Linux 2.6-10.rc3 8xx: debugging (over-writing) content of bd_in fo structure in the kernel booting code
Povolotsky, Alexander
Alexander.Povolotsky at marconi.com
Tue Jan 18 22:45:14 EST 2005
I am now suspecting that the content of my bd_info structure is set or is
handled incorrectly,
thus causing incorrect behavior of the serial driver upon kernel booting
(only 3 characters are printed correctly and the rest is the garbage - as I
reported before),
so I am trying (for debugging purposes) to over-write the values, passed
from bd_info
during the kernel booting, by the hard-coded "correct" values.
So far I tried forcing baud, bits, parity, flow directly in in
cpm_uart_console_setup()
( drivers/serial/cpm_uart/cpm_uar t_core.c ) - see below - it didn't help
...
Where in the kernel booting code the clock speed is handled (it also comes
from the bd_info)
- so I could try to force set clock speed there ?
Thanks,
Alex
****************************************************************
static int __init cpm_uart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
struct uart_cpm_port *pinfo;
int baud = 38400;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
port =
(struct uart_port
*)&cpm_uart_ports[cpm_uart_port_map[co->index]];
pinfo = (struct uart_cpm_port *)port;
pinfo->flags |= FLAG_CONSOLE;
if (options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
} else {
bd_t *bd = (bd_t *) __res;
if (bd->bi_baudrate)
baud = bd->bi_baudrate;
else
baud = 9600;
}
baud = 38400;
<<===========================================
parity = 'n';
<<===========================================
flow = 'n';
<<===========================================
bits = 8;
<<===========================================
/*
* Setup any port IO, connect any baud rate generators,
* etc. This is expected to be handled by board
* dependant code
*/
if (pinfo->set_lineif)
pinfo->set_lineif(pinfo);
if (IS_SMC(pinfo)) {
pinfo->smcp->smc_smcm &= ~(SMCM_RX | SMCM_TX);
pinfo->smcp->smc_smcmr &= ~(SMCMR_REN | SMCMR_TEN);
} else {
pinfo->sccp->scc_sccm &= ~(UART_SCCM_TX | UART_SCCM_RX);
pinfo->sccp->scc_gsmrl &= ~(SCC_GSMRL_ENR | SCC_GSMRL_ENT);
}
ret = cpm_uart_allocbuf(pinfo, 1);
if (ret)
return ret;
cpm_uart_initbd(pinfo);
if (IS_SMC(pinfo))
cpm_uart_init_smc(pinfo);
else
cpm_uart_init_scc(pinfo);
uart_set_options(port, co, baud, parity, bits, flow);
return 0;
}
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