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x86: qemu: fix cpu device in smp boot

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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>
This commit is contained in:
Miao Yan 2016-01-07 01:32:04 -08:00 committed by Bin Meng
parent b28cecdfb8
commit de752c5e73
2 changed files with 72 additions and 11 deletions
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72
arch/x86/cpu/mp_init.c
View File

@ -20,8 +20,11 @@
#include <asm/mtrr.h>
#include <asm/processor.h>
#include <asm/sipi.h>
#include <asm/fw_cfg.h>
#include <dm/device-internal.h>
#include <dm/uclass-internal.h>
#include <dm/lists.h>
#include <dm/root.h>
#include <linux/linkage.h>
DECLARE_GLOBAL_DATA_PTR;
@ -441,6 +444,69 @@ static int init_bsp(struct udevice **devp)
return 0;
}
#ifdef CONFIG_QEMU
static int qemu_cpu_fixup(void)
{
int ret;
int cpu_num;
int cpu_online;
struct udevice *dev, *pdev;
struct cpu_platdata *plat;
char *cpu;
/* first we need to find '/cpus' */
for (device_find_first_child(dm_root(), &pdev);
pdev;
device_find_next_child(&pdev)) {
if (!strcmp(pdev->name, "cpus"))
break;
}
if (!pdev) {
printf("unable to find cpus device\n");
return -ENODEV;
}
/* calculate cpus that are already bound */
cpu_num = 0;
for (uclass_find_first_device(UCLASS_CPU, &dev);
dev;
uclass_find_next_device(&dev)) {
cpu_num++;
}
/* get actual cpu number */
cpu_online = qemu_fwcfg_online_cpus();
if (cpu_online < 0) {
printf("unable to get online cpu number: %d\n", cpu_online);
return cpu_online;
}
/* bind addtional cpus */
dev = NULL;
for (; cpu_num < cpu_online; cpu_num++) {
/*
* allocate device name here as device_bind_driver() does
* not copy device name, 8 bytes are enough for
* sizeof("cpu@") + 3 digits cpu number + '\0'
*/
cpu = malloc(8);
if (!cpu) {
printf("unable to allocate device name\n");
return -ENOMEM;
}
sprintf(cpu, "cpu@%d", cpu_num);
ret = device_bind_driver(pdev, "cpu_qemu", cpu, &dev);
if (ret) {
printf("binding cpu@%d failed: %d\n", cpu_num, ret);
return ret;
}
plat = dev_get_parent_platdata(dev);
plat->cpu_id = cpu_num;
}
return 0;
}
#endif
int mp_init(struct mp_params *p)
{
int num_aps;
@ -454,6 +520,12 @@ int mp_init(struct mp_params *p)
if (ret)
return ret;
#ifdef CONFIG_QEMU
ret = qemu_cpu_fixup();
if (ret)
return ret;
#endif
ret = init_bsp(&cpu);
if (ret) {
debug("Cannot init boot CPU: err=%d\n", ret);

11
arch/x86/cpu/qemu/cpu.c
View File

@ -13,16 +13,6 @@
DECLARE_GLOBAL_DATA_PTR;
int cpu_qemu_bind(struct udevice *dev)
{
struct cpu_platdata *plat = dev_get_parent_platdata(dev);
plat->cpu_id = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
"intel,apic-id", -1);
return 0;
}
int cpu_qemu_get_desc(struct udevice *dev, char *buf, int size)
{
if (size < CPU_MAX_NAME_LEN)
@ -52,6 +42,5 @@ U_BOOT_DRIVER(cpu_qemu_drv) = {
.name = "cpu_qemu",
.id = UCLASS_CPU,
.of_match = cpu_qemu_ids,
.bind = cpu_qemu_bind,
.ops = &cpu_qemu_ops,
};