bus: mhi: core: Add support for creating and destroying MHI devices

This commit adds support for creating and destroying MHI devices. The
MHI devices binds to the MHI channels and are used to transfer data
between MHI host and client device.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/989

Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted from pm patch and cleaned up for upstream]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-5-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 124 insertions, 1 deletions

diff --git a/drivers/bus/mhi/core/Makefile b/drivers/bus/mhi/core/Makefile
index 2db32697c67f..77f7730da4bf 100644
--- a/drivers/bus/mhi/core/Makefile
+++ b/drivers/bus/mhi/core/Makefile
@@ -1,3 +1,3 @@
 obj-$(CONFIG_MHI_BUS) := mhi.o
 
-mhi-y := init.o
+mhi-y := init.o main.o
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
new file mode 100644
index 000000000000..7c35744ec0c0
--- /dev/null
+++ b/drivers/bus/mhi/core/main.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/mhi.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+int mhi_destroy_device(struct device *dev, void *data)
+{
+	struct mhi_device *mhi_dev;
+	struct mhi_controller *mhi_cntrl;
+
+	if (dev->bus != &mhi_bus_type)
+		return 0;
+
+	mhi_dev = to_mhi_device(dev);
+	mhi_cntrl = mhi_dev->mhi_cntrl;
+
+	/* Only destroy virtual devices thats attached to bus */
+	if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
+		return 0;
+
+	dev_dbg(&mhi_cntrl->mhi_dev->dev, "destroy device for chan:%s\n",
+		 mhi_dev->chan_name);
+
+	/* Notify the client and remove the device from MHI bus */
+	device_del(dev);
+	put_device(dev);
+
+	return 0;
+}
+
+static void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
+{
+	struct mhi_driver *mhi_drv;
+
+	if (!mhi_dev->dev.driver)
+		return;
+
+	mhi_drv = to_mhi_driver(mhi_dev->dev.driver);
+
+	if (mhi_drv->status_cb)
+		mhi_drv->status_cb(mhi_dev, cb_reason);
+}
+
+/* Bind MHI channels to MHI devices */
+void mhi_create_devices(struct mhi_controller *mhi_cntrl)
+{
+	struct mhi_chan *mhi_chan;
+	struct mhi_device *mhi_dev;
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	int i, ret;
+
+	mhi_chan = mhi_cntrl->mhi_chan;
+	for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) {
+		if (!mhi_chan->configured || mhi_chan->mhi_dev ||
+		    !(mhi_chan->ee_mask & BIT(mhi_cntrl->ee)))
+			continue;
+		mhi_dev = mhi_alloc_device(mhi_cntrl);
+		if (!mhi_dev)
+			return;
+
+		mhi_dev->dev_type = MHI_DEVICE_XFER;
+		switch (mhi_chan->dir) {
+		case DMA_TO_DEVICE:
+			mhi_dev->ul_chan = mhi_chan;
+			mhi_dev->ul_chan_id = mhi_chan->chan;
+			break;
+		case DMA_FROM_DEVICE:
+			/* We use dl_chan as offload channels */
+			mhi_dev->dl_chan = mhi_chan;
+			mhi_dev->dl_chan_id = mhi_chan->chan;
+			break;
+		default:
+			dev_err(dev, "Direction not supported\n");
+			put_device(&mhi_dev->dev);
+			return;
+		}
+
+		get_device(&mhi_dev->dev);
+		mhi_chan->mhi_dev = mhi_dev;
+
+		/* Check next channel if it matches */
+		if ((i + 1) < mhi_cntrl->max_chan && mhi_chan[1].configured) {
+			if (!strcmp(mhi_chan[1].name, mhi_chan->name)) {
+				i++;
+				mhi_chan++;
+				if (mhi_chan->dir == DMA_TO_DEVICE) {
+					mhi_dev->ul_chan = mhi_chan;
+					mhi_dev->ul_chan_id = mhi_chan->chan;
+				} else {
+					mhi_dev->dl_chan = mhi_chan;
+					mhi_dev->dl_chan_id = mhi_chan->chan;
+				}
+				get_device(&mhi_dev->dev);
+				mhi_chan->mhi_dev = mhi_dev;
+			}
+		}
+
+		/* Channel name is same for both UL and DL */
+		mhi_dev->chan_name = mhi_chan->name;
+		dev_set_name(&mhi_dev->dev, "%04x_%s", mhi_chan->chan,
+			     mhi_dev->chan_name);
+
+		/* Init wakeup source if available */
+		if (mhi_dev->dl_chan && mhi_dev->dl_chan->wake_capable)
+			device_init_wakeup(&mhi_dev->dev, true);
+
+		ret = device_add(&mhi_dev->dev);
+		if (ret)
+			put_device(&mhi_dev->dev);
+	}
+}