[PATCH v3 2/4] bus: fsl-mc: add fsl-mc userspace support

Ioana Ciornei
2018-11-20T15:40:37Z

Adding userspace support for the MC (Management Complex) means exporting
an ioctl capable device file representing the root resource container.

This new functionality in the fsl-mc bus driver intends to provide
userspace applications an interface to interact with the MC firmware.

Commands that are composed in userspace are sent to the MC firmware
through the FSL_MC_SEND_MC_COMMAND ioctl. By default the implicit MC
I/O portal is used for this operation, but if the implicit one is busy,
a dynamic portal is allocated and then freed upon execution.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
---
Changes in v2:
- use root dprc MC portal by default
- create the uapi misc device from the root dprc probe function
Changes in v3:
- use dev_ instead of pr_
- remove dynamic_instance_count and uapi_created variables
- do not assign true to a u32
- return the actual error code (the decision to defer is for the caller)

Documentation/ioctl/ioctl-number.txt | 1 +
drivers/bus/fsl-mc/Kconfig | 7 ++
drivers/bus/fsl-mc/Makefile | 3 +
drivers/bus/fsl-mc/dprc-driver.c | 14 ++-
drivers/bus/fsl-mc/fsl-mc-private.h | 39 ++++++++
drivers/bus/fsl-mc/fsl-mc-uapi.c | 168 +++++++++++++++++++++++++++++++++++
include/uapi/linux/fsl_mc.h | 9 ++
7 files changed, 240 insertions(+), 1 deletion(-)
create mode 100644 drivers/bus/fsl-mc/fsl-mc-uapi.c

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index af6f6ba..eaae7bf 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -171,6 +171,7 @@ Code Seq#(hex) Include File Comments
'R' 00-1F linux/random.h conflict!
'R' 01 linux/rfkill.h conflict!
'R' C0-DF net/bluetooth/rfcomm.h
+'R' E0 uapi/linux/fsl_mc.h
'S' all linux/cdrom.h conflict!
'S' 80-81 scsi/scsi_ioctl.h conflict!
'S' 82-FF scsi/scsi.h conflict!
diff --git a/drivers/bus/fsl-mc/Kconfig b/drivers/bus/fsl-mc/Kconfig
index c23c77c..cde6f40 100644
--- a/drivers/bus/fsl-mc/Kconfig
+++ b/drivers/bus/fsl-mc/Kconfig
@@ -14,3 +14,10 @@ config FSL_MC_BUS
architecture. The fsl-mc bus driver handles discovery of
DPAA2 objects (which are represented as Linux devices) and
binding objects to drivers.
+
+config FSL_MC_UAPI_SUPPORT
+ bool "Management Complex (MC) userspace support"
+ depends on FSL_MC_BUS
+ help
+ Provides userspace support for creating/destroying/configuring
+ DPAA2 objects in the Management Complex.
diff --git a/drivers/bus/fsl-mc/Makefile b/drivers/bus/fsl-mc/Makefile
index 3c518c7..4ae292a 100644
--- a/drivers/bus/fsl-mc/Makefile
+++ b/drivers/bus/fsl-mc/Makefile
@@ -16,3 +16,6 @@ mc-bus-driver-objs := fsl-mc-bus.o \
fsl-mc-allocator.o \
fsl-mc-msi.o \
dpmcp.o
+
+# MC userspace support
+obj-$(CONFIG_FSL_MC_UAPI_SUPPORT) += fsl-mc-uapi.o
diff --git a/drivers/bus/fsl-mc/dprc-driver.c b/drivers/bus/fsl-mc/dprc-driver.c
index 52c7e15..bab0d5a 100644
--- a/drivers/bus/fsl-mc/dprc-driver.c
+++ b/drivers/bus/fsl-mc/dprc-driver.c
@@ -647,6 +647,12 @@ static int dprc_probe(struct fsl_mc_device *mc_dev)
} else {
dev_set_msi_domain(&mc_dev->dev, mc_msi_domain);
msi_domain_set = true;
+
+ error = fsl_mc_uapi_create_device_file(mc_bus);
+ if (error < 0) {
+ error = -EPROBE_DEFER;
+ goto error_cleanup_msi_domain;
+ }
}
}

@@ -654,7 +660,7 @@ static int dprc_probe(struct fsl_mc_device *mc_dev)
&mc_dev->mc_handle);
if (error < 0) {
dev_err(&mc_dev->dev, "dprc_open() failed: %d\n", error);
- goto error_cleanup_msi_domain;
+ goto error_cleanup_uapi;
}

error = dprc_get_attributes(mc_dev->mc_io, 0, mc_dev->mc_handle,
@@ -706,6 +712,10 @@ static int dprc_probe(struct fsl_mc_device *mc_dev)
error_cleanup_open:
(void)dprc_close(mc_dev->mc_io, 0, mc_dev->mc_handle);

+error_cleanup_uapi:
+ if (fsl_mc_is_root_dprc(&mc_dev->dev))
+ fsl_mc_uapi_remove_device_file(mc_bus);
+
error_cleanup_msi_domain:
if (msi_domain_set)
dev_set_msi_domain(&mc_dev->dev, NULL);
@@ -774,6 +784,8 @@ static int dprc_remove(struct fsl_mc_device *mc_dev)
if (!fsl_mc_is_root_dprc(&mc_dev->dev)) {
fsl_destroy_mc_io(mc_dev->mc_io);
mc_dev->mc_io = NULL;
+ } else {
+ fsl_mc_uapi_remove_device_file(mc_bus);
}

dev_info(&mc_dev->dev, "DPRC device unbound from driver");
diff --git a/drivers/bus/fsl-mc/fsl-mc-private.h b/drivers/bus/fsl-mc/fsl-mc-private.h
index ea11b4f..07f00f8 100644
--- a/drivers/bus/fsl-mc/fsl-mc-private.h
+++ b/drivers/bus/fsl-mc/fsl-mc-private.h
@@ -10,6 +10,8 @@

#include <linux/fsl/mc.h>
#include <linux/mutex.h>
+#include <linux/ioctl.h>
+#include <linux/miscdevice.h>

/*
* Data Path Management Complex (DPMNG) General API
@@ -492,6 +494,22 @@ struct fsl_mc_resource_pool {
};

/**
+ * struct fsl_mc_uapi - information associated with a device file
+ * @misc: struct miscdevice linked to the root dprc
+ * @device: newly created device in /dev
+ * @mutex: mutex lock to serialize the open/release operations
+ * @local_instance_in_use: local MC I/O instance in use or not
+ * @static_mc_io: pointer to the static MC I/O object
+ */
+struct fsl_mc_uapi {
+ struct miscdevice misc;
+ struct device *device;
+ struct mutex mutex; /* serialize open/release operations */
+ u32 local_instance_in_use;
+ struct fsl_mc_io *static_mc_io;
+};
+
+/**
* struct fsl_mc_bus - logical bus that corresponds to a physical DPRC
* @mc_dev: fsl-mc device for the bus device itself.
* @resource_pools: array of resource pools (one pool per resource type)
@@ -500,6 +518,7 @@ struct fsl_mc_resource_pool {
* @irq_resources: Pointer to array of IRQ objects for the IRQ pool
* @scan_mutex: Serializes bus scanning
* @dprc_attr: DPRC attributes
+ * @uapi_misc: struct that abstracts the interaction with userspace
*/
struct fsl_mc_bus {
struct fsl_mc_device mc_dev;
@@ -507,6 +526,7 @@ struct fsl_mc_bus {
struct fsl_mc_device_irq *irq_resources;
struct mutex scan_mutex; /* serializes bus scanning */
struct dprc_attributes dprc_attr;
+ struct fsl_mc_uapi uapi_misc;
};

#define to_fsl_mc_bus(_mc_dev) \
@@ -561,4 +581,23 @@ int __must_check fsl_create_mc_io(struct device *dev,

bool fsl_mc_is_root_dprc(struct device *dev);

+#ifdef CONFIG_FSL_MC_UAPI_SUPPORT
+
+int fsl_mc_uapi_create_device_file(struct fsl_mc_bus *mc_bus);
+
+void fsl_mc_uapi_remove_device_file(struct fsl_mc_bus *mc_bus);
+
+#else
+
+static inline int fsl_mc_uapi_create_device_file(struct fsl_mc_bus *mc_bus)
+{
+ return 0;
+}
+
+static inline void fsl_mc_uapi_remove_device_file(struct fsl_mc_bus *mc_bus)
+{
+}
+
+#endif
+
#endif /* _FSL_MC_PRIVATE_H_ */
diff --git a/drivers/bus/fsl-mc/fsl-mc-uapi.c b/drivers/bus/fsl-mc/fsl-mc-uapi.c
new file mode 100644
index 0000000..71ff201
--- /dev/null
+++ b/drivers/bus/fsl-mc/fsl-mc-uapi.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Management Complex (MC) userspace support
+ *
+ * Copyright 2018 NXP
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+
+#include "fsl-mc-private.h"
+
+struct uapi_priv_data {
+ struct fsl_mc_uapi *uapi;
+ struct fsl_mc_io *mc_io;
+};
+
+static int fsl_mc_uapi_send_command(unsigned long arg,
+ struct fsl_mc_io *mc_io)
+{
+ struct fsl_mc_command mc_cmd;
+ int error;
+
+ error = copy_from_user(&mc_cmd, (void __user *)arg, sizeof(mc_cmd));
+ if (error)
+ return -EFAULT;
+
+ error = mc_send_command(mc_io, &mc_cmd);
+ if (error)
+ return error;
+
+ error = copy_to_user((void __user *)arg, &mc_cmd, sizeof(mc_cmd));
+ if (error)
+ return -EFAULT;
+
+ return 0;
+}
+
+static int fsl_mc_uapi_dev_open(struct inode *inode, struct file *filep)
+{
+ struct fsl_mc_device *root_mc_device;
+ struct uapi_priv_data *priv_data;
+ struct fsl_mc_io *dynamic_mc_io;
+ struct fsl_mc_uapi *mc_uapi;
+ struct fsl_mc_bus *mc_bus;
+ int error;
+
+ priv_data = kzalloc(sizeof(*priv_data), GFP_KERNEL);
+ if (!priv_data)
+ return -ENOMEM;
+
+ mc_uapi = container_of(filep->private_data, struct fsl_mc_uapi, misc);
+ mc_bus = container_of(mc_uapi, struct fsl_mc_bus, uapi_misc);
+ root_mc_device = &mc_bus->mc_dev;
+
+ mutex_lock(&mc_uapi->mutex);
+
+ if (!mc_uapi->local_instance_in_use) {
+ priv_data->mc_io = mc_uapi->static_mc_io;
+ mc_uapi->local_instance_in_use = 1;
+ } else {
+ error = fsl_mc_portal_allocate(root_mc_device, 0,
+ &dynamic_mc_io);
+ if (error) {
+ dev_dbg(&root_mc_device->dev,
+ "Could not allocate MC portal\n");
+ goto error_portal_allocate;
+ }
+
+ priv_data->mc_io = dynamic_mc_io;
+ }
+ priv_data->uapi = mc_uapi;
+ filep->private_data = priv_data;
+
+ mutex_unlock(&mc_uapi->mutex);
+
+ return 0;
+
+error_portal_allocate:
+ mutex_unlock(&mc_uapi->mutex);
+
+ return error;
+}
+
+static int fsl_mc_uapi_dev_release(struct inode *inode, struct file *filep)
+{
+ struct uapi_priv_data *priv_data;
+ struct fsl_mc_uapi *mc_uapi;
+ struct fsl_mc_io *mc_io;
+
+ priv_data = filep->private_data;
+ mc_uapi = priv_data->uapi;
+ mc_io = priv_data->mc_io;
+
+ mutex_lock(&mc_uapi->mutex);
+
+ if (mc_io == mc_uapi->static_mc_io)
+ mc_uapi->local_instance_in_use = 0;
+ else
+ fsl_mc_portal_free(mc_io);
+
+ kfree(filep->private_data);
+ filep->private_data = NULL;
+
+ mutex_unlock(&mc_uapi->mutex);
+
+ return 0;
+}
+
+static long fsl_mc_uapi_dev_ioctl(struct file *file,
+ unsigned int cmd,
+ unsigned long arg)
+{
+ struct uapi_priv_data *priv_data = file->private_data;
+ struct fsl_mc_device *root_mc_device;
+ struct fsl_mc_bus *mc_bus;
+ int error;
+
+ mc_bus = container_of(priv_data->uapi, struct fsl_mc_bus, uapi_misc);
+ root_mc_device = &mc_bus->mc_dev;
+
+ switch (cmd) {
+ case FSL_MC_SEND_MC_COMMAND:
+ error = fsl_mc_uapi_send_command(arg, priv_data->mc_io);
+ break;
+ default:
+ dev_dbg(&root_mc_device->dev, "unexpected ioctl call number\n");
+ error = -EINVAL;
+ }
+
+ return error;
+}
+
+static const struct file_operations fsl_mc_uapi_dev_fops = {
+ .owner = THIS_MODULE,
+ .open = fsl_mc_uapi_dev_open,
+ .release = fsl_mc_uapi_dev_release,
+ .unlocked_ioctl = fsl_mc_uapi_dev_ioctl,
+};
+
+int fsl_mc_uapi_create_device_file(struct fsl_mc_bus *mc_bus)
+{
+ struct fsl_mc_device *mc_dev = &mc_bus->mc_dev;
+ struct fsl_mc_uapi *mc_uapi = &mc_bus->uapi_misc;
+ int error;
+
+ mc_uapi->misc.minor = MISC_DYNAMIC_MINOR;
+ mc_uapi->misc.name = dev_name(&mc_dev->dev);
+ mc_uapi->misc.fops = &fsl_mc_uapi_dev_fops;
+
+ error = misc_register(&mc_uapi->misc);
+ if (error)
+ return error;
+
+ mc_uapi->static_mc_io = mc_bus->mc_dev.mc_io;
+
+ mutex_init(&mc_uapi->mutex);
+
+ return 0;
+}
+
+void fsl_mc_uapi_remove_device_file(struct fsl_mc_bus *mc_bus)
+{
+ misc_deregister(&mc_bus->uapi_misc.misc);
+}
diff --git a/include/uapi/linux/fsl_mc.h b/include/uapi/linux/fsl_mc.h
index 6c19cfc..4989c1b 100644
--- a/include/uapi/linux/fsl_mc.h
+++ b/include/uapi/linux/fsl_mc.h
@@ -16,10 +16,19 @@
* struct fsl_mc_command - Management Complex (MC) command structure
* @header: MC command header
* @params: MC command parameters
+ *
+ * Used by FSL_MC_SEND_MC_COMMAND
*/
struct fsl_mc_command {
__le64 header;
__le64 params[MC_CMD_NUM_OF_PARAMS];
};

+#define FSL_MC_SEND_CMD_IOCTL_TYPE 'R'
+#define FSL_MC_SEND_CMD_IOCTL_SEQ 0xE0
+
+#define FSL_MC_SEND_MC_COMMAND \
+ _IOWR(FSL_MC_SEND_CMD_IOCTL_TYPE, FSL_MC_SEND_CMD_IOCTL_SEQ, \
+ struct fsl_mc_command)
+
#endif /* _UAPI_FSL_MC_H_ */
--
1.9.1