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>
This commit is contained in:
AKASHI Takahiro 2020-10-15 13:25:16 +09:00 committed by Tom Rini
parent 16389a74c5
commit 82e21b391b
2 changed files with 31 additions and 3 deletions

View File

@ -401,11 +401,19 @@ config DEBUG_UART_MTK
driver will be available until the real driver model serial is
running.
config DEBUG_UART_XEN
bool "XEN Hypervisor Console"
depends on XEN_SERIAL
help
Select this to enable a debug UART using the serial_xen driver. You
will not have to provide any parameters to make this work. The driver
will be available until the real driver-model serial is running.
endchoice
config DEBUG_UART_BASE
hex "Base address of UART"
depends on DEBUG_UART
depends on DEBUG_UART && !DEBUG_UART_XEN
default 0 if DEBUG_UART_SANDBOX
help
This is the base address of your UART for memory-mapped UARTs.
@ -415,7 +423,7 @@ config DEBUG_UART_BASE
config DEBUG_UART_CLOCK
int "UART input clock"
depends on DEBUG_UART
depends on DEBUG_UART && !DEBUG_UART_XEN
default 0 if DEBUG_UART_SANDBOX
help
The UART input clock determines the speed of the internal UART
@ -427,7 +435,7 @@ config DEBUG_UART_CLOCK
config DEBUG_UART_SHIFT
int "UART register shift"
depends on DEBUG_UART
depends on DEBUG_UART && !DEBUG_UART_XEN
default 0 if DEBUG_UART
help
Some UARTs (notably ns16550) support different register layouts

View File

@ -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