add support for cdiv (sample clock) bit clock synchronization

git-svn-id: https://svn.openpcd.org:2342/trunk@248 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

1 files changed, 103 insertions, 0 deletions

diff --git a/firmware/src/picc/tc_cdiv_sync.c b/firmware/src/picc/tc_cdiv_sync.c
new file mode 100644
index 0000000..5762c2c
--- /dev/null
+++ b/firmware/src/picc/tc_cdiv_sync.c
@@ -0,0 +1,103 @@
+/* Synchronize TC_CDIV divided sample clock with the SOF of the packet */
+
+#define PIO_DATA	AT91C_PIO_PA27
+
+#include <lib_AT91SAM7.h>
+#include <AT91SAM7.h>
+#include <os/dbgu.h>
+#include "../openpcd.h"
+
+//#define USE_IRQ
+#define DISABLE
+
+static u_int8_t enabled;
+
+static void pio_data_change(u_int32_t pio)
+{
+	DEBUGPCRF("PIO=%d", pio);
+
+	if (pio != 27)
+		return;
+
+	/* FIXME: start ssc if we're in one-shot mode */
+	//ssc_rx_start();
+}
+
+static void __ramfunc cdsync_cb(void)
+{
+	if (*AT91C_PIOA_ISR & PIO_DATA) {
+		/* we get one interrupt for each change. If now, after the
+		 * change the level is low, then it must have been a falling
+		 * edge */
+		if (*AT91C_PIOA_PDSR & PIO_DATA) {
+			*AT91C_TC0_CCR = AT91C_TC_SWTRG;
+			DEBUGP("SWTRG CV=0x%08x ", *AT91C_TC0_CV);
+#ifdef DISABLE
+			DEBUGP("CDIV_SYNC_FLIP ");
+			*AT91C_PIOA_IDR = PIO_DATA;
+#endif
+			//ssc_rx_start();
+		}
+	}
+#if 0
+	AT91F_AIC_ClearIt(AT91C_BASE_AIC, AT91C_ID_PIOA);
+	AT91F_AIC_ClearIt(AT91C_BASE_AIC, AT91C_ID_FIQ);
+#endif
+	DEBUGPCR("");
+}
+
+/* re-enable cdiv_sync FIQ after it has been disabled by our one-shot logic */
+void tc_cdiv_sync_reset(void)
+{
+#ifdef DISABLE
+	if (enabled) {
+		u_int32_t tmp = *AT91C_PIOA_ISR;
+		DEBUGP("CDIV_SYNC_FLOP ");
+		*AT91C_PIOA_IER = PIO_DATA;
+	}
+#endif
+}
+
+void tc_cdiv_sync_disable(void)
+{
+	enabled = 0;	
+	*AT91C_PIOA_IDR = PIO_DATA;
+}
+
+void tc_cdiv_sync_enable(void)
+{
+	enabled = 1;
+
+	DEBUGP("CDIV_SYNC_ENABLE ");
+	tc_cdiv_sync_reset();
+}
+
+extern void (*fiq_handler)(void);
+void tc_cdiv_sync_init(void)
+{
+	DEBUGPCRF("initializing");
+
+	enabled = 0;
+
+	AT91F_PIOA_CfgPMC();
+
+#ifdef USE_IRQ
+	/* Configure IRQ */
+	AT91F_AIC_ConfigureIt(AT91C_BASE_AIC, AT91C_ID_PIOA,
+			      AT91C_AIC_PRIOR_HIGHEST, 
+			      AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &cdsync_cb);
+#else
+	/* Configure FIQ */
+	AT91F_AIC_ConfigureIt(AT91C_BASE_AIC, AT91C_ID_FIQ,
+			      //0, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &cdsync_cb);
+			      0, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &fiq_handler);
+	/* enable fast forcing for PIOA interrupt */
+	*AT91C_AIC_FFER = (1 << AT91C_ID_PIOA);
+
+	/* register pio irq handler */
+	pio_irq_register(PIO_DATA, &pio_data_change);
+#endif
+	AT91F_AIC_EnableIt(AT91C_BASE_AIC, AT91C_ID_PIOA);
+
+	tc_cdiv_sync_disable();
+}