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modified busy waiting loops (new function: waitfor(us, condition) to only wait for a certain time until the expected condition comes true, otherwise just return without the job done

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This commit is contained in:
Markus Fröschle
2012-11-17 14:22:34 +00:00
parent 08b35e4997
commit 913ea1f46a
3 changed files with 79 additions and 13 deletions
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44
sources/sysinit.c
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@@ -11,6 +11,7 @@
#include "cache.h"
#include "sysinit.h"
#include "bas_printf.h"
#include "bas_types.h"
extern void xprintf_before_copy(const char *fmt, ...);
#define xprintf xprintf_before_copy
@@ -25,14 +26,28 @@ extern volatile long _VRAM; /* start address of video ram from linker script */
* wait for the specified number of us on slice timer 0. Replaces the original routines that had
* the number of useconds to wait for hardcoded in their name.
*/
void wait(uint32_t us)
inline void wait(uint32_t us)
{
uint32_t target = MCF_SLT_SCNT(0) - (us * 132);
while (MCF_SLT_SCNT(0) > target);
}
/*
* the same as above, with a checker function which gets called while
* busy waiting and allows for an early return if it returns true
*/
inline bool waitfor(uint32_t us, int (*condition)(void))
{
uint32_t target = MCF_SLT_SCNT(0) - (us * 132);
do
{
if ((*condition)())
return TRUE;
} while (MCF_SLT_SCNT(0) > target);
return FALSE;
}
/*
* init SLICE TIMER 0
* all = 32.538 sec = 30.736mHz
@@ -472,12 +487,25 @@ void test_upd720101(void)
xprintf("finished\r\n");
}
static bool i2c_transfer_finished(void)
{
if (MCF_I2C_I2SR & MCF_I2C_I2SR_IIF)
return TRUE;
return FALSE;
}
static void wait_i2c_transfer_finished(void)
{
while (!(MCF_I2C_I2SR & MCF_I2C_I2SR_IIF)); /* wait until interrupt bit has been set */
waitfor(100000, i2c_transfer_finished); /* wait until interrupt bit has been set */
MCF_I2C_I2SR &= ~MCF_I2C_I2SR_IIF; /* clear interrupt bit (byte transfer finished */
}
static bool i2c_bus_free(void)
{
return (MCF_I2C_I2SR & MCF_I2C_I2SR_IBB);
}
/*
* TFP410 (DVI) on
*/
@@ -508,7 +536,7 @@ void dvi_on(void) {
/* i2c enable, master mode, transmit acknowledge */
MCF_I2C_I2CR = MCF_I2C_I2CR_IEN | MCF_I2C_I2CR_MSTA | MCF_I2C_I2CR_MTX;
MCF_I2C_I2DR = 0x7a; /* send data: address of TFP410 */
MCF_I2C_I2DR = 0x7a; /* send data: address of TFP410 */
wait_i2c_transfer_finished();
if (MCF_I2C_I2SR & MCF_I2C_I2SR_RXAK) /* next try if no acknowledge */
@@ -524,13 +552,13 @@ void dvi_on(void) {
if (MCF_I2C_I2SR & MCF_I2C_I2SR_RXAK) /* next try if no acknowledge */
continue;
MCF_I2C_I2CR &= 0xef; //~MCF_I2C_I2CR_MTX; /* switch to receive mode */
dummyByte = MCF_I2C_I2DR; /* dummy read */
MCF_I2C_I2CR &= 0xef; //~MCF_I2C_I2CR_MTX; /* switch to receive mode */
dummyByte = MCF_I2C_I2DR; /* dummy read */
wait_i2c_transfer_finished();
MCF_I2C_I2CR |= MCF_I2C_I2CR_TXAK; /* transmit acknowledge enable */
receivedByte = MCF_I2C_I2DR; /* read a byte */
receivedByte = MCF_I2C_I2DR; /* read a byte */
wait_i2c_transfer_finished();
@@ -544,7 +572,7 @@ void dvi_on(void) {
MCF_I2C_I2CR = 0x0; // stop
MCF_I2C_I2SR = 0x0; // clear sr
while ((MCF_I2C_I2SR & MCF_I2C_I2SR_IBB)); /* wait for bus free */
waitfor(10000, i2c_bus_free);
MCF_I2C_I2CR = 0xb0; // on tx master
MCF_I2C_I2DR = 0x7A;
@@ -566,7 +594,7 @@ void dvi_on(void) {
dummyByte = MCF_I2C_I2DR; // dummy read
MCF_I2C_I2SR = 0x0; // clear sr
while ((MCF_I2C_I2SR & MCF_I2C_I2SR_IBB)); /* wait until bus free */
waitfor(10000, i2c_bus_free);
MCF_I2C_I2CR = 0xb0;
MCF_I2C_I2DR = 0x7A;