On Tuesday 06 September 2011 17:58:38 Shawn Guo wrote:

It adds smp and cpu hotplug support for imx6q.
+static u32 twd_saved_regs[4];
+static int twd_irq;
+
+/*
+ * Resuming from ARM Dormant/Shutdown mode, the boot procedure will
+ * re-setup local timer for secondary cores.  For primary core, it
+ * has to take care of itself with the following pair of functions
+ * during suspend/resume.
+ */
+void imx_local_timer_pre_suspend(void)
+{
+	twd_saved_regs[0] = __raw_readl(twd_base + TWD_TIMER_LOAD);
+	twd_saved_regs[1] = __raw_readl(twd_base + TWD_TIMER_COUNTER);
+	twd_saved_regs[2] = __raw_readl(twd_base + TWD_TIMER_CONTROL);
+	twd_saved_regs[3] = __raw_readl(twd_base + TWD_TIMER_INTSTAT);
+}
+
+void imx_local_timer_post_resume(void)
+{
+	__raw_writel(twd_saved_regs[0], twd_base + TWD_TIMER_LOAD);
+	__raw_writel(twd_saved_regs[1], twd_base + TWD_TIMER_COUNTER);
+	__raw_writel(twd_saved_regs[2], twd_base + TWD_TIMER_CONTROL);
+	__raw_writel(twd_saved_regs[3], twd_base + TWD_TIMER_INTSTAT);
+
+	gic_enable_ppi(twd_irq);
+}

readl_relaxed()?

+extern void v7_secondary_startup(void);
+
+#define IMX_SCU_VIRT_BASE	0xf4a00000
+
+static void __iomem *scu_base = ((void __iomem *)(IMX_SCU_VIRT_BASE));

It's a little bit silly to have a variable for the base and then initialize
it statically. Not sure what the best solution is here.

+static struct map_desc scu_io_desc __initdata = {
+	.virtual	= IMX_SCU_VIRT_BASE,
+	.pfn		= 0, /* run-time */
+	.length		= SZ_4K,
+	.type		= MT_DEVICE,
+};
+
+void __init imx_scu_map_io(void)
+{
+	unsigned long base;
+
+	/* Get SCU base */
+	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
+
+	scu_io_desc.pfn = __phys_to_pfn(base);
+	iotable_init(&scu_io_desc, 1);
+}

Maybe we can simply define a platform-independent where the SCU gets mapped?
That would get rid of most of the platform specific SCU code, at least for
those platforms that can reliably read the scu base.

+/*
+ * Initialise the CPU possible map early - this describes the CPUs
+ * which may be present or become present in the system.
+ */
+void __init smp_init_cpus(void)
+{
+	int i, ncores;
+
+	ncores = scu_get_core_count(scu_base);
+
+	for (i = 0; i < ncores; i++)
+		set_cpu_possible(i, true);
+
+	set_smp_cross_call(gic_raise_softirq);
+}
+
+void imx_smp_prepare(void)
+{
+	scu_enable(scu_base);
+}
+
+void __init platform_smp_prepare_cpus(unsigned int max_cpus)
+{
+	imx_smp_prepare();
+}

Then these functions could also be moved into the smp_scu file as generic
helpers that can be used by all similar platforms.

	Arnd