引言
ORPSoC的硬件平台是包含SD card controller控制器的，但是对应的linux里面却没有对应的linux的驱动程序，这使ORPSoC的SD card的使用收到了很大的限制。没有驱动，硬件是不能工作的，SD卡控制器的驱动，linux提供了非常好的framework,在写驱动时只要开发者=关心最底层的部分，就是和硬件直接打交道的部分，即linuxMMC framework的HOST部分。
本小节并不介绍linux的MMC的framework，而把注意力放在核心部分，即直接对硬件的操作，即写一个简单的linux driver来验证一下硬件的正确性。
1，linux的MMC/SD的framework
虽然本小节并不介绍符合linux MMC框架的SD卡控制器的驱动，但是作为必须了解的部分，会对编写真正的驱动有帮助，在此简单介绍一下。
如下图，整个框架分为三层，上面两层与硬件无关，有linux提供，下面一层（host）由用户编写，所以我们在编写SD卡控制器的驱动时，只需要填充实现HOST层的接口函数即可。
2，硬件部分
1>什么是SD Host 控制器，如下图：
2>ipcore的下载与例化：
ORPSoC的sd card控制器的ipcore可以在官网下载：
http://opencores.org/project,sdcard_mass_storage_controller
当然只下载下来是不能使用的，还要在挂在wishbone总线上才行，还用DMA的连线和中断连线，即例化工作。ORPSoC的例化工作已经做了，所以对于使用ORPSoC的，这部分工作就省掉了。
关于ORPSoC的中断使用情况，前面已经介绍过了，请参考：
http://blog.csdn.net/rill_zhen/article/details/8894856
关于ipcore的例化，前面也已经介绍过了，请参考：
http://blog.csdn.net/rill_zhen/article/details/8722664
和
http://blog.csdn.net/rill_zhen/article/details/8784510
以及
http://blog.csdn.net/rill_zhen/article/details/8849149
3>SD card controller的wishbone slave地址
要想控制SD卡控制器，必须要知道其对应的总线地址，如下图，为0x9e，即其设备起始地址为0x9e00_0000
4>SD卡控制器的中断号
通过之前对ORPSoC的中断系统的分析可知，SDC使用的中断号为14,15,16三个：
http://blog.csdn.net/rill_zhen/article/details/8894856
本小节并不处理SD卡控制器的中断部分。
3，软件部分
通过上面的分析之后，仔细看一下从官网下载ipcore时附带的datasheet，我们就可以开始编写一个简单的linux驱动了，本驱动只测试硬件的正确性。
关于如何编写ipcore的linux驱动，和具体的操作步骤，也已经介绍过了，请参考：
http://blog.csdn.net/rill_zhen/article/details/8700937
下面是code list:
1>sdcmsc.c:
/*
*Rill 130617
*rillzhen@gmail.com
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/blkdev.h>
#include <linux/ioport.h>
#include <asm/io.h>
#include "sdcmsc.h"
MODULE_LICENSE("Dual BSD/GPL");
#define MMC_BLOCK_MAJOR 179
void __iomem *sdcmsc_base = NULL;
static int sdcmsc_card_cmd(unsigned cmd, unsigned arg,
unsigned *response){
unsigned reg;
unsigned temp;
// printk(KERN_ALERT "OK before SDCMSC_COMMAND
");
// reg = ioread32(sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
// printk(KERN_ALERT "sdcmsc_int_status before:0x%x
",reg);
// Send command to card
cmd = le32_to_cpu(cmd);
iowrite32(cmd, sdcmsc_base + SDCMSC_COMMAND);
arg = le32_to_cpu(arg);
iowrite32(arg, sdcmsc_base + SDCMSC_ARGUMENT);
// printk(KERN_ALERT "OK after SDCMSC_ARGUMENT
");
// Wait for response
unsigned mask = SDCMSC_NORMAL_INT_STATUS_EI | SDCMSC_NORMAL_INT_STATUS_CC;
// printk(KERN_ALERT "CMD:%d, ARGUMENT:%d
", cmd, arg);
do {
reg = ioread32(sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
reg=cpu_to_le32(reg);
// printk(KERN_ALERT "reg:0x%x
",reg);
} while(!(reg&mask));
iowrite32(0, sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
printk(KERN_ALERT "OK after SDCMSC_NORMAL_INT_STATUS
");
//Optionally read response register
if(response) {
temp = ioread32(sdcmsc_base + SDCMSC_RESPONSE);
temp = cpu_to_le32(temp);
*response = temp;
}
// Check for errors
if(reg & SDCMSC_NORMAL_INT_STATUS_EI) {
printk(KERN_ALERT "Come on baby!
");
reg = ioread32(sdcmsc_base + SDCMSC_ERROR_INT_STATUS);
reg=cpu_to_le32(reg);
printk(KERN_ALERT "ERROR_INT_STATUS:0x%x
",reg);
if(reg & (1 << 3)) printk(KERN_ALERT "Command index error
");
if(reg & (1 << 1)) printk(KERN_ALERT "Command CRC error
");
if(reg & (1 << 0)) printk(KERN_ALERT "Command timeout
");
return 0;
}
else{
return 1;
}
}
int sdcmsc_card_init(void)
{
unsigned cmd;
unsigned reg;
unsigned arg;
int is_v20;
int is_sdhc;
unsigned rca;
unsigned card_capacity;
printk(KERN_ALERT "Before first iowrite32
");
// Set highest possible timeout
reg = le32_to_cpu(0xFFFE);
iowrite32(reg,sdcmsc_base + SDCMSC_TIMEOUT);
printk(KERN_ALERT "After first iowrite32
");
//Reset the peripheral
reg = le32_to_cpu(1);
iowrite32(reg, sdcmsc_base + SDCMSC_SOFTWARE_RESET);
reg = le32_to_cpu(2);
iowrite32(reg, sdcmsc_base + SDCMSC_CLOCK_DIVIDER);
reg = le32_to_cpu(0);
iowrite32(reg, sdcmsc_base + SDCMSC_SOFTWARE_RESET);
// iowrite32(0xFFFF, sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
// reg =ioread32(sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
// reg=cpu_to_le32(reg);
// printk(KERN_ALERT "Test Int_status:0x%x
", reg);
// iowrite32(0, sdcmsc_base + SDCMSC_NORMAL_INT_STATUS);
printk(KERN_ALERT "Ok at 1
");
//Send CMD0 to switch the card to idle state
cmd = SDCMSC_COMMAND_CMDI(0);
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
printk(KERN_ALERT "OK at 2
");
// Send CMD8 offering 2.7V to 3.6V range
// If the card doesn't response it means either:
// 1. Card supports v2.0 but can't communicate using current voltage levels
// 2. Card doesn't support v2.0
cmd = SDCMSC_COMMAND_CMDI(8) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
is_v20 = sdcmsc_card_cmd(cmd, 0x1AA, NULL);
if(is_v20)
printk(KERN_ALERT "This is sd version 2.0
");
else
printk(KERN_ALERT "This isn't sd version 2.0
");
do {
reg = ioread32(sdcmsc_base + SDCMSC_CARD_STATUS);
reg = cpu_to_le32(reg);
} while(reg & SDCMSC_CARD_STATUS_CICMD);
unsigned tCounter=0;
// Repeat ACMD41 until card set the busy bit to 1
// Since ACMD is an extended command, it must be preceded
// by CMD55
/* do {
printk(KERN_ALERT "%d times
",++tCounter);
cmd = SDCMSC_COMMAND_CMDI(55) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
cmd = SDCMSC_COMMAND_CMDI(41)
| SDCMSC_COMMAND_RTS_48;
arg = is_v20 ?
0x40FF8000 :
0x00FF8000;
if(!sdcmsc_card_cmd(cmd, arg, ®)) return 0;
} while(!(reg & 0x80000000));
printk(KERN_ALERT "Before is_sdhc!
");
is_sdhc = !!(reg & 0x40000000); */
is_sdhc=1;
// Issue CMD2 to switch from ready state to ident. Unfortunately, it is
// not possible to read whole CID because the command can be issued only
// once, and the peripheral can store only 32bit of the command at once.
cmd = SDCMSC_COMMAND_CMDI(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
printk(KERN_ALERT "after command 2
");
//Issue CMD3 to get RCA and switch from ident state to stby
cmd = SDCMSC_COMMAND_CMDI(3) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0, ®)) return 0;
rca = reg & 0xFFFF0000;
printk(KERN_ALERT "after command 3
");
//Calculate card capacity. Use information stored in CSD register.
if(is_sdhc) {
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(1) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, rca, ®)) return 0;
card_capacity = reg & 0x3F;
card_capacity <<=16;
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, rca, ®)) return 0;
reg >>=16;
card_capacity |= reg;
card_capacity +=1;
card_capacity *=1000;
}
else {
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(1) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, rca, ®)) return 0;
unsigned read_bl_len = (reg >>16) & 0x0F;
unsigned c_size = reg & 0x3FF;
c_size <<= 2;
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, rca, ®)) return 0;
c_size |= (reg >>30) & 0x03;
unsigned c_size_mult = (reg >> 15) & 0x07;
card_capacity = c_size + 1;
card_capacity *= 1 << (c_size_mult + 2);
card_capacity *= 1 << (read_bl_len);
card_capacity >>= 9;
}
// Put card in transfer state
cmd = SDCMSC_COMMAND_CMDI(7) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, rca, ®)) return 0;
if(reg != 0x700) return 0;
// Set block size to 512
cmd = SDCMSC_COMMAND_CMDI(16) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd ,512, NULL)) return 0;
// Set 4-bits bus mode
cmd = SDCMSC_COMMAND_CMDI(55) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, rca, NULL)) return 0;
cmd = SDCMSC_COMMAND_CMDI(6) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0x02, NULL)) return 0;
return 1;
}
static int ocores_sdcmsc_init(void)
{
int res;
res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
// if(res) return res;
printk(KERN_ALERT "test successfully before request_mem_region!
");
if(!request_mem_region(SDCMSC_BASE,SDCMSC_ADR_LEN,"ocores-sdcmsc"))
{
printk(KERN_ALERT "ocores-sdcmsc request_mem_region fails!");
return -1;
}
printk(KERN_ALERT "test successfully before request_mem_region!
");
sdcmsc_base = ioremap(SDCMSC_BASE,SDCMSC_ADR_LEN);
if(!sdcmsc_base)
{
printk(KERN_ALERT "ocores-sdcmsc ioremap failed!");
return -1;
}
printk(KERN_ALERT "test successfully after ioremap!
");
sdcmsc_card_init();
}
static void ocores_sdcmsc_exit(void)
{
unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
}
module_init(ocores_sdcmsc_init);
module_exit(ocores_sdcmsc_exit);
2>sdcmsc.h
/* *Rill 130617 *rillzhen@gmail.com */ // SDCMSC address space #define SDCMSC_BASE 0x9e000000 #define SDCMSC_ADR_LEN 0xa0 // Register space #define SDCMSC_ARGUMENT 0x00 #define SDCMSC_COMMAND 0x04 #define SDCMSC_CARD_STATUS 0x08 #define SDCMSC_RESPONSE 0x0C #define SDCMSC_CONTROLLER_SETTING 0x1C #define SDCMSC_BLOCK_SIZE 0x20 #define SDCMSC_POWER_CONTROL 0x24 #define SDCMSC_SOFTWARE_RESET 0x28 #define SDCMSC_TIMEOUT 0x2C #define SDCMSC_NORMAL_INT_STATUS 0x30 #define SDCMSC_ERROR_INT_STATUS 0x34 #define SDCMSC_NORMAL_INT_ENABLE 0x38 #define SDCMSC_ERROR_INT_ENABLE 0x3C #define SDCMSC_CAPABILITY 0x48 #define SDCMSC_CLOCK_DIVIDER 0x4C #define SDCMSC_BD_BUFFER_STATUS 0x50 #define SDCMSC_DAT_INT_STATUS 0x54 #define SDCMSC_DAT_INT_ENABLE 0x58 #define SDCMSC_BD_RX 0x60 #define SDCMSC_BD_TX 0x80 // SDCMSC_COMMAND bits #define SDCMSC_COMMAND_CMDI(x) (x << 8) #define SDCMSC_COMMAND_CMDW(x) (x << 6) #define SDCMSC_COMMAND_CICE 0x10 #define SDCMSC_COMMAND_CIRC 0x08 #define SDCMSC_COMMAND_RTS_48 0x02 #define SDCMSC_COMMAND_RTS_136 0x01 //SDCMSC_CARD_STATUS bits #define SDCMSC_CARD_STATUS_CICMD 0x01 // SDCMSC_NORMAL_INT_STATUS bits #define SDCMSC_NORMAL_INT_STATUS_EI 0x8000 #define SDCMSC_NORMAL_INT_STATUS_CC 0x0001 // SDCMSC_DAT_INT_STATUS #define SDCMSC_DAT_INT_STATUS_TRS 0x01
3>makefile
# #Rill 130617 #rillzhen@gmail.com # ifneq ($(KERNELRELEASE), ) obj-m := sdcmsc.o else KERNELDIR ?= /home/openrisc/soc-design/linux PWD := $(shell pwd) default: $(MAKE) -C $(KERNELDIR) M=$(PWD) modules ARCH=openrisc CROSS_COMPILE=or32-linux- clean: rm -rf .*.cmd *.o *.mod.c *.ko .tm_versions *.order *.symvers endif
4，验证结果
找一个小的sd卡，插到ORPSoC板子的SD卡插槽里面，
将驱动insmod到板子上，可以看到插入的SD卡的版本信息（v2.0），验证的后面几步没有成功，但是已经说明SD卡控制器是可以工作的，如下图:
5，需要注意的问题
在验证的过程中，一定注意以下两个问题：
1>大小端的问题：
ORPSoC的OpenRisc是大端的，但是ipcore内部是小端操作的，所以在控制ipcore时一定要做字节序（byteorder）的转换，这个问题在之前的blog中也提到过，调用函数如下：
cpu_to_le32() 和le32_to_cpu()
2>SD卡控制器命令的timeout：
尽量设置的大一点，如果太小，发送CMD就会超时（可以通过读取状态寄存器获得失败原因）。至于为什么出现这种情况，现在还不清楚。
6，小结
本小节只是对sd卡控制器的硬件的一个简单验证，并不是一个完整的SD卡控制器的linux驱动，但是能确定硬件的正确性，意义也是很大的。至于如何编写符合linux MMC/SD框架的驱动，那是另外的话题了，并且有很多资料可以参考，这里就不再赘述。
7，附录
ecos下的sd card controller的driver：
1>代码获取
SVN地址：可以用svn客户端下载。也可以下载整个ecos-3.0工程，以获得更多信息。
http://opencores.org/ocsvn/openrisc/openrisc/trunk/rtos/ecos-3.0/packages/devs/disk/opencores/sdcmsc/current/src/if_sdcmsc.c
如果不想安装svn，可以通过wensvn访问，地址如下：
2>codelist
如果连一个新窗口也懒得打开，那么版本为798时的代码如下：
if_sdcmsc.c：
//==========================================================================
//
// if_sdcmsc.c
//
// Provide a disk device driver for SDCard Mass Storage Controller
//
//==========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 2004, 2006 Free Software Foundation, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later
// version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author: Piotr Skrzypek
// Date: 2012-05-01
//
//####DESCRIPTIONEND####
//==========================================================================
#include <pkgconf/system.h>
#include <cyg/infra/cyg_type.h>
#include <cyg/infra/cyg_ass.h>
#include <cyg/infra/diag.h>
#include <cyg/hal/hal_arch.h>
#include <cyg/hal/hal_if.h>
#include <cyg/hal/hal_intr.h>
#include <string.h>
#include <errno.h>
#include <cyg/io/io.h>
#include <cyg/io/devtab.h>
#include <cyg/io/disk.h>
// Settings exported from CDL
#include <pkgconf/devs_disk_opencores_sdcmsc.h>
// SDCMSC address space
#define SDCMSC_BASE 0x9e000000
// Register space
#define SDCMSC_ARGUMENT 0x00
#define SDCMSC_COMMAND 0x04
#define SDCMSC_CARD_STATUS 0x08
#define SDCMSC_RESPONSE 0x0C
#define SDCMSC_CONTROLLER_SETTING 0x1C
#define SDCMSC_BLOCK_SIZE 0x20
#define SDCMSC_POWER_CONTROL 0x24
#define SDCMSC_SOFTWARE_RESET 0x28
#define SDCMSC_TIMEOUT 0x2C
#define SDCMSC_NORMAL_INT_STATUS 0x30
#define SDCMSC_ERROR_INT_STATUS 0x34
#define SDCMSC_NORMAL_INT_ENABLE 0x38
#define SDCMSC_ERROR_INT_ENABLE 0x3C
#define SDCMSC_CAPABILITY 0x48
#define SDCMSC_CLOCK_DIVIDER 0x4C
#define SDCMSC_BD_BUFFER_STATUS 0x50
#define SDCMSC_DAT_INT_STATUS 0x54
#define SDCMSC_DAT_INT_ENABLE 0x58
#define SDCMSC_BD_RX 0x60
#define SDCMSC_BD_TX 0x80
// SDCMSC_COMMAND bits
#define SDCMSC_COMMAND_CMDI(x) (x << 8)
#define SDCMSC_COMMAND_CMDW(x) (x << 6)
#define SDCMSC_COMMAND_CICE 0x10
#define SDCMSC_COMMAND_CIRC 0x08
#define SDCMSC_COMMAND_RTS_48 0x02
#define SDCMSC_COMMAND_RTS_136 0x01
//SDCMSC_CARD_STATUS bits
#define SDCMSC_CARD_STATUS_CICMD 0x01
// SDCMSC_NORMAL_INT_STATUS bits
#define SDCMSC_NORMAL_INT_STATUS_EI 0x8000
#define SDCMSC_NORMAL_INT_STATUS_CC 0x0001
// SDCMSC_DAT_INT_STATUS
#define SDCMSC_DAT_INT_STATUS_TRS 0x01
typedef struct cyg_sdcmsc_disk_info_t {
int is_v20;
int is_sdhc;
cyg_uint32 rca;
int connected;
} cyg_sdcmsc_disk_info_t;
static int sdcmsc_card_cmd(cyg_uint32 cmd,
cyg_uint32 arg,
cyg_uint32 *response) {
// Send command to card
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_COMMAND, cmd);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_ARGUMENT, arg);
// Wait for response
cyg_uint32 reg;
cyg_uint32 mask = SDCMSC_NORMAL_INT_STATUS_EI |
SDCMSC_NORMAL_INT_STATUS_CC;
do {
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_NORMAL_INT_STATUS, reg);
} while(!(reg & mask));
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_NORMAL_INT_STATUS, 0);
// Optionally read response register
if(response) {
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_RESPONSE, *response);
}
// Check for errors
if(reg & SDCMSC_NORMAL_INT_STATUS_EI) {
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_ERROR_INT_STATUS, reg);
if(reg & (1 << 3)) diag_printf("Command index error
");
if(reg & (1 << 1)) diag_printf("Command CRC error
");
if(reg & (1 << 0)) diag_printf("Command timeout
");
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_ERROR_INT_STATUS, 0);
return 0;
}
else {
return 1;
}
}
// Card initialization and identification implemented according to
// Physical Layer Simplified Specification Version 3.01
static int sdcmsc_card_init(cyg_sdcmsc_disk_info_t *data,
char *serial,
char *firmware_rev,
char *model_num,
cyg_uint32 *capacity) {
cyg_uint32 reg;
cyg_uint32 cmd;
cyg_uint32 arg;
// Send CMD0 to switch the card to idle state
cmd = SDCMSC_COMMAND_CMDI(0);
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
// Send CMD8 offering 2.7V to 3.6V range
// If the card doesn't responde it means either:
// 1. Card supports v2.0 but can't communicate using
// current voltage levels
// 2. Card does not support v2.0
cmd = SDCMSC_COMMAND_CMDI(8) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
data->is_v20 = sdcmsc_card_cmd(cmd, 0x1AA, NULL);
do {
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_CARD_STATUS, reg);
} while(reg & SDCMSC_CARD_STATUS_CICMD);
// Repeat ACMD41 until card set the busy bit to 1
// Since ACMD is an extended command, it must be preceded
// by CMD55
do {
cmd = SDCMSC_COMMAND_CMDI(55) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
cmd = SDCMSC_COMMAND_CMDI(41) |
SDCMSC_COMMAND_RTS_48;
arg = data->is_v20 ?
0x40FF8000 :
0x00FF8000;
if(!sdcmsc_card_cmd(cmd, arg, ®)) return 0;
} while(!(reg & 0x80000000));
data->is_sdhc = !!(reg & 0x40000000);
// Issue CMD2 to switch from ready state to ident. Unfortunately, it is
// not possible to read whole CID because the command can be issued only
// once, and the peripheral can store only 32bit of the command at once.
cmd = SDCMSC_COMMAND_CMDI(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, 0, NULL)) return 0;
// Issue CMD3 to get RCA and switch from ident state to stby.
cmd = SDCMSC_COMMAND_CMDI(3) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0, ®)) return 0;
data->rca = reg & 0xFFFF0000;
// Calculate card capacity. Use information stored in CSD register.
cyg_uint32 card_capacity;
if(data->is_sdhc) {
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(1) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
card_capacity = reg & 0x3F;
card_capacity <<= 16;
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
reg >>= 16;
card_capacity |= reg;
card_capacity += 1;
card_capacity *= 1000;
}
else {
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(1) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
cyg_uint32 read_bl_len = (reg >> 16) & 0x0F;
cyg_uint32 c_size = reg & 0x3FF;
c_size <<= 2;
cmd = SDCMSC_COMMAND_CMDI(9) |
SDCMSC_COMMAND_CMDW(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
c_size |= (reg >> 30) & 0x03;
cyg_uint32 c_size_mult = (reg >> 15) & 0x07;
card_capacity = c_size + 1;
card_capacity *= 1 << (c_size_mult + 2);
card_capacity *= 1 << (read_bl_len);
card_capacity >>= 9;
}
// Fill disk identification struct using information in CID register
// use OEM/APPlication ID field to fill model_num,
// Product revision field to fill firmware_rev,
// and Product serial number to field to fill serial
cmd = SDCMSC_COMMAND_CMDI(10) |
SDCMSC_COMMAND_CMDW(0) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
model_num[0] = (reg >> 16) & 0xFF;
model_num[1] = (reg >> 8) & 0xFF;
model_num[2] = 0;
cmd = SDCMSC_COMMAND_CMDI(10) |
SDCMSC_COMMAND_CMDW(2) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
firmware_rev[0] = (reg >> 24) & 0xFF;
firmware_rev[1] = 0;
serial[0] = (reg >> 16) & 0xFF;
serial[1] = (reg >> 8) & 0xFF;
serial[2] = reg & 0xFF;
cmd = SDCMSC_COMMAND_CMDI(10) |
SDCMSC_COMMAND_CMDW(3) |
SDCMSC_COMMAND_RTS_136;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
serial[3] = (reg >> 24) & 0xFF;
// Put card in transfer state
cmd = SDCMSC_COMMAND_CMDI(7) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, data->rca, ®)) return 0;
if(reg != 0x700) return 0;
// Set block size to 512
cmd = SDCMSC_COMMAND_CMDI(16) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 512, NULL)) return 0;
// Set 4-bits bus mode
cmd = SDCMSC_COMMAND_CMDI(55) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, data->rca, NULL)) return 0;
cmd = SDCMSC_COMMAND_CMDI(6) |
SDCMSC_COMMAND_CICE |
SDCMSC_COMMAND_CIRC |
SDCMSC_COMMAND_RTS_48;
if(!sdcmsc_card_cmd(cmd, 0x02, NULL)) return 0;
return 1;
}
static int sdcmsc_card_queue(cyg_sdcmsc_disk_info_t *data,
int direction_transmit,
int block_addr,
cyg_uint32 buffer_addr) {
// SDSC cards use byte addressing, while SDHC use block addressing.
// It is therefore required to multiply the address by 512 if
// we are dealing with SDSC card, to remain compatible with the API.
if(!data->is_sdhc) {
block_addr <<= 9;
}
if(direction_transmit) {
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_BD_TX, buffer_addr);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_BD_TX, block_addr);
}
else {
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_BD_RX, buffer_addr);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_BD_RX, block_addr);
}
// Now wait for the response
cyg_uint32 reg;
do {
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_DAT_INT_STATUS, reg);
} while(!reg);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_DAT_INT_STATUS, 0);
// Check for errors
if(reg == SDCMSC_DAT_INT_STATUS_TRS) {
return 1;
}
else {
if(reg & (1 << 5)) diag_printf("Transmission error
");
if(reg & (1 << 4)) diag_printf("Command error
");
if(reg & (1 << 2)) diag_printf("FIFO error
");
if(reg & (1 << 1)) diag_printf("Retry error
");
return 0;
}
}
// This is an API function. Is is called once, in the beginning
static cyg_bool sdcmsc_disk_init(struct cyg_devtab_entry* tab) {
// Set highest possible timeout
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_TIMEOUT, 0xFFFE);
// Reset the peripheral
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_SOFTWARE_RESET, 1);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_CLOCK_DIVIDER, 2);
HAL_WRITE_UINT32(SDCMSC_BASE + SDCMSC_SOFTWARE_RESET, 0);
// Call upper level
disk_channel* ch = (disk_channel*) tab->priv;
return (*ch->callbacks->disk_init)(tab);
}
// This function is called when user mounts the disk
static Cyg_ErrNo sdcmsc_disk_lookup(struct cyg_devtab_entry** tab,
struct cyg_devtab_entry *sub_tab,
const char* name) {
disk_channel *ch = (disk_channel*) (*tab)->priv;
cyg_sdcmsc_disk_info_t *data = (cyg_sdcmsc_disk_info_t*) ch->dev_priv;
// If the card was not initialized yet, it's time to do it
// and call disk_connected callback
if(!data->connected) {
cyg_disk_identify_t id;
// Pass dummy CHS geometry and hope the upper level
// will use LBA mode. To guess CHS we would need to
// analyze partition table and confront LBA and CHS
// addresses. And it would work only if proper LBA
// field is stored in MBR. Is is definitely something
// that should be done by upper level.
id.cylinders_num = 1;
id.heads_num = 1;
id.sectors_num = 1;
id.phys_block_size = 1;
id.max_transfer = 512;
// Initialize the card
data->connected = sdcmsc_card_init(data,
id.serial,
id.firmware_rev,
id.model_num,
&id.lba_sectors_num);
if(data->connected) {
// Let upper level know there is a new disk
(*ch->callbacks->disk_connected)(*tab, &id);
}
}
// Call upper level
return (*ch->callbacks->disk_lookup)(tab, sub_tab, name);
}
// API function to read block from the disk
static Cyg_ErrNo sdcmsc_disk_read(disk_channel* ch,
void* buf,
cyg_uint32 blocks,
cyg_uint32 first_block) {
cyg_sdcmsc_disk_info_t *data = (cyg_sdcmsc_disk_info_t*) ch->dev_priv;
int i;
int result;
cyg_uint32 reg;
for(i = 0; i < blocks; i++) {
// Check for free receive buffers
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_BD_BUFFER_STATUS, reg);
reg >>= 8;
reg &= 0xFF;
if(reg == 0) {
return -EIO;
}
result = sdcmsc_card_queue(data, 0, first_block, (cyg_uint32) buf);
if(!result) {
return -EIO;
}
}
return ENOERR;
}
// API function to write block to disk
static Cyg_ErrNo sdcmsc_disk_write(disk_channel* ch,
const void* buf,
cyg_uint32 blocks,
cyg_uint32 first_block) {
cyg_sdcmsc_disk_info_t *data = (cyg_sdcmsc_disk_info_t*) ch->dev_priv;
int i;
int result;
cyg_uint32 reg;
for(i = 0; i < blocks; i++) {
// Check for free transmit buffers
HAL_READ_UINT32(SDCMSC_BASE + SDCMSC_BD_BUFFER_STATUS, reg);
reg &= 0xFF;
if(reg == 0) {
return -EIO;
}
result = sdcmsc_card_queue(data, 1, first_block, (cyg_uint32) buf);
if(!result) {
return -EIO;
}
}
return ENOERR;
}
// API function to fetch driver configuration and disk info.
static Cyg_ErrNo sdcmsc_disk_get_config(disk_channel* ch,
cyg_uint32 key,
const void* buf,
cyg_uint32* len) {
CYG_UNUSED_PARAM(disk_channel*, ch);
CYG_UNUSED_PARAM(cyg_uint32, key);
CYG_UNUSED_PARAM(const void*, buf);
CYG_UNUSED_PARAM(cyg_uint32*, len);
return -EINVAL;
}
// API function to update driver status information.
static Cyg_ErrNo sdcmsc_disk_set_config(disk_channel* ch,
cyg_uint32 key,
const void* buf,
cyg_uint32* len) {
cyg_sdcmsc_disk_info_t *data = (cyg_sdcmsc_disk_info_t*) ch->dev_priv;
if(key == CYG_IO_SET_CONFIG_DISK_UMOUNT) {
if(ch->info->mounts == 0) {
data->connected = false;
return (ch->callbacks->disk_disconnected)(ch);
}
else {
return ENOERR;
}
}
else {
return -EINVAL;
}
}
// Register the driver in the system
static cyg_sdcmsc_disk_info_t cyg_sdcmsc_disk0_hwinfo = {
.connected = 0
};
DISK_FUNS(cyg_sdcmsc_disk_funs,
sdcmsc_disk_read,
sdcmsc_disk_write,
sdcmsc_disk_get_config,
sdcmsc_disk_set_config
);
DISK_CONTROLLER(cyg_sdcmsc_disk_controller_0, cyg_sdcmsc_disk0_hwinfo);
DISK_CHANNEL(cyg_sdcmsc_disk0_channel,
cyg_sdcmsc_disk_funs,
cyg_sdcmsc_disk0_hwinfo,
cyg_sdcmsc_disk_controller_0,
true, //mbr supported
4 //partitions
);
BLOCK_DEVTAB_ENTRY(cyg_sdcmsc_disk0_devtab_entry,
CYGDAT_DEVS_DISK_OPENCORES_SDCMSC_DISK0_NAME,
0,
&cyg_io_disk_devio,
&sdcmsc_disk_init,
&sdcmsc_disk_lookup,
&cyg_sdcmsc_disk0_channel);
// EOF if_sdcmsc.c
可以参考这个代码来完成后续的符合linux下MMC/SD framework的驱动的编写工作。
enjoy！