[PATCH 22/25 v6] xen/arm: vpl011: Add support for vuart console in xenconsole

[Bhupinder Thakur <bhupinder.thakur@linaro.org>]

This patch finally adds the support for vuart console. It adds
two new fields in the console initialization:

- optional
- prefer_gnttab

optional flag tells whether the console is optional.

prefer_gnttab tells whether the ring buffer should be allocated using
grant table.

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>
---
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>

Changes since v4:
- Renamed VUART_CFLAGS- to CFLAGS_vuart- in the Makefile as per the convention.

 config/arm32.mk           |  1 +
 config/arm64.mk           |  1 +
 tools/console/Makefile    |  3 ++-
 tools/console/daemon/io.c | 29 ++++++++++++++++++++++++++++-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/config/arm32.mk b/config/arm32.mk
index f95228e..b9f23fe 100644
--- a/config/arm32.mk
+++ b/config/arm32.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_32 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/config/arm64.mk b/config/arm64.mk
index aa45772..861d0a4 100644
--- a/config/arm64.mk
+++ b/config/arm64.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_64 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/tools/console/Makefile b/tools/console/Makefile
index c8b0300..1cddb6e 100644
--- a/tools/console/Makefile
+++ b/tools/console/Makefile
@@ -11,6 +11,7 @@ LDLIBS += $(SOCKET_LIBS)
 
 LDLIBS_xenconsoled += $(UTIL_LIBS)
 LDLIBS_xenconsoled += -lrt
+CFLAGS_vuart-$(CONFIG_VUART_CONSOLE) = -DCONFIG_VUART_CONSOLE
 
 BIN      = xenconsoled xenconsole
 
@@ -28,7 +29,7 @@ clean:
 distclean: clean
 
 daemon/main.o: daemon/_paths.h
-daemon/io.o: CFLAGS += $(CFLAGS_libxenevtchn) $(CFLAGS_libxengnttab)
+daemon/io.o: CFLAGS += $(CFLAGS_libxenevtchn) $(CFLAGS_libxengnttab) $(CFLAGS_vuart-y)
 xenconsoled: $(patsubst %.c,%.o,$(wildcard daemon/*.c))
 	$(CC) $(LDFLAGS) $^ -o $@ $(LDLIBS) $(LDLIBS_libxenevtchn) $(LDLIBS_libxengnttab) $(LDLIBS_xenconsoled) $(APPEND_LDFLAGS)
 
diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index 49f085c..c6d4cae 100644
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -107,12 +107,16 @@ struct console {
 	xenevtchn_port_or_error_t remote_port;
 	struct xencons_interface *interface;
 	struct domain *d;
+	bool optional;
+	bool prefer_gnttab;
 };
 
 struct console_data {
 	const char *const xsname;
 	const char *const ttyname;
 	const char *const log_suffix;
+	bool optional;
+	bool prefer_gnttab;
 };
 
 static struct console_data console_data[] = {
@@ -120,7 +124,18 @@ static struct console_data console_data[] = {
 		.xsname = "/console",
 		.ttyname = "tty",
 		.log_suffix = "",
+		.optional = false,
+		.prefer_gnttab = true,
 	},
+#if defined(CONFIG_VUART_CONSOLE)
+	{
+		.xsname = "/vuart/0",
+		.ttyname = "tty",
+		.log_suffix = "-vuart0",
+		.optional = true,
+		.prefer_gnttab = false,
+	},
+#endif
 };
 
 #define MAX_CONSOLE (sizeof(console_data)/sizeof(struct console_data))
@@ -655,8 +670,18 @@ static int console_create_ring(struct console *con)
 			"ring-ref", "%u", &ring_ref,
 			"port", "%i", &remote_port,
 			NULL);
+
 	if (err)
+	{
+		/*
+		 * This is a normal condition for optional consoles: they might not be
+		 * present on xenstore at all. In that case, just return without error.
+		*/
+		if (con->optional)
+			err = 0;
+
 		goto out;
+	}
 
 	snprintf(path, sizeof(path), "%s/type", con->xspath);
 	type = xs_read(xs, XBT_NULL, path, NULL);
@@ -670,7 +695,9 @@ static int console_create_ring(struct console *con)
 	if (ring_ref != con->ring_ref && con->ring_ref != -1)
 		console_unmap_interface(con);
 
-	if (!con->interface && xgt_handle) {
+	if (!con->interface &&
+	    xgt_handle &&
+	    con->prefer_gnttab) {
 		/* Prefer using grant table */
 		con->interface = xengnttab_map_grant_ref(xgt_handle,
 			dom->domid, GNTTAB_RESERVED_CONSOLE,
-- 
2.7.4


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