net: iosm: shared memory protocol

1) Defines messaging protocol for handling Transfer Descriptor
   in both UL/DL direction.
2) Ring buffer management.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wwan/iosm/iosm_ipc_protocol.c

@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include "iosm_ipc_imem.h"
+#include "iosm_ipc_protocol.h"
+#include "iosm_ipc_protocol_ops.h"
+#include "iosm_ipc_pm.h"
+#include "iosm_ipc_task_queue.h"
+
+int ipc_protocol_tq_msg_send(struct iosm_protocol *ipc_protocol,
+			     enum ipc_msg_prep_type msg_type,
+			     union ipc_msg_prep_args *prep_args,
+			     struct ipc_rsp *response)
+{
+	int index = ipc_protocol_msg_prep(ipc_protocol->imem, msg_type,
+					  prep_args);
+
+	/* Store reference towards caller specified response in response ring
+	 * and signal CP
+	 */
+	if (index >= 0 && index < IPC_MEM_MSG_ENTRIES) {
+		ipc_protocol->rsp_ring[index] = response;
+		ipc_protocol_msg_hp_update(ipc_protocol->imem);
+	}
+
+	return index;
+}
+
+/* Callback for message send */
+static int ipc_protocol_tq_msg_send_cb(struct iosm_imem *ipc_imem, int arg,
+				       void *msg, size_t size)
+{
+	struct ipc_call_msg_send_args *send_args = msg;
+	struct iosm_protocol *ipc_protocol = ipc_imem->ipc_protocol;
+
+	return ipc_protocol_tq_msg_send(ipc_protocol, send_args->msg_type,
+					send_args->prep_args,
+					send_args->response);
+}
+
+/* Remove reference to a response. This is typically used when a requestor timed
+ * out and is no longer interested in the response.
+ */
+static int ipc_protocol_tq_msg_remove(struct iosm_imem *ipc_imem, int arg,
+				      void *msg, size_t size)
+{
+	struct iosm_protocol *ipc_protocol = ipc_imem->ipc_protocol;
+
+	ipc_protocol->rsp_ring[arg] = NULL;
+	return 0;
+}
+
+int ipc_protocol_msg_send(struct iosm_protocol *ipc_protocol,
+			  enum ipc_msg_prep_type prep,
+			  union ipc_msg_prep_args *prep_args)
+{
+	struct ipc_call_msg_send_args send_args;
+	unsigned int exec_timeout;
+	struct ipc_rsp response;
+	int index;
+
+	exec_timeout = (ipc_protocol_get_ap_exec_stage(ipc_protocol) ==
+					IPC_MEM_EXEC_STAGE_RUN ?
+				IPC_MSG_COMPLETE_RUN_DEFAULT_TIMEOUT :
+				IPC_MSG_COMPLETE_BOOT_DEFAULT_TIMEOUT);
+
+	/* Trap if called from non-preemptible context */
+	might_sleep();
+
+	response.status = IPC_MEM_MSG_CS_INVALID;
+	init_completion(&response.completion);
+
+	send_args.msg_type = prep;
+	send_args.prep_args = prep_args;
+	send_args.response = &response;
+
+	/* Allocate and prepare message to be sent in tasklet context.
+	 * A positive index returned form tasklet_call references the message
+	 * in case it needs to be cancelled when there is a timeout.
+	 */
+	index = ipc_task_queue_send_task(ipc_protocol->imem,
+					 ipc_protocol_tq_msg_send_cb, 0,
+					 &send_args, 0, true);
+
+	if (index < 0) {
+		dev_err(ipc_protocol->dev, "msg %d failed", prep);
+		return index;
+	}
+
+	/* Wait for the device to respond to the message */
+	switch (wait_for_completion_timeout(&response.completion,
+					    msecs_to_jiffies(exec_timeout))) {
+	case 0:
+		/* Timeout, there was no response from the device.
+		 * Remove the reference to the local response completion
+		 * object as we are no longer interested in the response.
+		 */
+		ipc_task_queue_send_task(ipc_protocol->imem,
+					 ipc_protocol_tq_msg_remove, index,
+					 NULL, 0, true);
+		dev_err(ipc_protocol->dev, "msg timeout");
+		ipc_uevent_send(ipc_protocol->pcie->dev, UEVENT_MDM_TIMEOUT);
+		break;
+	default:
+		/* We got a response in time; check completion status: */
+		if (response.status != IPC_MEM_MSG_CS_SUCCESS) {
+			dev_err(ipc_protocol->dev,
+				"msg completion status error %d",
+				response.status);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int ipc_protocol_msg_send_host_sleep(struct iosm_protocol *ipc_protocol,
+					    u32 state)
+{
+	union ipc_msg_prep_args prep_args = {
+		.sleep.target = 0,
+		.sleep.state = state,
+	};
+
+	return ipc_protocol_msg_send(ipc_protocol, IPC_MSG_PREP_SLEEP,
+				     &prep_args);
+}
+
+void ipc_protocol_doorbell_trigger(struct iosm_protocol *ipc_protocol,
+				   u32 identifier)
+{
+	ipc_pm_signal_hpda_doorbell(&ipc_protocol->pm, identifier, true);
+}
+
+bool ipc_protocol_pm_dev_sleep_handle(struct iosm_protocol *ipc_protocol)
+{
+	u32 ipc_status = ipc_protocol_get_ipc_status(ipc_protocol);
+	u32 requested;
+
+	if (ipc_status != IPC_MEM_DEVICE_IPC_RUNNING) {
+		dev_err(ipc_protocol->dev,
+			"irq ignored, CP IPC state is %d, should be RUNNING",
+			ipc_status);
+
+		/* Stop further processing. */
+		return false;
+	}
+
+	/* Get a copy of the requested PM state by the device and the local
+	 * device PM state.
+	 */
+	requested = ipc_protocol_pm_dev_get_sleep_notification(ipc_protocol);
+
+	return ipc_pm_dev_slp_notification(&ipc_protocol->pm, requested);
+}
+
+static int ipc_protocol_tq_wakeup_dev_slp(struct iosm_imem *ipc_imem, int arg,
+					  void *msg, size_t size)
+{
+	struct iosm_pm *ipc_pm = &ipc_imem->ipc_protocol->pm;
+
+	/* Wakeup from device sleep if it is not ACTIVE */
+	ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_HS, true);
+
+	ipc_pm_trigger(ipc_pm, IPC_PM_UNIT_HS, false);
+
+	return 0;
+}
+
+void ipc_protocol_s2idle_sleep(struct iosm_protocol *ipc_protocol, bool sleep)
+{
+	ipc_pm_set_s2idle_sleep(&ipc_protocol->pm, sleep);
+}
+
+bool ipc_protocol_suspend(struct iosm_protocol *ipc_protocol)
+{
+	if (!ipc_pm_prepare_host_sleep(&ipc_protocol->pm))
+		goto err;
+
+	ipc_task_queue_send_task(ipc_protocol->imem,
+				 ipc_protocol_tq_wakeup_dev_slp, 0, NULL, 0,
+				 true);
+
+	if (!ipc_pm_wait_for_device_active(&ipc_protocol->pm)) {
+		ipc_uevent_send(ipc_protocol->pcie->dev, UEVENT_MDM_TIMEOUT);
+		goto err;
+	}
+
+	/* Send the sleep message for sync sys calls. */
+	dev_dbg(ipc_protocol->dev, "send TARGET_HOST, ENTER_SLEEP");
+	if (ipc_protocol_msg_send_host_sleep(ipc_protocol,
+					     IPC_HOST_SLEEP_ENTER_SLEEP)) {
+		/* Sending ENTER_SLEEP message failed, we are still active */
+		ipc_protocol->pm.host_pm_state = IPC_MEM_HOST_PM_ACTIVE;
+		goto err;
+	}
+
+	ipc_protocol->pm.host_pm_state = IPC_MEM_HOST_PM_SLEEP;
+	return true;
+err:
+	return false;
+}
+
+bool ipc_protocol_resume(struct iosm_protocol *ipc_protocol)
+{
+	if (!ipc_pm_prepare_host_active(&ipc_protocol->pm))
+		return false;
+
+	dev_dbg(ipc_protocol->dev, "send TARGET_HOST, EXIT_SLEEP");
+	if (ipc_protocol_msg_send_host_sleep(ipc_protocol,
+					     IPC_HOST_SLEEP_EXIT_SLEEP)) {
+		ipc_protocol->pm.host_pm_state = IPC_MEM_HOST_PM_SLEEP;
+		return false;
+	}
+
+	ipc_protocol->pm.host_pm_state = IPC_MEM_HOST_PM_ACTIVE;
+
+	return true;
+}
+
+struct iosm_protocol *ipc_protocol_init(struct iosm_imem *ipc_imem)
+{
+	struct iosm_protocol *ipc_protocol =
+		kzalloc(sizeof(*ipc_protocol), GFP_KERNEL);
+	struct ipc_protocol_context_info *p_ci;
+	u64 addr;
+
+	if (!ipc_protocol)
+		return NULL;
+
+	ipc_protocol->dev = ipc_imem->dev;
+	ipc_protocol->pcie = ipc_imem->pcie;
+	ipc_protocol->imem = ipc_imem;
+	ipc_protocol->p_ap_shm = NULL;
+	ipc_protocol->phy_ap_shm = 0;
+
+	ipc_protocol->old_msg_tail = 0;
+
+	ipc_protocol->p_ap_shm =
+		pci_alloc_consistent(ipc_protocol->pcie->pci,
+				     sizeof(*ipc_protocol->p_ap_shm),
+				     &ipc_protocol->phy_ap_shm);
+
+	if (!ipc_protocol->p_ap_shm) {
+		dev_err(ipc_protocol->dev, "pci shm alloc error");
+		kfree(ipc_protocol);
+		return NULL;
+	}
+
+	/* Prepare the context info for CP. */
+	addr = ipc_protocol->phy_ap_shm;
+	p_ci = &ipc_protocol->p_ap_shm->ci;
+	p_ci->device_info_addr =
+		addr + offsetof(struct ipc_protocol_ap_shm, device_info);
+	p_ci->head_array =
+		addr + offsetof(struct ipc_protocol_ap_shm, head_array);
+	p_ci->tail_array =
+		addr + offsetof(struct ipc_protocol_ap_shm, tail_array);
+	p_ci->msg_head = addr + offsetof(struct ipc_protocol_ap_shm, msg_head);
+	p_ci->msg_tail = addr + offsetof(struct ipc_protocol_ap_shm, msg_tail);
+	p_ci->msg_ring_addr =
+		addr + offsetof(struct ipc_protocol_ap_shm, msg_ring);
+	p_ci->msg_ring_entries = cpu_to_le16(IPC_MEM_MSG_ENTRIES);
+	p_ci->msg_irq_vector = IPC_MSG_IRQ_VECTOR;
+	p_ci->device_info_irq_vector = IPC_DEVICE_IRQ_VECTOR;
+
+	ipc_mmio_set_contex_info_addr(ipc_imem->mmio, addr);
+
+	ipc_pm_init(ipc_protocol);
+
+	return ipc_protocol;
+}
+
+void ipc_protocol_deinit(struct iosm_protocol *proto)
+{
+	pci_free_consistent(proto->pcie->pci, sizeof(*proto->p_ap_shm),
+			    proto->p_ap_shm, proto->phy_ap_shm);
+
+	ipc_pm_deinit(proto);
+	kfree(proto);
+}