AM335x通过GPMC接口与FPGA通讯驱动问题

一步一步做应该是没问题的，我按照那个步骤做过

没出现你说的这个问题

你是怎么把GPMC驱动程序添加到board-am335xevm.c文件中的

pinmux初始化是要放在board-am335xevm.c中的。

整个驱动加载是要按照Linux的驱动加载方法做的，建议你去网上找一些驱动加载的例程学习下

你好，我将pinmux初始化添加到board-am335xev.c中，在/driver目录下新建文件夹fpga，在里面添加fpga.c  Kconfig   Makefile三个文件。

fpag.c内容为：

/*
Char device driver fpga.
Do a global replace of 'fpga' with your driver name.
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/gpio.h>

#include <plat/gpmc.h>
#include "plat/gpio.h"
#include "plat/dma.h"

#include "asm/uaccess.h"
#include "asm/io.h"
#include "asm/atomic.h"

#include <linux/io.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <mach/gpio.h>
#include <plat/mux.h>


#define USER_BUFF_SIZE 128


struct fpga_dev {
dev_t devt;
struct cdev cdev;
struct semaphore sem;
struct class *class;
char *user_buff;
};

static struct fpga_dev fpga_dev;

unsigned long mem_base;
static void __iomem *fpga_base;
static void __iomem *gpmc_base;

/* GPMC register offsets */
#define GPMC_REVISION 0x00
#define GPMC_SYSCONFIG 0x10
#define GPMC_SYSSTATUS 0x14
#define GPMC_IRQSTATUS 0x18
#define GPMC_IRQENABLE 0x1c
#define GPMC_TIMEOUT_CONTROL 0x40
#define GPMC_ERR_ADDRESS 0x44
#define GPMC_ERR_TYPE 0x48
#define GPMC_CONFIG 0x50
#define GPMC_STATUS 0x54
#define GPMC_PREFETCH_CONFIG1 0x1e0
#define GPMC_PREFETCH_CONFIG2 0x1e4
#define GPMC_PREFETCH_CONTROL 0x1ec
#define GPMC_PREFETCH_STATUS 0x1f0
#define GPMC_ECC_CONFIG 0x1f4
#define GPMC_ECC_CONTROL 0x1f8
#define GPMC_ECC_SIZE_CONFIG 0x1fc
#define GPMC_ECC1_RESULT 0x200
#define GPMC_ECC_BCH_RESULT_0 0x240

#define GPMC_BASE_ADDR 0x50000000
#define GPMC_CS 1
#define GPMC_CS0 0x60
#define GPMC_CS_SIZE 0x30
#if 0
#define STNOR_GPMC_CONFIG1 0x28601000
#define STNOR_GPMC_CONFIG2 0x00011001
#define STNOR_GPMC_CONFIG3 0x00020201
#define STNOR_GPMC_CONFIG4 0x08031003
#define STNOR_GPMC_CONFIG5 0x000f1111
#define STNOR_GPMC_CONFIG6 0x0f030080
#endif
#define STNOR_GPMC_CONFIG1 0x00000000
#define STNOR_GPMC_CONFIG2 0x001e1f00
#define STNOR_GPMC_CONFIG3 0x001f1f00
#define STNOR_GPMC_CONFIG4 0x1f03ff31
#define STNOR_GPMC_CONFIG5 0x001c1f1f
#define STNOR_GPMC_CONFIG6 0x8f070080
#define STNOR_GPMC_CONFIG7 0x00000050
static const u32 gpmc_nor[7] = {
STNOR_GPMC_CONFIG1,
STNOR_GPMC_CONFIG2,
STNOR_GPMC_CONFIG3,
STNOR_GPMC_CONFIG4,
STNOR_GPMC_CONFIG5,
STNOR_GPMC_CONFIG6,
STNOR_GPMC_CONFIG7
};

static ssize_t fpga_write(struct file *filp, const char __user *buff,size_t count, loff_t *f_pos)
{
ssize_t status;
size_t len = USER_BUFF_SIZE - 1;
int i,tmp;

if (count == 0)
return 0;

if (down_interruptible(&fpga_dev.sem))
return -ERESTARTSYS;

if (len > count)
len = count;

memset(fpga_dev.user_buff, 0, USER_BUFF_SIZE);

if (copy_from_user(fpga_dev.user_buff, buff, len)) {
status = -EFAULT;
goto fpga_write_done;
}

/* do something with the user data */

printk("fpga_write \n");
for (i = 0; i < len; i=i+2) {
//tmp = fpga_dev.user_buff | fpga_dev.user_buff[i+1] << 8;
tmp = fpga_dev.user_buff[i];
writew(tmp,fpga_base+i);
}

for (i = 0; i < len; i++) {
printk("0x%x ",fpga_dev.user_buff);
}

printk("\n");

fpga_write_done:

up(&fpga_dev.sem);

return status;
}

static ssize_t fpga_read(struct file *filp, char __user *buff,
size_t count, loff_t *offp)
{
printk("fpga_read \n");
ssize_t status;
size_t len;
// int i,tmp;

/*
Generic user progs like cat will continue calling until we
return zero. So if *offp != 0, we know this is at least the
second call.
*/
if (*offp > 0)
return 0;

if (down_interruptible(&fpga_dev.sem))
return -ERESTARTSYS;

strcpy(fpga_dev.user_buff, "fpga driver data goes here\n");

len = strlen(fpga_dev.user_buff);

if (len > count)
len = count;

if (copy_to_user(buff, fpga_dev.user_buff, len)) {
status = -EFAULT;
goto fpga_read_done;
}

fpga_read_done:

up(&fpga_dev.sem);

return status;
}

static int fpga_open(struct inode *inode, struct file *filp)
{
int status = 0;
printk(KERN_ALERT "dan fpga_open()\n");
if (down_interruptible(&fpga_dev.sem))
return -ERESTARTSYS;

if (!fpga_dev.user_buff) {
fpga_dev.user_buff = kmalloc(USER_BUFF_SIZE, GFP_KERNEL);

if (!fpga_dev.user_buff) {
printk(KERN_ALERT "fpga_open: user_buff alloc failed\n");
status = -ENOMEM;
}
}

up(&fpga_dev.sem);

return status;
}

static const struct file_operations fpga_fops = {
.owner = THIS_MODULE,
.open = fpga_open,
.read = fpga_read,
.write = fpga_write,
};

static int __init fpga_init_cdev(void)
{
int error;
u32 val;
printk(KERN_ALERT"dan_fpga_init_cdev()\n");
fpga_dev.devt = MKDEV(0, 0);

error = alloc_chrdev_region(&fpga_dev.devt, 0, 1, "fpga");
if (error) {
printk(KERN_ALERT "alloc_chrdev_region() failed: %d\n", error);
return error;
}

cdev_init(&fpga_dev.cdev, &fpga_fops);
fpga_dev.cdev.owner = THIS_MODULE;

error = cdev_add(&fpga_dev.cdev, fpga_dev.devt, 1);
if (error) {
printk(KERN_ALERT "cdev_add() failed: %d\n", error);
unregister_chrdev_region(fpga_dev.devt, 1);
return error;
}

printk("Getting Chip Select\n");

// val = 0xf64;
// gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG7, val);
//gpmc_base = ioremap(GPMC_BASE_ADDR, SZ_4K);
if (gpmc_cs_request(GPMC_CS, SZ_4K, (unsigned long *)&mem_base) < 0){
printk(KERN_ERR "Failed request for GPMC mem for usrp_e\n");
return -1;
}
printk("Got CS0, address = %lx\n", mem_base);

val = gpmc_read_reg(GPMC_REVISION);
printk("GPMC revision %d.%d\n", (val >> 4) & 0x0f, val & 0x0f);


gpmc_write_reg(GPMC_IRQENABLE, 0);
gpmc_write_reg(GPMC_TIMEOUT_CONTROL, 0);


gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG1, gpmc_nor[0]);
gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG2, gpmc_nor[1]);
gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG3, gpmc_nor[2]);
gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG4, gpmc_nor[3]);
gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG5, gpmc_nor[4]);
gpmc_cs_write_reg(GPMC_CS, GPMC_CS_CONFIG6, gpmc_nor[5]);

val = gpmc_cs_read_reg(GPMC_CS, GPMC_CS_CONFIG7);
printk("GPMC_CS_CONFIG7 value 0x%x\n", val);

#if 0
if (gpmc_cs_request(GPMC_CS, SZ_2K, (unsigned long *)&mem_base) < 0){
printk(KERN_ERR "Failed request for GPMC mem for usrp_e\n");
return -1;
}

printk("Got CS0, address = %lx\n", mem_base);
#endif
#if 0
if (!request_mem_region(mem_base, SZ_2K, "mem_fpga")) {
printk(KERN_ERR "Request_mem_region failed.\n");
gpmc_cs_free(GPMC_CS);
return -1;
}
#endif
fpga_base = ioremap(mem_base, SZ_4K);




return 0;
}

static int __init fpga_init_class(void)
{
struct device *device;

fpga_dev.class = class_create(THIS_MODULE, "fpga");

if (IS_ERR(fpga_dev.class)) {
printk(KERN_ALERT "class_create(fpga) failed\n");
return PTR_ERR(fpga_dev.class);
}

device = device_create(fpga_dev.class, NULL, fpga_dev.devt, NULL,
"fpga");

if (IS_ERR(device)) {
class_destroy(fpga_dev.class);
return PTR_ERR(device);
}

return 0;
}

static int __init fpga_init(void)
{
printk(KERN_INFO "fpga_init()\n");

memset(&fpga_dev, 0, sizeof(struct fpga_dev));

sema_init(&fpga_dev.sem, 1);

if (fpga_init_cdev())
goto init_fail_1;

if (fpga_init_class())
goto init_fail_2;

return 0;

init_fail_2:
cdev_del(&fpga_dev.cdev);
unregister_chrdev_region(fpga_dev.devt, 1);

init_fail_1:

return -1;
}
module_init(fpga_init);

static void __exit fpga_exit(void)
{
printk(KERN_INFO "fpga_exit()\n");

device_destroy(fpga_dev.class, fpga_dev.devt);
class_destroy(fpga_dev.class);

cdev_del(&fpga_dev.cdev);
unregister_chrdev_region(fpga_dev.devt, 1);

release_mem_region(mem_base, SZ_2K);
gpmc_cs_free(GPMC_CS);
iounmap(fpga_base);

if (fpga_dev.user_buff)
kfree(fpga_dev.user_buff);
}
module_exit(fpga_exit);


MODULE_AUTHOR("dan");
MODULE_DESCRIPTION("fpga driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION("0.1");

Kongfig中内容为：

menu MENU_FPGA
config FPGA
tristate "Fpga"
---help---
This is ARM Fpga driver file
endmenu

Makefile中内容为：

obj-$(CONFIG_FPGA)          += fpga.o

然后修改/drivers中的Kcongfig和Makefile文件。

在menuconfig图形配置界面中选中添加的fpga驱动

运行：make ARCH=arm CROSS_COMPILE=arm-arago-linux-gnueabi- uImage

将生成的uImage拷贝到SD卡中，结果出现以下错误

Unable to handle kernel NULL pointer dereference at virtual address 00000010
[ 1.041913] pgd = c0004000
[ 1.044746] [00000010] *pgd=00000000
[ 1.048478] Internal error: Oops: 5 [#1]
[ 1.052562] Modules linked in:
[ 1.055750] CPU: 0 Not tainted (3.2.0 #9)
[ 1.060305] PC is at gpmc_cs_request+0x68/0x160
[ 1.065037] LR is at fpga_init+0x100/0x298
[ 1.069306] pc : [<c0021abc>] lr : [<c05c1ba8>] psr: 80000013
[ 1.069313] sp : cf81df18 ip : cf81df60 fp : cf81df5c
[ 1.081273] r10: 01000000 r9 : 00000000 r8 : 00000000
[ 1.086717] r7 : c0640c6c r6 : c06648e8 r5 : 00000000 r4 : 00000001
[ 1.093518] r3 : 00000001 r2 : c06648e8 r1 : 00000000 r0 : 00000001
[ 1.100322] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 1.107939] Control: 10c5387d Table: 80004019 DAC: 00000015
[ 1.113926] Process swapper (pid: 1, stack limit = 0xcf81c2f0)
[ 1.120004] Stack: (0xcf81df18 to 0xcf81e000)
[ 1.124544] df00: 00000000 00000000
[ 1.133071] df20: 00000000 c05c1aa8 cf81df4c cf81df38 c042186c c0664890 00000001 c055c928
[ 1.141599] df40: 00000000 00000000 00000000 c05c1aa8 cf81df84 cf81df60 c05c1ba8 c0021a60
[ 1.150126] df60: c055b3f8 00000000 c0640700 c05d9644 cf81c000 00000000 cf81dfdc cf81df88
[ 1.158654] df80: c000876c c05c1ab4 c0074ecc c00f6a80 0000007f c00f68fc cf81dfbc 32318e78
[ 1.167181] dfa0: 00000037 00000000 cf81dfc4 0000018c c06078e0 c05d954c c05d9644 c0040388
[ 1.175708] dfc0: 00000013 00000000 00000000 00000000 cf81dff4 cf81dfe0 c059c884 c000873c
[ 1.184235] dfe0: 00000000 c059c7e8 00000000 cf81dff8 c0040388 c059c7f4 afe7ef95 cb83f1ce
[ 1.192755] Backtrace:
[ 1.195316] [<c0021a54>] (gpmc_cs_request+0x0/0x160) from [<c05c1ba8>] (fpga_init+0x100/0x298)
[ 1.204301] [<c05c1aa8>] (fpga_init+0x0/0x298) from [<c000876c>] (do_one_initcall+0x3c/0x180)
[ 1.213185] r7:00000000 r6:cf81c000 r5:c05d9644 r4:c0640700
[ 1.219113] [<c0008730>] (do_one_initcall+0x0/0x180) from [<c059c884>] (kernel_init+0x9c/0x130)
[ 1.228195] [<c059c7e8>] (kernel_init+0x0/0x130) from [<c0040388>] (do_exit+0x0/0x67c)
[ 1.236444] r5:c059c7e8 r4:00000000
[ 1.240178] Code: e1a0aa13 e35a0201 83e0800b 8afffff1 (e5952010)
[ 1.246581] ---[ end trace 1987bd5a2a5c8fca ]---
[ 1.251405] Kernel panic - not syncing: Attempted to kill init!
[ 1.257584] Backtrace:
[ 1.260162] [<c0017978>] (dump_backtrace+0x0/0x110) from [<c04216a0>] (dump_stack+0x18/0x1c)
[ 1.268967] r6:c05fc1f4 r5:c05fc1f4 r4:c0641648 r3:c05fabc8
[ 1.274902] [<c0421688>] (dump_stack+0x0/0x1c) from [<c0421710>] (panic+0x6c/0x1a0)
[ 1.282900] [<c04216a4>] (panic+0x0/0x1a0) from [<c0040934>] (do_exit+0x5ac/0x67c)
[ 1.290788] r3:cf81bd24 r2:cf81dcfc r1:cf81dcfc r0:c050df10
[ 1.296710] r7:cf81bc00
[ 1.299357] [<c0040388>] (do_exit+0x0/0x67c) from [<c0017c68>] (die+0x128/0x2d8)
[ 1.307072] r7:cf81dd6a
[ 1.309722] [<c0017b40>] (die+0x0/0x2d8) from [<c001a2f4>] (__do_kernel_fault+0x7c/0x8c)
[ 1.318172] [<c001a278>] (__do_kernel_fault+0x0/0x8c) from [<c001a458>] (do_page_fault+0x154/0x1f0)
[ 1.327608] r8:00000005 r7:00000005 r6:00000010 r5:cf81ded0 r4:00000000
[ 1.334437] r3:cf81ded0
[ 1.337177] [<c001a304>] (do_page_fault+0x0/0x1f0) from [<c001a604>] (do_translation_fault+0xa4/0xa8)
[ 1.346804] [<c001a560>] (do_translation_fault+0x0/0xa8) from [<c00083a4>] (do_DataAbort+0x3c/0xa0)
[ 1.356240] r7:00000005 r6:c05e06bc r5:00000010 r4:00000005
[ 1.362169] [<c0008368>] (do_DataAbort+0x0/0xa0) from [<c0013e58>] (__dabt_svc+0x38/0x60)
[ 1.370701] Exception stack(0xcf81ded0 to 0xcf81df18)
[ 1.375975] dec0: 00000001 00000000 c06648e8 00000001
[ 1.384512] dee0: 00000001 00000000 c06648e8 c0640c6c 00000000 00000000 01000000 cf81df5c
[ 1.393047] df00: cf81df60 cf81df18 c05c1ba8 c0021abc 80000013 ffffffff
[ 1.399939] r8:00000000 r7:cf81df04 r6:ffffffff r5:80000013 r4:c0021abc
[ 1.406963] [<c0021a54>] (gpmc_cs_request+0x0/0x160) from [<c05c1ba8>] (fpga_init+0x100/0x298)
[ 1.415957] [<c05c1aa8>] (fpga_init+0x0/0x298) from [<c000876c>] (do_one_initcall+0x3c/0x180)
[ 1.424850] r7:00000000 r6:cf81c000 r5:c05d9644 r4:c0640700
[ 1.430771] [<c0008730>] (do_one_initcall+0x0/0x180) from [<c059c884>] (kernel_init+0x9c/0x130)
[ 1.439855] [<c059c7e8>] (kernel_init+0x0/0x130) from [<c0040388>] (do_exit+0x0/0x67c)
[ 1.448115] r5:c059c7e8 r4:00000000

程序失败，请问是什么原因，谢谢。

xiangzhen meng 你好，问题解决了吗？我现在也遇到同样的问题，另我用的是CS2-FPGA, CS0-NAND;

CS2的CONFIG配置如下：

#define STNOR_GPMC_CONFIG1 0x00001010 
#define STNOR_GPMC_CONFIG2 0x0002020f 
#define STNOR_GPMC_CONFIG3 0x0002020f 
#define STNOR_GPMC_CONFIG4 0x000f000f
#define STNOR_GPMC_CONFIG5 0x00031f1f 
#define STNOR_GPMC_CONFIG6 0x04000fc2
#define STNOR_GPMC_CONFIG7 0x00000f40

一当去加载fpga.ko模块式在执行gpmc_cs_request后就出现同样的奔溃问题

Unable to handle kernel NULL pointer dereference at virtual address 00000010

....

请问改怎么解决呀

这种情况一般是和NAND的空间分配出现冲突，最好能把FPGA分配到的基地址打印出来

比较命令啊 你的代码中有空指针啊

“Unable to handle kernel NULL pointer dereference at virtual address 00000010”