zephyr/drivers/console/rtt_console.c
Gerard Marull-Paretas a5fd0d184a init: remove the need for a dummy device pointer in SYS_INIT functions
The init infrastructure, found in `init.h`, is currently used by:

- `SYS_INIT`: to call functions before `main`
- `DEVICE_*`: to initialize devices

They are all sorted according to an initialization level + a priority.
`SYS_INIT` calls are really orthogonal to devices, however, the required
function signature requires a `const struct device *dev` as a first
argument. The only reason for that is because the same init machinery is
used by devices, so we have something like:

```c
struct init_entry {
	int (*init)(const struct device *dev);
	/* only set by DEVICE_*, otherwise NULL */
	const struct device *dev;
}
```

As a result, we end up with such weird/ugly pattern:

```c
static int my_init(const struct device *dev)
{
	/* always NULL! add ARG_UNUSED to avoid compiler warning */
	ARG_UNUSED(dev);
	...
}
```

This is really a result of poor internals isolation. This patch proposes
a to make init entries more flexible so that they can accept sytem
initialization calls like this:

```c
static int my_init(void)
{
	...
}
```

This is achieved using a union:

```c
union init_function {
	/* for SYS_INIT, used when init_entry.dev == NULL */
	int (*sys)(void);
	/* for DEVICE*, used when init_entry.dev != NULL */
	int (*dev)(const struct device *dev);
};

struct init_entry {
	/* stores init function (either for SYS_INIT or DEVICE*)
	union init_function init_fn;
	/* stores device pointer for DEVICE*, NULL for SYS_INIT. Allows
	 * to know which union entry to call.
	 */
	const struct device *dev;
}
```

This solution **does not increase ROM usage**, and allows to offer clean
public APIs for both SYS_INIT and DEVICE*. Note that however, init
machinery keeps a coupling with devices.

**NOTE**: This is a breaking change! All `SYS_INIT` functions will need
to be converted to the new signature. See the script offered in the
following commit.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

init: convert SYS_INIT functions to the new signature

Conversion scripted using scripts/utils/migrate_sys_init.py.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

manifest: update projects for SYS_INIT changes

Update modules with updated SYS_INIT calls:

- hal_ti
- lvgl
- sof
- TraceRecorderSource

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: devicetree: devices: adjust test

Adjust test according to the recently introduced SYS_INIT
infrastructure.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

tests: kernel: threads: adjust SYS_INIT call

Adjust to the new signature: int (*init_fn)(void);

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2023-04-12 14:28:07 +00:00

93 lines
2.1 KiB
C

/* rtt_console.c - Console messages to a RAM buffer that is then read by
* the Segger J-Link debugger
*/
/*
* Copyright (c) 2016 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/kernel.h>
#include <zephyr/sys/printk.h>
#include <zephyr/device.h>
#include <zephyr/init.h>
#include <SEGGER_RTT.h>
extern void __printk_hook_install(int (*fn)(int));
extern void __stdout_hook_install(int (*fn)(int));
static bool host_present;
/** @brief Wait for fixed period.
*
*/
static void wait(void)
{
if (!IS_ENABLED(CONFIG_MULTITHREADING) || k_is_in_isr()) {
if (IS_ENABLED(CONFIG_RTT_TX_RETRY_IN_INTERRUPT)) {
k_busy_wait(1000*CONFIG_RTT_TX_RETRY_DELAY_MS);
}
} else {
k_msleep(CONFIG_RTT_TX_RETRY_DELAY_MS);
}
}
static int rtt_console_out(int character)
{
char c = (char)character;
unsigned int cnt;
int max_cnt = CONFIG_RTT_TX_RETRY_CNT;
do {
SEGGER_RTT_LOCK();
cnt = SEGGER_RTT_WriteNoLock(0, &c, 1);
SEGGER_RTT_UNLOCK();
/* There are two possible reasons for not writing any data to
* RTT:
* - The host is not connected and not reading the data.
* - The buffer got full and will be read by the host.
* These two situations are distinguished using the following
* algorithm:
* At the beginning, the module assumes that the host is active,
* so when no data is read, it busy waits and retries.
* If, after retrying, the host reads the data, the module
* assumes that the host is active. If it fails, the module
* assumes that the host is inactive and stores that
* information. On next call, only one attempt takes place.
* The host is marked as active if the attempt is successful.
*/
if (cnt) {
/* byte processed - host is present. */
host_present = true;
} else if (host_present) {
if (max_cnt) {
wait();
max_cnt--;
continue;
} else {
host_present = false;
}
}
break;
} while (1);
return character;
}
static int rtt_console_init(void)
{
#ifdef CONFIG_PRINTK
__printk_hook_install(rtt_console_out);
#endif
__stdout_hook_install(rtt_console_out);
return 0;
}
SYS_INIT(rtt_console_init, PRE_KERNEL_1, CONFIG_CONSOLE_INIT_PRIORITY);