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Subject[PATCH v2 4/7] mhi_bus: core: add support for handling ioctl cmds
Date
User space clients use RS232 control signaling mechanism to
communicate call status between host and modem. Adding support
to handle ioctl commands from user space.

Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Reviewed-by: Tony Truong <truong@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
---
drivers/bus/mhi/core/Makefile | 2 +-
drivers/bus/mhi/core/mhi_dtr.c | 218 ++++++++++++++++++++++++++++++++++++++++
drivers/bus/mhi/core/mhi_init.c | 8 +-
3 files changed, 226 insertions(+), 2 deletions(-)
create mode 100644 drivers/bus/mhi/core/mhi_dtr.c

diff --git a/drivers/bus/mhi/core/Makefile b/drivers/bus/mhi/core/Makefile
index a6015ab..a743fbf 100644
--- a/drivers/bus/mhi/core/Makefile
+++ b/drivers/bus/mhi/core/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_MHI_BUS) +=mhi_init.o mhi_main.o mhi_pm.o mhi_boot.o
+obj-$(CONFIG_MHI_BUS) +=mhi_init.o mhi_main.o mhi_pm.o mhi_boot.o mhi_dtr.o
diff --git a/drivers/bus/mhi/core/mhi_dtr.c b/drivers/bus/mhi/core/mhi_dtr.c
new file mode 100644
index 0000000..5c2409b
--- /dev/null
+++ b/drivers/bus/mhi/core/mhi_dtr.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/termios.h>
+#include <linux/wait.h>
+#include <linux/mhi.h>
+#include "mhi_internal.h"
+
+struct __packed dtr_ctrl_msg {
+ u32 preamble;
+ u32 msg_id;
+ u32 dest_id;
+ u32 size;
+ u32 msg;
+};
+
+#define CTRL_MAGIC (0x4C525443)
+#define CTRL_MSG_DTR BIT(0)
+#define CTRL_MSG_RTS BIT(1)
+#define CTRL_MSG_DCD BIT(0)
+#define CTRL_MSG_DSR BIT(1)
+#define CTRL_MSG_RI BIT(3)
+#define CTRL_HOST_STATE (0x10)
+#define CTRL_DEVICE_STATE (0x11)
+#define CTRL_GET_CHID(dtr) (dtr->dest_id & 0xFF)
+
+static int mhi_dtr_tiocmset(struct mhi_controller *mhi_cntrl,
+ struct mhi_device *mhi_dev,
+ u32 tiocm)
+{
+ struct dtr_ctrl_msg *dtr_msg = NULL;
+ struct mhi_chan *dtr_chan = mhi_cntrl->dtr_dev->ul_chan;
+ spinlock_t *res_lock = &mhi_dev->dev.devres_lock;
+ u32 cur_tiocm;
+ int ret = 0;
+
+ cur_tiocm = mhi_dev->tiocm & ~(TIOCM_CD | TIOCM_DSR | TIOCM_RI);
+
+ tiocm &= (TIOCM_DTR | TIOCM_RTS);
+
+ /* state did not changed */
+ if (cur_tiocm == tiocm)
+ return 0;
+
+ mutex_lock(&dtr_chan->mutex);
+
+ dtr_msg = kzalloc(sizeof(*dtr_msg), GFP_KERNEL);
+ if (!dtr_msg) {
+ ret = -ENOMEM;
+ goto tiocm_exit;
+ }
+
+ dtr_msg->preamble = CTRL_MAGIC;
+ dtr_msg->msg_id = CTRL_HOST_STATE;
+ dtr_msg->dest_id = mhi_dev->ul_chan_id;
+ dtr_msg->size = sizeof(u32);
+ if (tiocm & TIOCM_DTR)
+ dtr_msg->msg |= CTRL_MSG_DTR;
+ if (tiocm & TIOCM_RTS)
+ dtr_msg->msg |= CTRL_MSG_RTS;
+
+ reinit_completion(&dtr_chan->completion);
+ ret = mhi_queue_transfer(mhi_cntrl->dtr_dev, DMA_TO_DEVICE, dtr_msg,
+ sizeof(*dtr_msg), MHI_EOT);
+ if (ret)
+ goto tiocm_exit;
+
+ ret = wait_for_completion_timeout(&dtr_chan->completion,
+ msecs_to_jiffies(mhi_cntrl->timeout_ms));
+ if (!ret) {
+ dev_err(mhi_cntrl->dev, "Failed to recv transfer callback\n");
+ ret = -EIO;
+ goto tiocm_exit;
+ }
+
+ ret = 0;
+ spin_lock_irq(res_lock);
+ mhi_dev->tiocm &= ~(TIOCM_DTR | TIOCM_RTS);
+ mhi_dev->tiocm |= tiocm;
+ spin_unlock_irq(res_lock);
+
+tiocm_exit:
+ kfree(dtr_msg);
+ mutex_unlock(&dtr_chan->mutex);
+
+ return ret;
+}
+
+long mhi_ioctl(struct mhi_device *mhi_dev, unsigned int cmd, unsigned long arg)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ int ret;
+
+ /* ioctl not supported by this controller */
+ if (!mhi_cntrl->dtr_dev)
+ return -EIO;
+
+ switch (cmd) {
+ case TIOCMGET:
+ return mhi_dev->tiocm;
+ case TIOCMSET:
+ {
+ u32 tiocm;
+
+ ret = get_user(tiocm, (u32 *)arg);
+ if (ret)
+ return ret;
+
+ return mhi_dtr_tiocmset(mhi_cntrl, mhi_dev, tiocm);
+ }
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL(mhi_ioctl);
+
+static void mhi_dtr_dl_xfer_cb(struct mhi_device *mhi_dev,
+ struct mhi_result *mhi_result)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct dtr_ctrl_msg *dtr_msg = mhi_result->buf_addr;
+ u32 chan;
+ spinlock_t *res_lock;
+
+ if (mhi_result->bytes_xferd != sizeof(*dtr_msg)) {
+ dev_err(mhi_cntrl->dev, "Unexpected length %zu received\n",
+ mhi_result->bytes_xferd);
+ return;
+ }
+
+ chan = CTRL_GET_CHID(dtr_msg);
+ if (chan >= mhi_cntrl->max_chan)
+ return;
+
+ mhi_dev = mhi_cntrl->mhi_chan[chan].mhi_dev;
+ if (!mhi_dev)
+ return;
+
+ res_lock = &mhi_dev->dev.devres_lock;
+ spin_lock_irq(res_lock);
+ mhi_dev->tiocm &= ~(TIOCM_CD | TIOCM_DSR | TIOCM_RI);
+
+ if (dtr_msg->msg & CTRL_MSG_DCD)
+ mhi_dev->tiocm |= TIOCM_CD;
+
+ if (dtr_msg->msg & CTRL_MSG_DSR)
+ mhi_dev->tiocm |= TIOCM_DSR;
+
+ if (dtr_msg->msg & CTRL_MSG_RI)
+ mhi_dev->tiocm |= TIOCM_RI;
+ spin_unlock_irq(res_lock);
+}
+
+static void mhi_dtr_ul_xfer_cb(struct mhi_device *mhi_dev,
+ struct mhi_result *mhi_result)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_chan *dtr_chan = mhi_cntrl->dtr_dev->ul_chan;
+
+ if (!mhi_result->transaction_status)
+ complete(&dtr_chan->completion);
+}
+
+static void mhi_dtr_remove(struct mhi_device *mhi_dev)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+
+ mhi_cntrl->dtr_dev = NULL;
+}
+
+static int mhi_dtr_probe(struct mhi_device *mhi_dev,
+ const struct mhi_device_id *id)
+{
+ struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+ int ret;
+
+ ret = mhi_prepare_for_transfer(mhi_dev);
+ if (!ret)
+ mhi_cntrl->dtr_dev = mhi_dev;
+
+ return ret;
+}
+
+static const struct mhi_device_id mhi_dtr_table[] = {
+ { .chan = "IP_CTRL" },
+ {},
+};
+
+static struct mhi_driver mhi_dtr_driver = {
+ .id_table = mhi_dtr_table,
+ .remove = mhi_dtr_remove,
+ .probe = mhi_dtr_probe,
+ .ul_xfer_cb = mhi_dtr_ul_xfer_cb,
+ .dl_xfer_cb = mhi_dtr_dl_xfer_cb,
+ .driver = {
+ .name = "MHI_DTR",
+ .owner = THIS_MODULE,
+ }
+};
+
+int __init mhi_dtr_init(void)
+{
+ return mhi_driver_register(&mhi_dtr_driver);
+}
diff --git a/drivers/bus/mhi/core/mhi_init.c b/drivers/bus/mhi/core/mhi_init.c
index 43a700d..b09767a 100644
--- a/drivers/bus/mhi/core/mhi_init.c
+++ b/drivers/bus/mhi/core/mhi_init.c
@@ -1293,10 +1293,16 @@ struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl)

static int __init mhi_init(void)
{
+ int ret;
+
/* parent directory */
debugfs_create_dir(mhi_bus_type.name, NULL);

- return bus_register(&mhi_bus_type);
+ ret = bus_register(&mhi_bus_type);
+
+ if (!ret)
+ mhi_dtr_init();
+ return ret;
}
postcore_initcall(mhi_init);

--
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