ASoC: Intel: avs: Inter process communication

Implement the IPC between Intel audio firmware and kernel driver. The
IPC allows transmission of requests, handling of responses as well as
unsolicited (i.e. firmware-generated) notifications.

A subscription mechanism is added to enable different parts of the
driver to register for specific notifications.

The part of the DSP boot process that involves sending ROM message
requires an extra step - must be followed by unstall operation of
MAIN_CORE. All other types of messages do not require such specific
handling, so separate set of functions is provided for sending these.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220311153544.136854-5-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 376 insertions, 0 deletions

diff --git a/sound/soc/intel/avs/ipc.c b/sound/soc/intel/avs/ipc.c
new file mode 100644
index 000000000000..b1986a82945d
--- /dev/null
+++ b/sound/soc/intel/avs/ipc.c
@@ -0,0 +1,376 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright(c) 2021-2022 Intel Corporation. All rights reserved.
+//
+// Authors: Cezary Rojewski <cezary.rojewski@intel.com>
+//          Amadeusz Slawinski <amadeuszx.slawinski@linux.intel.com>
+//
+
+#include <linux/slab.h>
+#include <sound/hdaudio_ext.h>
+#include "avs.h"
+#include "messages.h"
+#include "registers.h"
+
+#define AVS_IPC_TIMEOUT_MS	300
+
+static void avs_dsp_receive_rx(struct avs_dev *adev, u64 header)
+{
+	struct avs_ipc *ipc = adev->ipc;
+	union avs_reply_msg msg = AVS_MSG(header);
+
+	ipc->rx.header = header;
+	/* Abort copying payload if request processing was unsuccessful. */
+	if (!msg.status)
+		memcpy_fromio(ipc->rx.data, avs_uplink_addr(adev), ipc->rx.size);
+}
+
+static void avs_dsp_process_notification(struct avs_dev *adev, u64 header)
+{
+	struct avs_notify_mod_data mod_data;
+	union avs_notify_msg msg = AVS_MSG(header);
+	size_t data_size = 0;
+	void *data = NULL;
+
+	/* Ignore spurious notifications until handshake is established. */
+	if (!adev->ipc->ready && msg.notify_msg_type != AVS_NOTIFY_FW_READY) {
+		dev_dbg(adev->dev, "FW not ready, skip notification: 0x%08x\n", msg.primary);
+		return;
+	}
+
+	/* Calculate notification payload size. */
+	switch (msg.notify_msg_type) {
+	case AVS_NOTIFY_FW_READY:
+		break;
+
+	case AVS_NOTIFY_PHRASE_DETECTED:
+		data_size = sizeof(struct avs_notify_voice_data);
+		break;
+
+	case AVS_NOTIFY_RESOURCE_EVENT:
+		data_size = sizeof(struct avs_notify_res_data);
+		break;
+
+	case AVS_NOTIFY_MODULE_EVENT:
+		/* To know the total payload size, header needs to be read first. */
+		memcpy_fromio(&mod_data, avs_uplink_addr(adev), sizeof(mod_data));
+		data_size = sizeof(mod_data) + mod_data.data_size;
+		break;
+
+	default:
+		dev_info(adev->dev, "unknown notification: 0x%08x\n", msg.primary);
+		break;
+	}
+
+	if (data_size) {
+		data = kmalloc(data_size, GFP_KERNEL);
+		if (!data)
+			return;
+
+		memcpy_fromio(data, avs_uplink_addr(adev), data_size);
+	}
+
+	/* Perform notification-specific operations. */
+	switch (msg.notify_msg_type) {
+	case AVS_NOTIFY_FW_READY:
+		dev_dbg(adev->dev, "FW READY 0x%08x\n", msg.primary);
+		adev->ipc->ready = true;
+		complete(&adev->fw_ready);
+		break;
+
+	default:
+		break;
+	}
+
+	kfree(data);
+}
+
+void avs_dsp_process_response(struct avs_dev *adev, u64 header)
+{
+	struct avs_ipc *ipc = adev->ipc;
+
+	/*
+	 * Response may either be solicited - a reply for a request that has
+	 * been sent beforehand - or unsolicited (notification).
+	 */
+	if (avs_msg_is_reply(header)) {
+		/* Response processing is invoked from IRQ thread. */
+		spin_lock_irq(&ipc->rx_lock);
+		avs_dsp_receive_rx(adev, header);
+		ipc->rx_completed = true;
+		spin_unlock_irq(&ipc->rx_lock);
+	} else {
+		avs_dsp_process_notification(adev, header);
+	}
+
+	complete(&ipc->busy_completion);
+}
+
+irqreturn_t avs_dsp_irq_handler(int irq, void *dev_id)
+{
+	struct avs_dev *adev = dev_id;
+	struct avs_ipc *ipc = adev->ipc;
+	u32 adspis, hipc_rsp, hipc_ack;
+	irqreturn_t ret = IRQ_NONE;
+
+	adspis = snd_hdac_adsp_readl(adev, AVS_ADSP_REG_ADSPIS);
+	if (adspis == UINT_MAX || !(adspis & AVS_ADSP_ADSPIS_IPC))
+		return ret;
+
+	hipc_ack = snd_hdac_adsp_readl(adev, SKL_ADSP_REG_HIPCIE);
+	hipc_rsp = snd_hdac_adsp_readl(adev, SKL_ADSP_REG_HIPCT);
+
+	/* DSP acked host's request */
+	if (hipc_ack & SKL_ADSP_HIPCIE_DONE) {
+		/*
+		 * As an extra precaution, mask done interrupt. Code executed
+		 * due to complete() found below does not assume any masking.
+		 */
+		snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCCTL,
+				      AVS_ADSP_HIPCCTL_DONE, 0);
+
+		complete(&ipc->done_completion);
+
+		/* tell DSP it has our attention */
+		snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCIE,
+				      SKL_ADSP_HIPCIE_DONE,
+				      SKL_ADSP_HIPCIE_DONE);
+		/* unmask done interrupt */
+		snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCCTL,
+				      AVS_ADSP_HIPCCTL_DONE,
+				      AVS_ADSP_HIPCCTL_DONE);
+		ret = IRQ_HANDLED;
+	}
+
+	/* DSP sent new response to process */
+	if (hipc_rsp & SKL_ADSP_HIPCT_BUSY) {
+		/* mask busy interrupt */
+		snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCCTL,
+				      AVS_ADSP_HIPCCTL_BUSY, 0);
+
+		ret = IRQ_WAKE_THREAD;
+	}
+
+	return ret;
+}
+
+irqreturn_t avs_dsp_irq_thread(int irq, void *dev_id)
+{
+	struct avs_dev *adev = dev_id;
+	union avs_reply_msg msg;
+	u32 hipct, hipcte;
+
+	hipct = snd_hdac_adsp_readl(adev, SKL_ADSP_REG_HIPCT);
+	hipcte = snd_hdac_adsp_readl(adev, SKL_ADSP_REG_HIPCTE);
+
+	/* ensure DSP sent new response to process */
+	if (!(hipct & SKL_ADSP_HIPCT_BUSY))
+		return IRQ_NONE;
+
+	msg.primary = hipct;
+	msg.ext.val = hipcte;
+	avs_dsp_process_response(adev, msg.val);
+
+	/* tell DSP we accepted its message */
+	snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCT,
+			      SKL_ADSP_HIPCT_BUSY, SKL_ADSP_HIPCT_BUSY);
+	/* unmask busy interrupt */
+	snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCCTL,
+			      AVS_ADSP_HIPCCTL_BUSY, AVS_ADSP_HIPCCTL_BUSY);
+
+	return IRQ_HANDLED;
+}
+
+static bool avs_ipc_is_busy(struct avs_ipc *ipc)
+{
+	struct avs_dev *adev = to_avs_dev(ipc->dev);
+	u32 hipc_rsp;
+
+	hipc_rsp = snd_hdac_adsp_readl(adev, SKL_ADSP_REG_HIPCT);
+	return hipc_rsp & SKL_ADSP_HIPCT_BUSY;
+}
+
+static int avs_ipc_wait_busy_completion(struct avs_ipc *ipc, int timeout)
+{
+	u32 repeats_left = 128; /* to avoid infinite looping */
+	int ret;
+
+again:
+	ret = wait_for_completion_timeout(&ipc->busy_completion, msecs_to_jiffies(timeout));
+
+	/* DSP could be unresponsive at this point. */
+	if (!ipc->ready)
+		return -EPERM;
+
+	if (!ret) {
+		if (!avs_ipc_is_busy(ipc))
+			return -ETIMEDOUT;
+		/*
+		 * Firmware did its job, either notification or reply
+		 * has been received - now wait until it's processed.
+		 */
+		wait_for_completion_killable(&ipc->busy_completion);
+	}
+
+	/* Ongoing notification's bottom-half may cause early wakeup */
+	spin_lock(&ipc->rx_lock);
+	if (!ipc->rx_completed) {
+		if (repeats_left) {
+			/* Reply delayed due to notification. */
+			repeats_left--;
+			reinit_completion(&ipc->busy_completion);
+			spin_unlock(&ipc->rx_lock);
+			goto again;
+		}
+
+		spin_unlock(&ipc->rx_lock);
+		return -ETIMEDOUT;
+	}
+
+	spin_unlock(&ipc->rx_lock);
+	return 0;
+}
+
+static void avs_ipc_msg_init(struct avs_ipc *ipc, struct avs_ipc_msg *reply)
+{
+	lockdep_assert_held(&ipc->rx_lock);
+
+	ipc->rx.header = 0;
+	ipc->rx.size = reply ? reply->size : 0;
+	ipc->rx_completed = false;
+
+	reinit_completion(&ipc->done_completion);
+	reinit_completion(&ipc->busy_completion);
+}
+
+static void avs_dsp_send_tx(struct avs_dev *adev, struct avs_ipc_msg *tx)
+{
+	tx->header |= SKL_ADSP_HIPCI_BUSY;
+
+	if (tx->size)
+		memcpy_toio(avs_downlink_addr(adev), tx->data, tx->size);
+	snd_hdac_adsp_writel(adev, SKL_ADSP_REG_HIPCIE, tx->header >> 32);
+	snd_hdac_adsp_writel(adev, SKL_ADSP_REG_HIPCI, tx->header & UINT_MAX);
+}
+
+static int avs_dsp_do_send_msg(struct avs_dev *adev, struct avs_ipc_msg *request,
+			       struct avs_ipc_msg *reply, int timeout)
+{
+	struct avs_ipc *ipc = adev->ipc;
+	int ret;
+
+	if (!ipc->ready)
+		return -EPERM;
+
+	mutex_lock(&ipc->msg_mutex);
+
+	spin_lock(&ipc->rx_lock);
+	avs_ipc_msg_init(ipc, reply);
+	avs_dsp_send_tx(adev, request);
+	spin_unlock(&ipc->rx_lock);
+
+	ret = avs_ipc_wait_busy_completion(ipc, timeout);
+	if (ret) {
+		if (ret == -ETIMEDOUT) {
+			dev_crit(adev->dev, "communication severed: %d, rebooting dsp..\n", ret);
+
+			avs_ipc_block(ipc);
+		}
+		goto exit;
+	}
+
+	ret = ipc->rx.rsp.status;
+	if (reply) {
+		reply->header = ipc->rx.header;
+		if (reply->data && ipc->rx.size)
+			memcpy(reply->data, ipc->rx.data, reply->size);
+	}
+
+exit:
+	mutex_unlock(&ipc->msg_mutex);
+	return ret;
+}
+
+int avs_dsp_send_msg_timeout(struct avs_dev *adev, struct avs_ipc_msg *request,
+			     struct avs_ipc_msg *reply, int timeout)
+{
+	return avs_dsp_do_send_msg(adev, request, reply, timeout);
+}
+
+int avs_dsp_send_msg(struct avs_dev *adev, struct avs_ipc_msg *request,
+		     struct avs_ipc_msg *reply)
+{
+	return avs_dsp_send_msg_timeout(adev, request, reply, adev->ipc->default_timeout_ms);
+}
+
+static int avs_dsp_do_send_rom_msg(struct avs_dev *adev, struct avs_ipc_msg *request, int timeout)
+{
+	struct avs_ipc *ipc = adev->ipc;
+	int ret;
+
+	mutex_lock(&ipc->msg_mutex);
+
+	spin_lock(&ipc->rx_lock);
+	avs_ipc_msg_init(ipc, NULL);
+	avs_dsp_send_tx(adev, request);
+	spin_unlock(&ipc->rx_lock);
+
+	/* ROM messages must be sent before main core is unstalled */
+	ret = avs_dsp_op(adev, stall, AVS_MAIN_CORE_MASK, false);
+	if (!ret) {
+		ret = wait_for_completion_timeout(&ipc->done_completion, msecs_to_jiffies(timeout));
+		ret = ret ? 0 : -ETIMEDOUT;
+	}
+
+	mutex_unlock(&ipc->msg_mutex);
+
+	return ret;
+}
+
+int avs_dsp_send_rom_msg_timeout(struct avs_dev *adev, struct avs_ipc_msg *request, int timeout)
+{
+	return avs_dsp_do_send_rom_msg(adev, request, timeout);
+}
+
+int avs_dsp_send_rom_msg(struct avs_dev *adev, struct avs_ipc_msg *request)
+{
+	return avs_dsp_send_rom_msg_timeout(adev, request, adev->ipc->default_timeout_ms);
+}
+
+void avs_dsp_interrupt_control(struct avs_dev *adev, bool enable)
+{
+	u32 value, mask;
+
+	/*
+	 * No particular bit setting order. All of these are required
+	 * to have a functional SW <-> FW communication.
+	 */
+	value = enable ? AVS_ADSP_ADSPIC_IPC : 0;
+	snd_hdac_adsp_updatel(adev, AVS_ADSP_REG_ADSPIC, AVS_ADSP_ADSPIC_IPC, value);
+
+	mask = AVS_ADSP_HIPCCTL_DONE | AVS_ADSP_HIPCCTL_BUSY;
+	value = enable ? mask : 0;
+	snd_hdac_adsp_updatel(adev, SKL_ADSP_REG_HIPCCTL, mask, value);
+}
+
+int avs_ipc_init(struct avs_ipc *ipc, struct device *dev)
+{
+	ipc->rx.data = devm_kzalloc(dev, AVS_MAILBOX_SIZE, GFP_KERNEL);
+	if (!ipc->rx.data)
+		return -ENOMEM;
+
+	ipc->dev = dev;
+	ipc->ready = false;
+	ipc->default_timeout_ms = AVS_IPC_TIMEOUT_MS;
+	init_completion(&ipc->done_completion);
+	init_completion(&ipc->busy_completion);
+	spin_lock_init(&ipc->rx_lock);
+	mutex_init(&ipc->msg_mutex);
+
+	return 0;
+}
+
+void avs_ipc_block(struct avs_ipc *ipc)
+{
+	ipc->ready = false;
+}