u-boot/arch/riscv/cpu/cpu.c
Sean Anderson 768502e2a7 riscv: Clear pending IPIs on initialization
Even though we no longer call smp_function if an IPI was not sent by
U-Boot, we still need to clear any IPIs which were pending from the
execution environment. Otherwise, secondary harts will busy-wait in
secondary_hart_loop, instead of relaxing.

Along with the previous commit ("riscv: Use a valid bit to ignore
already-pending IPIs"), this fixes SMP booting on the Kendryte K210.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Rick Chen <rick@andestech.com>
2020-09-30 08:54:52 +08:00

142 lines
3.1 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 <init.h>
#include <log.h>
#include <asm/encoding.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.
*/
#ifdef CONFIG_OF_PRIOR_STAGE
phys_addr_t prior_stage_fdt_address __attribute__((section(".data")));
#endif
#ifndef CONFIG_XIP
u32 hart_lottery __attribute__((section(".data"))) = 0;
/*
* 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
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 arch_cpu_init_dm(void)
{
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;
}
int arch_early_init_r(void)
{
return riscv_cpu_probe();
}