sysmobts: Support older firmware on the RevB hardware

For the firmware used on RevB the GsmL1_Prim_t was bigger than
the femtobts control structure. Solve it by introducing a macro
that will select the biggest size and use this macro. This is a
follow up fix for 08fce19cfce84432fbf8293318486a96437a3427.

4 files changed, 17 insertions, 3 deletions

diff --git a/src/osmo-bts-sysmo/femtobts.h b/src/osmo-bts-sysmo/femtobts.h
index fd5142bc..a880562d 100644
--- a/src/osmo-bts-sysmo/femtobts.h
+++ b/src/osmo-bts-sysmo/femtobts.h
@@ -21,6 +21,14 @@
 #define SUPERFEMTO_API_VERSION SUPERFEMTO_API(2,2,0)
 #endif
 
+/*
+ * Depending on the firmware version either GsmL1_Prim_t or SuperFemto_Prim_t
+ * is the bigger struct. For earlier firmware versions the GsmL1_Prim_t was the
+ * bigger struct.
+ */
+#define SYSMOBTS_PRIM_SIZE \
+	(OSMO_MAX(sizeof(SuperFemto_Prim_t), sizeof(GsmL1_Prim_t)) + 128)
+
 enum l1prim_type {
 	L1P_T_REQ,
 	L1P_T_CONF,
diff --git a/src/osmo-bts-sysmo/l1_fwd_main.c b/src/osmo-bts-sysmo/l1_fwd_main.c
index e2b0d5ec..527a559e 100644
--- a/src/osmo-bts-sysmo/l1_fwd_main.c
+++ b/src/osmo-bts-sysmo/l1_fwd_main.c
@@ -93,7 +93,7 @@ int l1if_handle_sysprim(struct femtol1_hdl *fl1h, struct msgb *msg)
 /* data has arrived on the udp socket */
 static int udp_read_cb(struct osmo_fd *ofd)
 {
-	struct msgb *msg = msgb_alloc_headroom(sizeof(SuperFemto_Prim_t) + 128, 128, "udp_rx");
+	struct msgb *msg = msgb_alloc_headroom(SYSMOBTS_PRIM_SIZE, 128, "udp_rx");
 	struct l1fwd_hdl *l1fh = ofd->data;
 	struct femtol1_hdl *fl1h = l1fh->fl1h;
 	int rc;
diff --git a/src/osmo-bts-sysmo/l1_transp_fwd.c b/src/osmo-bts-sysmo/l1_transp_fwd.c
index 1a1aa4f9..129afe79 100644
--- a/src/osmo-bts-sysmo/l1_transp_fwd.c
+++ b/src/osmo-bts-sysmo/l1_transp_fwd.c
@@ -64,7 +64,7 @@ static const uint16_t fwd_udp_ports[] = {
 
 static int fwd_read_cb(struct osmo_fd *ofd)
 {
-	struct msgb *msg = msgb_alloc_headroom(sizeof(SuperFemto_Prim_t) + 128, 128, "udp_rx");
+	struct msgb *msg = msgb_alloc_headroom(SYSMOBTS_PRIM_SIZE, 128, "udp_rx");
 	struct femtol1_hdl *fl1h = ofd->data;
 	int rc;
 
diff --git a/src/osmo-bts-sysmo/l1_transp_hw.c b/src/osmo-bts-sysmo/l1_transp_hw.c
index d4b99780..0bfc5089 100644
--- a/src/osmo-bts-sysmo/l1_transp_hw.c
+++ b/src/osmo-bts-sysmo/l1_transp_hw.c
@@ -82,11 +82,17 @@ static const char *wr_devnames[] = {
 #endif
 };
 
+/*
+ * Make sure that all structs we read fit into the SYSMOBTS_PRIM_SIZE
+ */
+osmo_static_assert(sizeof(GsmL1_Prim_t) + 128 <= SYSMOBTS_PRIM_SIZE, prim)
+osmo_static_assert(sizeof(SuperFemto_Prim_t) + 128 <= SYSMOBTS_PRIM_SIZE, prim)
+
 /* 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 msgb *msg = msgb_alloc_headroom(SYSMOBTS_PRIM_SIZE, 128, "1l_fd");
 	struct femtol1_hdl *fl1h = ofd->data;
 	int rc;