DMC0_TIMING_PWR		0x09C80232	// TimingPower

#define	DMC1_MEMCONTROL		0x00202400	// MemControl	BL=4, 2 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off

#define DMC1_MEMCONFIG_0	0x40C01323	// MemConfig0	512MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
#define DMC1_MEMCONFIG_1	0x00E01323	// MemConfig1

#define DMC1_TIMINGA_REF	0x00000618	// TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4
#define DMC1_TIMING_ROW		0x28233289	// TimingRow	for @200MHz
#define DMC1_TIMING_DATA	0x23240304	// TimingData	CL=3
#define	DMC1_TIMING_PWR		0x08280232	// TimingPower


#endif



.global sdram_asm_init

sdram_asm_init:	
	ldr	r0, =0xf1e00000
	ldr	r1, =0x0
	str	r1, [r0, #0x0]
	像这种寄存器的设置,你在数据手册中,
	找不到有意义的描述,
	可以理解为怎么设置都行?

	/* DMC0 Drive Strength (Setting 2X) */
	设置IO端口驱动强度,
	总线的物理表现就是很多个引脚,
	设置合适的驱动以抗干扰,
	数据手册P200
	
	ldr	r0, =ELFIN_GPIO_BASE
	此处ro = 0xE0200000,
	可以理解为定了一个基地址,
	还有很多类似的宏定义在我们的.h文件里面
	#include "s5pv210.h"
	
	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_0DRV_SR_OFFSET]		
	0xAAAA = 1010 1010 1010 1010
	高16位,没说,就设为0吧,
	寄存器中对应0b10,就是2X,
	这里设置为多少,我们无从去计算判断,
	只能参考官方给出的参考代码,
	
	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_1DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_2DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_3DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_4DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_5DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_6DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP1_7DRV_SR_OFFSET]

	ldr	r1, =0x00002AAA
	str	r1, [r0, #MP1_8DRV_SR_OFFSET]

	
	/* DMC1 Drive Strength (Setting 2X) */
	
	ldr	r0, =ELFIN_GPIO_BASE
	
	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_0DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_1DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_2DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_3DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_4DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_5DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_6DRV_SR_OFFSET]

	ldr	r1, =0x0000AAAA
	str	r1, [r0, #MP2_7DRV_SR_OFFSET]

	ldr	r1, =0x00002AAA
	str	r1, [r0, #MP2_8DRV_SR_OFFSET]
	这些驱动强度的设置,设置方法都是一样的,
	
	
	/* DMC0 initialization at single Type*/
	设置时钟,对着手册来看这些值,看都对应吧
	这里的功能主要是开启DLL(dram pll)
	然后等待锁存,
	对应27步中的2~4步。
注意00101000这个数值,你怎么样从数据手册中看到,	
	ldr	r0, =APB_DMC_0_BASE

	ldr	r1, =0x00101000				@PhyControl0 DLL parameter setting, manual 0x00101000
	str	r1, [r0, #DMC_PHYCONTROL0]
  	
	ldr	r1, =0x00000086				@PhyControl1 DLL parameter setting, LPDDR/LPDDR2 Case
	str	r1, [r0, #DMC_PHYCONTROL1]

	ldr	r1, =0x00101002				@PhyControl0 DLL on
	str	r1, [r0, #DMC_PHYCONTROL0]

	ldr	r1, =0x00101003				@PhyControl0 DLL start
	str	r1, [r0, #DMC_PHYCONTROL0]

find_lock_val:
	ldr	r1, [r0, #DMC_PHYSTATUS]		@Load Phystatus register value
	and	r2, r1, #0x7
	cmp	r2, #0x7				@Loop until DLL is locked
	bne	find_lock_val
	
	and	r1, #0x3fc0 
	mov	r2, r1, LSL #18
	orr	r2, r2, #0x100000
	orr	r2 ,r2, #0x1000	
		
	orr	r1, r2, #0x3				@Force Value locking
	str	r1, [r0, #DMC_PHYCONTROL0]
	
#if 0	/* Memory margin test 10.01.05 */
	orr	r1, r2, #0x1				@DLL off
	str	r1, [r0, #DMC_PHYCONTROL0]
#endif
	/* setting DDR2 */
	ldr	r1, =0x0FFF2010				@ConControl auto refresh off
	str	r1, [r0, #DMC_CONCONTROL]

	ldr	r1, =DMC0_MEMCONTROL			@MemControl BL=4, 1 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off
	str	r1, [r0, #DMC_MEMCONTROL]
	
	ldr	r1, =DMC0_MEMCONFIG_0			@MemConfig0 256MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
	str	r1, [r0, #DMC_MEMCONFIG0]

	ldr	r1, =DMC0_MEMCONFIG_1			@MemConfig1
	str	r1, [r0, #DMC_MEMCONFIG1]

	ldr	r1, =0xFF000000				@PrechConfig
	str	r1, [r0, #DMC_PRECHCONFIG]
	
	ldr	r1, =DMC0_TIMINGA_REF			@TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4E)
	str	r1, [r0, #DMC_TIMINGAREF]
	
	ldr	r1, =DMC0_TIMING_ROW			@TimingRow	for @200MHz
	str	r1, [r0, #DMC_TIMINGROW]

	ldr	r1, =DMC0_TIMING_DATA			@TimingData	CL=3
	str	r1, [r0, #DMC_TIMINGDATA]
	
	ldr	r1, =DMC0_TIMING_PWR			@TimingPower
	str	r1, [r0, #DMC_TIMINGPOWER]

	ldr	r1, =0x07000000				@DirectCmd	chip0 Deselect
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x01000000				@DirectCmd	chip0 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00020000				@DirectCmd	chip0 EMRS2
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00030000				@DirectCmd	chip0 EMRS3
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010400				@DirectCmd	chip0 EMRS1 (MEM DLL on, DQS# disable)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00000542				@DirectCmd	chip0 MRS (MEM DLL reset) CL=4, BL=4
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01000000				@DirectCmd	chip0 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05000000				@DirectCmd	chip0 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05000000				@DirectCmd	chip0 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00000442				@DirectCmd	chip0 MRS (MEM DLL unreset)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010780				@DirectCmd	chip0 EMRS1 (OCD default)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010400				@DirectCmd	chip0 EMRS1 (OCD exit)
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x07100000				@DirectCmd	chip1 Deselect
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01100000				@DirectCmd	chip1 PALL
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00120000				@DirectCmd	chip1 EMRS2
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00130000				@DirectCmd	chip1 EMRS3
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00110400				@DirectCmd	chip1 EMRS1 (MEM DLL on, DQS# disable)
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00100542				@DirectCmd	chip1 MRS (MEM DLL reset) CL=4, BL=4
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x01100000				@DirectCmd	chip1 PALL
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x05100000				@DirectCmd	chip1 REFA
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x05100000				@DirectCmd	chip1 REFA
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00100442				@DirectCmd	chip1 MRS (MEM DLL unreset)
	str	r1, [r0, #DMC_DIRECTCMD]
	
	ldr	r1, =0x00110780				@DirectCmd	chip1 EMRS1 (OCD default)
	str	r1, [r0, #DMC_DIRECTCMD]
		
	ldr	r1, =0x00110400				@DirectCmd	chip1 EMRS1 (OCD exit)
	str	r1, [r0, #DMC_DIRECTCMD]
		
	ldr	r1, =0x0FF02030				@ConControl	auto refresh on
	str	r1, [r0, #DMC_CONCONTROL]
		
	ldr	r1, =0xFFFF00FF				@PwrdnConfig
	str	r1, [r0, #DMC_PWRDNCONFIG]
		
	ldr	r1, =0x00202400				@MemControl	BL=4, 2 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off
	str	r1, [r0, #DMC_MEMCONTROL]
	
// 上面是DRAM0初始化步骤
/*******************************************************************************************/	
// 下面是DRAM1初始化步骤,两者没有联系,是并列的。

	/* DMC1 initialization */
	ldr	r0, =APB_DMC_1_BASE
	ldr	r1, =0x00101000				@Phycontrol0 DLL parameter setting
	str	r1, [r0, #DMC_PHYCONTROL0]

	
	ldr	r1, =0x00000086				@Phycontrol1 DLL parameter setting
	str	r1, [r0, #DMC_PHYCONTROL1]
	ldr	r1, =0x00101002				@PhyControl0 DLL on
	str	r1, [r0, #DMC_PHYCONTROL0]
	ldr	r1, =0x00101003				@PhyControl0 DLL start
	str	r1, [r0, #DMC_PHYCONTROL0]
	
	
	
find_lock_val1:
	ldr	r1, [r0, #DMC_PHYSTATUS]		@Load Phystatus register value
	and	r2, r1, #0x7
	cmp	r2, #0x7				@Loop until DLL is locked
	bne	find_lock_val1
	
	and	r1, #0x3fc0 
	mov	r2, r1, LSL #18
	orr	r2, r2, #0x100000
	orr	r2, r2, #0x1000
		
	orr	r1, r2, #0x3				@Force Value locking
	str	r1, [r0, #DMC_PHYCONTROL0]
	
#if 0	/* Memory margin test 10.01.05 */
	orr	r1, r2, #0x1				@DLL off
	str	r1, [r0, #DMC_PHYCONTROL0]
#endif

	/* settinf fot DDR2 */
	ldr	r0, =APB_DMC_1_BASE

	ldr	r1, =0x0FFF2010				@auto refresh off
	str	r1, [r0, #DMC_CONCONTROL]

	ldr	r1, =DMC1_MEMCONTROL			@MemControl	BL=4, 2 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off
	str	r1, [r0, #DMC_MEMCONTROL]

	ldr	r1, =DMC1_MEMCONFIG_0			@MemConfig0	512MB config, 8 banks,Mapping Method[12:15]0:linear, 1:linterleaved, 2:Mixed
	str	r1, [r0, #DMC_MEMCONFIG0]

	ldr	r1, =DMC1_MEMCONFIG_1			@MemConfig1
	str	r1, [r0, #DMC_MEMCONFIG1]

	ldr	r1, =0xFF000000
	str	r1, [r0, #DMC_PRECHCONFIG]

	ldr	r1, =DMC1_TIMINGA_REF			@TimingAref	7.8us*133MHz=1038(0x40E), 100MHz=780(0x30C), 20MHz=156(0x9C), 10MHz=78(0x4
	str	r1, [r0, #DMC_TIMINGAREF]

	ldr	r1, =DMC1_TIMING_ROW			@TimingRow	for @200MHz
	str	r1, [r0, #DMC_TIMINGROW]

	ldr	r1, =DMC1_TIMING_DATA			@TimingData	CL=3
	str	r1, [r0, #DMC_TIMINGDATA]

	ldr	r1, =DMC1_TIMING_PWR			@TimingPower
	str	r1, [r0, #DMC_TIMINGPOWER]


	ldr	r1, =0x07000000				@DirectCmd	chip0 Deselect
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01000000				@DirectCmd	chip0 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00020000				@DirectCmd	chip0 EMRS2
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00030000				@DirectCmd	chip0 EMRS3
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010400				@DirectCmd	chip0 EMRS1 (MEM DLL on, DQS# disable)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00000542				@DirectCmd	chip0 MRS (MEM DLL reset) CL=4, BL=4
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01000000				@DirectCmd	chip0 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05000000				@DirectCmd	chip0 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05000000				@DirectCmd	chip0 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00000442				@DirectCmd	chip0 MRS (MEM DLL unreset)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010780				@DirectCmd	chip0 EMRS1 (OCD default)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00010400				@DirectCmd	chip0 EMRS1 (OCD exit)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x07100000				@DirectCmd	chip1 Deselect
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01100000				@DirectCmd	chip1 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00120000				@DirectCmd	chip1 EMRS2
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00130000				@DirectCmd	chip1 EMRS3
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00110440				@DirectCmd	chip1 EMRS1 (MEM DLL on, DQS# disable)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00100542				@DirectCmd	chip1 MRS (MEM DLL reset) CL=4, BL=4
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x01100000				@DirectCmd	chip1 PALL
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05100000				@DirectCmd	chip1 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x05100000				@DirectCmd	chip1 REFA
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00100442				@DirectCmd	chip1 MRS (MEM DLL unreset)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00110780				@DirectCmd	chip1 EMRS1 (OCD default)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x00110400				@DirectCmd	chip1 EMRS1 (OCD exit)
	str	r1, [r0, #DMC_DIRECTCMD]

	ldr	r1, =0x0FF02030				@ConControl	auto refresh on
	str	r1, [r0, #DMC_CONCONTROL]

	ldr	r1, =0xFFFF00FF				@PwrdnConfig	
	str	r1, [r0, #DMC_PWRDNCONFIG]

	ldr	r1, =DMC1_MEMCONTROL			@MemControl	BL=4, 2 chip, DDR2 type, dynamic self refresh, force precharge, dynamic power down off
	str	r1, [r0, #DMC_MEMCONTROL]
	// 函数返回
	mov pc, lr






下面是dram相关数据手册的一些资料,

The controller includes an advanced embeddedscheduler(调度器) to utilize(使用) memory device efficiently and an optimized(最佳化)pipeline(流水线)stage(阶段) to minimize latency(延迟)


Compatible(兼容) with JEDEC DDR2, low power DDR and low power DDR2 SDRAMspecification(规范)


Supports QoSscheme(方案) to ensure low latency for some applications


Supports excellent chip/bankinterleaving(交错) and memory interrupting


Supports outstanding exclusive(暂且解释为:专用的,独家的) accesses


An Initialization procedure consists of PHY(物理的) DLL initialization,


the controller must assert(维护) and hold CKE to a logic low level. 


bit-fields(字段,位域)


13. Confirm whether stable clock isissued(发出) minimum 200us after power on


17. Issue an EMRS2command using the DirectCmd register to program(设置,编排) the operating parameters(参数).


26. If there are two external memory chips, perform(执行) steps 14~25 for chip1 memory device.

 If OCD calibration(校准) is not used, issue an EMRS command to set OCD Calibration Default.


The difference between the linear(线性) mapping(映射) method and the interleaved(交叉存取) method is that the bank and
row order is different.


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