u-boot/arch/riscv/cpu/cpu.c
Rick Chen e0465f80bd riscv: Introduce AVAILABLE_HARTS
In SMP all harts will register themself in available_hart
during start up. Then main hart will send IPI to other harts
according to this variables. But this mechanism may not
guarantee that all other harts can jump to next stage.

When main hart is sending IPI to other hart according to
available_harts, but other harts maybe still not finish the
registration. Then the SMP booting will miss some harts finally.
So let it become an option and it will be enabled by default.

Please refer to the discussion:
https://www.mail-archive.com/u-boot@lists.denx.de/msg449997.html

Signed-off-by: Rick Chen <rick@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
2022-09-26 14:29:13 +08:00

166 lines
3.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
*/
#include <common.h>
#include <cpu.h>
#include <dm.h>
#include <dm/lists.h>
#include <event.h>
#include <init.h>
#include <log.h>
#include <asm/encoding.h>
#include <asm/system.h>
#include <dm/uclass-internal.h>
#include <linux/bitops.h>
/*
* The variables here must be stored in the data section since they are used
* before the bss section is available.
*/
#if !CONFIG_IS_ENABLED(XIP)
u32 hart_lottery __section(".data") = 0;
#ifdef CONFIG_AVAILABLE_HARTS
/*
* The main hart running U-Boot has acquired available_harts_lock until it has
* finished initialization of global data.
*/
u32 available_harts_lock = 1;
#endif
#endif
static inline bool supports_extension(char ext)
{
#ifdef CONFIG_CPU
struct udevice *dev;
char desc[32];
uclass_find_first_device(UCLASS_CPU, &dev);
if (!dev) {
debug("unable to find the RISC-V cpu device\n");
return false;
}
if (!cpu_get_desc(dev, desc, sizeof(desc))) {
/* skip the first 4 characters (rv32|rv64) */
if (strchr(desc + 4, ext))
return true;
}
return false;
#else /* !CONFIG_CPU */
#if CONFIG_IS_ENABLED(RISCV_MMODE)
return csr_read(CSR_MISA) & (1 << (ext - 'a'));
#else /* !CONFIG_IS_ENABLED(RISCV_MMODE) */
#warning "There is no way to determine the available extensions in S-mode."
#warning "Please convert your board to use the RISC-V CPU driver."
return false;
#endif /* CONFIG_IS_ENABLED(RISCV_MMODE) */
#endif /* CONFIG_CPU */
}
static int riscv_cpu_probe(void)
{
#ifdef CONFIG_CPU
int ret;
/* probe cpus so that RISC-V timer can be bound */
ret = cpu_probe_all();
if (ret)
return log_msg_ret("RISC-V cpus probe failed\n", ret);
#endif
return 0;
}
/*
* This is called on secondary harts just after the IPI is init'd. Currently
* there's nothing to do, since we just need to clear any existing IPIs, and
* that is handled by the sending of an ipi itself.
*/
#if CONFIG_IS_ENABLED(SMP)
static void dummy_pending_ipi_clear(ulong hart, ulong arg0, ulong arg1)
{
}
#endif
int riscv_cpu_setup(void *ctx, struct event *event)
{
int ret;
ret = riscv_cpu_probe();
if (ret)
return ret;
/* Enable FPU */
if (supports_extension('d') || supports_extension('f')) {
csr_set(MODE_PREFIX(status), MSTATUS_FS);
csr_write(CSR_FCSR, 0);
}
if (CONFIG_IS_ENABLED(RISCV_MMODE)) {
/*
* Enable perf counters for cycle, time,
* and instret counters only
*/
#ifdef CONFIG_RISCV_PRIV_1_9
csr_write(CSR_MSCOUNTEREN, GENMASK(2, 0));
csr_write(CSR_MUCOUNTEREN, GENMASK(2, 0));
#else
csr_write(CSR_MCOUNTEREN, GENMASK(2, 0));
#endif
/* Disable paging */
if (supports_extension('s'))
#ifdef CONFIG_RISCV_PRIV_1_9
csr_read_clear(CSR_MSTATUS, SR_VM);
#else
csr_write(CSR_SATP, 0);
#endif
}
#if CONFIG_IS_ENABLED(SMP)
ret = riscv_init_ipi();
if (ret)
return ret;
/*
* Clear all pending IPIs on secondary harts. We don't do anything on
* the boot hart, since we never send an IPI to ourselves, and no
* interrupts are enabled
*/
ret = smp_call_function((ulong)dummy_pending_ipi_clear, 0, 0, 0);
if (ret)
return ret;
#endif
return 0;
}
EVENT_SPY(EVT_DM_POST_INIT, riscv_cpu_setup);
int arch_early_init_r(void)
{
int ret;
ret = riscv_cpu_probe();
if (ret)
return ret;
if (IS_ENABLED(CONFIG_SYSRESET_SBI))
device_bind_driver(gd->dm_root, "sbi-sysreset",
"sbi-sysreset", NULL);
return 0;
}
/**
* harts_early_init() - A callback function called by start.S to configure
* feature settings of each hart.
*
* In a multi-core system, memory access shall be careful here, it shall
* take care of race conditions.
*/
__weak void harts_early_init(void)
{
}