Re: [U-Boot] [PATCH v5 6/8] x86: qemu: fix cpu device in smp boot

[Bin Meng]

On Mon, Jan 4, 2016 at 4:00 PM, Miao Yan  wrote:
> 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 
> ---
>  arch/x86/cpu/mp_init.c  | 73 
> +
>  arch/x86/cpu/qemu/cpu.c |  5 
>  2 files changed, 73 insertions(+), 5 deletions(-)
>

[snip]

>  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;
>  }

Yep, this cpu_qemu_bind can be removed.

>

Reviewed-by: Bin Meng 
Tested-by: Bin Meng 
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Re: [U-Boot] [PATCH v5 6/8] x86: qemu: fix cpu device in smp boot

[Miao Yan]

2016-01-06 8:25 GMT+08:00 Simon Glass :
> On 4 January 2016 at 01:00, Miao Yan  wrote:
>> 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 
>> ---
>>  arch/x86/cpu/mp_init.c  | 73 
>> +
>>  arch/x86/cpu/qemu/cpu.c |  5 
>>  2 files changed, 73 insertions(+), 5 deletions(-)
>
> Reviewed-by: Simon Glass 
>
> Maybe cpu_qemu_bind() isn't needed now?

Right, this can be removed.

Hi Bin, do you have any comments on this one ?

Thanks,
Miao
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Re: [U-Boot] [PATCH v5 6/8] x86: qemu: fix cpu device in smp boot

[Simon Glass]

On 4 January 2016 at 01:00, Miao Yan  wrote:
> 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 
> ---
>  arch/x86/cpu/mp_init.c  | 73 
> +
>  arch/x86/cpu/qemu/cpu.c |  5 
>  2 files changed, 73 insertions(+), 5 deletions(-)

Reviewed-by: Simon Glass 

Maybe cpu_qemu_bind() isn't needed now?
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[U-Boot] [PATCH v5 6/8] x86: qemu: fix cpu device in smp boot

[Miao Yan]

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 
---
 arch/x86/cpu/mp_init.c  | 73 +
 arch/x86/cpu/qemu/cpu.c |  5 
 2 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c
index 2a3ce48..d217ff0 100644
--- a/arch/x86/cpu/mp_init.c
+++ b/arch/x86/cpu/mp_init.c
@@ -20,8 +20,11 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
+#include 
+#include 
 #include 
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -441,6 +444,70 @@ 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;
+device_find_next_child()) {
+   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;
+uclass_find_next_device()) {
+   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);
+   cpu[7] = '\0';
+   ret = device_bind_driver(pdev, "cpu_qemu", cpu, );
+   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 +521,12 @@ 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();
if (ret) {
debug("Cannot init boot CPU: err=%d\n", ret);
diff --git a/arch/x86/cpu/qemu/cpu.c b/arch/x86/cpu/qemu/cpu.c
index a4bf53d..e8f486d 100644
--- a/arch/x86/cpu/qemu/cpu.c
+++ b/arch/x86/cpu/qemu/cpu.c
@@ -15,11 +15,6 @@ 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;
 }
 
-- 
1.9.1

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