Implements a char device for flashing Modem FW image while Device
is in boot rom phase and for collecting traces on modem crash.
Signed-off-by: M Chetan Kumar <m.chetan.kumar@xxxxxxxxx>
---
drivers/net/wwan/iosm/iosm_ipc_sio.c | 188 +++++++++++++++++++++++++++++++++++
drivers/net/wwan/iosm/iosm_ipc_sio.h | 72 ++++++++++++++
2 files changed, 260 insertions(+)
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_sio.c
create mode 100644 drivers/net/wwan/iosm/iosm_ipc_sio.h
diff --git a/drivers/net/wwan/iosm/iosm_ipc_sio.c b/drivers/net/wwan/iosm/iosm_ipc_sio.c
new file mode 100644
index 000000000000..c35e7c6face1
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_sio.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Intel Corporation.
+ */
+
+#include <linux/poll.h>
+#include <asm/ioctls.h>
+
+#include "iosm_ipc_sio.h"
+
+/* Open a shared memory device and initialize the head of the rx skbuf list. */
+static int ipc_sio_fop_open(struct inode *inode, struct file *filp)
+{
+ struct iosm_sio *ipc_sio =
+ container_of(filp->private_data, struct iosm_sio, misc);
+
+ if (test_and_set_bit(0, &ipc_sio->sio_is_open))
+ return -EBUSY;
+
+ ipc_sio->channel_id = imem_sys_sio_open(ipc_sio->imem_instance);
+
+ if (ipc_sio->channel_id < 0)
+ return -EIO;
+
+ return 0;
+}
+
+static int ipc_sio_fop_release(struct inode *inode, struct file *filp)
+{
+ struct iosm_sio *ipc_sio =
+ container_of(filp->private_data, struct iosm_sio, misc);
+
+ if (ipc_sio->channel_id < 0)
+ return -EINVAL;
+
+ imem_sys_sio_close(ipc_sio);
+
+ clear_bit(0, &ipc_sio->sio_is_open);
+
+ return 0;
+}
+
+/* Copy the data from skbuff to the user buffer */
+static ssize_t ipc_sio_fop_read(struct file *filp, char __user *buf,
+ size_t size, loff_t *l)
+{
+ struct sk_buff *skb = NULL;
+ struct iosm_sio *ipc_sio;
+ bool is_blocking;
+
+ if (!buf)
+ return -EINVAL;
+
+ ipc_sio = container_of(filp->private_data, struct iosm_sio, misc);
+
+ is_blocking = !(filp->f_flags & O_NONBLOCK);
+
+ /* only log in blocking mode to reduce flooding the log */
+ if (is_blocking)
+ dev_dbg(ipc_sio->dev, "sio read chid[%d] size=%zu",
+ ipc_sio->channel_id, size);
+
+ /* First provide the pending skbuf to the user. */
+ if (ipc_sio->rx_pending_buf) {
+ skb = ipc_sio->rx_pending_buf;
+ ipc_sio->rx_pending_buf = NULL;
+ }
+
+ /* Check rx queue until skb is available */
+ while (!skb) {
+ skb = skb_dequeue(&ipc_sio->rx_list);
+ if (skb)
+ break;
+
+ if (!is_blocking)
+ return -EAGAIN;
+ /* Suspend the user app and wait a certain time for data
+ * from CP.
+ */
+ if (WAIT_FOR_TIMEOUT(&ipc_sio->read_sem, IPC_READ_TIMEOUT) <
+ 0) {
+ return -ETIMEDOUT;
+ }
+ }
+
+ return imem_sys_sio_read(ipc_sio, buf, size, skb);
+}
+
+/* Route the user data to the shared memory layer. */
+static ssize_t ipc_sio_fop_write(struct file *filp, const char __user *buf,
+ size_t size, loff_t *l)
+{
+ struct iosm_sio *ipc_sio;
+ bool is_blocking;
+
+ if (!buf)
+ return -EINVAL;
+
+ ipc_sio = container_of(filp->private_data, struct iosm_sio, misc);
+
+ is_blocking = !(filp->f_flags & O_NONBLOCK);
+
+ if (ipc_sio->channel_id < 0)
+ return -EPERM;
+
+ return imem_sys_sio_write(ipc_sio, buf, size, is_blocking);
+}
+
+/* poll for applications using nonblocking I/O */
+static __poll_t ipc_sio_fop_poll(struct file *filp, poll_table *wait)
+{
+ struct iosm_sio *ipc_sio =
+ container_of(filp->private_data, struct iosm_sio, misc);
+ __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* writable */
+
+ /* Just registers wait_queue hook. This doesn't really wait. */
+ poll_wait(filp, &ipc_sio->poll_inq, wait);
+
+ /* Test the fill level of the skbuf rx queue. */
+ if (!skb_queue_empty(&ipc_sio->rx_list) || ipc_sio->rx_pending_buf)
+ mask |= EPOLLIN | EPOLLRDNORM; /* readable */
+
+ return mask;
+}
+
+struct iosm_sio *ipc_sio_init(struct iosm_imem *ipc_imem, const char *name)
+{
+ static const struct file_operations fops = {
+ .owner = THIS_MODULE,
+ .open = ipc_sio_fop_open,
+ .release = ipc_sio_fop_release,
+ .read = ipc_sio_fop_read,
+ .write = ipc_sio_fop_write,
+ .poll = ipc_sio_fop_poll,
+ };
+
+ struct iosm_sio *ipc_sio = kzalloc(sizeof(*ipc_sio), GFP_KERNEL);
+
+ if (!ipc_sio)
+ return NULL;
+
+ ipc_sio->dev = ipc_imem->dev;
+ ipc_sio->pcie = ipc_imem->pcie;
+ ipc_sio->imem_instance = ipc_imem;
+
+ ipc_sio->channel_id = -1;
+ ipc_sio->sio_is_open = 0;
+ atomic_set(&ipc_sio->dreg_called, 0);
+
+ init_completion(&ipc_sio->read_sem);
+
+ skb_queue_head_init(&ipc_sio->rx_list);
+ init_waitqueue_head(&ipc_sio->poll_inq);
+ init_waitqueue_head(&ipc_sio->poll_outq);
+
+ strncpy(ipc_sio->devname, name, sizeof(ipc_sio->devname) - 1);
+ ipc_sio->devname[IPC_SIO_DEVNAME_LEN - 1] = '\0';
+
+ ipc_sio->misc.minor = MISC_DYNAMIC_MINOR;
+ ipc_sio->misc.name = ipc_sio->devname;
+ ipc_sio->misc.fops = &fops;
+ ipc_sio->misc.mode = IPC_CHAR_DEVICE_DEFAULT_MODE;
+
+ if (misc_register(&ipc_sio->misc) != 0) {
+ kfree(ipc_sio);
+ return NULL;
+ }
+
+ return ipc_sio;
+}
+
+void ipc_sio_deinit(struct iosm_sio *ipc_sio)
+{
+ if (atomic_cmpxchg(&ipc_sio->dreg_called, 0, 1) != 0)
+ return;
+
+ misc_deregister(&ipc_sio->misc);
+
+ /* Wakeup the user app. */
+ complete(&ipc_sio->read_sem);
+
+ ipc_pcie_kfree_skb(ipc_sio->pcie, ipc_sio->rx_pending_buf);
+ ipc_sio->rx_pending_buf = NULL;
+
+ skb_queue_purge(&ipc_sio->rx_list);
+
+ kfree(ipc_sio);
+}
diff --git a/drivers/net/wwan/iosm/iosm_ipc_sio.h b/drivers/net/wwan/iosm/iosm_ipc_sio.h
new file mode 100644
index 000000000000..d2a8e91ea117
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_sio.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_SIO_H
+#define IOSM_IPC_SIO_H
+
+#include <linux/miscdevice.h>
+#include <linux/skbuff.h>
+
+#include "iosm_ipc_imem_ops.h"
+
+/* IPC char. device default mode. Only privileged user can access. */
+#define IPC_CHAR_DEVICE_DEFAULT_MODE 0600
+
+/**
+ * struct iosm_sio - State of the char driver layer.
+ * @misc: OS misc device component
+ * @imem_instance: imem instance
+ * @dev: Pointer to device struct
+ * @pcie: PCIe component
+ * @rx_pending_buf: Storage for skb when its data has not been fully read
+ * @misc: OS misc device component
+ * @devname: Device name
+ * @channel_id: Channel ID as received from ipc_sio_ops.open
+ * @rx_list: Downlink skbuf list received from CP.
+ * @read_sem: Needed for the blocking read or downlink transfer
+ * @poll_inq: Read queues to support the poll system call
+ * @poll_outq: write queues to support the poll system call
+ * @sio_is_open: Sio Open flag to restricts the number of concurrent open
+ * operations to one
+ * @mbim_is_open: Mbim Open flag to restricts the number of concurrent
+ * open operations to one
+ * @dreg_called: dreg_called indicates that deregister has been called.
+ * This makes sure dreg is only executed once.
+ * @wmaxcommand: Max buffer size
+ */
+struct iosm_sio {
+ struct miscdevice misc;
+ void *imem_instance;
+ struct device *dev;
+ struct iosm_pcie *pcie;
+ struct sk_buff *rx_pending_buf;
+ char devname[IPC_SIO_DEVNAME_LEN];
+ int channel_id;
+ struct sk_buff_head rx_list;
+ struct completion read_sem;
+ wait_queue_head_t poll_inq;
+ wait_queue_head_t poll_outq;
+ unsigned long sio_is_open;
+ unsigned long mbim_is_open;
+ atomic_t dreg_called;
+ u16 wmaxcommand;
+};
+
+/**
+ * ipc_sio_init - Allocate and create a character device
+ * @ipc_imem: Pointer to iosm_imem structure
+ * @name: Pointer to character device name
+ *
+ * Returns: Pointer to sio instance on success and NULL on failure
+ */
+struct iosm_sio *ipc_sio_init(struct iosm_imem *ipc_imem, const char *name);
+
+/**
+ * ipc_sio_deinit - Free all the memory allocated for the ipc sio structure.
+ * @ipc_sio: Pointer to the ipc sio data-struct
+ */
+void ipc_sio_deinit(struct iosm_sio *ipc_sio);
+
+#endif
--
2.12.3
