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hw/i2c/bitbang_i2c: Trace state changes 

Trace bitbang state machine changes with trace events.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Message-id: 20230111085016.44551-5-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2023-01-11 09:50:15 +01:00 committed by Peter Maydell
parent dc575b5e03
commit 1e5b1899cc
2 changed files with 31 additions and 5 deletions
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33
hw/i2c/bitbang_i2c.c
View File

@ -16,6 +16,7 @@
#include "hw/sysbus.h"
#include "qemu/module.h"
#include "qom/object.h"
#include "trace.h"
//#define DEBUG_BITBANG_I2C
@ -26,15 +27,41 @@ do { printf("bitbang_i2c: " fmt , ## __VA_ARGS__); } while (0)
#define DPRINTF(fmt, ...) do {} while(0)
#endif
/* bitbang_i2c_state enum to name */
static const char * const sname[] = {
#define NAME(e) [e] = stringify(e)
NAME(STOPPED),
[SENDING_BIT7] = "SENDING_BIT7 (START)",
NAME(SENDING_BIT6),
NAME(SENDING_BIT5),
NAME(SENDING_BIT4),
NAME(SENDING_BIT3),
NAME(SENDING_BIT2),
NAME(SENDING_BIT1),
NAME(SENDING_BIT0),
NAME(WAITING_FOR_ACK),
[RECEIVING_BIT7] = "RECEIVING_BIT7 (ACK)",
NAME(RECEIVING_BIT6),
NAME(RECEIVING_BIT5),
NAME(RECEIVING_BIT4),
NAME(RECEIVING_BIT3),
NAME(RECEIVING_BIT2),
NAME(RECEIVING_BIT1),
NAME(RECEIVING_BIT0),
NAME(SENDING_ACK),
NAME(SENT_NACK)
#undef NAME
};
static void bitbang_i2c_set_state(bitbang_i2c_interface *i2c,
bitbang_i2c_state state)
{
trace_bitbang_i2c_state(sname[i2c->state], sname[state]);
i2c->state = state;
}
static void bitbang_i2c_enter_stop(bitbang_i2c_interface *i2c)
{
DPRINTF("STOP\n");
if (i2c->current_addr >= 0)
i2c_end_transfer(i2c->bus);
i2c->current_addr = -1;
@ -73,7 +100,6 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level)
return bitbang_i2c_nop(i2c);
}
if (level == 0) {
DPRINTF("START\n");
/* START condition. */
bitbang_i2c_set_state(i2c, SENDING_BIT7);
i2c->current_addr = -1;
@ -122,7 +148,6 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level)
/* NACK (either addressing a nonexistent device, or the
* device we were sending to decided to NACK us).
*/
DPRINTF("Got NACK\n");
bitbang_i2c_set_state(i2c, SENT_NACK);
bitbang_i2c_enter_stop(i2c);
return bitbang_i2c_ret(i2c, 1);
@ -147,11 +172,9 @@ int bitbang_i2c_set(bitbang_i2c_interface *i2c, int line, int level)
case SENDING_ACK:
if (data != 0) {
DPRINTF("NACKED\n");
bitbang_i2c_set_state(i2c, SENT_NACK);
i2c_nack(i2c->bus);
} else {
DPRINTF("ACKED\n");
bitbang_i2c_set_state(i2c, RECEIVING_BIT7);
}
return bitbang_i2c_ret(i2c, 1);

3
hw/i2c/trace-events
View File

@ -1,5 +1,8 @@
# See docs/devel/tracing.rst for syntax documentation.
# bitbang_i2c.c
bitbang_i2c_state(const char *old_state, const char *new_state) "state %s -> %s"
# core.c
i2c_event(const char *event, uint8_t address) "%s(addr:0x%02x)"