[PATCH v4 20/28] ARM: owl: Implement CPU enable-method for S500

quoted

+static int s500_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+       unsigned long timeout;
+       int ret;
+
+       ret = s500_wakeup_secondary(cpu);
+       if (ret)
+               return ret;
+
+       udelay(10);
+
+       spin_lock(&boot_lock);
+
+       /*
+        * The secondary processor is waiting to be released from
+        * the holding pen - release it, then wait for it to flag
+        * that it has been released by resetting pen_release.
+        */
+       write_pen_release(cpu_logical_map(cpu));
+       smp_send_reschedule(cpu);
+
+       timeout = jiffies + (1 * HZ);
+       while (time_before(jiffies, timeout)) {
+               if (pen_release == -1)
+                       break;
+       }
+
+       writel(0, timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
+       writel(0, timer_base_addr + OWL_CPU1_FLAG + (cpu - 1) * 4);
+
+       spin_unlock(&boot_lock);
+
+       return pen_release != -1 ? -ENOSYS : 0;
+}

This looks more complicated than necessary. Why do you need the holding
pen when you have a register to start up the CPU?

It seems you missed my question here. Can you please follow up, and
if possible send a patch to remove the pen_release logic that appears
to be unnecessary here?

        Arnd