syslog/rpmsg: Don't overwrite up_putc

Hook into syslog subsystem like ramlog approach

drivers/syslog/syslog_channel.c

@@ -47,6 +47,8 @@
 
 #ifdef CONFIG_RAMLOG_SYSLOG
 #  include <nuttx/syslog/ramlog.h>
+#elif defined(CONFIG_SYSLOG_RPMSG)
+#  include <nuttx/syslog/syslog_rpmsg.h>
 #elif defined(CONFIG_ARCH_LOWPUTC)
 #  include <nuttx/arch.h>
 #endif
@@ -59,7 +61,7 @@
 
 #if defined(CONFIG_ARCH_LOWPUTC)
 #  define HAVE_LOWPUTC
-#elif !defined(CONFIG_RAMLOG_SYSLOG)
+#elif !defined(CONFIG_RAMLOG_SYSLOG) && !defined(CONFIG_SYSLOG_RPMSG)
 #  define NEED_LOWPUTC
 #endif
 
@@ -83,6 +85,13 @@ const struct syslog_channel_s g_default_channel =
   ramlog_putc,
   syslog_default_flush
 };
+#elif defined(CONFIG_SYSLOG_RPMSG)
+const struct syslog_channel_s g_default_channel =
+{
+  syslog_rpmsg_putc,
+  syslog_rpmsg_putc,
+  syslog_default_flush
+};
 #elif defined(HAVE_LOWPUTC)
 const struct syslog_channel_s g_default_channel =
 {

drivers/syslog/syslog_rpmsg.c

@@ -44,7 +44,6 @@
 #include <errno.h>
 #include <string.h>
 
-#include <nuttx/arch.h>
 #include <nuttx/irq.h>
 #include <nuttx/rptun/openamp.h>
 #include <nuttx/syslog/syslog.h>
@@ -347,7 +346,7 @@ static int syslog_rpmsg_ept_cb(FAR struct rpmsg_endpoint *ept, FAR void *data,
  * Public Functions
  ****************************************************************************/
 
-int up_putc(int ch)
+int syslog_rpmsg_putc(int ch)
 {
   FAR struct syslog_rpmsg_s *priv = &g_syslog_rpmsg;
   irqstate_t flags;

include/nuttx/syslog/syslog_rpmsg.h

@@ -59,6 +59,7 @@ extern "C"
 int syslog_rpmsg_init_early(FAR const char *cpu_name, FAR void *buffer,
                             size_t size);
 int syslog_rpmsg_init(void);
+int syslog_rpmsg_putc(int ch);
 #endif
 
 #ifdef CONFIG_SYSLOG_RPMSG_SERVER