commit 19b8766459 upstream.
Each physical partition can provide multiple services each with UUID.
Each such service can be presented as logical partition with a unique
combination of VM ID and UUID. The number of distinct UUID in a system
will be less than or equal to the number of logical partitions.
However, currently it fails to register more than one logical partition
or service within a physical partition as the device name contains only
VM ID while both VM ID and UUID are maintained in the partition information.
The kernel complains with the below message:
| sysfs: cannot create duplicate filename '/devices/arm-ffa-8001'
| CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc7 #8
| Hardware name: FVP Base RevC (DT)
| Call trace:
| dump_backtrace+0xf8/0x118
| show_stack+0x18/0x24
| dump_stack_lvl+0x50/0x68
| dump_stack+0x18/0x24
| sysfs_create_dir_ns+0xe0/0x13c
| kobject_add_internal+0x220/0x3d4
| kobject_add+0x94/0x100
| device_add+0x144/0x5d8
| device_register+0x20/0x30
| ffa_device_register+0x88/0xd8
| ffa_setup_partitions+0x108/0x1b8
| ffa_init+0x2ec/0x3a4
| do_one_initcall+0xcc/0x240
| do_initcall_level+0x8c/0xac
| do_initcalls+0x54/0x94
| do_basic_setup+0x1c/0x28
| kernel_init_freeable+0x100/0x16c
| kernel_init+0x20/0x1a0
| ret_from_fork+0x10/0x20
| kobject_add_internal failed for arm-ffa-8001 with -EEXIST, don't try to
| register things with the same name in the same directory.
| arm_ffa arm-ffa: unable to register device arm-ffa-8001 err=-17
| ARM FF-A: ffa_setup_partitions: failed to register partition ID 0x8001
By virtue of being random enough to avoid collisions when generated in a
distributed system, there is no way to compress UUID keys to the number
of bits required to identify each. We can eliminate '-' in the name but
it is not worth eliminating 4 bytes and add unnecessary logic for doing
that. Also v1.0 doesn't provide the UUID of the partitions which makes
it hard to use the same for the device name.
So to keep it simple, let us alloc an ID using ida_alloc() and append the
same to "arm-ffa" to make up a unique device name. Also stash the id value
in ffa_dev to help freeing the ID later when the device is destroyed.
Fixes: e781858488 ("firmware: arm_ffa: Add initial FFA bus support for device enumeration")
Reported-by: Lucian Paul-Trifu <lucian.paul-trifu@arm.com>
Link: https://lore.kernel.org/r/20230419-ffa_fixes_6-4-v2-3-d9108e43a176@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Most of the MEM_* APIs share the same parameters, so they can be
generalised. Currently only MEM_SHARE is implemented and the user space
interface for that is not added yet.
Link: https://lore.kernel.org/r/20210521151033.181846-6-sudeep.holla@arm.com
Tested-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Parse the FFA nodes from the device-tree and register all the partitions
whose services will be used in the kernel.
In order to also enable in-kernel users of FFA interface, let us add
simple set of operations for such devices.
The in-kernel users are registered without the character device interface.
Link: https://lore.kernel.org/r/20210521151033.181846-5-sudeep.holla@arm.com
Tested-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
The Arm FF for Armv8-A specification has concept of endpoints or
partitions. In the Normal world, a partition could be a VM when
the Virtualization extension is enabled or the kernel itself.
In order to handle multiple partitions, we can create a FFA device for
each such partition on a dedicated FFA bus. Similarly, different drivers
requiring FFA transport can be registered on the same bus. We can match
the device and drivers using UUID. This is mostly for the in-kernel
users with FFA drivers.
Link: https://lore.kernel.org/r/20210521151033.181846-2-sudeep.holla@arm.com
Tested-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
