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serial: 8250: Only get RSA resource when required

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The probe for Remote Supervisor Adapter is limited to port i/o
addresses which match one of the probe_rsa[] module parameter
addresses. Limit RSA resource acquire to matching i/o ports.

The result is a saner probe policy: only perform optional probes
when specified rather than by default.

NB: It is possible for userspace to set the port type == PORT_RSA
with ioctl(TIOCSSERIAL) and then autoconfig with ioctl(TIOCSERCONFIG),
which if it fails, may leave the port type set to PORT_RSA. Since
this may have previously resulted in a working RSA port, this behavior
is preserved.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2015-02-24 14:25:13 -05:00 committed by Greg Kroah-Hartman
parent cd52b7599c
commit 3b81c26c92
1 changed files with 18 additions and 14 deletions
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32
drivers/tty/serial/8250/8250_core.c
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@ -1228,16 +1228,9 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
/*
* Only probe for RSA ports if we got the region.
*/
if (port->type == PORT_16550A && probeflags & PROBE_RSA) {
int i;
for (i = 0 ; i < probe_rsa_count; ++i) {
if (probe_rsa[i] == port->iobase && __enable_rsa(up)) {
port->type = PORT_RSA;
break;
}
}
}
if (port->type == PORT_16550A && probeflags & PROBE_RSA &&
__enable_rsa(up))
port->type = PORT_RSA;
#endif
serial_out(up, UART_LCR, save_lcr);
@ -3008,7 +3001,7 @@ static void register_dev_spec_attr_grp(struct uart_8250_port *up)
static void serial8250_config_port(struct uart_port *port, int flags)
{
struct uart_8250_port *up = up_to_u8250p(port);
int probeflags = PROBE_ANY;
int probeflags = 0;
int ret;
if (port->type == PORT_8250_CIR)
@ -3023,9 +3016,20 @@ static void serial8250_config_port(struct uart_port *port, int flags)
return;
#ifdef CONFIG_SERIAL_8250_RSA
ret = serial8250_request_rsa_resource(up);
if (ret < 0)
probeflags &= ~PROBE_RSA;
if (port->type == PORT_RSA) {
if (serial8250_request_rsa_resource(up) == 0)
probeflags |= PROBE_RSA;
} else if (flags & UART_CONFIG_TYPE) {
int i;
for (i = 0 ; i < probe_rsa_count; ++i) {
if (probe_rsa[i] == port->iobase) {
if (serial8250_request_rsa_resource(up) == 0)
probeflags |= PROBE_RSA;
break;
}
}
}
#endif
if (port->iotype != up->cur_iotype)