The Qualcomm remote file system protocol is used by certain remoteprocs,
in particular the modem, to read and write persistent storage in
platforms where only the application CPU has physical storage access.

The protocol is based on a set of QMI-encoded control-messages and a
shared memory buffer for exchaning the data. This driver implements the
latter, providing the user space service access to the carved out chunk
of memory.

Signed-off-by: Bjorn Andersson <redacted>
---

Changes since v2:
- Renamed driver to "rmtfs_mem" in attempt to clarify that this is not a
  file system, but some chunk of memory.

Changes since v1:
- RFSA device represented direclty by the reserved-memory node

 drivers/of/platform.c        |   1 +
 drivers/soc/qcom/Kconfig     |  11 ++
 drivers/soc/qcom/Makefile    |   1 +
 drivers/soc/qcom/rmtfs_mem.c | 272 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 285 insertions(+)
 create mode 100644 drivers/soc/qcom/rmtfs_mem.c

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>