mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-07-06 03:06:16 +09:00
6b6024eadb
There are two enable methods supported by ARM64 Linux; psci and
spin-table. The latter is simpler and helpful for quick SoC bring
up. My main motivation for this patch is to improve the spin-table
support, which allows us to boot an ARMv8 system without the ARM
Trusted Firmware.
Currently, we have multi-entry code in arch/arm/cpu/armv8/start.S
and the spin-table is supported in a really ad-hoc way, and I see
some problems:
- We must hard-code CPU_RELEASE_ADDR so that it matches the
"cpu-release-addr" property in the DT that comes from the
kernel tree.
- The Documentation/arm64/booting.txt in Linux requires that
the release address must be zero-initialized, but it is not
cared by the common code in U-Boot. We must do it in a board
function.
- There is no systematic way to protect the spin-table code from
the kernel. We are supposed to do it in a board specific manner,
but it is difficult to predict where the spin-table code will be
located after the relocation. So, it also makes difficult to
hard-code /memreserve/ in the DT of the kernel.
So, here is a patch to solve those problems; the DT is run-time
modified to reserve the spin-table code (+ cpu-release-addr).
Also, the "cpu-release-addr" property is set to an appropriate
address after the relocation, which means we no longer need the
hard-coded CPU_RELEASE_ADDR.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
/*
|
|
* Copyright (C) 2016 Socionext Inc.
|
|
* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <libfdt.h>
|
|
#include <asm/spin_table.h>
|
|
|
|
int spin_table_update_dt(void *fdt)
|
|
{
|
|
int cpus_offset, offset;
|
|
const char *prop;
|
|
int ret;
|
|
unsigned long rsv_addr = (unsigned long)&spin_table_reserve_begin;
|
|
unsigned long rsv_size = &spin_table_reserve_end -
|
|
&spin_table_reserve_begin;
|
|
|
|
cpus_offset = fdt_path_offset(fdt, "/cpus");
|
|
if (cpus_offset < 0)
|
|
return -ENODEV;
|
|
|
|
for (offset = fdt_first_subnode(fdt, cpus_offset);
|
|
offset >= 0;
|
|
offset = fdt_next_subnode(fdt, offset)) {
|
|
prop = fdt_getprop(fdt, offset, "device_type", NULL);
|
|
if (!prop || strcmp(prop, "cpu"))
|
|
continue;
|
|
|
|
/*
|
|
* In the first loop, we check if every CPU node specifies
|
|
* spin-table. Otherwise, just return successfully to not
|
|
* disturb other methods, like psci.
|
|
*/
|
|
prop = fdt_getprop(fdt, offset, "enable-method", NULL);
|
|
if (!prop || strcmp(prop, "spin-table"))
|
|
return 0;
|
|
}
|
|
|
|
for (offset = fdt_first_subnode(fdt, cpus_offset);
|
|
offset >= 0;
|
|
offset = fdt_next_subnode(fdt, offset)) {
|
|
prop = fdt_getprop(fdt, offset, "device_type", NULL);
|
|
if (!prop || strcmp(prop, "cpu"))
|
|
continue;
|
|
|
|
ret = fdt_setprop_u64(fdt, offset, "cpu-release-addr",
|
|
(unsigned long)&spin_table_cpu_release_addr);
|
|
if (ret)
|
|
return -ENOSPC;
|
|
}
|
|
|
|
ret = fdt_add_mem_rsv(fdt, rsv_addr, rsv_size);
|
|
if (ret)
|
|
return -ENOSPC;
|
|
|
|
printf(" Reserved memory region for spin-table: addr=%lx size=%lx\n",
|
|
rsv_addr, rsv_size);
|
|
|
|
return 0;
|
|
}
|