Hi,
I am working adding support of parallel port of ST16C552 in u-boot but have some weird initialization problems.So I list my related programs and questions as follows for any further help.
***Problems*** 1. How come board_parallel_init became invalid when I put it in lib_ppc/board.c board_init_f() for debugging?
2. Why could I only get 0x00 or 0xff initialization results for the parallel port-PD0-PD7 when I changed par_port->pr1 in ns16552.c as different values like 0x55 or 0xAA?It seemed that the PR register only accpected 0x00 or 0xff as it's first value.But I could change it's value correctly by u-boot command.
3. What's meaning of "__attribute__ ((packed))" in NS16552 structure definition?I copyed it from ns16550.h but don't understand it's function.
***16C552 parallel port register content*** u-boot>md fa010000 fa010000: ff67e0e0 ff67e0e0 ff67e0e0 ff67e0e0 .g fa010010: ff67e0e0 ff67e0e0 ff67e0e0 ff67e0e0 .g u-boot>mm.b fa010000 fa010000: ff ? 55 fa010001: 67 ? 55 fa010002: e0 ? e4 fa010003: e4 ? e4 fa010004: 55 ? . u-boot>md fa010000 fa010000: 5567e4e4 5567e4e4 5567e4e4 5567e4e4 Ug. fa010010: 5567e4e4 5567e4e4 5567e4e4 5567e4e4 Ug. u-boot>
When setting 'par_port->pr1 = 0xAA' ,it displayed: fa010000: ff67e0e0 ff67e0e0 ff67e0e0 ff67e0e0
***Program*** [MYBOARD.h] /*------------------------------------- * NS16552 PRINTER PORT Configuration */
#define CFG_PORT_BASE 0xFA010000 #define CFG_NS16552 #define CONFIG_PARALLEL #define CFG_NS16552_PORT CFG_PORT_BASE
#ifdef CONFIG_PARALLEL #define CFG_BR6_PRELIM 0xFA010401 /* REGISTER CS6 */ #define CFG_OR6_PRELIM 0xFFFF0040 #endif
[include/ns16552.h]
#ifdef CONFIG_PARALLEL /* Sam */ struct NS16552 { unsigned short pr0; /* 0 */ unsigned short sr; /* 1 */ unsigned short com; /* 2 */ } __attribute__ ((packed)); #endif
#define pr1 pr0 #define iosel sr /* Sam */ #define con com
void NS16552_init (NS16552_t par_port);
[driver/ns16552.c]
#include <config.h> #ifdef CFG_NS16552 #include <ns16552.h>
void NS16552_init (NS16552_t par_port) { par_port->iosel = 0x55; par_port->pr1 = 0xFF; par_port->con = (CON_LOGIC3 | CON_LOGIC2 | ~CON_INTP | CON_INIT );
} #endif
[driver/parallel.c]
#include <ns16552.h>
static NS16552_t port = (NS16552_t) CFG_NS16552_PORT;
int parallel_init (void) { NS16552_init (port); return (0); }
[lib_ppc/board.c]
#include <config.h>
--In board_init_r()---
#if defined(CONFIG_MYBOARD) board_parallel_init(); #endif
Sorry for disturbing your nice weekend by many questions!Thanks in advance!
Sam
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