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 | 266 +++++++++++++++++++++++++++++++++++
drivers/net/wwan/iosm/iosm_ipc_sio.h | 78 ++++++++++
2 files changed, 344 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..dfa7bff15c51
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_sio.c
@@ -0,0 +1,266 @@
+// 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"
+
+static struct mutex sio_floc; /* Mutex Lock for sio read */
+static struct mutex sio_floc_wr; /* Mutex Lock for sio write */
+
+/* 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);
+
+ struct iosm_sio_open_file *sio_op = kzalloc(sizeof(*sio_op),
+ GFP_KERNEL);
+ if (!sio_op)
+ return -ENOMEM;
+
+ if (test_and_set_bit(IS_OPEN, &ipc_sio->flag)) {
+ kfree(sio_op);
+ return -EBUSY;
+ }
+
+ ipc_sio->channel = imem_sys_sio_open(ipc_sio->ipc_imem);
+
+ if (!ipc_sio->channel) {
+ kfree(sio_op);
+ return -EIO;
+ }
+
+ mutex_lock(&sio_floc);
+
+ inode->i_private = sio_op;
+ ipc_sio->sio_fop = sio_op;
+ sio_op->sio_dev = ipc_sio;
+
+ mutex_unlock(&sio_floc);
+ return 0;
+}
+
+static int ipc_sio_fop_release(struct inode *inode, struct file *filp)
+{
+ struct iosm_sio_open_file *sio_op = inode->i_private;
+
+ mutex_lock(&sio_floc);
+
+ if (sio_op->sio_dev) {
+ clear_bit(IS_OPEN, &sio_op->sio_dev->flag);
+ imem_sys_sio_close(sio_op->sio_dev);
+ sio_op->sio_dev->sio_fop = NULL;
+ }
+
+ kfree(sio_op);
+
+ mutex_unlock(&sio_floc);
+ 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 iosm_sio_open_file *sio_op = filp->f_inode->i_private;
+ struct sk_buff *skb = NULL;
+ struct iosm_sio *ipc_sio;
+ ssize_t read_byt;
+ int ret_err;
+
+ if (!buf) {
+ ret_err = -EINVAL;
+ goto err;
+ }
+
+ mutex_lock(&sio_floc);
+
+ if (!sio_op->sio_dev) {
+ ret_err = -EIO;
+ goto err_free_lock;
+ }
+
+ ipc_sio = sio_op->sio_dev;
+
+ if (!(filp->f_flags & O_NONBLOCK))
+ set_bit(IS_BLOCKING, &ipc_sio->flag);
+
+ /* only log in blocking mode to reduce flooding the log */
+ if (test_bit(IS_BLOCKING, &ipc_sio->flag))
+ dev_dbg(ipc_sio->dev, "sio read chid[%d] size=%zu",
+ ipc_sio->channel->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 skb is available in rx_list or wait for skb in case of
+ * blocking read
+ */
+ while (!skb && !(skb = skb_dequeue(&ipc_sio->rx_list))) {
+ if (!test_bit(IS_BLOCKING, &ipc_sio->flag)) {
+ ret_err = -EAGAIN;
+ goto err_free_lock;
+ }
+ /* Suspend the user app and wait a certain time for data
+ * from CP.
+ */
+ wait_for_completion_interruptible_timeout
+ (&ipc_sio->read_sem, msecs_to_jiffies(IPC_READ_TIMEOUT));
+
+ if (test_bit(IS_DEINIT, &ipc_sio->flag)) {
+ ret_err = -EPERM;
+ goto err_free_lock;
+ }
+ }
+
+ read_byt = imem_sys_sio_read(ipc_sio, buf, size, skb);
+ mutex_unlock(&sio_floc);
+ return read_byt;
+
+err_free_lock:
+ mutex_unlock(&sio_floc);
+err:
+ return ret_err;
+}
+
+/* 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_open_file *sio_op = filp->f_inode->i_private;
+ struct iosm_sio *ipc_sio;
+ bool is_blocking;
+ ssize_t write_byt;
+ int ret_err;
+
+ if (!buf) {
+ ret_err = -EINVAL;
+ goto err;
+ }
+
+ mutex_lock(&sio_floc_wr);
+ if (!sio_op->sio_dev) {
+ ret_err = -EIO;
+ goto err_free_lock;
+ }
+
+ ipc_sio = sio_op->sio_dev;
+
+ is_blocking = !(filp->f_flags & O_NONBLOCK);
+ if (!is_blocking) {
+ if (test_bit(WRITE_IN_USE, &ipc_sio->flag)) {
+ ret_err = -EAGAIN;
+ goto err_free_lock;
+ }
+ }
+
+ write_byt = imem_sys_sio_write(ipc_sio, buf, size, is_blocking);
+ mutex_unlock(&sio_floc_wr);
+ return write_byt;
+
+err_free_lock:
+ mutex_unlock(&sio_floc_wr);
+err:
+ return ret_err;
+}
+
+/* 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 = 0;
+
+ /* 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 */
+
+ if (!test_bit(WRITE_IN_USE, &ipc_sio->flag))
+ mask |= EPOLLOUT | EPOLLWRNORM; /* writable */
+
+ 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->ipc_imem = ipc_imem;
+
+ mutex_init(&sio_floc);
+ mutex_init(&sio_floc_wr);
+ init_completion(&ipc_sio->read_sem);
+
+ skb_queue_head_init(&ipc_sio->rx_list);
+ init_waitqueue_head(&ipc_sio->poll_inq);
+
+ 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 (ipc_sio) {
+ misc_deregister(&ipc_sio->misc);
+
+ set_bit(IS_DEINIT, &ipc_sio->flag);
+ /* Applying memory barrier so that ipc_sio->flag is updated
+ * before being read
+ */
+ smp_mb__after_atomic();
+ if (test_bit(IS_BLOCKING, &ipc_sio->flag)) {
+ complete(&ipc_sio->read_sem);
+ complete(&ipc_sio->channel->ul_sem);
+ }
+
+ mutex_lock(&sio_floc);
+ mutex_lock(&sio_floc_wr);
+
+ ipc_pcie_kfree_skb(ipc_sio->pcie, ipc_sio->rx_pending_buf);
+ skb_queue_purge(&ipc_sio->rx_list);
+
+ if (ipc_sio->sio_fop)
+ ipc_sio->sio_fop->sio_dev = NULL;
+
+ mutex_unlock(&sio_floc_wr);
+ mutex_unlock(&sio_floc);
+
+ 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..fedc14d5f3c2
--- /dev/null
+++ b/drivers/net/wwan/iosm/iosm_ipc_sio.h
@@ -0,0 +1,78 @@
+/* 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
+
+#define IS_OPEN 0
+#define IS_BLOCKING 1
+#define WRITE_IN_USE 2
+#define IS_DEINIT 3
+
+/**
+ * struct iosm_sio_open_file - Reference to struct iosm_sio
+ * @sio_dev: iosm_sio instance
+ */
+struct iosm_sio_open_file {
+ struct iosm_sio *sio_dev;
+};
+
+/**
+ * struct iosm_sio - State of the char driver layer.
+ * @misc: OS misc device component
+ * @sio_fop: reference to iosm_sio structure
+ * @ipc_imem: 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: Channel instance
+ * @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
+ * @flag: Flags to monitor state of device
+ * @wmaxcommand: Max buffer size
+ */
+struct iosm_sio {
+ struct miscdevice misc;
+ struct iosm_sio_open_file *sio_fop;
+ struct iosm_imem *ipc_imem;
+ struct device *dev;
+ struct iosm_pcie *pcie;
+ struct sk_buff *rx_pending_buf;
+ char devname[IPC_SIO_DEVNAME_LEN];
+ struct ipc_mem_channel *channel;
+ struct sk_buff_head rx_list;
+ struct completion read_sem;
+ wait_queue_head_t poll_inq;
+ unsigned long flag;
+ 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 - Dellocate and free resource for a character device.
+ * @ipc_sio: Pointer to the ipc sio data-struct
+ */
+void ipc_sio_deinit(struct iosm_sio *ipc_sio);
+
+#endif
--
2.12.3
