For driver subsystems that are not tightly integrated into the OpenSBI
init sequence, it is not important that the drivers are initialized in
any particular order. By putting all of these drivers in one array, they
can all be initialized with a single pass through the devicetree. This
saves about 10 ms of boot time on HiFive Unmatched.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
These drivers were merged on an experimental basis without the RPMI
specification being frozen. As a result, they may not be compatible with
the frozen version of the RPMI protocol. Additionally, their devicetree
bindings have not been reviewed and are subject to change. Warn the user
that these drivers make no compatibility guarantees, and that their
behavior and devicetree bindings may change incompatibly in future
versions of OpenSBI.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Currently, each driver subsystem contains its own code for matching
drivers against the platform's devicetree blob. This bloats firmware
size because the several FDT scanning loops are almost exact copies of
each other, and is confusing because the loops do have some subtle
differences. Furthermore, the existing match algorithm is inefficient:
it scans the FDT structure separately for each driver in the list. A
faster algorithm scans the FDT blob only once, matching all drivers in
the list for each `compatible` property seen.
Add new helpers implementing this faster algorithm. Since they must
iterate through the list of drivers, the driver structure cannot be
opaque. However, since the driver list is an array of pointers, the
`struct fdt_driver` can be embedded in a subsystem-specific driver
structure if needed. These three helpers cover all existing use cases
for driver initialization within OpenSBI.
An additional benefit of centralized driver initialization is the
consistent use of fdt_node_is_enabled().
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
