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sim: bfin: implement loop back support in the UARTs 

The UART has a LOOP_ENA bit in its MCR register where writes to the THR
go to the RBR.  Implement support for this mode.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Mike Frysinger 2011-05-14 15:59:09 +00:00
parent ba4a8bdd81
commit 28fe96b798
4 changed files with 62 additions and 23 deletions
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15
sim/bfin/ChangeLog
View File

@ -1,3 +1,18 @@
2011-05-14 Mike Frysinger <vapier@gentoo.org>
* dv-bfin_uart.c (bfin_uart_write_byte): Add a mcr arg. Declare a
local uart. When LOOP_ENA is set in mcr, write to the saved byte
and count fields of the uart.
(bfin_uart_io_write_buffer): Pass uart->mcr to bfin_uart_write_byte
and bfin_uart_get_next_byte.
(bfin_uart_get_next_byte): Add a mcr arg. Move uart->saved_count
check first, and skip the remaining code when LOOP_ENA is set in mcr.
* dv-bfin_uart.h (bfin_uart_write_byte): Add an mcr argument.
(bfin_uart_get_next_byte): Likewise.
(XOFF, MRTS, RFIT, RFRT, LOOP_ENA, FCPOL, ARTS, ACTS): Define.
* dv-bfin_uart2.c (bfin_uart_io_write_buffer): Padd uart->mcr when
calling bfin_uart_write_byte and bfin_uart_get_next_byte.
2011-05-09 Mike Frysinger <vapier@gentoo.org>
* dv-bfin_uart2.c (bfin_uart_io_read_buffer): Clear DR/THRE/TEMT bits

52
sim/bfin/dv-bfin_uart.c
View File

@ -117,10 +117,21 @@ bfin_uart_reschedule (struct hw *me)
}
bu16
bfin_uart_write_byte (struct hw *me, bu16 thr)
bfin_uart_write_byte (struct hw *me, bu16 thr, bu16 mcr)
{
struct bfin_uart *uart = hw_data (me);
unsigned char ch = thr;
if (mcr & LOOP_ENA)
{
/* XXX: This probably doesn't work exactly right with
external FIFOs ... */
uart->saved_byte = thr;
uart->saved_count = 1;
}
bfin_uart_write_buffer (me, &ch, 1);
return thr;
}
@ -149,7 +160,7 @@ bfin_uart_io_write_buffer (struct hw *me, const void *source,
uart->dll = value;
else
{
uart->thr = bfin_uart_write_byte (me, value);
uart->thr = bfin_uart_write_byte (me, value, uart->mcr);
if (uart->ier & ETBEI)
hw_port_event (me, DV_PORT_TX, 1);
@ -184,7 +195,7 @@ bfin_uart_io_write_buffer (struct hw *me, const void *source,
/* Switch between socket and stdin on the fly. */
bu16
bfin_uart_get_next_byte (struct hw *me, bu16 rbr, bool *fresh)
bfin_uart_get_next_byte (struct hw *me, bu16 rbr, bu16 mcr, bool *fresh)
{
SIM_DESC sd = hw_system (me);
struct bfin_uart *uart = hw_data (me);
@ -197,23 +208,26 @@ bfin_uart_get_next_byte (struct hw *me, bu16 rbr, bool *fresh)
fresh = &_fresh;
*fresh = false;
if (status & DV_SOCKSER_DISCONNECTED)
if (uart->saved_count > 0)
{
if (uart->saved_count > 0)
*fresh = true;
rbr = uart->saved_byte;
--uart->saved_count;
}
else if (mcr & LOOP_ENA)
{
/* RX is disconnected, so only return local data. */
}
else if (status & DV_SOCKSER_DISCONNECTED)
{
char byte;
int ret = sim_io_poll_read (sd, 0/*STDIN*/, &byte, 1);
if (ret > 0)
{
*fresh = true;
rbr = uart->saved_byte;
--uart->saved_count;
}
else
{
char byte;
int ret = sim_io_poll_read (sd, 0/*STDIN*/, &byte, 1);
if (ret > 0)
{
*fresh = true;
rbr = byte;
}
rbr = byte;
}
}
else
@ -239,7 +253,7 @@ bfin_uart_get_status (struct hw *me)
}
else
lsr |= (status & DV_SOCKSER_INPUT_EMPTY ? 0 : DR) |
(status & DV_SOCKSER_OUTPUT_EMPTY ? TEMT | THRE : 0);
(status & DV_SOCKSER_OUTPUT_EMPTY ? TEMT | THRE : 0);
return lsr;
}
@ -266,7 +280,7 @@ bfin_uart_io_read_buffer (struct hw *me, void *dest,
dv_store_2 (dest, uart->dll);
else
{
uart->rbr = bfin_uart_get_next_byte (me, uart->rbr, NULL);
uart->rbr = bfin_uart_get_next_byte (me, uart->rbr, uart->mcr, NULL);
dv_store_2 (dest, uart->rbr);
}
break;

14
sim/bfin/dv-bfin_uart.h
View File

@ -26,8 +26,8 @@
#define BFIN_MMR_UART_SIZE 0x30
struct bfin_uart;
bu16 bfin_uart_get_next_byte (struct hw *, bu16, bool *fresh);
bu16 bfin_uart_write_byte (struct hw *, bu16);
bu16 bfin_uart_get_next_byte (struct hw *, bu16, bu16, bool *fresh);
bu16 bfin_uart_write_byte (struct hw *, bu16, bu16);
bu16 bfin_uart_get_status (struct hw *);
unsigned bfin_uart_write_buffer (struct hw *, const unsigned char *, unsigned);
unsigned bfin_uart_read_buffer (struct hw *, unsigned char *, unsigned);
@ -51,4 +51,14 @@ void bfin_uart_reschedule (struct hw *);
#define ETBEI (1 << 1)
#define ELSI (1 << 2)
/* UART_MCR */
#define XOFF (1 << 0)
#define MRTS (1 << 1)
#define RFIT (1 << 2)
#define RFRT (1 << 3)
#define LOOP_ENA (1 << 4)
#define FCPOL (1 << 5)
#define ARTS (1 << 6)
#define ACTS (1 << 7)
#endif

4
sim/bfin/dv-bfin_uart2.c
View File

@ -89,7 +89,7 @@ bfin_uart_io_write_buffer (struct hw *me, const void *source,
switch (mmr_off)
{
case mmr_offset(thr):
uart->thr = bfin_uart_write_byte (me, value);
uart->thr = bfin_uart_write_byte (me, value, uart->mcr);
if (uart->ier & ETBEI)
hw_port_event (me, DV_PORT_TX, 1);
break;
@ -142,7 +142,7 @@ bfin_uart_io_read_buffer (struct hw *me, void *dest,
switch (mmr_off)
{
case mmr_offset(rbr):
uart->rbr = bfin_uart_get_next_byte (me, uart->rbr, NULL);
uart->rbr = bfin_uart_get_next_byte (me, uart->rbr, uart->mcr, NULL);
dv_store_2 (dest, uart->rbr);
break;
case mmr_offset(ier_set):