We update kendryte/k210 to use new mechanism of having builtin DTB
where we convert k210.dts to C source and further compile-n-link it
with libplatsbi.a.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Currently, we can only include one DTB as builtin for a platform
using FDT_PAYLOAD_DTB make variable in platform config.mk.

This patch adds new mechanism using which we can convert any DTS
file to C source and futher compile-n-link it with libplatsbi.a.

The generated C source will have the DTB contents as an array
"const char <varprefix>_start[]" where <varprefix> is specified
in platform objects.mk makefile.

Example1
--------
If we have built-in k210.dts and desired <varprefix> is
"dt_k210" then specify following in platform objects.mk:
platform-objs-y += k210.o
platform-varprefix-k210.o = dt_k210

Example2
--------
If we have built-in abc/k210.dts and desired <varprefix> is
"dt_abc_k210" then specify following in platform objects.mk:
platform-objs-y += abc/k210.o
platform-varprefix-abc-k210.o = dt_abc_k210

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

In order to use GCC style defines and macros in DTS, we should
preporcess builtin DTS before converting it to DTB.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Currently, the fw_platform_init() does not return anything but we can
further improve by allowing fw_platform_init() to return updated FDT
location.

It is certainly not mandatory for fw_platform_init() to return a new
location of FDT (or modify FDT). In fact, the fw_platform_init() can
always return the original FDT location (i.e. 'arg1') unmodified.

This new capability of fw_platform_init() will allow platforms to:
1. Have multiple built-in FDTs and select one
2. Modify FDT before using based on platform specific straps or OTP

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Currently, we are ORing FW_OPTIONS with the options passed by
previous booting stage to fw_dynamic. This causes confusion
because compiling fw_dynamic with FW_OPTIONS=0x2 does not force
enable boot prints as the U-Boot SPL passes options=0x1 in
fw_dyanmic_info.

The best thing to do is always prefer FW_OPTIONS when available.
This is intuitive for OpenSBI users and easy in debugging.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Currently, fw_prev_arg1() is called after fw_platform_init() which
caused builtin DTB to be not available to fw_platform_init().

To allow builtin DTB available to fw_platform_init(), we should
call fw_save_info() and fw_prev_arg1() before fw_platform_init().

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

The make rule for builtin DTB compilation does not consider
out-of-tree platforms so this patch fixes it.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We can have multiple matching DT nodes of the same FDT timer driver
so in this case we should call cold_init() for all matching DT nodes
instead of just first matching DT node.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We can have multiple matching DT nodes of the same FDT ipi driver
so in this case we should call cold_init() for all matching DT nodes
instead of just first matching DT node.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

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>

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>

We can have multiple matching DT nodes of the same FDT irqchip
driver so in this case we should call cold_init() for all matching
DT nodes instead of just first matching DT node.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

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>

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>

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>

Cc: Abner Chang <abner.chang@hpe.com>
Signed-off-by: Daniel Schaefer <git@danielschaefer.me>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

It is not mandatory for a RISC-V systems to implement all PMP
regions so we have to check all PMPADDRx CSRs to determine excat
number of supported PMP regions.

Signed-off-by: Anup Patel <anup.patel@wdc.com>

This patch does few cosmetic improvements to HART feature detection:
1. Remove sbi_ perfix from HART feature detection functions
   because all local/static functions in sbi_hart.c don't have
   sbi_ prefix
2. Remove sbi_hart_set_feature() because it's quite small and
   local/static in sbi_hart.c

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

It makes more sense to have scratch pointer as parameter in
HART feature APIs because:
1. We already have scratch pointer at places where these APIs
   are used.
2. This is consistent with lot of other APIs in sbi_hart.h

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

On platforms with continuous HART ids starting from zero:
0 <= boot HART id < platform HART count

The above co-relation of boot HART id and platform HART count
is true for most RISC-V platfors so it's better to print platform
HART count just before boot HART id.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We remove extra spaces from boot time prints.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We do following improvements for get_feature_str():
1. We should return "none" from get_feature_str() no features
   available instead of sbi_boot_prints() explicitly handling
   failure.
2. We don't need to return failure (just like misa_xlen())
   because we are returning "none" for no features and we are
   truncating output when space is not available.
3. Based on 1 and 2, the sbi_boot_prints() can be further
   simplified.
4. No need for two char[] in sbi_boot_prints()

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We should detect HART features in sbi_hart_init() before
mstatus_init(), delegate_traps() and pmp_init().

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Signed-off-by: Daniel Schaefer <git@danielschaefer.me>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

Currently, unprivileged access functions uses few additional instructions
which are redundant. It also uses specific registers which are not necessary.

Remove those additional instructions and let the compiler choose the
registers.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

We have now clear distinction between platform and hart features.
Modify the boot print messages to print hart specific features in
a string format.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

We have now clear distinction between platform and hart features.
Modify the boot print messages to print platform features in a string
format. In the process, this patch moved relatively larger functions
to its own file from platform.h header file.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

As per the RISC-V specification, time value can be obtained from a time
CSR implemented in hardware or a MMIO based IP block. Qemu virt machine
already supports timer csr while CLINT provides the timer for other
platforms.

Implement a hart specific timer feature that can be detected at runtime.
As CSR based timer implementation are faster than MMIO address based, it
is always preferred over MMIO based one.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

Any platform feature that belongs to a hart, have already been moved to
hart features and are detected at run time. The remaining platform features
are identical to platform default features.

Use the platform default features instead of defining a separate copy of it.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

PMP & performance counters belong to a hart rather than a platform.
In addition to that, these features enable reading/writing from a
particular csr. Thus, they can be detected and set at runtime rather
than compile time.

Move PMP/MCOUNTEREN/SCOUNTEREN features to hart and detect them at runtime.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

There may be some features which are hart specific rather than a platform
specific feature. Add a framework to support that.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

As per RISC-V ISA, pmp is not mandatory. Currently, we only add reserved
memory node in DT only if PMP is present. That allows supervisor to access
the memory where OpenSBI continue to exist without realizing it for non-pmp
based platforms. It may result in corrupting OpenSBI. That's why OpenSBI
should at least let the supervisor know where it continue to exist.
This a best effort service provided by OpenSBI expecting that supervisor
software is not buggy and properly sets up its memory after parsing the
reserved-memory device tree node.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

There may be few common mathematics helper functions which can be used
anywhere in OpenSBI project.

Add a separate math helper function file to add these functions.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

As RISC-V ISA allows many CSRs such as pmp, s/mcounteren to be optional
in hardware, OpenSBI should provide an option to dynamically detect
these csr access capability at run time.

Implement a csr read/write access check helper macros.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

Unprivileged trap handler can be reused for any cases where the executing
code expects a trap.

Rename it to "expected" trap handler as it will be used in other cases in
future.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

Doxygen does not support italic text in page title so fix
some of the markdown files accordingly.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

Currently, all markdown pages are randomly arranged in table of
contents so to fix this we treat top-level README.md as mainpage
and enable Doxygen TREEVIEW.

Also, there should not be any text before title of a markdown
page so we move project copyright as separate section in top-level
README.md.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

We add platform requirements document to clarify OpenSBI
expectations from a RISC-V platform.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>

The generic platform provides IPI and timer functionality based on
DT node provided in the FDT passed by previous booting stage. This
patch updates generic platform documentation about IPI and timer
expectations.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

The generic platform will try to select serial console based on the
stdout-path DT property in /chosen DT node hence we document this.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>