Commit Graph

69 Commits

Author SHA1 Message Date
Anup Patel
9f73669959 lib: utils/irqchip: Add IMSIC library
We add simple IMSIC library which is independent of hardware description
format (FDT or ACPI). This IMSIC library can be used by custom OpenSBI
platform support to setup IMSIC for external interrupts.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
2022-02-15 20:36:24 +05:30
Anup Patel
6dde43584f lib: utils/sys: Extend HTIF library to allow custom base address
Some of RISC-V emulators provide HTIF at fixed base address so for
such emulators users have to hard-code HTIF base address in the
linker script.

To address this problem, we let users optionally provide fixed HTIF
base address via platform support (or device tree).

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Dong Du <Dd_nirvana@sjtu.edu.cn>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
2022-01-11 18:17:49 +05:30
Gabriel Somlo
52af6e4b52 lib: utils: Add LiteX UART support
Add support for the UART provided by the LiteX SoC
framework (https://github.com/enjoy-digital/litex),
based on its FDT info (described in the Linux tree at
Documentation/devicetree/bindings/serial/litex,liteuart.yaml).

Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-11-18 13:22:02 +05:30
Nikita Shubin
6ca6bcafb7 lib: utils/i2c: Add simple FDT based I2C framework
FDT based I2C framework on the top of I2C library.

The drivers are probed on demand by fdt_i2c_adapter_get
function.

Tested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
2021-11-12 10:19:45 +05:30
Nikita Shubin
2c964a2e15 lib: utils/i2c: Add generic I2C configuration library
Helper library to keep track of registered I2C adapters,
identified by dts offset, basic send/read functions and
adapter configuration (enable, set dividers, etc...).

Tested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
2021-11-12 10:17:50 +05:30
Nikita Shubin
1d462e0397 lib: utils/reset: separate driver init func
Move driver init code to separate function, so it can be reused
elsewhere.

Tested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
2021-11-12 10:16:23 +05:30
Heinrich Schuchardt
be245acfff lib: sbi: error handling in fdt_reset_init()
The initialization of a reset driver may fail for various reasons, like
a PMIC based reset driver not finding the required I2C driver. The return
code of the init routine may take other error values than -ENODEV.

If the initialization of a reset driver fails, this should not lead to the
board hanging. It is enough that the reset driver does not call
sbi_system_reset_add_device() to avoid invoking the driver for a device
that could not be initialized.

Change the return type of fdt_reset_init() to void.
Print a message if an error occurs.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Dong Du <Dd_nirvana@sjtu.edu.cn>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-11-08 10:50:48 +05:30
Nikita Shubin
0979ffda12 lib: utils/gpio: use list for drivers
Convert static array to sbi_list.

This removes size limitation, makes add/remove more efficient and
saves space.

Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-11-03 15:57:56 +05:30
Alexandre Ghiti
c891acca17 include: sbi_utils: Introduce an helper to get fdt base address
This simply adds an helper to get fdt address which is more explicit than
sbi_scratch_thishart_arg1_ptr.

Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-11-02 11:23:16 +05:30
Anup Patel
12e7af9ab7 lib: sbi: Add timer frequency to struct sbi_timer_device
Generic mdelay() and udelay() functions can be provided by the
sbi_timer framework if timer frequency is available in the timer
instance provided by the platform support or timer driver.

This patch adds timer frequency (timer_freq) member in the
struct sbi_timer_device for above purpose.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-09-26 19:52:10 +05:30
Anup Patel
72154f4708 lib: utils/fdt: Add fdt_parse_timebase_frequency() function
We add fdt_parse_timebase_frequency() function which can be used
by ACLINT mtimer driver and platform code to get timebase frequency.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-09-26 19:52:07 +05:30
Anup Patel
7aa6c9aa96 lib: utils/timer: Simplify MTIMER synchronization
We simplify MTIMER synchronization as follows:

1) Detect MTIMER devices with unique (or non-shared) MTIME
   register at boot-time
2) Select first MTIMER device with no associated HART as our
   reference MTIMER device
3) Only synchronize MTIMER devices with unique (or non-shared)
   MTIME register using reference MTIMER device
4) Directly update the MTIME register at time of synchronization
   because MTIME is a read/write register.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-08-14 09:07:42 +05:30
Anup Patel
f3a0eb8583 lib: utils/fdt: Extend fdt_parse_aclint_node() function
The fdt_parse_aclint_node() is used to parse DT node for SiFive
CLINT, ACLINT MTIMER, and ACLINT MSWI devices.

The ACLINT MTIMER has undergone following changes:
1) MTIMER DT node now requires separate addresses in for MTIME
   register and MTIMECMPx registers in the reg DT property.
2) MTIMER DT node might have no interrupts-extended DT property
   when the MTIMER device has no associated HARTs (i.e. the
   MTIMER device has no MTIMECMPx registers)

This patch extends fdt_parse_aclint_node() to handle above
mentioned changes in ACLINT MTIMER DT bindings.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-08-14 09:02:39 +05:30
Anup Patel
7a3a0cce4d lib: utils: Extend fdt_get_node_addr_size() for multiple register sets
We add "index" parameter to fdt_get_node_addr_size() API so that
calling function can specify index of desired register set. This
will allow fdt_get_node_addr_size() to handle DT nodes with
multiple register sets.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-08-14 09:02:36 +05:30
Anup Patel
e0d1b9db8a lib: utils/timer: Allow separate base addresses for MTIME and MTIMECMP
We extend the ACLINT library to support separate base addresses
for MTIME and MTIMECMP registers.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-08-14 09:02:33 +05:30
Bin Meng
47a47654e8 lib: utils/fdt: Change addr and size to uint64_t
The maximum address and size encoded in DT are 64-bit numbers, so we
should use uint64_t for 'addr' and 'size' in fdt_get_node_addr_size().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-08-07 17:26:51 +05:30
Anup Patel
c14f1fe0df lib: utils/gpio: Add simple FDT based GPIO framework
We add a simple FDT based GPIO framework which is built on top
of generic GPIO library. The phandle of FDT GPIO chip DT node
is treated as unique GPIO chip ID required by the generic GPIO
library. The FDT based GPIO chip drivers will be probed on-demand
from fdt_gpio_pin_get() called by the GPIO client drivers.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-07-17 13:41:17 +05:30
Anup Patel
36b8effe4a lib: utils/gpio: Add generic GPIO configuration library
We add generic GPIO configuration library which is independent of
hardware description format (FDT or ACPI). The OpenSBI platform
support or GPIO drivers can register GPIO chip instances which
can be discovered and used by different GPIO clients. Each GPIO
chip instance has a unique ID which can be used by GPIO clients
to lookup GPIO chip instance.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-07-17 11:42:51 +05:30
Anup Patel
e931f387b2 lib: utils/fdt: Add fdt_parse_phandle_with_args() API
The libfdt project does not have a generic API to parse phandle
with args from a DT node so we add fdt_parse_phandle_with_args()
for this purpose. This new API will be useful to FDT based drivers.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2021-07-17 11:40:49 +05:30
Atish Patra
ae72ec0915 utils: fdt: Add fdt helper functions to parse PMU DT nodes
The PMU DT node bindings are defined in docs/pmu_support.md
Add few fdt helper functions to parse the DT node and update the
event-counter mapping tables.

Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
2021-07-11 10:27:57 +05:30
Anup Patel
a731c7e369 platform: Replace CLINT library usage with ACLINT library
The ACLINT devices are backward compatible with SiFive CLINT
so we replace all CLINT library usage in various platforms
with ACLINT library. As a result of this replacement, the
CLINT library is not used by any part of OpenSBI hence we
remove it.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-06-24 09:39:55 +05:30
Anup Patel
bd5d2089b8 lib: utils: Add FDT parsing API common for both ACLINT and CLINT
We add fdt_parse_aclint_node() which can parse both ACLINT and
CLINT DT nodes. This means fdt_parse_clint_node() is not required
anymore so we remove it as well.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-06-24 09:39:48 +05:30
Anup Patel
5a049fe1d6 lib: utils/ipi: Add ACLINT MSWI library
We add common ACLINT MSWI library similar to the CLINT library
so that OpenSBI platforms can use it.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-06-24 09:39:44 +05:30
Anup Patel
4519e29c51 lib: utils/timer: Add ACLINT MTIMER library
We add common ACLINT MTIMER library similar to the CLINT library
so that OpenSBI platforms can use it.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-06-24 09:38:47 +05:30
Daniel Cederman
117fb6dcb1 lib: utils/serial: Add support for Gaisler APBUART
This patch adds support for the UART used by the NOEL-V processor.

Cobham Gaisler's NOEL-V RISC-V processor IP is available under GPL
and commercial license and is described in more detail at
https://www.gaisler.com/noelv.

Signed-off-by: Daniel Cederman <cederman@gaisler.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2021-05-06 14:21:07 +05:30
Anup Patel
043d088e39 lib: sbi: Simplify system reset platform operations
Instead of having system_reset_check() and system_reset() callbacks
in platform operations, it will be much simpler for reset driver to
directly register these operations as a device to the sbi_system
implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2021-04-28 17:25:00 +05:30
Anup Patel
dc39c7b630 lib: sbi: Simplify ipi platform operations
Instead of having ipi_send() and ipi_clear() callbacks in
platform operations, it will be much simpler for ipi driver
to directly register these operations as a device to sbi_ipi
implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2021-04-28 17:03:31 +05:30
Anup Patel
559a8f1d3b lib: sbi: Simplify timer platform operations
Instead of having timer_value(), timer_event_start(), and
timer_event_stop() callbacks in platform operations, it will
be much simpler for timer driver to directly register these
operations as device to the sbi_timer implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2021-04-28 17:00:49 +05:30
Anup Patel
068ca086af lib: sbi: Simplify console platform operations
Instead of having console_putc() and console_getc() callbacks in
platform operations, it will be much simpler for console driver to
directly register these operations as device to the sbi_console
implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2021-04-28 16:58:23 +05:30
Bin Meng
ca3f35821b lib/utils: Drop the 'compat' parameter of fdt_plic_fixup()
At present fdt_plic_fixup() accepts a 'compat' parameter for PLIC
compatible string. In preparation to support the new DT bindings,
drop this and use "riscv,plic0" directly in fdt_plic_fixup().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2021-04-01 10:27:28 +05:30
Anup Patel
6fc1986f50 lib: utils: Remove fdt_domain_get() function
The fdt_domain_get() function is now redundant because the
fdt_domains_populate() function can explicitly register new
domains using the sbi_domain_register() function.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-12-16 10:10:25 +05:30
Anup Patel
2179777364 lib: utils: Allow FDT domain iteration functions to fail
We extend fdt_iterate_each_domain() and fdt_iterate_each_memregion()
functions to allow underlying iteration function to fail. This will
help us catch more domain misconfiguration issues at boot time.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-12-16 10:10:19 +05:30
Anup Patel
ba741ea0ad lib: utils: Add helper routines to populate domains from FDT
We add various helper routines to populate domains, iterate domains,
iterate domain memregions, and parse HART to domain assignment from
the FDT.

These helper routines can be used by platform support code and FDT
fixup code.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-12-04 21:10:44 +05:30
Anup Patel
5c429ae213 lib: sbi: Improve system reset platform operations
To implement the SBI SRST extension, we need two platform operations
for system reset:
1) system_reset_check() - This operation will check whether given
   reset type and reason are supported by the platform
2) system_reset() - This operation will do the actual platform
   system reset and it will not return if reset type and reason
   are supported by the platform

This patch updates system reset related code everywhere as-per above.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-12-01 17:10:31 +05:30
Vijai Kumar K
db56ef367c platform: Add support for Shakti C-class SoC from IIT-M
C-Class is a member of the SHAKTI family of processors from Indian
Institute of Technology - Madras(IIT-M).
It is an extremely configurable and commercial-grade 5-stage in-order
core supporting the standard RV64GCSUN ISA extensions.

https://gitlab.com/shaktiproject/cores/c-class/blob/master/README.md

We add OpenSBI support for Shakti C-class SoC.

Signed-off-by: Vijai Kumar K <vijai@behindbytes.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2020-06-19 09:21:46 +05:30
Alexandre Ghiti
6966ad0abe platform/lib: Allow the OS to map the regions that are protected by PMP
This is achieved by removing the 'no-map' property from the
'reserved-memory' node when PMP is present, otherwise we keep it as it
offers a small protection if the OS does not map this region at all.
A new callback in platform_override is introduced and allows to fixup the
device-tree. It is used here to override this new default behaviour on
SiFive Fu540 platforms that has an erratum that prevents S-mode software
to access a PMP protected region using 1GB page table mapping.

If PMP is present, telling the OS not to map the reserved regions does not
add much protection since it only avoids access to regions that are already
protected by PMP. But by not allowing the OS to map those regions, it
creates holes in the OS system memory map and prevents the use of
hugepages which would generate, among other benefits, less TLB miss.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
2020-06-15 09:25:44 +05:30
Anup Patel
569dd64b72 lib: utils: Add fdt_parse_clint_node() function
We add fdt_parse_clint_node() function which will be used by
fdt_ipi_clint and fdt_timer_clint drivers to parse CLINT details
from DT node.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-23 10:36:46 +05:30
Anup Patel
a9a9751185 lib: utils: Allow CLINT functions to be used for multiple CLINTs
We extend CLINT cold init function to have a "struct clint_data *"
parameter pointing to CLINT details. This allows platforms to use
CLINT functions for multiple CLINT instances.

When multiple CLINTs are present, the platform can also provide
one of the CLINT as reference CLINT for other CLINTs. This will
help CLINTs to sync their time value with reference CLINT using
a time_delta computed in warm init function.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-23 10:36:43 +05:30
Anup Patel
2c685c214f lib: utils: Extend fdt_find_match() Implementation
We extend fdt_find_match() implementation by adding node offset
parameter which represents the first node to match from.

The improved fdt_find_match() can be used to find multiple
match nodes.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-23 10:36:33 +05:30
Anup Patel
446a9c6d1e lib: utils: Allow PLIC functions to be used for multiple PLICs
We extend all PLIC functions to have a "struct plic_data *"
parameter pointing to PLIC details. This allows platforms to
use these functions for multiple PLIC instances.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-23 10:36:29 +05:30
Anup Patel
73d6ef3b29 lib: utils: Remove redundant parameters from PLIC init functions
The "target_hart" and "hart_count" parameters of PLIC cold and
warm init functions are only used for sanity checks and not
required in PLIC initialization.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-23 10:36:26 +05:30
Anup Patel
7cc6fa4d8a lib: utils: Add simple FDT reset framework
We add simple reset framework which will select and use reset driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 10:31:37 +05:30
Anup Patel
76a89403c8 lib: utils: Add simple FDT serial framework
We add simple serial framework which will select and use serial driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 10:02:39 +05:30
Anup Patel
75322a634b lib: utils: Add simple FDT irqchip framework
We add simple irqchip framework which will select and use irqchip driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 10:00:35 +05:30
Anup Patel
76f0f81407 lib: utils: Add simple FDT ipi framework
We add simple ipi framework which will select and use ipi driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 09:58:01 +05:30
Anup Patel
8ff2b94ea1 lib: utils: Add simple FDT timer framework
We add simple timer framework which will select and use timer driver
based on details in FDT passed by previous booting stage.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 09:57:55 +05:30
Anup Patel
f0eb503db4 lib: utils: Add fdt_parse_plic_node() function
We add fdt_parse_plic_node() function which will allow us to parse
a particular DT node as PLIC node. This will be useful in parsing
the DT node which we have found by matching compatible string.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 09:45:53 +05:30
Anup Patel
44dd7be3b2 lib: utils: Add fdt_parse_max_hart_id() API
We add fdt_parse_max_hart_id() API which return max HART id based
on CPU DT nodes. This will be used by generic FDT based drivers in
subsequent patches.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-05-01 09:44:55 +05:30
Anup Patel
19e966b862 lib: utils: Add fdt_parse_hart_id() function
Parsing HART id from a CPU DT node is a common requirement for
RISC-V systems. The newly added fdt_parse_hart_id() also helps
reduce duplicate code between fdt_cpu_fixup() function and
fdt_parse_hart_count() function.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2020-05-01 09:43:07 +05:30
Anup Patel
66185b3ec9 lib: utils: Add fdt_parse_sifive_uart_node() function
We add fdt_parse_sifive_uart_node() function which will allow
us to parse a particular DT node as SiFive UART node. This will
be useful in parsing the node pointed by stdout-path.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
2020-05-01 09:40:31 +05:30