|
|
本帖最后由 zc_fly 于 2014-8-19 16:53 编辑
5 \3 T& ~5 ?. \. s% V
3 s7 ^9 U# k `/ t$ G$ \3 bOMAPL138的ARM端对共享区内存进行直接访问,代码如下所示:#include <stdio.h>
! u t/ e* n5 B: O- t3 |% g) ^#include <unistd.h>
# n( ?- {+ |2 v1 W! n#include <sys/mman.h>! g! O1 r+ I3 H4 a- A' b
#include <sys/types.h>5 k4 f* O$ m: h" @0 w( j6 P
#include <fcntl.h>
0 l" U# H$ g5 ?4 }) R \( e( {) w" P8 _2 U8 @9 q5 P
#define SHAER_RAM_BASE_ADDR (0x80000000) % f5 r1 p; n4 f: _
6 {: X# A! } i# A; _+ Xtypedef struct
: H* c4 @. o; c{
# i2 Z1 {* a. ~* ? unsigned int a;7 T, f% r5 F. B
unsigned int b;) G4 Z8 u1 x9 | }3 N
unsigned int packet_cout;, `3 u6 ^' X$ M; D( x
}RX_MSG_PROTOCOL, *pRX_MSG_PROTOCOL;
# r" g1 u! I9 P2 i" f
* l$ P O7 ~7 `; u5 c0 r" u8 Xvoid read_MSG_buffer(pRX_MSG_PROTOCOL pshreRAM);" u3 P6 @9 d2 R' V8 ?: F9 g
unsigned int count_copy = 0;
, O" ? }6 a; J. Y2 X0 [" N
+ b6 z5 m; c* f
+ v, b/ V- r0 K; O* l" c3 Yint main()
: ~( ]/ }2 n6 D7 q0 x3 Y{
+ d5 b/ [$ [1 ]1 H pRX_MSG_PROTOCOL pshreRAM = NULL;( u* q. s0 t5 b: M. B3 H- N
pshreRAM = (pRX_MSG_PROTOCOL)SHAER_RAM_BASE_ADDR;
; \' P! V3 A* S& a3 Y1 N* j
: T! ]. W9 C+ R5 u1 z) [3 c while(1)- E! e# z# u" ?4 Q+ @# j
{
3 a' f/ y$ f# K3 m) o- f read_MSG_buffer(pshreRAM);
7 _- G4 ^% V" `) h7 b$ {3 | } @& U8 q; k( S7 e! x- _
}
8 a5 J+ J P6 s8 {
* ^0 `$ N. k9 N" y; [void read_MSG_buffer(pRX_MSG_PROTOCOL pshreRAM) [4 T8 H9 q7 j' b+ Y2 v
{, k l. c" u2 G) Z" `5 a1 ^9 ~! X
RX_MSG_PROTOCOL buf;
! J2 P- w5 n% p3 J8 L; _
4 V2 F! g) [+ |# b S6 _ buf.a = pshreRAM->a;
( X ^7 C. U2 g5 K, }/ L buf.b = pshreRAM->b;- B' W; T4 N. N/ N
buf.packet_cout = pshreRAM->packet_cout;4 K# z/ p1 [7 b8 S5 |
" A: I( W* }" h d* E! b5 m if(buf.packet_cout != count_copy)
- s/ o8 |) Y7 [ O( B {! e1 c* _& L7 X8 C4 U$ x5 \/ i% c" d
printf("a is %d\n", buf.a);
* n$ d5 c- Z7 T8 P printf("b is %d\n", buf.b);
# k% I! v/ k8 t printf("count is %d\n", buf.packet_cout);) S( H: @0 \8 b( q0 r$ V, S* A) W
count_copy = buf.packet_cout;
6 {. Y) A$ \9 h8 g9 O7 l4 K0 z }
, P3 P( N# d8 ^' _5 ^7 e+ x else" r1 R* y/ @4 d1 C$ u
{- R. }- I1 ?2 m) |& Z3 H, E7 Q/ A u5 i8 x
printf("No effective message!");
# Q7 ` D- f' G0 B# v. O& O$ p0 \ }, x* |0 _+ r; N G( F- o$ p' E
}
, E( ?$ S6 v0 Y) R& p1 e& A7 F$ w1 V. V& l3 R
4 v5 o. @6 ]9 X1 [" J. ~" }; U但是出现segmentation fault的问题,这是什么原因啊???我在DSP端烧写了一段小程序,向共享区0x80000000位置写入数据,用CCS 测试发现写入成功。
8 I3 _: D5 f2 y; I8 p6 A8 L7 ?使用下面代码,对内存使用了mmap函数后:# y5 A% ^, z# z' R/ \6 F; a
#include <stdio.h>4 U9 q Q+ S) l& Y2 h
#include <unistd.h>
% \! _1 n0 N ^' I) T6 r4 C: j#include <sys/mman.h>
( l& H) I y3 }#include <sys/types.h># A8 m3 P* B u# l# F
#include <fcntl.h>" A3 }+ q s# E" |2 }% r
7 \/ W" p; t% f* N: o: v! o4 P#define SHAER_RAM_BASE_ADDR (0x80000000), }$ _% m, H; N
#define SHAER_RAM_SIZE (0x20000)
9 A+ Y& x' M6 F8 z- _% @
5 g6 |8 x: z6 M, z/ _* J+ [typedef struct
/ T$ r1 D# u! z) J' s{
, @$ p$ b' h$ N+ y4 j. m0 O- s unsigned int a;
6 j* s/ h7 o! _$ i0 y6 e! h unsigned int b;- y+ {6 l8 m, _2 ^
unsigned int packet_cout;8 M# \# r5 B4 A% V0 H# `* K
}RX_MSG_PROTOCOL, *pRX_MSG_PROTOCOL;8 a* `6 c. Y, W2 I3 j' c5 e* _: f
! ~# n9 _, U+ F! t. r0 a* w X/ x4 wvoid read_MSG_buffer(int *baseaddr);
% y* A3 T1 f+ Z {/ L* Runsigned int count_copy = 0;& u) d5 Z+ Q `# v" |
7 L4 H) `" i" c$ D: Y0 `* L
int main()
8 w% j( W! Q- r Q{
. J I& l6 H) W7 X k int fd;
4 H6 ?* N( @- C1 \ int *mem = NULL;; E8 J7 k, L s
- k5 j- L. |) f- p- D if((fd = open("/dev/mem", O_RDWR)) <0)
! w9 L/ t J1 ` x0 ?7 c {# B' F$ H, ~$ [5 C& e( L/ Q7 a
perror("open error");
- M) l" ^2 N8 G return -1;
& t. a. c' `4 O! P, C }) w; ~# H( I* ?7 w7 F( h
0 W4 W( u8 L* _* Q8 y* O1 u7 a mem = mmap((void *)SHAER_RAM_BASE_ADDR, SHAER_RAM_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
H1 Z8 w8 V3 g+ T! b! X( w2 o0 ^( k6 R, Y9 [& L& j1 y
while(1)
, H* Q6 W7 g2 x1 w4 O3 ^ {
- f* E! W4 h6 c read_MSG_buffer(mem);) U, ~- F. t7 y7 |+ q
}
5 f7 @' F6 E) @8 N7 M}
- d3 A! m% d( X7 F3 H5 S1 r7 W0 E9 R. Y+ G. W+ V4 r/ n
void read_MSG_buffer(int *baseaddr)) n$ x' W. q: V9 e+ m& T
{# G1 {9 g9 A+ O" ?
pRX_MSG_PROTOCOL pshreRAM = NULL;1 s: {4 L+ r' y- P9 l6 U& w4 `: ~
& Z9 w; g d- b( ^4 _
pshreRAM = (pRX_MSG_PROTOCOL)baseaddr; y* S6 r, Q- L1 L- K
5 D7 U1 i5 m. l7 `
if(pshreRAM->packet_cout != count_copy)
V& V& T6 K' |& ?5 k9 Y {$ E. [7 S) w9 B
printf("a is %d\n", pshreRAM->a);
* H/ f1 S) }. R) {3 y printf("b is %d\n", pshreRAM->b);
% t* z) k- c: B printf("count is %d\n", pshreRAM->packet_cout);
: w0 x9 M a3 P/ G count_copy = pshreRAM->packet_cout;
% O. ^7 C1 Z2 |1 |4 C, O' h5 ] }2 F- N F( ^2 u6 U/ I& ?7 A
else
8 o# d5 ^6 P4 ?7 q {2 A! r7 k" n: A) r/ x
printf("No effective message!\n");3 G& f6 \! k" N) M0 D
}
4 ?6 J: z) S5 l; ]}# L5 H* z! x% n7 J: \5 m
: j- V/ k8 \! [/ Q. [" M! E
没有出现segmentation fault这个错误,但是读出来的数据均为0。这该怎样解决啊???主要问题还是在Linux系统下,OMAPL138是否可以直接访问映射地址???该怎样实现???
" D% M! W: G& w" y5 U$ Z! f; [7 x) P
) ?8 N4 ?. T# t9 [% d
' b2 x5 x# p$ d# V* L b9 J8 S
5 d9 n' v$ U1 [; c |
|