introduce support for new ngff_cardem board

This adds support for the new ngff_cardem board, a board that
basically combines a ngff breakout board with a built-in SIMtrace2.

Cardem works, but depending on the modem it might need a adjusted ATR to
ensure a lower baud  rate is used by the modem, high rates might lead
to weird power cycling of the card after a few transfers.

Trace was also tested and appears to work as expected.

Change-Id: Ia96124fbe8a752c98e7fd4096d542a3b2b9bc255

firmware/libboard/ngff_cardem/source/wwan_perst.c

@@ -0,0 +1,127 @@
+/* Code to control the PERST lines of attached modems
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA
+ */
+/* Depending on the board this is running on,  it might be possible
+ * for the controller to set the status of the PERST input line of
+ * the cellular modem.  If the board supports this, it sets the
+ * PIN_PERST1 and/or PIN_PERST2 defines in its board.h file.
+ */
+#include "board.h"
+#include "trace.h"
+#include "wwan_perst.h"
+#include <osmocom/core/timer.h>
+
+struct wwan_perst {
+	uint8_t idx;
+	const Pin pin;
+	struct osmo_timer_list timer;
+};
+
+#ifdef PIN_PERST1
+static struct wwan_perst perst1 = {
+	.idx = 0,
+	.pin = PIN_PERST1,
+};
+#endif
+
+#ifdef PIN_PERST2
+static struct wwan_perst perst2 = {
+	.idx = 1,
+	.pin = PIN_PERST2,
+};
+#endif
+
+static int initialized = 0;
+
+static void perst_tmr_cb(void *data)
+{
+	struct wwan_perst *perst = data;
+	/* release the (low-active) reset */
+	TRACE_INFO("%u: De-asserting modem reset\r\n", perst->idx);
+	PIO_Clear(&perst->pin);
+}
+
+static struct wwan_perst *get_perst_for_modem(int modem_nr)
+{
+	if (!initialized) {
+		TRACE_ERROR("Somebody forgot to call wwan_perst_init()\r\n");
+		wwan_perst_init();
+	}
+
+	switch (modem_nr) {
+#ifdef PIN_PERST1
+	case 0:
+		return &perst1;
+#endif
+#ifdef PIN_PERST2
+	case 1:
+		return &perst2;
+#endif
+	default:
+		return NULL;
+	}
+}
+
+int wwan_perst_do_reset_pulse(int modem_nr, unsigned int duration_ms)
+{
+	struct wwan_perst *perst = get_perst_for_modem(modem_nr);
+	if (!perst)
+		return -1;
+
+	TRACE_INFO("%u: Asserting modem reset\r\n", modem_nr);
+	PIO_Set(&perst->pin);
+	osmo_timer_schedule(&perst->timer, duration_ms/1000, (duration_ms%1000)*1000);
+
+	return 0;
+}
+
+int wwan_perst_set(int modem_nr, int active)
+{
+	struct wwan_perst *perst = get_perst_for_modem(modem_nr);
+	if (!perst)
+		return -1;
+
+	osmo_timer_del(&perst->timer);
+	if (active) {
+		TRACE_INFO("%u: Asserting modem reset\r\n", modem_nr);
+		PIO_Set(&perst->pin);
+	} else {
+		TRACE_INFO("%u: De-asserting modem reset\r\n", modem_nr);
+		PIO_Clear(&perst->pin);
+	}
+
+	return 0;
+}
+
+int wwan_perst_init(void)
+{
+	int num_perst = 0;
+#ifdef PIN_PERST1
+	PIO_Configure(&perst1.pin, 1);
+	perst1.timer.cb = perst_tmr_cb;
+	perst1.timer.data = (void *) &perst1;
+	num_perst++;
+#endif
+
+#ifdef PIN_PERST2
+	PIO_Configure(&perst2.pin, 1);
+	perst2.timer.cb = perst_tmr_cb;
+	perst2.timer.data = (void *) &perst2;
+	num_perst++;
+#endif
+	initialized = 1;
+	return num_perst;
+}