how to get a physical address from the mmaped address area?
hychon at genetel.co.kr
Sat Jul 21 17:25:56 EST 2001
I want to "how to get a physical address from the mmaped address area !
I am working a HDLC program (not device driver) as Embedded Linux
system , that used SCC2 on the MPC860T target board .
I worked initialzed SCC2 and allocat memory buffer with the
kernel-2.2.13 based on PowerPC arch .
In my program, I allocated the BD (Buffer Descriptor) in a temporary
place of DPMEM.
RxTxBD = (BDRINGS *)(&IMMR->udata_bd[0x600]);
IMMR->PRAM[PAGE2].pg.scc.h.rbase = (UHWORD)&RxTxBD->RxBD; /*
(UHWORD)0x2E00; /* 2 */
case 1 : BD state not change and down .the system
case 2 : BD state are change
I think that the RBASE and TBASE in SCC PARAM is a physical address of
I want to get a place of BD in DPMEM itself and retun as physical
address. (as if , CPM get a BD pointer in commproc.c file )
Question1) How to get a place(pointer) of BD in DPMEM and give RBASE
(TBASE) the physical address ?
And Buffer are allocated in a virtual area , by following
mem_addr_buf1 = mmap(0,1024,(PROT_READ|PROT_WRITE),MAP_SHARED,
buf = (unsigned char *)mem_addr_buf1;
when I write buf as Buffer addr of BD, that do not change Buffer
I think that don't find the buffer address
and the Buffer pointer of BD structure was recognized as physical
address of the Buffer (buf) .
Question2) How to get a buffer address pointer of BD struct (a place of
Buffer) from kernel (virtual address) as physical address?
Help me !
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