TC_CDIV (carrier divisor) is part of both PICC and PCD, move it to 'os'

git-svn-id: https://svn.openpcd.org:2342/trunk@150 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

2 files changed, 124 insertions, 0 deletions

diff --git a/openpcd/firmware/src/os/tc_cdiv.c b/openpcd/firmware/src/os/tc_cdiv.c
new file mode 100644
index 0000000..b15f7b1
--- /dev/null
+++ b/openpcd/firmware/src/os/tc_cdiv.c
@@ -0,0 +1,101 @@
+/* OpenPC TC (Timer / Clock) support code
+ * (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
+ *
+ * This idea of this code is to feed the 13.56MHz carrier clock of RC632
+ * into TCLK1, which is routed to XC1.  Then configure TC0 to divide this
+ * clock by a configurable divider.
+ *
+ * PICC Simulator Side:
+ * In order to support responding to synchronous frames (REQA/WUPA/ANTICOL),
+ * we need a second Timer/Counter (TC1).  This unit is reset by an external
+ * event (rising edge of modulation pause PCD->PICC) connected to TIOB2, and
+ * counts up to a configurable number of carrier clock cycles (RA). Once the
+ * RA value is reached, TIOA2 will see a rising edge.  This rising edge will
+ * be interconnected to TF (Tx Frame) of the SSC to start transmitting our
+ * synchronous response.
+ *
+ */
+
+#include <lib_AT91SAM7.h>
+#include <AT91SAM7.h>
+#include <os/dbgu.h>
+
+#include "../openpcd.h"
+#include <os/tc_cdiv.h>
+
+static AT91PS_TCB tcb = AT91C_BASE_TCB;
+
+/* set carrier divider to a specific */
+void tc_cdiv_set_divider(u_int16_t div)
+{
+	tcb->TCB_TC0.TC_RC = div;
+
+	/* set to 50% duty cycle */
+	tcb->TCB_TC0.TC_RA = 1;
+	tcb->TCB_TC0.TC_RB = 1 + (div >> 1);
+}
+
+void tc_cdiv_phase_add(int16_t inc)
+{
+	tcb->TCB_TC0.TC_RA = (tcb->TCB_TC0.TC_RA + inc) % tcb->TCB_TC0.TC_RC;
+	tcb->TCB_TC0.TC_RB = (tcb->TCB_TC0.TC_RB + inc) % tcb->TCB_TC0.TC_RC;
+
+	/* FIXME: can this be done more elegantly? */
+	if (tcb->TCB_TC0.TC_RA == 0) {
+		tcb->TCB_TC0.TC_RA += 1;
+		tcb->TCB_TC0.TC_RB += 1;
+	}
+}
+
+void tc_cdiv_init(void)
+{
+	/* Cfg PA28(TCLK1), PA0(TIOA0), PA1(TIOB0), PA20(TCLK2) as Periph B */
+	AT91F_PIO_CfgPeriph(AT91C_BASE_PIOA, 0, 
+			    OPENPCD_PIO_CARRIER_IN |
+			    OPENPCD_PIO_CARRIER_DIV_OUT |
+			    OPENPCD_PIO_CDIV_HELP_OUT |
+			    OPENPCD_PIO_CDIV_HELP_IN);
+
+	AT91F_PMC_EnablePeriphClock(AT91C_BASE_PMC, 
+				    ((unsigned int) 1 << AT91C_ID_TC0));
+
+	/* Enable Clock for TC0 */
+	tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKEN;
+
+	/* Connect TCLK1 to XC1, TCLK2 to XC2 */
+	tcb->TCB_BMR &= ~(AT91C_TCB_TC1XC1S | AT91C_TCB_TC2XC2S);
+	tcb->TCB_BMR |=  (AT91C_TCB_TC1XC1S_TCLK1 | AT91C_TCB_TC2XC2S_TCLK2);
+
+	/* Clock XC1, Wave mode, Reset on RC comp
+	 * TIOA0 on RA comp = set, * TIOA0 on RC comp = clear,
+	 * TIOB0 on EEVT = set, TIOB0 on RB comp = clear,
+	 * EEVT = XC2 (TIOA0) */
+	tcb->TCB_TC0.TC_CMR = AT91C_TC_CLKS_XC1 | AT91C_TC_WAVE |
+			      AT91C_TC_WAVESEL_UP_AUTO | 
+			      AT91C_TC_ACPA_SET | AT91C_TC_ACPC_CLEAR |
+			      AT91C_TC_BEEVT_SET | AT91C_TC_BCPB_CLEAR |
+			      AT91C_TC_EEVT_XC2 | AT91C_TC_ETRGEDG_RISING;
+
+	tc_cdiv_set_divider(128);
+
+	/* Reset to start timers */
+	tcb->TCB_BCR = 1;
+}
+
+void tc_cdiv_print(void)
+{
+	DEBUGP("TCB_BMR=0x%08x ", tcb->TCB_BMR);
+	DEBUGP("TC0_CV=0x%08x ", tcb->TCB_TC0.TC_CV);
+	DEBUGP("TC0_CMR=0x%08x ", tcb->TCB_TC0.TC_CMR);
+	DEBUGPCR("TC0_SR=0x%08x", tcb->TCB_TC0.TC_SR);
+
+	DEBUGPCR("TC0_RA=0x%04x, TC0_RB=0x%04x, TC0_RC=0x%04x",
+		 tcb->TCB_TC0.TC_RA, tcb->TCB_TC0.TC_RB, tcb->TCB_TC0.TC_RC);
+}
+
+void tc_cdiv_fini(void)
+{
+	tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKDIS;
+	AT91F_PMC_DisablePeriphClock(AT91C_BASE_PMC,
+				     ((unsigned int) 1 << AT91C_ID_TC0));
+}
diff --git a/openpcd/firmware/src/os/tc_cdiv.h b/openpcd/firmware/src/os/tc_cdiv.h
new file mode 100644
index 0000000..8b4031d
--- /dev/null
+++ b/openpcd/firmware/src/os/tc_cdiv.h
@@ -0,0 +1,23 @@
+#ifndef _TC_CDIV_H
+#define _TC_CDIV_H
+
+#include <sys/types.h>
+
+extern void tc_cdiv_phase_add(int16_t inc);
+extern void tc_cdiv_set_divider(u_int16_t div);
+
+static inline void tc_cdiv_phase_inc(void)
+{
+       tc_cdiv_phase_add(1);
+}
+
+static inline void tc_cdiv_phase_dec(void)
+{
+       tc_cdiv_phase_add(-1);
+}
+
+extern void tc_cdiv_print(void);
+extern void tc_cdiv_init(void);
+extern void tc_cdiv_fini(void);
+
+#endif