zephyr/drivers/serial/uart_hvc_xen.c

295 lines
6.9 KiB
C

/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/arch/arm64/hypercall.h>
#include <zephyr/xen/console.h>
#include <zephyr/xen/events.h>
#include <zephyr/xen/generic.h>
#include <zephyr/xen/hvm.h>
#include <zephyr/xen/public/io/console.h>
#include <zephyr/xen/public/sched.h>
#include <zephyr/xen/public/xen.h>
#include <zephyr/device.h>
#include <zephyr/init.h>
#include <zephyr/kernel.h>
#include <zephyr/sys/device_mmio.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(uart_hvc_xen, CONFIG_UART_LOG_LEVEL);
static struct hvc_xen_data xen_hvc_data = {0};
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void hvc_uart_evtchn_cb(void *priv);
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static int read_from_ring(const struct device *dev, char *str, int len)
{
int recv = 0;
struct hvc_xen_data *hvc_data = dev->data;
XENCONS_RING_IDX cons = hvc_data->intf->in_cons;
XENCONS_RING_IDX prod = hvc_data->intf->in_prod;
XENCONS_RING_IDX in_idx = 0;
compiler_barrier();
__ASSERT((prod - cons) <= sizeof(hvc_data->intf->in),
"Invalid input ring buffer");
while (cons != prod && recv < len) {
in_idx = MASK_XENCONS_IDX(cons, hvc_data->intf->in);
str[recv] = hvc_data->intf->in[in_idx];
recv++;
cons++;
}
compiler_barrier();
hvc_data->intf->in_cons = cons;
notify_evtchn(hvc_data->evtchn);
return recv;
}
static int write_to_ring(const struct device *dev, const char *str, int len)
{
int sent = 0;
struct hvc_xen_data *hvc_data = dev->data;
XENCONS_RING_IDX cons = hvc_data->intf->out_cons;
XENCONS_RING_IDX prod = hvc_data->intf->out_prod;
XENCONS_RING_IDX out_idx = 0;
compiler_barrier();
__ASSERT((prod - cons) <= sizeof(hvc_data->intf->out),
"Invalid output ring buffer");
while ((sent < len) && ((prod - cons) < sizeof(hvc_data->intf->out))) {
out_idx = MASK_XENCONS_IDX(prod, hvc_data->intf->out);
hvc_data->intf->out[out_idx] = str[sent];
prod++;
sent++;
}
compiler_barrier();
hvc_data->intf->out_prod = prod;
if (sent) {
notify_evtchn(hvc_data->evtchn);
}
return sent;
}
static int xen_hvc_poll_in(const struct device *dev,
unsigned char *c)
{
int ret = 0;
char temp;
ret = read_from_ring(dev, &temp, sizeof(temp));
if (!ret) {
/* Char was not received */
return -1;
}
*c = temp;
return 0;
}
static void xen_hvc_poll_out(const struct device *dev,
unsigned char c)
{
/* Not a good solution (notifying HV every time), but needed for poll_out */
(void) write_to_ring(dev, &c, sizeof(c));
}
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static int xen_hvc_fifo_fill(const struct device *dev, const uint8_t *tx_data,
int len)
{
int ret = 0, sent = 0;
while (len) {
sent = write_to_ring(dev, tx_data, len);
ret += sent;
tx_data += sent;
len -= sent;
if (len) {
/* Need to be able to read it from another domain */
HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
}
}
return ret;
}
static int xen_hvc_fifo_read(const struct device *dev, uint8_t *rx_data,
const int size)
{
return read_from_ring(dev, rx_data, size);
}
static void xen_hvc_irq_tx_enable(const struct device *dev)
{
/*
* Need to explicitly call UART callback on TX enabling to
* process available buffered TX actions, because no HV events
* will be generated on tx_enable.
*/
hvc_uart_evtchn_cb(dev->data);
}
static int xen_hvc_irq_tx_ready(const struct device *dev)
{
return 1;
}
static void xen_hvc_irq_rx_enable(const struct device *dev)
{
/*
* Need to explicitly call UART callback on RX enabling to
* process available buffered RX actions, because no HV events
* will be generated on rx_enable.
*/
hvc_uart_evtchn_cb(dev->data);
}
static int xen_hvc_irq_tx_complete(const struct device *dev)
{
/*
* TX is performed by copying in ring buffer by fifo_fill,
* so it will be always completed.
*/
return 1;
}
static int xen_hvc_irq_rx_ready(const struct device *dev)
{
struct hvc_xen_data *data = dev->data;
/* RX is ready only if data is available in ring buffer */
return (data->intf->in_prod != data->intf->in_cons);
}
static int xen_hvc_irq_is_pending(const struct device *dev)
{
return xen_hvc_irq_rx_ready(dev);
}
static int xen_hvc_irq_update(const struct device *dev)
{
/* Nothing needs to be updated before actual ISR */
return 1;
}
static void xen_hvc_irq_callback_set(const struct device *dev,
uart_irq_callback_user_data_t cb, void *user_data)
{
struct hvc_xen_data *data = dev->data;
data->irq_cb = cb;
data->irq_cb_data = user_data;
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static const struct uart_driver_api xen_hvc_api = {
.poll_in = xen_hvc_poll_in,
.poll_out = xen_hvc_poll_out,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = xen_hvc_fifo_fill,
.fifo_read = xen_hvc_fifo_read,
.irq_tx_enable = xen_hvc_irq_tx_enable,
.irq_tx_ready = xen_hvc_irq_tx_ready,
.irq_rx_enable = xen_hvc_irq_rx_enable,
.irq_tx_complete = xen_hvc_irq_tx_complete,
.irq_rx_ready = xen_hvc_irq_rx_ready,
.irq_is_pending = xen_hvc_irq_is_pending,
.irq_update = xen_hvc_irq_update,
.irq_callback_set = xen_hvc_irq_callback_set,
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
};
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static void hvc_uart_evtchn_cb(void *priv)
{
struct hvc_xen_data *data = priv;
if (data->irq_cb) {
data->irq_cb(data->dev, data->irq_cb_data);
}
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
int xen_console_init(const struct device *dev)
{
int ret = 0;
uint64_t console_pfn = 0;
uintptr_t console_addr = 0;
struct hvc_xen_data *data = dev->data;
data->dev = dev;
ret = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, DOMID_SELF, &data->evtchn);
if (ret) {
LOG_ERR("%s: failed to get Xen console evtchn, ret = %d\n",
__func__, ret);
return ret;
}
ret = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, DOMID_SELF, &console_pfn);
if (ret) {
LOG_ERR("%s: failed to get Xen console PFN, ret = %d\n",
__func__, ret);
return ret;
}
console_addr = (uintptr_t) (console_pfn << XEN_PAGE_SHIFT);
device_map(DEVICE_MMIO_RAM_PTR(dev), console_addr, XEN_PAGE_SIZE,
K_MEM_CACHE_WB);
data->intf = (struct xencons_interface *) DEVICE_MMIO_GET(dev);
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
bind_event_channel(data->evtchn, hvc_uart_evtchn_cb, data);
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
LOG_INF("Xen HVC inited successfully\n");
return 0;
}
DEVICE_DT_DEFINE(DT_NODELABEL(xen_hvc), xen_console_init, NULL, &xen_hvc_data,
NULL, PRE_KERNEL_1, CONFIG_XEN_HVC_INIT_PRIORITY,
&xen_hvc_api);
#ifdef CONFIG_XEN_EARLY_CONSOLEIO
extern void __printk_hook_install(int (*fn)(int));
extern void __stdout_hook_install(int (*fn)(int));
int xen_consoleio_putc(int c)
{
char symbol = (char) c;
HYPERVISOR_console_io(CONSOLEIO_write, sizeof(symbol), &symbol);
return c;
}
int consoleio_hooks_set(void)
{
/* Will be replaced with poll_in/poll_out by uart_console.c later on boot */
__stdout_hook_install(xen_consoleio_putc);
__printk_hook_install(xen_consoleio_putc);
return 0;
}
SYS_INIT(consoleio_hooks_set, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
#endif /* CONFIG_XEN_EARLY_CONSOLEIO */