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Re: [Xen-devel] [PATCH] xen/arm: midway: implement SMP



On 11/18/2013 02:27 PM, Julien Grall wrote:
Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
  xen/arch/arm/platforms/midway.c | 22 ++++++++++++++++++++++
  1 file changed, 22 insertions(+)

diff --git a/xen/arch/arm/platforms/midway.c b/xen/arch/arm/platforms/midway.c
index 399056b..3b9fcfc 100644
--- a/xen/arch/arm/platforms/midway.c
+++ b/xen/arch/arm/platforms/midway.c
@@ -47,6 +47,27 @@ static uint32_t midway_quirks(void)
      return PLATFORM_QUIRK_DOM0_MAPPING_11;
  }

+static int __init midway_cpu_up(int cpu)

Wouldn't it make more sense to do this initialization in smp_init() instead of here per CPU? init_secondary() is fixed and thus we will not write different values for each core. I guess it does not really matter, I was just wondering whether this would be a saner approach (and I think your first version was this way, right?)

Thanks,
Andre.

P.S. BTW: Any reason we instantiate cpu_up() for all platforms where they are actually NOPs? I think the platform code only calls a function if it is non-NULL, so we could just skip all of this: cpu_up() {return 0;} definition.

+{
+    void __iomem *pens;
+
+    pens = ioremap_nocache(0, PAGE_SIZE);
+    if ( !pens )
+    {
+        dprintk(XENLOG_ERR, "Unable to map midway pens MMIO\n");
+        return -EFAULT;
+    }
+
+    printk("Set cpu pen %u to %"PRIpaddr" (%p)\n",
+           cpu, __pa(init_secondary), init_secondary);
+
+    writel(__pa(init_secondary), pens + 0x40 + cpu * 0x10);
+
+    iounmap(pens);
+
+    return 0;
+}
+
  static const char * const midway_dt_compat[] __initconst =
  {
      "calxeda,ecx-2000",
@@ -57,6 +78,7 @@ PLATFORM_START(midway, "CALXEDA MIDWAY")
      .compatible = midway_dt_compat,
      .reset = midway_reset,
      .quirks = midway_quirks,
+    .cpu_up = midway_cpu_up,
  PLATFORM_END

  /*



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