[v3,4/5] soc: qcom: Remote filesystem memory driver

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index ee89f096f0f3..e7548c9a9915 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -498,6 +498,7 @@  EXPORT_SYMBOL_GPL(of_platform_default_populate);
 
 #ifndef CONFIG_PPC
 static const struct of_device_id reserved_mem_matches[] = {
+	{ .compatible = "qcom,rmtfs-mem" },
 	{ .compatible = "ramoops" },
 	{}
 };
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 9fca977ef18d..6dff89eaf3f8 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -24,6 +24,17 @@  config QCOM_PM
 	  modes. It interface with various system drivers to put the cores in
 	  low power modes.
 
+config QCOM_RMTFS_MEM
+	tristate "Qualcomm Remote Filesystem memory driver"
+	depends on ARCH_QCOM
+	help
+	  The Qualcomm remote filesystem memory driver is used for allocating
+	  and exposing regions of shared memory with remote processors for the
+	  purpose of exchanging sector-data between the remote filesystem
+	  service and its clients.
+
+	  Say y here if you intend to boot the modem remoteproc.
+
 config QCOM_SMEM
 	tristate "Qualcomm Shared Memory Manager (SMEM)"
 	depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 414f0de274fa..541c1f40d126 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,6 +1,7 @@ 
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_PM)	+=	spm.o
+obj-$(CONFIG_QCOM_RMTFS_MEM)	+= rmtfs_mem.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=	smem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
new file mode 100644
index 000000000000..2e7c955e7cf0
--- /dev/null
+++ b/drivers/soc/qcom/rmtfs_mem.c
@@ -0,0 +1,272 @@ 
+/*
+ * Copyright (c) 2017 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/cdev.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/of_fdt.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/qcom_scm.h>
+
+#define QCOM_RMTFS_MEM_DEV_MAX	(MINORMASK + 1)
+
+static dev_t qcom_rmtfs_mem_major;
+
+struct qcom_rmtfs_mem {
+	struct device dev;
+	struct cdev cdev;
+
+	void *base;
+	phys_addr_t addr;
+	phys_addr_t size;
+
+	unsigned int client_id;
+};
+
+static ssize_t qcom_rmtfs_mem_show(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf);
+
+static DEVICE_ATTR(phys_addr, 0400, qcom_rmtfs_mem_show, NULL);
+static DEVICE_ATTR(size, 0400, qcom_rmtfs_mem_show, NULL);
+static DEVICE_ATTR(client_id, 0400, qcom_rmtfs_mem_show, NULL);
+
+static ssize_t qcom_rmtfs_mem_show(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
+							struct qcom_rmtfs_mem,
+							dev);
+
+	if (attr == &dev_attr_phys_addr)
+		return sprintf(buf, "%pa\n", &rmtfs_mem->addr);
+	if (attr == &dev_attr_size)
+		return sprintf(buf, "%pa\n", &rmtfs_mem->size);
+	if (attr == &dev_attr_client_id)
+		return sprintf(buf, "%d\n", rmtfs_mem->client_id);
+
+	return -EINVAL;
+}
+
+static struct attribute *qcom_rmtfs_mem_attrs[] = {
+	&dev_attr_phys_addr.attr,
+	&dev_attr_size.attr,
+	&dev_attr_client_id.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(qcom_rmtfs_mem);
+
+static int qcom_rmtfs_mem_open(struct inode *inode, struct file *filp)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = container_of(inode->i_cdev,
+							struct qcom_rmtfs_mem,
+							cdev);
+
+	get_device(&rmtfs_mem->dev);
+	filp->private_data = rmtfs_mem;
+
+	return 0;
+}
+static ssize_t qcom_rmtfs_mem_read(struct file *filp,
+			      char __user *buf, size_t count, loff_t *f_pos)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
+
+	if (*f_pos >= rmtfs_mem->size)
+		return 0;
+
+	if (*f_pos + count >= rmtfs_mem->size)
+		count = rmtfs_mem->size - *f_pos;
+
+	if (copy_to_user(buf, rmtfs_mem->base + *f_pos, count))
+		return -EFAULT;
+
+	*f_pos += count;
+	return count;
+}
+
+static ssize_t qcom_rmtfs_mem_write(struct file *filp,
+			       const char __user *buf, size_t count,
+			       loff_t *f_pos)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
+
+	if (*f_pos >= rmtfs_mem->size)
+		return 0;
+
+	if (*f_pos + count >= rmtfs_mem->size)
+		count = rmtfs_mem->size - *f_pos;
+
+	if (copy_from_user(rmtfs_mem->base + *f_pos, buf, count))
+		return -EFAULT;
+
+	*f_pos += count;
+	return count;
+}
+
+static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
+
+	put_device(&rmtfs_mem->dev);
+
+	return 0;
+}
+
+static const struct file_operations qcom_rmtfs_mem_fops = {
+	.owner = THIS_MODULE,
+	.open = qcom_rmtfs_mem_open,
+	.read = qcom_rmtfs_mem_read,
+	.write = qcom_rmtfs_mem_write,
+	.release = qcom_rmtfs_mem_release,
+	.llseek = default_llseek,
+};
+
+static void qcom_rmtfs_mem_release_device(struct device *dev)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
+							struct qcom_rmtfs_mem,
+							dev);
+
+	kfree(rmtfs_mem);
+}
+
+static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct reserved_mem *rmem;
+	struct qcom_rmtfs_mem *rmtfs_mem;
+	u32 client_id;
+	int ret;
+
+	rmem = of_reserved_mem_get(node);
+	if (!rmem) {
+		dev_err(&pdev->dev, "failed to acquire memory region\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32(node, "qcom,client-id", &client_id);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
+		return ret;
+
+	}
+
+	rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL);
+	if (!rmtfs_mem)
+		return -ENOMEM;
+
+	rmtfs_mem->addr = rmem->base;
+	rmtfs_mem->client_id = client_id;
+	rmtfs_mem->size = rmem->size;
+
+	device_initialize(&rmtfs_mem->dev);
+	rmtfs_mem->dev.parent = &pdev->dev;
+	rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
+
+	rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
+					rmtfs_mem->size, MEMREMAP_WC);
+	if (IS_ERR(rmtfs_mem->base)) {
+		dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
+		ret = PTR_ERR(rmtfs_mem->base);
+		goto put_device;
+	}
+
+	cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
+	rmtfs_mem->cdev.owner = THIS_MODULE;
+
+	dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
+	rmtfs_mem->dev.id = client_id;
+	rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
+
+	ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
+		goto put_device;
+	}
+
+	rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
+
+	dev_set_drvdata(&pdev->dev, rmtfs_mem);
+
+	return 0;
+
+remove_cdev:
+	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
+put_device:
+	put_device(&rmtfs_mem->dev);
+
+	return ret;
+}
+
+static int qcom_rmtfs_mem_remove(struct platform_device *pdev)
+{
+	struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
+
+	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
+	put_device(&rmtfs_mem->dev);
+
+	return 0;
+}
+
+static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
+	{ .compatible = "qcom,rmtfs-mem" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
+
+static struct platform_driver qcom_rmtfs_mem_driver = {
+	.probe = qcom_rmtfs_mem_probe,
+	.remove = qcom_rmtfs_mem_remove,
+	.driver  = {
+		.name  = "qcom_rmtfs_mem",
+		.of_match_table = qcom_rmtfs_mem_of_match,
+	},
+};
+
+static int qcom_rmtfs_mem_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
+				  QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
+	if (ret < 0) {
+		pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
+		return ret;
+	}
+
+	ret = platform_driver_register(&qcom_rmtfs_mem_driver);
+	if (ret < 0) {
+		pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
+		unregister_chrdev_region(qcom_rmtfs_mem_major,
+					 QCOM_RMTFS_MEM_DEV_MAX);
+	}
+
+	return ret;
+}
+module_init(qcom_rmtfs_mem_init);
+
+static void qcom_rmtfs_mem_exit(void)
+{
+	platform_driver_unregister(&qcom_rmtfs_mem_driver);
+	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
+}
+module_exit(qcom_rmtfs_mem_exit);