1 /*
2 * Copyright (c) 2021 EPAM Systems
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 *
6 * This driver implements input/output API for Xen domain through the
7 * Xen consoleio interface. This should be used only for Zephyr as initial
8 * domain (Dom0). For unprivileged domains regular ring buffer HVC driver
9 * should be used (uart_hvc_xen.c), this console will not be available.
10 */
11
12 #include <zephyr/arch/arm64/hypercall.h>
13 #include <zephyr/xen/public/xen.h>
14
15 #include <zephyr/device.h>
16 #include <zephyr/drivers/uart.h>
17 #include <zephyr/init.h>
18 #include <zephyr/kernel.h>
19
20 #define DT_DRV_COMPAT xen_hvc_consoleio
21
xen_consoleio_poll_in(const struct device * dev,unsigned char * c)22 static int xen_consoleio_poll_in(const struct device *dev,
23 unsigned char *c)
24 {
25 int ret = 0;
26 char temp;
27
28 ret = HYPERVISOR_console_io(CONSOLEIO_read, sizeof(temp), &temp);
29 if (!ret) {
30 /* Char was not received */
31 return -1;
32 }
33
34 *c = temp;
35 return 0;
36 }
37
xen_consoleio_poll_out(const struct device * dev,unsigned char c)38 static void xen_consoleio_poll_out(const struct device *dev,
39 unsigned char c)
40 {
41 (void) HYPERVISOR_console_io(CONSOLEIO_write, sizeof(c), &c);
42 }
43
44 static const struct uart_driver_api xen_consoleio_hvc_api = {
45 .poll_in = xen_consoleio_poll_in,
46 .poll_out = xen_consoleio_poll_out,
47 };
48
xen_consoleio_init(const struct device * dev)49 static int xen_consoleio_init(const struct device *dev)
50 {
51 /* Nothing to do, but still needed for device API */
52 return 0;
53 }
54
55 DEVICE_DT_INST_DEFINE(0, xen_consoleio_init, NULL, NULL,
56 NULL, PRE_KERNEL_1, CONFIG_XEN_HVC_INIT_PRIORITY,
57 &xen_consoleio_hvc_api);
58
