subsys/logging/log_backend_adsp_hda.c

/*
 * Copyright (c) 2022 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/arch/xtensa/cache.h>
#include <zephyr/logging/log_backend.h>
#include <zephyr/logging/log_core.h>
#include <zephyr/logging/log_output.h>
#include <zephyr/logging/log_output_dict.h>
#include <zephyr/logging/log_backend_std.h>
#include <zephyr/logging/log_backend_adsp_hda.h>
#include <zephyr/drivers/dma.h>
#include <zephyr/kernel.h>

static uint32_t log_format_current = CONFIG_LOG_BACKEND_ADSP_HDA_OUTPUT_DEFAULT;
static const struct device *const hda_log_dev =
	DEVICE_DT_GET(DT_NODELABEL(hda_host_in));
static uint32_t hda_log_chan;

/*
 * HDA requires 128 byte aligned data and 128 byte aligned transfers.
 */
#define ALIGNMENT DMA_BUF_ALIGNMENT(DT_NODELABEL(hda_host_in))
static __aligned(ALIGNMENT) uint8_t hda_log_buf[CONFIG_LOG_BACKEND_ADSP_HDA_SIZE];
static volatile uint32_t hda_log_buffered;
static struct k_timer hda_log_timer;
static adsp_hda_log_hook_t hook;
static uint32_t write_idx;
static struct k_spinlock hda_log_lock;

/* atomic bit flags for state */
#define HDA_LOG_DMA_READY 0
#define HDA_LOG_PANIC_MODE 1
static atomic_t hda_log_flags;


/**
 * Flush the buffered log to the HDA stream
 *
 * If @kconfig{CONFIG_LOG_BACKEND_ADSP_HDA_PADDING} is enabled
 * the buffer is extended with '\0' characters to align the buffer
 * to 128 bytes.
 */
static uint32_t hda_log_flush(void)
{
	if (hda_log_buffered == 0) {
		return 0;
	}

	uint32_t nearest128 = hda_log_buffered & ~((128) - 1);

#ifdef CONFIG_LOG_BACKEND_ADSP_HDA_PADDING
	if (nearest128 != hda_log_buffered) {
		uint32_t next128 = nearest128 + 128;
		uint32_t padding = next128 - hda_log_buffered;

		for (int i = 0; i < padding; i++) {
			hda_log_buf[write_idx] = '\0';
			hda_log_buffered++;
			write_idx++;
		}
		nearest128 = hda_log_buffered & ~((128) - 1);
	}
	__ASSERT(hda_log_buffered == nearest128,
		"Expected flush length to be 128 byte aligned");
#endif

#if !(IS_ENABLED(CONFIG_KERNEL_COHERENCE))
	z_xtensa_cache_flush(hda_log_buf, CONFIG_LOG_BACKEND_ADSP_HDA_SIZE);
#endif
	dma_reload(hda_log_dev, hda_log_chan, 0, 0, nearest128);

	hda_log_buffered = hda_log_buffered - nearest128;

	return nearest128;
}

static int hda_log_out(uint8_t *data, size_t length, void *ctx)
{
	int ret;
	bool do_log_flush;
	struct dma_status status;

	k_spinlock_key_t key = k_spin_lock(&hda_log_lock);

	/* Defaults when DMA not yet initialized */
	uint32_t dma_free = sizeof(hda_log_buf);
	uint32_t write_pos = 0;

	if (atomic_test_bit(&hda_log_flags, HDA_LOG_DMA_READY)) {
		ret = dma_get_status(hda_log_dev, hda_log_chan, &status);
		if (ret != 0) {
			ret = length;
			goto out;
		}

		/* The hardware tells us what space we have available, and where to
		 * start writing. If the buffer is full we have no space.
		 */
		if (status.free <= 0) {
			ret = length;
			goto out;
		}

		dma_free = status.free;
		write_pos = status.write_position;
	}

	/* Account for buffered writes since last dma_reload
	 *
	 * No underflow should be possible here, status.free is the apparent
	 * free space in the buffer from the DMA's read/write positions.
	 * When dma_reload is called status.free may be reduced by
	 * the nearest 128 divisible value of hda_log_buffered,
	 * where hda_log_buffered is then subtracted by the same amount.
	 * After which status.free should only increase in value.
	 *
	 * Assert this trueth though, just in case.
	 */
	__ASSERT_NO_MSG(dma_free > hda_log_buffered);
	uint32_t available = dma_free - hda_log_buffered;

	/* If there isn't enough space for the message there's an overflow */
	if (available < length) {
		ret = 0;
		goto out;
	}

	/* Copy over the message to the buffer */
	write_idx = write_pos + hda_log_buffered;

	if (write_idx > sizeof(hda_log_buf)) {
		write_idx -= sizeof(hda_log_buf);
	}

	size_t copy_len = (write_idx + length) < sizeof(hda_log_buf) ? length
		: sizeof(hda_log_buf) - write_idx;

	memcpy(&hda_log_buf[write_idx], data, copy_len);
	write_idx += copy_len;

	/* There may be a wrapped copy */
	size_t wrap_copy_len = length - copy_len;

	if (wrap_copy_len != 0) {
		memcpy(&hda_log_buf[0], &data[copy_len], wrap_copy_len);
		write_idx = wrap_copy_len;
	}

	ret = length;
	hda_log_buffered += length;

	uint32_t written = 0;

out:
	/* If DMA_READY changes from unset to set during this call, that is
	 * perfectly acceptable. The default values for write_pos and dma_free
	 * are the correct values if that occurs.
	 */
	do_log_flush = ((hda_log_buffered > sizeof(hda_log_buf)/2) ||
			  atomic_test_bit(&hda_log_flags, HDA_LOG_PANIC_MODE))
			  && atomic_test_bit(&hda_log_flags, HDA_LOG_DMA_READY);

	/* Flush if there's a hook set AND dma is ready */
	if (do_log_flush && hook != NULL) {
		written = hda_log_flush();
	}

	k_spin_unlock(&hda_log_lock, key);

	/* The hook may have log calls and needs to be done outside of the spin
	 * lock to avoid recursion on the spin lock (deadlocks) in cases of
	 * direct logging.
	 */
	if (hook != NULL && written  > 0) {
		hook(written);
	}

	return ret;
}
/**
 * 128 bytes is the smallest transferrable size for HDA so use that
 * and encompass almost all log lines in the formatter before flushing
 * and memcpy'ing to the HDA buffer.
 */
#define LOG_BUF_SIZE 128
static uint8_t log_buf[LOG_BUF_SIZE];
LOG_OUTPUT_DEFINE(log_output_adsp_hda, hda_log_out, log_buf, LOG_BUF_SIZE);

static void hda_log_periodic(struct k_timer *tm)
{
	ARG_UNUSED(tm);

	uint32_t written = 0;
	k_spinlock_key_t key = k_spin_lock(&hda_log_lock);


	if (hook != NULL) {
		written = hda_log_flush();
	}


	/* The hook may have log calls and needs to be done outside of the spin
	 * lock to avoid recursion on the spin lock (deadlocks) in cases of
	 * direct logging.
	 */
	if (hook != NULL && written  > 0) {
		hook(written);
	}

	k_spin_unlock(&hda_log_lock, key);
}

static inline void dropped(const struct log_backend *const backend,
			   uint32_t cnt)
{
	ARG_UNUSED(backend);

	if (IS_ENABLED(CONFIG_LOG_DICTIONARY_SUPPORT)) {
		log_dict_output_dropped_process(&log_output_adsp_hda, cnt);
	} else {
		log_output_dropped_process(&log_output_adsp_hda, cnt);
	}
}

static void panic(struct log_backend const *const backend)
{
	ARG_UNUSED(backend);

	/* will immediately flush all future writes once set */
	atomic_set_bit(&hda_log_flags, HDA_LOG_PANIC_MODE);

	/* flushes the log queue */
	log_backend_std_panic(&log_output_adsp_hda);
}

static int format_set(const struct log_backend *const backend, uint32_t log_type)
{
	ARG_UNUSED(backend);

	log_format_current = log_type;

	return 0;
}

static volatile uint32_t counter;

static void process(const struct log_backend *const backend,
		union log_msg_generic *msg)
{
	ARG_UNUSED(backend);
	uint32_t flags = log_backend_std_get_flags();

	log_format_func_t log_output_func = log_format_func_t_get(log_format_current);

	log_output_func(&log_output_adsp_hda, &msg->log, flags);
}

/**
 * Lazily initialized, while the DMA may not be setup we continue
 * to buffer log messages untilt he buffer is full.
 */
static void init(const struct log_backend *const backend)
{
	ARG_UNUSED(backend);

	hda_log_buffered = 0;
}

const struct log_backend_api log_backend_adsp_hda_api = {
	.process = process,
	.dropped = IS_ENABLED(CONFIG_LOG_MODE_IMMEDIATE) ? NULL : dropped,
	.panic = panic,
	.format_set = format_set,
	.init = init,
};

LOG_BACKEND_DEFINE(log_backend_adsp_hda, log_backend_adsp_hda_api, true);

void adsp_hda_log_init(adsp_hda_log_hook_t fn, uint32_t channel)
{
	hook = fn;

	int res;

	__ASSERT(device_is_ready(hda_log_dev), "DMA device is not ready");

	hda_log_chan = dma_request_channel(hda_log_dev, &channel);
	__ASSERT(hda_log_chan >= 0, "No valid DMA channel");
	__ASSERT(hda_log_chan == channel, "Not requested channel");

	hda_log_buffered = 0;

	/* configure channel */
	struct dma_block_config hda_log_dma_blk_cfg = {
		.block_size = CONFIG_LOG_BACKEND_ADSP_HDA_SIZE,
		.source_address = (uint32_t)(uintptr_t)&hda_log_buf,
	};

	struct dma_config hda_log_dma_cfg = {
		.channel_direction = MEMORY_TO_HOST,
		.block_count = 1,
		.head_block = &hda_log_dma_blk_cfg,
		.source_data_size = 4,
	};

	res = dma_config(hda_log_dev, hda_log_chan, &hda_log_dma_cfg);
	__ASSERT(res == 0, "DMA config failed");

	res = dma_start(hda_log_dev, hda_log_chan);
	__ASSERT(res == 0, "DMA start failed");

	atomic_set_bit(&hda_log_flags, HDA_LOG_DMA_READY);

	k_timer_init(&hda_log_timer, hda_log_periodic, NULL);
	k_timer_start(&hda_log_timer,
		      K_MSEC(CONFIG_LOG_BACKEND_ADSP_HDA_FLUSH_TIME),
		      K_MSEC(CONFIG_LOG_BACKEND_ADSP_HDA_FLUSH_TIME));

}

#ifdef CONFIG_LOG_BACKEND_ADSP_HDA_CAVSTOOL

#include <intel_adsp_ipc.h>
#include <cavstool.h>

#define CHANNEL 6
#define IPC_TIMEOUT K_MSEC(1500)

static inline void hda_ipc_msg(const struct device *dev, uint32_t data,
			       uint32_t ext, k_timeout_t timeout)
{
	__ASSERT(intel_adsp_ipc_send_message_sync(dev, data, ext, timeout),
		"Unexpected ipc send message failure, try increasing IPC_TIMEOUT");
}


void adsp_hda_log_cavstool_hook(uint32_t written)
{
	/* We *must* send this, but we may be in a timer ISR, so we are
	 * forced into a retry loop without timeouts and such.
	 */
	bool done = false;

	/*  Send IPC message notifying log data has been written */
	do {
		done = intel_adsp_ipc_send_message(INTEL_ADSP_IPC_HOST_DEV, IPCCMD_HDA_PRINT,
					     (written << 8) | CHANNEL);
	} while (!done);


	/* Wait for confirmation log data has been received */
	do {
		done = intel_adsp_ipc_is_complete(INTEL_ADSP_IPC_HOST_DEV);
	} while (!done);

}

int adsp_hda_log_cavstool_init(const struct device *dev)
{
	ARG_UNUSED(dev);

	hda_ipc_msg(INTEL_ADSP_IPC_HOST_DEV, IPCCMD_HDA_RESET, CHANNEL, IPC_TIMEOUT);
	hda_ipc_msg(INTEL_ADSP_IPC_HOST_DEV, IPCCMD_HDA_CONFIG,
		    CHANNEL | (CONFIG_LOG_BACKEND_ADSP_HDA_SIZE << 8), IPC_TIMEOUT);
	adsp_hda_log_init(adsp_hda_log_cavstool_hook, CHANNEL);
	hda_ipc_msg(INTEL_ADSP_IPC_HOST_DEV, IPCCMD_HDA_START, CHANNEL, IPC_TIMEOUT);

	return 0;
}

SYS_INIT(adsp_hda_log_cavstool_init, POST_KERNEL, 99);

#endif /* CONFIG_LOG_BACKEND_ADSP_HDA_CAVSTOOL */