net: iosm: shared memory I/O operations

1) Binds logical channel between host-device for communication.
2) Implements device specific(Char/Net) IO operations.

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_imem_ops.c

@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#include <linux/delay.h>
+
+#include "iosm_ipc_chnl_cfg.h"
+#include "iosm_ipc_imem.h"
+#include "iosm_ipc_imem_ops.h"
+#include "iosm_ipc_port.h"
+#include "iosm_ipc_task_queue.h"
+
+/* Open a packet data online channel between the network layer and CP. */
+int ipc_imem_sys_wwan_open(struct iosm_imem *ipc_imem, int if_id)
+{
+	dev_dbg(ipc_imem->dev, "%s if id: %d",
+		ipc_imem_phase_get_string(ipc_imem->phase), if_id);
+
+	/* The network interface is only supported in the runtime phase. */
+	if (ipc_imem_phase_update(ipc_imem) != IPC_P_RUN) {
+		dev_err(ipc_imem->dev, "net:%d : refused phase %s", if_id,
+			ipc_imem_phase_get_string(ipc_imem->phase));
+		return -EIO;
+	}
+
+	/* check for the interafce id
+	 * if if_id 1 to 8 then create IP MUX channel sessions.
+	 * To start MUX session from 0 as network interface id would start
+	 * from 1 so map it to if_id = if_id - 1
+	 */
+	if (if_id >= IP_MUX_SESSION_START && if_id <= IP_MUX_SESSION_END)
+		return ipc_mux_open_session(ipc_imem->mux, if_id - 1);
+
+	return -EINVAL;
+}
+
+/* Release a net link to CP. */
+void ipc_imem_sys_wwan_close(struct iosm_imem *ipc_imem, int if_id,
+			     int channel_id)
+{
+	if (ipc_imem->mux && if_id >= IP_MUX_SESSION_START &&
+	    if_id <= IP_MUX_SESSION_END)
+		ipc_mux_close_session(ipc_imem->mux, if_id - 1);
+}
+
+/* Tasklet call to do uplink transfer. */
+static int ipc_imem_tq_cdev_write(struct iosm_imem *ipc_imem, int arg,
+				  void *msg, size_t size)
+{
+	ipc_imem->ev_cdev_write_pending = false;
+	ipc_imem_ul_send(ipc_imem);
+
+	return 0;
+}
+
+/* Through tasklet to do sio write. */
+static int ipc_imem_call_cdev_write(struct iosm_imem *ipc_imem)
+{
+	if (ipc_imem->ev_cdev_write_pending)
+		return -1;
+
+	ipc_imem->ev_cdev_write_pending = true;
+
+	return ipc_task_queue_send_task(ipc_imem, ipc_imem_tq_cdev_write, 0,
+					NULL, 0, false);
+}
+
+/* Function for transfer UL data */
+int ipc_imem_sys_wwan_transmit(struct iosm_imem *ipc_imem,
+			       int if_id, int channel_id, struct sk_buff *skb)
+{
+	int ret = -EINVAL;
+
+	if (!ipc_imem || channel_id < 0)
+		goto out;
+
+	/* Is CP Running? */
+	if (ipc_imem->phase != IPC_P_RUN) {
+		dev_dbg(ipc_imem->dev, "phase %s transmit",
+			ipc_imem_phase_get_string(ipc_imem->phase));
+		ret = -EIO;
+		goto out;
+	}
+
+	if (if_id >= IP_MUX_SESSION_START && if_id <= IP_MUX_SESSION_END)
+		/* Route the UL packet through IP MUX Layer */
+		ret = ipc_mux_ul_trigger_encode(ipc_imem->mux,
+						if_id - 1, skb);
+	else
+		dev_err(ipc_imem->dev,
+			"invalid if_id %d: ", if_id);
+out:
+	return ret;
+}
+
+/* Initialize wwan channel */
+void ipc_imem_wwan_channel_init(struct iosm_imem *ipc_imem,
+				enum ipc_mux_protocol mux_type)
+{
+	struct ipc_chnl_cfg chnl_cfg = { 0 };
+
+	ipc_imem->cp_version = ipc_mmio_get_cp_version(ipc_imem->mmio);
+
+	/* If modem version is invalid (0xffffffff), do not initialize WWAN. */
+	if (ipc_imem->cp_version == -1) {
+		dev_err(ipc_imem->dev, "invalid CP version");
+		return;
+	}
+
+	ipc_chnl_cfg_get(&chnl_cfg, ipc_imem->nr_of_channels);
+	ipc_imem_channel_init(ipc_imem, IPC_CTYPE_WWAN, chnl_cfg,
+			      IRQ_MOD_OFF);
+
+	/* WWAN registration. */
+	ipc_imem->wwan = ipc_wwan_init(ipc_imem, ipc_imem->dev);
+	if (!ipc_imem->wwan)
+		dev_err(ipc_imem->dev,
+			"failed to register the ipc_wwan interfaces");
+}
+
+/* Map SKB to DMA for transfer */
+static int ipc_imem_map_skb_to_dma(struct iosm_imem *ipc_imem,
+				   struct sk_buff *skb)
+{
+	struct iosm_pcie *ipc_pcie = ipc_imem->pcie;
+	char *buf = skb->data;
+	int len = skb->len;
+	dma_addr_t mapping;
+	int ret;
+
+	ret = ipc_pcie_addr_map(ipc_pcie, buf, len, &mapping, DMA_TO_DEVICE);
+
+	if (ret)
+		goto err;
+
+	BUILD_BUG_ON(sizeof(*IPC_CB(skb)) > sizeof(skb->cb));
+
+	IPC_CB(skb)->mapping = mapping;
+	IPC_CB(skb)->direction = DMA_TO_DEVICE;
+	IPC_CB(skb)->len = len;
+	IPC_CB(skb)->op_type = (u8)UL_DEFAULT;
+
+err:
+	return ret;
+}
+
+/* return true if channel is ready for use */
+static bool ipc_imem_is_channel_active(struct iosm_imem *ipc_imem,
+				       struct ipc_mem_channel *channel)
+{
+	enum ipc_phase phase;
+
+	/* Update the current operation phase. */
+	phase = ipc_imem->phase;
+
+	/* Select the operation depending on the execution stage. */
+	switch (phase) {
+	case IPC_P_RUN:
+	case IPC_P_PSI:
+	case IPC_P_EBL:
+		break;
+
+	case IPC_P_ROM:
+		/* Prepare the PSI image for the CP ROM driver and
+		 * suspend the flash app.
+		 */
+		if (channel->state != IMEM_CHANNEL_RESERVED) {
+			dev_err(ipc_imem->dev,
+				"ch[%d]:invalid channel state %d,expected %d",
+				channel->channel_id, channel->state,
+				IMEM_CHANNEL_RESERVED);
+			goto channel_unavailable;
+		}
+		goto channel_available;
+
+	default:
+		/* Ignore uplink actions in all other phases. */
+		dev_err(ipc_imem->dev, "ch[%d]: confused phase %d",
+			channel->channel_id, phase);
+		goto channel_unavailable;
+	}
+	/* Check the full availability of the channel. */
+	if (channel->state != IMEM_CHANNEL_ACTIVE) {
+		dev_err(ipc_imem->dev, "ch[%d]: confused channel state %d",
+			channel->channel_id, channel->state);
+		goto channel_unavailable;
+	}
+
+channel_available:
+	return true;
+
+channel_unavailable:
+	return false;
+}
+
+/* Release a sio link to CP. */
+void ipc_imem_sys_cdev_close(struct iosm_cdev *ipc_cdev)
+{
+	struct iosm_imem *ipc_imem = ipc_cdev->ipc_imem;
+	struct ipc_mem_channel *channel = ipc_cdev->channel;
+	enum ipc_phase curr_phase;
+	int status = 0;
+	u32 tail = 0;
+
+	curr_phase = ipc_imem->phase;
+
+	/* If current phase is IPC_P_OFF or SIO ID is -ve then
+	 * channel is already freed. Nothing to do.
+	 */
+	if (curr_phase == IPC_P_OFF) {
+		dev_err(ipc_imem->dev,
+			"nothing to do. Current Phase: %s",
+			ipc_imem_phase_get_string(curr_phase));
+		return;
+	}
+
+	if (channel->state == IMEM_CHANNEL_FREE) {
+		dev_err(ipc_imem->dev, "ch[%d]: invalid channel state %d",
+			channel->channel_id, channel->state);
+		return;
+	}
+
+	/* If there are any pending TDs then wait for Timeout/Completion before
+	 * closing pipe.
+	 */
+	if (channel->ul_pipe.old_tail != channel->ul_pipe.old_head) {
+		ipc_imem->app_notify_ul_pend = 1;
+
+		/* Suspend the user app and wait a certain time for processing
+		 * UL Data.
+		 */
+		status = wait_for_completion_interruptible_timeout
+			 (&ipc_imem->ul_pend_sem,
+			  msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
+		if (status == 0) {
+			dev_dbg(ipc_imem->dev,
+				"Pend data Timeout UL-Pipe:%d Head:%d Tail:%d",
+				channel->ul_pipe.pipe_nr,
+				channel->ul_pipe.old_head,
+				channel->ul_pipe.old_tail);
+		}
+
+		ipc_imem->app_notify_ul_pend = 0;
+	}
+
+	/* If there are any pending TDs then wait for Timeout/Completion before
+	 * closing pipe.
+	 */
+	ipc_protocol_get_head_tail_index(ipc_imem->ipc_protocol,
+					 &channel->dl_pipe, NULL, &tail);
+
+	if (tail != channel->dl_pipe.old_tail) {
+		ipc_imem->app_notify_dl_pend = 1;
+
+		/* Suspend the user app and wait a certain time for processing
+		 * DL Data.
+		 */
+		status = wait_for_completion_interruptible_timeout
+			 (&ipc_imem->dl_pend_sem,
+			  msecs_to_jiffies(IPC_PEND_DATA_TIMEOUT));
+		if (status == 0) {
+			dev_dbg(ipc_imem->dev,
+				"Pend data Timeout DL-Pipe:%d Head:%d Tail:%d",
+				channel->dl_pipe.pipe_nr,
+				channel->dl_pipe.old_head,
+				channel->dl_pipe.old_tail);
+		}
+
+		ipc_imem->app_notify_dl_pend = 0;
+	}
+
+	/* Due to wait for completion in messages, there is a small window
+	 * between closing the pipe and updating the channel is closed. In this
+	 * small window there could be HP update from Host Driver. Hence update
+	 * the channel state as CLOSING to aviod unnecessary interrupt
+	 * towards CP.
+	 */
+	channel->state = IMEM_CHANNEL_CLOSING;
+
+	ipc_imem_pipe_close(ipc_imem, &channel->ul_pipe);
+	ipc_imem_pipe_close(ipc_imem, &channel->dl_pipe);
+
+	ipc_imem_channel_free(channel);
+}
+
+/* Open a PORT link to CP and return the channel */
+struct ipc_mem_channel *ipc_imem_sys_port_open(struct iosm_imem *ipc_imem,
+					       int chl_id, int hp_id)
+{
+	struct ipc_mem_channel *channel;
+	int ch_id;
+
+	/* The PORT interface is only supported in the runtime phase. */
+	if (ipc_imem_phase_update(ipc_imem) != IPC_P_RUN) {
+		dev_err(ipc_imem->dev, "PORT open refused, phase %s",
+			ipc_imem_phase_get_string(ipc_imem->phase));
+		return NULL;
+	}
+
+	ch_id = ipc_imem_channel_alloc(ipc_imem, chl_id, IPC_CTYPE_CTRL);
+
+	if (ch_id < 0) {
+		dev_err(ipc_imem->dev, "reservation of an PORT chnl id failed");
+		return NULL;
+	}
+
+	channel = ipc_imem_channel_open(ipc_imem, ch_id, hp_id);
+
+	if (!channel) {
+		dev_err(ipc_imem->dev, "PORT channel id open failed");
+		return NULL;
+	}
+
+	return channel;
+}
+
+/* transfer skb to modem */
+int ipc_imem_sys_cdev_write(struct iosm_cdev *ipc_cdev, struct sk_buff *skb)
+{
+	struct ipc_mem_channel *channel = ipc_cdev->channel;
+	struct iosm_imem *ipc_imem = ipc_cdev->ipc_imem;
+	int ret = -EIO;
+
+	if (!ipc_imem_is_channel_active(ipc_imem, channel) ||
+	    ipc_imem->phase == IPC_P_OFF_REQ)
+		goto out;
+
+	ret = ipc_imem_map_skb_to_dma(ipc_imem, skb);
+
+	if (ret)
+		goto out;
+
+	/* Add skb to the uplink skbuf accumulator. */
+	skb_queue_tail(&channel->ul_list, skb);
+
+	ret = ipc_imem_call_cdev_write(ipc_imem);
+
+	if (ret) {
+		skb_dequeue_tail(&channel->ul_list);
+		dev_err(ipc_cdev->dev, "channel id[%d] write failed\n",
+			ipc_cdev->channel->channel_id);
+	}
+out:
+	return ret;
+}