From 82e21b391bd315f6fe0e0b79326af8a141e9cca7 Mon Sep 17 00:00:00 2001
From: AKASHI Takahiro <takahiro.akashi@linaro.org>
Date: Thu, 15 Oct 2020 13:25:16 +0900
Subject: serial: serial_xen: add DEBUG_UART support

By using a hypervisor call, we can implement DEBUG_UART on xen.
This will allow us to see messages even earlier than serial_init().

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 drivers/serial/serial_xen.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'drivers/serial/serial_xen.c')

diff --git a/drivers/serial/serial_xen.c b/drivers/serial/serial_xen.c
index ed191829f0..34c90ece40 100644
--- a/drivers/serial/serial_xen.c
+++ b/drivers/serial/serial_xen.c
@@ -5,6 +5,7 @@
  */
 #include <common.h>
 #include <cpu_func.h>
+#include <debug_uart.h>
 #include <dm.h>
 #include <serial.h>
 #include <watchdog.h>
@@ -15,11 +16,14 @@
 #include <xen/events.h>
 
 #include <xen/interface/sched.h>
+#include <xen/interface/xen.h>
 #include <xen/interface/hvm/hvm_op.h>
 #include <xen/interface/hvm/params.h>
 #include <xen/interface/io/console.h>
 #include <xen/interface/io/ring.h>
 
+#include <asm/xen/hypercall.h>
+
 DECLARE_GLOBAL_DATA_PTR;
 
 u32 console_evtchn;
@@ -178,3 +182,19 @@ U_BOOT_DRIVER(serial_xen) = {
 	.flags			= DM_FLAG_PRE_RELOC,
 };
 
+#if defined(CONFIG_DEBUG_UART_XEN)
+static inline void _debug_uart_init(void) {}
+
+static inline void _debug_uart_putc(int c)
+{
+#if CONFIG_IS_ENABLED(ARM)
+	xen_debug_putc(c);
+#else
+	/* the type cast should work on LE only */
+	HYPERVISOR_console_io(CONSOLEIO_write, 1, (char *)&ch);
+#endif
+}
+
+DEBUG_UART_FUNCS
+
+#endif
-- 
cgit