u-boot/arch/x86/cpu/qemu/cpu.c
Miao Yan de752c5e73 x86: qemu: fix cpu device in smp boot
Currently, when booting with more that one CPU enabled, U-Boot scans
'cpu' node in device tree and calculates CPU number. This does not scale
well as changing CPU number also requires modifying .dts and re-compiling
U-Boot.

This patch uses fw_cfg interface provided by QEMU to detect online CPU
number at runtime, and dynamically adds 'cpu' device to U-Boot's driver
model.

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2016-01-13 12:20:16 +08:00

46 lines
821 B
C

/*
* Copyright (C) 2015, Miao Yan <yanmiaobest@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <cpu.h>
#include <dm.h>
#include <errno.h>
#include <asm/cpu.h>
#include <asm/fw_cfg.h>
DECLARE_GLOBAL_DATA_PTR;
int cpu_qemu_get_desc(struct udevice *dev, char *buf, int size)
{
if (size < CPU_MAX_NAME_LEN)
return -ENOSPC;
cpu_get_name(buf);
return 0;
}
static int cpu_qemu_get_count(struct udevice *dev)
{
return qemu_fwcfg_online_cpus();
}
static const struct cpu_ops cpu_qemu_ops = {
.get_desc = cpu_qemu_get_desc,
.get_count = cpu_qemu_get_count,
};
static const struct udevice_id cpu_qemu_ids[] = {
{ .compatible = "cpu-qemu" },
{ }
};
U_BOOT_DRIVER(cpu_qemu_drv) = {
.name = "cpu_qemu",
.id = UCLASS_CPU,
.of_match = cpu_qemu_ids,
.ops = &cpu_qemu_ops,
};