本文详细介绍了如何设计一个带有DMA功能的IP核心，并解决了虚实地址转换的问题。通过Linux驱动验证了虚实转换的正确性，确保了软件与硬件之间的数据一致性。
引言
之前，我们在讨论基于ORPSoC的ipcore设计时提到过DMA的问题，当时我们实现DMA的功能时，访问的是local memory，并没有使用主存（即外部的SDRAM），使用的是本地的一块存储区域。所以也就不存在虚实地址转换的问题。但是，要想实现一个规范的，通用的，真正意义上的附带有DMA功能的ipcore，虚实地址转换就是必须要解决的问题了。
比如，软件要vga controller通过DMA显示一帧图片，软件必须把这帧图片的物理地址告诉vga controller，但是软件中使用的都是虚拟地址，所以就必须做虚实地址转换操作才行，当然，vga controller模块有local TLB的除外，这里介绍的是外部ipcore共用主TLB。
关于之前带有DMA功能的ipcore的设计，请参考：
http://blog.youkuaiyun.com/rill_zhen/article/details/8784510
本小节就解决这个问题。
1，基本思想
1>整体介绍
本小节实现一个ipcore，实现与软件的存储器访问共享。
2>验证步骤
1》软件（驱动）使用virt_adr=kmalloc(4,GFP_DMA);获得一个虚拟地址。
2》将这个虚拟地址转换为物理地址：phy_adr=virt_to_phys(virt_adr);
3》软件向这个虚拟地址写值：*virt_adr=0x6789bcdf;
3》软件将这个物理地址发送给ipcore。
4》ipcore根据这个物理地址进行读取，获得这个地址的值
5》将两个值进行比较，确认虚拟地址和物理地址是否是同一块SDRAM区域。
6》将上述过程反过来，ipcore向物理地址写值（这个值软件事先知道），软件读对应的虚拟地址，然后进行对比。
2，硬件部分
1>硬件组成与操作步骤
基于ORPSoC平台，
1》编写slave模块，接受软件的指令，控制master模块；
2》编写master模块根据slave的控制来访存；
3》编写顶层模块mycore，instanceslave和master两个模块；
4》修改orpsoc_top.v例化mycore。
5》以上步骤在前面的blog中有详细的介绍，请参考，这里不再赘述。
2>代码实现
下面是RTL实现代码：
1》myslave.v
/*
*
* rill create 130618
* rillzhen@gmail.com
*/
module myslave
(
wb_clk,
wb_rst,
wb_dat_i,
wb_adr_i,
wb_sel_i,
wb_cti_i,
wb_bte_i,
wb_we_i,
wb_cyc_i,
wb_stb_i,
wb_dat_o,
wb_ack_o,
wb_err_o,
wb_rty_o,
address_o,
value_o,
write_o,
read_o,
write_ack,
read_ack,
value_ack
);
input wb_clk;
input wb_rst;
input [31:0] wb_adr_i;
input wb_stb_i;
input wb_cyc_i;
input [2:0] wb_cti_i;
input [1:0] wb_bte_i;
input [31:0] wb_dat_i;
input [3:0] wb_sel_i;
input wb_we_i;
output reg [31:0] wb_dat_o;
output reg wb_ack_o;
output wb_err_o;
output wb_rty_o;
output reg [31:0] address_o;
output reg [31:0] value_o;
output reg write_o;
output reg read_o;
input write_ack;
input read_ack;
input [31:0] value_ack;
parameter address_adr =8'h04;
parameter value_adr =8'h08;
parameter wr_adr =8'h18;
parameter write_done_adr =8'h0c;
parameter read_done_adr =8'h10;
parameter value_ack_adr =8'h14;
parameter err_code =32'habcd_1234;
parameter read_command =32'h0000_0002;
parameter write_command =32'h0000_0001;
parameter s_idle =9'b000000001;
parameter s_write_done =9'b000000010;
parameter s_read_done =9'b000000100;
parameter s_read =9'b000001000;
parameter s_write =9'b000010000;
parameter s_read_pause =9'b000100000;
parameter s_write_pause1 =9'b001000000;
parameter s_write_pause2 =9'b010000000;
parameter s_write_pause3 =9'b100000000;
reg [8:0] state,next_state;
reg [31:0] value_reg;
reg write_done;
reg read_done;
reg [31:0] address_reg;
reg [31:0] value_i_reg;
reg [31:0] wr_reg;
assign wb_err_o=0;
assign wb_rty_o=0;
always @(posedge wb_clk)
if(wb_rst)
state<=s_idle;
else
state<=next_state;
always @(*)
begin
case(state)
s_idle:
begin
if(write_ack)
next_state=s_write_done;
else if(read_ack)
next_state=s_read_done;
else if(wb_stb_i && wb_cyc_i && wb_we_i)
next_state=s_write;
else if(wb_stb_i && wb_cyc_i && !wb_we_i)
next_state=s_read;
else
next_state=s_idle;
end
s_write_done:
begin
next_state=s_idle;
end
s_read_done:
begin
next_state=s_idle;
end
s_write:
begin
next_state=s_write_pause1;
end
s_write_pause1:
begin
next_state=s_write_pause2;
end
s_read:
begin
next_state=s_read_pause;
end
s_read_pause:
begin
next_state=s_idle;
end
s_write_pause2:
begin
next_state=s_write_pause3;
end
s_write_pause3:
begin
next_state=s_idle;
end
default:
begin
next_state=s_idle;
end
endcase
end
always @(posedge wb_clk)
if(wb_rst)
begin
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
value_reg<=0;
read_done<=0;
write_done<=0;
address_reg<=0;
value_i_reg<=0;
wr_reg <=0;
wb_dat_o<=0;
wb_ack_o<=0;
end
else
begin
case(next_state)
s_idle:
begin
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
wb_dat_o<=0;
wb_ack_o<=0;
end
s_read_done:
begin
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
wb_dat_o<=0;
wb_ack_o<=0;
read_done<=1'b1;
value_reg<=value_ack;
end
s_write_done:
begin
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
wb_dat_o<=0;
wb_ack_o<=0;
write_done<=1'b1;
end
s_read:
begin
if(wb_adr_i[7:0] == value_ack_adr)
wb_dat_o<={value_reg[7:0],value_reg[15:8],value_reg[23:16],value_reg[31:24]};
else if(wb_adr_i[7:0] == write_done_adr)
wb_dat_o<=write_done;
else if(wb_adr_i[7:0] == read_done_adr)
wb_dat_o<=read_done;
else if(wb_adr_i[7:0] == address_adr)
wb_dat_o<={address_reg[7:0],address_reg[15:8],address_reg[23:16],address_reg[31:24]};
else if(wb_adr_i[7:0] == wr_adr)
wb_dat_o<=wr_reg;
else if(wb_adr_i[7:0] == value_adr)
wb_dat_o<=value_i_reg;
else
wb_dat_o<=wb_adr_i;
wb_ack_o<=0;
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
end
s_read_pause:
begin
wb_dat_o<=wb_dat_o;
wb_ack_o<=1'b1;
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
end
s_write:
begin
if(wb_adr_i[7:0]== address_adr)
address_reg<={wb_dat_i[7:0],wb_dat_i[15:8],wb_dat_i[23:16],wb_dat_i[31:24]};
else if(wb_adr_i[7:0] == value_adr)
value_i_reg<=wb_dat_i;
else if(wb_adr_i[7:0] == wr_adr)
wr_reg <= wb_dat_i;
wb_ack_o <=0;
wb_dat_o <=0;
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
end
s_write_pause1:
begin
if(wr_reg == read_command)
begin
read_o<=1'b1;
address_o<=address_reg;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
// address_reg<=0;
// wr_reg<=0;
// value_reg<=0;
// read_done<=0;
end
else if(wr_reg == write_command)
begin
write_o<=1'b1;
// address_o<={address_reg[7:0],address_reg[15:8],address_reg[23:16],address_reg[31:24]};
address_o<=address_reg;
value_o<=value_i_reg;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
// value_i_reg<=0;
// address_reg<=0;
// wr_reg <=0;
// write_done<=0;
end
else
begin
write_o<=0;
read_o<=0;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
address_o<=0;
value_o<=0;
end
end
s_write_pause2:
begin
if(wr_reg == read_command)
begin
read_o<=1'b1;
address_o<=address_reg;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
// address_reg<=0;
// wr_reg<=0;
// value_reg<=0;
// read_done<=0;
end
else if(wr_reg == write_command)
begin
write_o<=1'b1;
// address_o<={address_reg[7:0],address_reg[15:8],address_reg[23:16],address_reg[31:24]};
address_o<=address_reg;
value_o<=value_i_reg;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
// value_i_reg<=0;
// address_reg<=0;
// wr_reg <=0;
// write_done<=0;
end
else
begin
write_o<=0;
read_o<=0;
// wb_ack_o<=1'b1;
// wb_dat_o<=0;
address_o<=0;
value_o<=0;
end
end
s_write_pause3:
begin
if(wr_reg == read_command)
begin
read_o<=0;
address_o<=0;
wb_ack_o<=1'b1;
wb_dat_o<=0;
address_reg<=0;
wr_reg<=0;
value_reg<=0;
read_done<=0;
end
else if(wr_reg == write_command)
begin
write_o<=0;
address_o<=0;
value_o<=0;
wb_ack_o<=1'b1;
wb_dat_o<=0;
address_reg<=0;
wr_reg<=0;
value_i_reg<=0;
write_done<=0;
end
else
begin
write_o<=0;
read_o<=0;
wb_ack_o<=1'b1;
wb_dat_o<=0;
address_o<=0;
value_o<=0;
end
end
default:
begin
address_o<=0;
value_o <=0;
write_o <=0;
read_o <=0;
value_reg<=0;
read_done<=0;
write_done<=0;
address_reg<=0;
value_i_reg<=0;
wr_reg <=0;
wb_dat_o<=0;
wb_ack_o<=0;
end
endcase
end
endmodule
2》mymaster.v
/*
*
* rill create 130618
* rillzhen@gmail.com
*/
module mymaster
(
wb_clk,
wb_rst,
wb_adr_o,
wb_dat_o,
wb_sel_o,
wb_we_o,
wb_cyc_o,
wb_stb_o,
wb_cti_o,
wb_bte_o,
wb_dat_i,
wb_ack_i,
wb_err_i,
wb_rty_i,
write_i ,
read_i ,
address_i,
value_i ,
write_ack ,
read_ack,
value_o
);
//wishbone interface
input wb_clk;
input wb_rst;
input wb_ack_i;
input wb_err_i;
input wb_rty_i;
input [31:0] wb_dat_i;
output reg [31:0] wb_adr_o;
output reg [31:0] wb_dat_o;
output reg wb_cyc_o;
output reg wb_stb_o;
output reg [3:0] wb_sel_o;
output reg wb_we_o;
output reg [2:0] wb_cti_o;
output reg [1:0] wb_bte_o;
input write_i;
input read_i;
input [31:0] address_i;
input [31:0] value_i;
output reg [31:0] value_o;
output reg write_ack;
output reg read_ack;
parameter m_idle = 9'b000000001;
parameter m_write_ready = 9'b010000000;
parameter m_read_ready = 9'b100000000;
parameter m_write_begin = 9'b000000010;
parameter m_write_wait = 9'b000000100;
parameter m_write_done = 9'b000001000;
parameter m_read_begin = 9'b000010000;
parameter m_read_wait = 9'b000100000;
parameter m_read_done = 9'b001000000;
parameter cti_default = 3'b000;
parameter bte_default = 2'b00;
parameter sel_default = 4'b1111;
reg [8:0] state,next_state;
always @(posedge wb_clk)
if(wb_rst)
state<=m_idle;
else
state<=next_state;
always @(*)
case(state)
m_idle:
begin
if(write_i)
next_state=m_write_ready;
else if(read_i)
next_state=m_read_ready;
else
next_state=m_idle;
end
m_write_ready:
begin
next_state=m_write_begin;
end
m_read_ready:
begin
next_state=m_read_begin;
end
m_write_begin:
begin
next_state=m_write_wait;
end
m_write_wait:
begin
if(wb_ack_i)
next_state=m_write_done;
else
next_state=m_write_wait;
end
m_write_done:
begin
next_state=m_idle;
end
m_read_begin:
begin
next_state=m_read_wait;
end
m_read_wait:
begin
if(wb_ack_i)
next_state=m_read_done;
else
next_state=m_read_wait;
end
m_read_done:
begin
next_state=m_idle;
end
default:
begin
next_state=m_idle;
end
endcase
always @ (posedge wb_clk)
if(wb_rst)
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_sel_o<=sel_default;
wb_we_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_cti_o<=cti_default;
wb_bte_o<=bte_default;
write_ack<=0;
read_ack<=0;
value_o <=0;
end
else
begin
case(next_state)
m_idle:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_sel_o<=sel_default;
wb_we_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_cti_o<=cti_default;
wb_bte_o<=bte_default;
write_ack<=0;
read_ack<=0;
value_o <=0;
end
m_write_ready:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_we_o<=0;
end
m_read_ready:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_we_o<=0;
end
m_write_begin:
begin
wb_adr_o<=address_i;
wb_dat_o<=value_i;
wb_cyc_o<=1'b1;
wb_stb_o<=1'b1;
wb_we_o<=1'b1;
end
m_write_wait:
begin
wb_adr_o<=wb_adr_o;
wb_dat_o<=wb_dat_o;
wb_cyc_o<=wb_cyc_o;
wb_stb_o<=wb_stb_o;
wb_we_o<=wb_we_o;
end
m_write_done:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_we_o<=0;
write_ack<=1'b1;
end
m_read_begin:
begin
wb_adr_o<=address_i;
wb_dat_o<=0;
wb_cyc_o<=1'b1;
wb_stb_o<=1'b1;
wb_we_o<=0;
end
m_read_wait:
begin
wb_adr_o<=wb_adr_o;
wb_dat_o<=wb_dat_o;
wb_cyc_o<=wb_cyc_o;
wb_stb_o<=wb_stb_o;
wb_we_o <=0;
end
m_read_done:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_we_o<=0;
read_ack<=1'b1;
value_o<=wb_dat_i;
end
default:
begin
wb_adr_o<=0;
wb_dat_o<=0;
wb_sel_o<=sel_default;
wb_we_o<=0;
wb_cyc_o<=0;
wb_stb_o<=0;
wb_cti_o<=cti_default;
wb_bte_o<=bte_default;
write_ack<=0;
read_ack<=0;
value_o <=0;
end
endcase
end
endmodule
3》mycore.v
/*
*
* rill create 130618
* rillzhen@gmail.com
*/
module mycore
(
//===slave interface signals
wb_clk,
wb_rst,
wbs_d_mycore_dat_o,
wbs_d_mycore_ack_o,
wbs_d_mycore_err_o,
wbs_d_mycore_rty_o,
wbs_d_mycore_adr_i,
wbs_d_mycore_dat_i,
wbs_d_mycore_sel_i,
wbs_d_mycore_we_i,
wbs_d_mycore_cyc_i,
wbs_d_mycore_stb_i,
wbs_d_mycore_cti_i,
wbs_d_mycore_bte_i,
//===master interface signals
wbm_d_mycore_dat_i,
wbm_d_mycore_ack_i,
wbm_d_mycore_err_i,
wbm_d_mycore_rty_i,
wbm_d_mycore_adr_o,
wbm_d_mycore_dat_o,
wbm_d_mycore_sel_o,
wbm_d_mycore_we_o,
wbm_d_mycore_cyc_o,
wbm_d_mycore_stb_o,
wbm_d_mycore_cti_o,
wbm_d_mycore_bte_o
);
input wb_clk;
input wb_rst;
output [31:0] wbs_d_mycore_dat_o;
output wbs_d_mycore_ack_o;
output wbs_d_mycore_err_o;
output wbs_d_mycore_rty_o;
input [31:0] wbs_d_mycore_adr_i;
input [31:0] wbs_d_mycore_dat_i;
input [3:0] wbs_d_mycore_sel_i;
input wbs_d_mycore_we_i;
input wbs_d_mycore_cyc_i;
input wbs_d_mycore_stb_i;
input [2:0] wbs_d_mycore_cti_i;
input [1:0] wbs_d_mycore_bte_i;
input [31:0] wbm_d_mycore_dat_i;
input wbm_d_mycore_ack_i;
input wbm_d_mycore_err_i;
input wbm_d_mycore_rty_i;
output [31:0] wbm_d_mycore_adr_o;
output [31:0] wbm_d_mycore_dat_o;
output [3:0] wbm_d_mycore_sel_o;
output wbm_d_mycore_we_o;
output wbm_d_mycore_cyc_o;
output wbm_d_mycore_stb_o;
output [2:0] wbm_d_mycore_cti_o;
output [1:0] wbm_d_mycore_bte_o;
wire [31:0] address;
wire [31:0] value;
wire write;
wire read;
wire read_ack;
wire write_ack;
wire [31:0] value_ack;
myslave myslave0
(
.wb_clk(wb_clk),
.wb_rst(wb_rst),
.wb_adr_i(wbs_d_mycore_adr_i),
.wb_dat_i(wbs_d_mycore_dat_i),
.wb_sel_i(wbs_d_mycore_sel_i),
.wb_we_i(wbs_d_mycore_we_i),
.wb_cyc_i(wbs_d_mycore_cyc_i),
.wb_stb_i(wbs_d_mycore_stb_i),
.wb_cti_i(wbs_d_mycore_cti_i),
.wb_bte_i(wbs_d_mycore_bte_i),
.wb_dat_o(wbs_d_mycore_dat_o),
.wb_ack_o(wbs_d_mycore_ack_o),
.wb_err_o(wbs_d_mycore_err_o),
.wb_rty_o(wbs_d_mycore_rty_o),
.address_o(address),
.value_o(value),
.write_o(write),
.read_o(read),
.write_ack(write_ack),
.read_ack(read_ack),
.value_ack(value_ack)
);
mymaster mymaster0
(
.wb_clk (wb_clk),
.wb_rst (wb_rst),
.wb_adr_o (wbm_d_mycore_adr_o),
.wb_dat_o (wbm_d_mycore_dat_o),
.wb_sel_o (wbm_d_mycore_sel_o),
.wb_we_o (wbm_d_mycore_we_o),
.wb_cyc_o (wbm_d_mycore_cyc_o),
.wb_stb_o (wbm_d_mycore_stb_o),
.wb_cti_o (wbm_d_mycore_cti_o),
.wb_bte_o (wbm_d_mycore_bte_o),
.wb_dat_i (wbm_d_mycore_dat_i),
.wb_ack_i (wbm_d_mycore_ack_i),
.wb_err_i (wbm_d_mycore_err_i),
.wb_rty_i (wbm_d_mycore_rty_i),
//internal signals
.write_i (write),
.read_i (read),
.address_i (address),
.value_i (value),
.write_ack (write_ack),
.read_ack (read_ack),
.value_o (value_ack)
);
endmodule
/************** EOF ****************/
3，软件部分
1>介绍
为了测试虚实转换的正确性，编写ipcore的linux驱动是必须的，以实现之前介绍的验证步骤，软件部分的操作流程，前面已经介绍了。这里直接将代码贴在这里，一目了然。
细心的读者可能会发现，在给ipcore传数据的时候并没有做byteorder的转换（大小端的问题，之前反复提到过），这是因为之前对字节序的转换是驱动做的，这次是硬件做的（RTL里面增加了相应的逻辑，请仔细看硬件部分的代码便知），道理一样，不必疑惑。
2>代码实现
还跟之前的驱动一样，共三部分组成。
1》ip_mkg.c
/*
*
* rill mkg driver
*
*/
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <asm/uaccess.h> /* get_user and put_user */
//#include <linux/clk.h>
//#include <linux/ioport.h>
#include <asm/io.h> /*ioremap*/
#include <linux/platform_device.h> /*cleanup_module*/
#include <linux/delay.h>
#include <asm-generic/io.h>
#include "ip_mkg.h"
void __iomem *g_mkg_mem_base = NULL;
void __iomem *g_mkg_core_base = NULL;
static int device_open(struct inode *inode, struct file *file)
{
g_mkg_mem_base = ioremap(MKG_MEM_BASE,MKG_MEM_LEN);
g_mkg_core_base = ioremap (MKG_CORE_BASE, MKG_CORE_LEN);
if(NULL == g_mkg_mem_base)
{
printk(KERN_ERR "mkg mem open ioremap error!\n");
return -1;
}
else
{
printk("mkg mem ioremap addr:%d!\n",(int)g_mkg_mem_base);
}
if(NULL == g_mkg_core_base)
{
printk(KERN_ERR "mkg core open ioremap error!\n");
return -1;
}
else
{
printk("mkg core ioremap addr:%d!\n",(int)g_mkg_core_base);
}
return 0;
}
static int device_release(struct inode *inode, struct file *file)
{
return 0;
}
static ssize_t device_read(struct file *filp, char *buffer, size_t length, loff_t *offset)
{
/*int ret_val = 0;
char * data = NULL;
data = (char*)kmalloc(4, GFP_KERNEL);
if((ret_val = copy_from_user(new_regs, (struct reg_data*)ioctl_param, sizeof(struct reg_data))) != 0)
ioread32(g_mkg_mem_base+length);
printk("============read:%d\n",);*/
return 1;
}
static ssize_t device_write(struct file *filp, const char *buffer, size_t count, loff_t *offset)
{
//iowrite32(2,g_mkg_mem_base);
return 1;
}
long device_ioctl(struct file *file, unsigned int ioctl_num, unsigned long ioctl_param)
{
#if 0
int ret_val = 0;
unsigned int ret = 0;
struct reg_data *new_regs;
printk("ioctl======\n");
switch(ioctl_num)
{
case IOCTL_REG_SET:
{
new_regs = (struct reg_data*)kmalloc(sizeof(struct reg_data), GFP_KERNEL);
if((ret_val = copy_from_user(new_regs, (struct reg_data*)ioctl_param, sizeof(struct reg_data))) != 0)
{
kfree(new_regs);
printk(KERN_ERR " error copy line_datafrom user.\n");
return -1;
}
//iowrite16(new_regs->value,g_mkg_mem_base+new_regs->addr);
kfree(new_regs);
}
break;
case IOCTL_REG_GET:
{
new_regs = (struct reg_data*)kmalloc(sizeof(struct reg_data), GFP_KERNEL);
if((ret_val = copy_from_user(new_regs, (struct reg_data*)ioctl_param, sizeof(struct reg_data))) != 0)
{
kfree(new_regs);
printk(KERN_ERR " error copy line_datafrom user.\n");
return -1;
}
//ret = ioread16(g_mkg_mem_base+new_regs->addr);
kfree(new_regs);
return ret;
}
break;
}
#endif
return -1;
}
struct file_operations our_file_ops = {
.unlocked_ioctl = device_ioctl,
.read = device_read,
.write = device_write,
.open = device_open,
.release = device_release,
.owner = THIS_MODULE,
};
int ToBigEndian(int lit_End)
{
char * p=(char *)&lit_End;
return (int)(p[0]<<24)+(int)(p[1]<<16)+(int)(p[2]<<8)+(int)(p[3]);
}
void test(void)
{
unsigned int * virt_adr;
unsigned int phy_adr;
int write_done=0,read_done=0,read_value=0;
unsigned int final_phy_adr;
char *p;
int read=0;
virt_adr=kmalloc(4,GFP_DMA);
if(!virt_adr)
printk("apply for kernel memory fails !\n");
phy_adr=virt_to_phys(virt_adr);
printk("virtual address !0x%x \n ",virt_adr);
printk("original physical address !0x%x \n",phy_adr);
*virt_adr=0x6789bcdf;
final_phy_adr=phy_adr;
// final_phy_adr=0x98000040;
printk("final physical address !0x%x \n ",final_phy_adr);
// test begin
// write first number : final_phy_adr
printk("test begin \n write first number : final_phy_adr\n");
iowrite32(final_phy_adr,g_mkg_core_base+0x4);
printk("write address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("write address : 0x%x \n",read);
iowrite32(0x3956abcd,g_mkg_core_base+0x8);
printk("write value done !\n");
read=ioread32(g_mkg_core_base+0x8);
printk("write value : 0x%x \n",read);
iowrite32(0x01000000,g_mkg_core_base+0x18);
printk("write command done !\n");
printk("write two number: final_phy_adr+4 \n");
// write two number: final_phy_adr+4
iowrite32(final_phy_adr+4,g_mkg_core_base+0x4);
printk("write address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("write address : 0x%x \n",read);
iowrite32(0x3956abcd,g_mkg_core_base+0x8);
printk("write value done !\n");
read=ioread32(g_mkg_core_base+0x8);
printk("write value : 0x%x \n",read);
iowrite32(0x01000000,g_mkg_core_base+0x18);
printk("write command done !\n");
// write third number: final_phy_adr-4
printk("write third number: final_phy_adr-4 \n");
iowrite32(final_phy_adr-4,g_mkg_core_base+0x4);
printk("write address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("write address : 0x%x \n",read);
iowrite32(0x3956abcd,g_mkg_core_base+0x8);
printk("write value done !\n");
read=ioread32(g_mkg_core_base+0x8);
printk("write value : 0x%x \n",read);
iowrite32(0x01000000,g_mkg_core_base+0x18);
printk("write command done !\n");
// write forth number: 0x98000040
printk("write forth number: 98000040 \n");
iowrite32(0x98000040,g_mkg_core_base+0x4);
printk("write address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("write address : 0x%x \n",read);
iowrite32(0x3956abcd,g_mkg_core_base+0x8);
printk("write value done !\n");
read=ioread32(g_mkg_core_base+0x8);
printk("write value : 0x%x \n",read);
iowrite32(0x01000000,g_mkg_core_base+0x18);
printk("write command done !\n");
read=ioread32(g_mkg_core_base+0x18);
printk("write command : 0x%x \n",read);
write_done=ioread32(g_mkg_core_base+0x0c);
// read first number : final_phy_adr
printk("read first number : final_phy_adr\n");
iowrite32(final_phy_adr,g_mkg_core_base+0x4);
printk("read address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("read address : 0x%x \n",read);
iowrite32(0x02000000,g_mkg_core_base+0x18);
printk("read commnad done !\n");
read=ioread32(g_mkg_core_base+0x18);
printk("read command : 0x%x \n",read);
read_done=ioread32(g_mkg_core_base+0x10);
read_value=ioread32(g_mkg_core_base+0x14);
printk("<write_done flag: 0x%x >\n",write_done);
printk("<read from or1200: 0x%x >\n",*virt_adr);
printk("<read_done flag: 0x%x >\n",read_done);
printk("<read_value flag: 0x%x >\n",read_value);
printk(" read second number : final_phy_adr+4\n");
// read second number : final_phy_adr+4
iowrite32(final_phy_adr+4,g_mkg_core_base+0x4);
printk("read address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("read address : 0x%x \n",read);
iowrite32(0x02000000,g_mkg_core_base+0x18);
printk("read commnad done !\n");
read=ioread32(g_mkg_core_base+0x18);
printk("read command : 0x%x \n",read);
read_done=ioread32(g_mkg_core_base+0x10);
read_value=ioread32(g_mkg_core_base+0x14);
printk("<read_done flag: 0x%x >\n",read_done);
printk("<read_value flag: 0x%x >\n",read_value);
printk(" read third number : final_phy_adr-4\n");
// read third number : final_phy_adr-4
iowrite32(final_phy_adr-4,g_mkg_core_base+0x4);
printk("read address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("read address : 0x%x \n",read);
iowrite32(0x02000000,g_mkg_core_base+0x18);
printk("read commnad done !\n");
read=ioread32(g_mkg_core_base+0x18);
printk("read command : 0x%x \n",read);
read_done=ioread32(g_mkg_core_base+0x10);
read_value=ioread32(g_mkg_core_base+0x14);
printk("<read_done flag: 0x%x >\n",read_done);
printk("<read_value flag: 0x%x >\n",read_value);
printk(" read forth number : 0x98000040\n");
// read forth number : 0x98000040
iowrite32(0x98000040,g_mkg_core_base+0x4);
printk("read address done !\n");
read=ioread32(g_mkg_core_base+0x4);
printk("read address : 0x%x \n",read);
iowrite32(0x02000000,g_mkg_core_base+0x18);
printk("read commnad done !\n");
read=ioread32(g_mkg_core_base+0x18);
printk("read command : 0x%x \n",read);
read_done=ioread32(g_mkg_core_base+0x10);
read_value=ioread32(g_mkg_core_base+0x14);
printk("<read_done flag: 0x%x >\n",read_done);
printk("<read_value flag: 0x%x >\n",read_value);
}
int init_module()
{
int ret_val;
int ret;
int ret2;
void __iomem *ret_from_request;
void __iomem *ret_from_request2;
//=== Allocate character device
ret_val = register_chrdev(MAJOR_NUM, DEVICE_NAME, &our_file_ops);
if (ret_val < 0)
{
printk(KERN_ALERT " device %s failed(%d)\n", DEVICE_NAME, ret_val);
return ret_val;
}
ret = check_mem_region(MKG_MEM_BASE, MKG_MEM_LEN);
if (ret < 0)
{
printk(KERN_ERR "mkg check_mem_region bussy error!\n");
return -1;
}
ret_from_request = request_mem_region(MKG_MEM_BASE, MKG_MEM_LEN, "ip_mkg");
ret2 = check_mem_region(MKG_CORE_BASE, MKG_CORE_LEN);
if (ret2 < 0)
{
printk(KERN_ERR "mkg check_mem_region bussy error!\n");
return -1;
}
ret_from_request2 = request_mem_region(MKG_CORE_BASE, MKG_CORE_LEN, "ip_mkg");
//===ioremap mkg registers
g_mkg_mem_base = ioremap(MKG_MEM_BASE,MKG_MEM_LEN);
if(NULL == g_mkg_mem_base)
{
printk(KERN_ERR "mkg mem ioremap error!\n");
return -1;
}
else
{
;//printk("mkg ioremap addr:%d!\n",(unsigned int)g_mkg_mem_base);
}
g_mkg_core_base = ioremap(MKG_CORE_BASE,MKG_CORE_LEN);
if(NULL == g_mkg_core_base)
{
printk(KERN_ERR "mkg core ioremap error!\n");
return -1;
}
else
{
;//printk("mkg ioremap addr:%d!\n",(unsigned int)g_mkg_mem_base);
}
printk("mkg module init done!\n");
test();
return 0;
}
void cleanup_module()
{
release_mem_region(MKG_MEM_BASE, MKG_MEM_LEN);
release_mem_region(MKG_CORE_BASE,MKG_CORE_LEN);
unregister_chrdev(MAJOR_NUM, DEVICE_NAME);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rill zhen:rill_zhen@126.com");
2》ip_mkg.h
#ifndef __IP_MKG_H__
#define __IP_MKG_H__
#define MAJOR_NUM 102
#define DEVICE_NAME "ip_mkg"
#define MKG_MEM_BASE 0x98000000
#define MKG_MEM_LEN 3072
#define MKG_CORE_BASE 0x97000000
#define MKG_CORE_LEN 128
#define IOCTL_REG_SET 0
#define IOCTL_REG_GET 1
struct reg_data
{
unsigned short addr;
int value;
};
#endif
3》makefile
请参考之前的写法，要编译的文件不同而已。
4，验证
1>将修改后的ORPSoC的工程进行综合
2>编译驱动生成ko文件，在板子上进行测试验证
3>具体操作步骤，前面的blog中有详细介绍，请参考：
http://blog.youkuaiyun.com/rill_zhen/article/details/8849149
和
http://blog.youkuaiyun.com/rill_zhen/article/details/8700937
4>结果
因为截屏的话，一屏显示不完整，故只将打印输出信息保存，如下：
可以看出，软件（使用虚拟地址）和硬件（使用物理地址）的访存操作为同一地址。
Please press Enter to activate this console.
# mkdir nfs
# mount -t nfs -o nolock 192.168.1.101:/home/openrisc/nfs nfs
# cd nfs
# insmod ip_mkg.ko
mkg module init done!
virtual address !0xc1526010
original physical address !0x1526010
final physical address !0x1526010
test begin
write first number : final_phy_adr
write address done !
write address : 0x1526010
write value done !
write value : 0x3956abcd
write command done !
write two number: final_phy_adr+4
write address done !
write address : 0x1526014
write value done !
write value : 0x3956abcd
write command done !
write third number: final_phy_adr-4
write address done !
write address : 0x152600c
write value done !
write value : 0x3956abcd
write command done !
write forth number: 98000040
write address done !
write address : 0x98000040
write value done !
write value : 0x3956abcd
write command done !
write command : 0x0
read first number : final_phy_adr
read address done !
read address : 0x1526010
read commnad done !
read command : 0x0
<write_done flag: 0x0 >
<read from or1200: 0xcdab5639 >
<read_done flag: 0x1000000 >
<read_value flag: 0xcdab5639 >
read second number : final_phy_adr+4
read address done !
read address : 0x1526014
read commnad done !
read command : 0x0
<read_done flag: 0x1000000 >
<read_value flag: 0xcdab5639 >
read third number : final_phy_adr-4
read address done !
read address : 0x152600c
read commnad done !
read command : 0x0
<read_done flag: 0x1000000 >
<read_value flag: 0xcdab5639 >
read forth number : 0x98000040
read address done !
read address : 0x98000040
read commnad done !
read command : 0x0
<read_done flag: 0x1000000 >
<read_value flag: 0xcdab5639 >
#
5，小结
虚实地址转换的问题解决了，中断的问题也解决了（请参考http://blog.youkuaiyun.com/rill_zhen/article/details/8894856），那么设计一个完整的具有DMA功能的ipcore，问题就不大了。
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