Adding direct access to DSP of sysmoBTS for PDTCH traffice

In order to use this feature, sysmoBTS requires option "-M", otherwise
the traffic is forwarded through socket interface.

This is essential, if PCU runs on processor of sysmoBTS. The reaction
time and delay of PDTCH frames could heavily degrade proper packet flow.

1 files changed, 215 insertions, 0 deletions

diff --git a/src/sysmo_l1_hw.c b/src/sysmo_l1_hw.c
new file mode 100644
index 00000000..87c2c55e
--- /dev/null
+++ b/src/sysmo_l1_hw.c
@@ -0,0 +1,215 @@
+/* Interface handler for Sysmocom L1 (real hardware) */
+
+/* (C) 2011 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <assert.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/timer.h>
+#include <osmocom/gsm/gsm_utils.h>
+
+#include <sysmocom/femtobts/superfemto.h>
+#include <sysmocom/femtobts/gsml1prim.h>
+#include <sysmocom/femtobts/gsml1const.h>
+#include <sysmocom/femtobts/gsml1types.h>
+
+#include "gprs_debug.h"
+#include "femtobts.h"
+#include "sysmo_l1_if.h"
+
+
+#ifdef HW_SYSMOBTS_V1
+#define DEV_SYS_DSP2ARM_NAME	"/dev/msgq/femtobts_dsp2arm"
+#define DEV_SYS_ARM2DSP_NAME	"/dev/msgq/femtobts_arm2dsp"
+#define DEV_L1_DSP2ARM_NAME	"/dev/msgq/gsml1_dsp2arm"
+#define DEV_L1_ARM2DSP_NAME	"/dev/msgq/gsml1_arm2dsp"
+#else
+#define DEV_SYS_DSP2ARM_NAME	"/dev/msgq/superfemto_dsp2arm"
+#define DEV_SYS_ARM2DSP_NAME	"/dev/msgq/superfemto_arm2dsp"
+#define DEV_L1_DSP2ARM_NAME	"/dev/msgq/gsml1_sig_dsp2arm"
+#define DEV_L1_ARM2DSP_NAME	"/dev/msgq/gsml1_sig_arm2dsp"
+
+#define DEV_TCH_DSP2ARM_NAME	"/dev/msgq/gsml1_tch_dsp2arm"
+#define DEV_TCH_ARM2DSP_NAME	"/dev/msgq/gsml1_tch_arm2dsp"
+#define DEV_PDTCH_DSP2ARM_NAME	"/dev/msgq/gsml1_pdtch_dsp2arm"
+#define DEV_PDTCH_ARM2DSP_NAME	"/dev/msgq/gsml1_pdtch_arm2dsp"
+#endif
+
+static const char *rd_devnames[] = {
+	[MQ_SYS_READ]	= DEV_SYS_DSP2ARM_NAME,
+	[MQ_L1_READ]	= DEV_L1_DSP2ARM_NAME,
+#ifndef HW_SYSMOBTS_V1
+	[MQ_TCH_READ]	= DEV_TCH_DSP2ARM_NAME,
+	[MQ_PDTCH_READ]	= DEV_PDTCH_DSP2ARM_NAME,
+#endif
+};
+
+static const char *wr_devnames[] = {
+	[MQ_SYS_WRITE]	= DEV_SYS_ARM2DSP_NAME,
+	[MQ_L1_WRITE]	= DEV_L1_ARM2DSP_NAME,
+#ifndef HW_SYSMOBTS_V1
+	[MQ_TCH_WRITE]	= DEV_TCH_ARM2DSP_NAME,
+	[MQ_PDTCH_WRITE]= DEV_PDTCH_ARM2DSP_NAME,
+#endif
+};
+
+/* callback when there's something to read from the l1 msg_queue */
+static int l1if_fd_cb(struct osmo_fd *ofd, unsigned int what)
+{
+	//struct msgb *msg = l1p_msgb_alloc();
+	struct msgb *msg = msgb_alloc_headroom(sizeof(SuperFemto_Prim_t) + 128,
+		128, "1l_fd");
+	struct femtol1_hdl *fl1h = ofd->data;
+	int rc;
+
+	msg->l1h = msg->data;
+	rc = read(ofd->fd, msg->l1h, msgb_tailroom(msg));
+	if (rc < 0) {
+		if (rc != -1) 
+			LOGP(DL1IF, LOGL_ERROR, "error reading from L1 msg_queue: %s\n",
+				strerror(errno));
+		msgb_free(msg);
+		return rc;
+	}
+	msgb_put(msg, rc);
+
+	switch (ofd->priv_nr) {
+	case MQ_SYS_WRITE:
+		if (rc != sizeof(SuperFemto_Prim_t))
+			LOGP(DL1IF, LOGL_NOTICE, "%u != "
+			     "sizeof(SuperFemto_Prim_t)\n", rc);
+		return l1if_handle_sysprim(fl1h, msg);
+	case MQ_L1_WRITE:
+#ifndef HW_SYSMOBTS_V1
+	case MQ_TCH_WRITE:
+	case MQ_PDTCH_WRITE:
+#endif
+		if (rc != sizeof(GsmL1_Prim_t))
+			LOGP(DL1IF, LOGL_NOTICE, "%u != "
+			     "sizeof(GsmL1_Prim_t)\n", rc);
+		return l1if_handle_l1prim(ofd->priv_nr, fl1h, msg);
+	default:
+		/* The compiler can't know that priv_nr is an enum. Assist. */
+		LOGP(DL1IF, LOGL_FATAL, "writing on a wrong queue: %d\n",
+			ofd->priv_nr);
+		exit(0);
+		break;
+	}
+};
+
+/* callback when we can write to one of the l1 msg_queue devices */
+static int l1fd_write_cb(struct osmo_fd *ofd, struct msgb *msg)
+{
+	int rc;
+
+	rc = write(ofd->fd, msg->l1h, msgb_l1len(msg));
+	if (rc < 0) {
+		LOGP(DL1IF, LOGL_ERROR, "error writing to L1 msg_queue: %s\n",
+			strerror(errno));
+		return rc;
+	} else if (rc < msg->len) {
+		LOGP(DL1IF, LOGL_ERROR, "short write to L1 msg_queue: "
+			"%u < %u\n", rc, msg->len);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+int l1if_transport_open(int q, struct femtol1_hdl *hdl)
+{
+	int rc;
+
+	/* Step 1: Open all msg_queue file descriptors */
+	struct osmo_fd *read_ofd = &hdl->read_ofd[q];
+	struct osmo_wqueue *wq = &hdl->write_q[q];
+	struct osmo_fd *write_ofd = &hdl->write_q[q].bfd;
+
+	rc = open(rd_devnames[q], O_RDONLY);
+	if (rc < 0) {
+		LOGP(DL1IF, LOGL_FATAL, "unable to open msg_queue: %s\n",
+			strerror(errno));
+		return rc;
+	}
+	read_ofd->fd = rc;
+	read_ofd->priv_nr = q;
+	read_ofd->data = hdl;
+	read_ofd->cb = l1if_fd_cb;
+	read_ofd->when = BSC_FD_READ;
+	rc = osmo_fd_register(read_ofd);
+	if (rc < 0) {
+		close(read_ofd->fd);
+		read_ofd->fd = -1;
+		return rc;
+	}
+
+	rc = open(wr_devnames[q], O_WRONLY);
+	if (rc < 0) {
+		LOGP(DL1IF, LOGL_FATAL, "unable to open msg_queue: %s\n",
+			strerror(errno));
+		goto out_read;
+	}
+	osmo_wqueue_init(wq, 10);
+	wq->write_cb = l1fd_write_cb;
+	write_ofd->fd = rc;
+	write_ofd->priv_nr = q;
+	write_ofd->data = hdl;
+	write_ofd->when = BSC_FD_WRITE;
+	rc = osmo_fd_register(write_ofd);
+	if (rc < 0) {
+		close(write_ofd->fd);
+		write_ofd->fd = -1;
+		goto out_read;
+	}
+
+	return 0;
+
+out_read:
+	close(hdl->read_ofd[q].fd);
+	osmo_fd_unregister(&hdl->read_ofd[q]);
+
+	return rc;
+}
+
+int l1if_transport_close(int q, struct femtol1_hdl *hdl)
+{
+	struct osmo_fd *read_ofd = &hdl->read_ofd[q];
+	struct osmo_fd *write_ofd = &hdl->write_q[q].bfd;
+
+	osmo_fd_unregister(read_ofd);
+	close(read_ofd->fd);
+	read_ofd->fd = -1;
+
+	osmo_fd_unregister(write_ofd);
+	close(write_ofd->fd);
+	write_ofd->fd = -1;
+
+	return 0;
+}