The existing MP initialization process works on QEMU multicore,
except that we need increase delay time for BSP to wait APs to
show up online. Use a Kconfig option to control the delay time
factor to the normal one.
Signed-off-by: Bin Meng <bmeng...@gmail.com>
---
arch/x86/cpu/mp_init.c | 4 ++++
arch/x86/cpu/qemu/Kconfig | 11 +++++++++++
arch/x86/dts/qemu-x86_i440fx.dts | 20 ++++++++++++++++++++
arch/x86/dts/qemu-x86_q35.dts | 20 ++++++++++++++++++++
configs/qemu-x86_defconfig | 4 ++++
doc/README.x86 | 5 +++++
6 files changed, 64 insertions(+)
diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c
index e686b28..f87201b 100644
--- a/arch/x86/cpu/mp_init.c
+++ b/arch/x86/cpu/mp_init.c
@@ -75,6 +75,10 @@ static int wait_for_aps(atomic_t *val, int target, int
total_delay,
int timeout = 0;
int delayed = 0;
+#ifdef CONFIG_QEMU
+ total_delay *= CONFIG_MPINIT_DELAY_FACTOR;
+#endif
+
while (atomic_read(val) != target) {
udelay(delay_step);
delayed += delay_step;
diff --git a/arch/x86/cpu/qemu/Kconfig b/arch/x86/cpu/qemu/Kconfig
index fb775d7..a690060 100644
--- a/arch/x86/cpu/qemu/Kconfig
+++ b/arch/x86/cpu/qemu/Kconfig
@@ -18,4 +18,15 @@ config SYS_CAR_SIZE
hex
default 0x10000
+config MPINIT_DELAY_FACTOR
+ int "QEMU multicore initialization delay factor"
+ depends on SMP
+ default 100
+ help
+ During multicore initialization after BSP sends SIPI to wake up APs,
+ U-Boot needs to wait some time for AP to show up online. The delay
+ time is good for real hardware, but seems not enough for QEMU. The
+ value of this option will be used as the multiplier to the normal
+ delay time.
+
endif
diff --git a/arch/x86/dts/qemu-x86_i440fx.dts b/arch/x86/dts/qemu-x86_i440fx.dts
index 0c522c8..e3c6fc3 100644
--- a/arch/x86/dts/qemu-x86_i440fx.dts
+++ b/arch/x86/dts/qemu-x86_i440fx.dts
@@ -24,6 +24,26 @@
stdout-path = "/serial";
};
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ device_type = "cpu";
+ compatible = "cpu-x86";
+ reg = <0>;
+ intel,apic-id = <0>;
+ };
+
+ cpu@1 {
+ device_type = "cpu";
+ compatible = "cpu-x86";
+ reg = <1>;
+ intel,apic-id = <1>;
+ };
+
+ };
+
pci {
compatible = "pci-x86";
#address-cells = <3>;
diff --git a/arch/x86/dts/qemu-x86_q35.dts b/arch/x86/dts/qemu-x86_q35.dts
index 5fbabc2..0305864 100644
--- a/arch/x86/dts/qemu-x86_q35.dts
+++ b/arch/x86/dts/qemu-x86_q35.dts
@@ -35,6 +35,26 @@
stdout-path = "/serial";
};
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ device_type = "cpu";
+ compatible = "cpu-x86";
+ reg = <0>;
+ intel,apic-id = <0>;
+ };
+
+ cpu@1 {
+ device_type = "cpu";
+ compatible = "cpu-x86";
+ reg = <1>;
+ intel,apic-id = <1>;
+ };
+
+ };
+
pci {
compatible = "pci-x86";
#address-cells = <3>;
diff --git a/configs/qemu-x86_defconfig b/configs/qemu-x86_defconfig
index a4c20bd..62c3f35 100644
--- a/configs/qemu-x86_defconfig
+++ b/configs/qemu-x86_defconfig
@@ -1,6 +1,9 @@
CONFIG_X86=y
CONFIG_DEFAULT_DEVICE_TREE="qemu-x86_i440fx"
+CONFIG_SMP=y
+CONFIG_MAX_CPUS=2
CONFIG_GENERATE_PIRQ_TABLE=y
+CONFIG_CMD_CPU=y
# CONFIG_CMD_IMLS is not set
# CONFIG_CMD_FLASH is not set
# CONFIG_CMD_SETEXPR is not set
@@ -9,6 +12,7 @@ CONFIG_BOOTSTAGE=y
CONFIG_BOOTSTAGE_REPORT=y
CONFIG_CMD_BOOTSTAGE=y
CONFIG_OF_CONTROL=y
+CONFIG_CPU=y
CONFIG_SPI_FLASH=y
CONFIG_VIDEO_VESA=y
CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
diff --git a/doc/README.x86 b/doc/README.x86
index 5d71244..1cab42c 100644
--- a/doc/README.x86
+++ b/doc/README.x86
@@ -281,6 +281,11 @@ QEMU emulates a graphic card which U-Boot supports.
Removing '-nographic' will
show QEMU's VGA console window. Note this will disable QEMU's serial output.
If you want to check both consoles, use '-serial stdio'.
+Multicore is also supported by QEMU via '-smp n' where n is the number of cores
+to instantiate. Currently the default U-Boot built for QEMU supports 2 cores.
+In order to support more cores, you need add additional cpu nodes in the device
+tree and change CONFIG_MAX_CPUS accordingly.
+
CPU Microcode
-------------
Modern CPUs usually require a special bit stream called microcode [8] to be
--
1.8.2.1
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