Re: [PATCH v2,2/5] powerpc/rcpm: add RCPM driver

On Wed, Aug 26, 2015 at 08:09:45PM +0800, Chenhui Zhao wrote:

+#ifdef CONFIG_PPC_BOOK3E
+static void qoriq_disable_thread(int cpu)
+{
+	int hw_cpu = get_hard_smp_processor_id(cpu);
+	int thread = cpu_thread_in_core(hw_cpu);
+
+	mtspr(SPRN_TENC, TEN_THREAD(thread));
+}
+#endif

This file is always used on book3e.  If the intent is to only build this
on 64-bit, use CONFIG_PPC64 rather than relying on the fact that this one
of the confusing mess of BOOKE/BOOK3E symbols is 64-bit-only.

+static void rcpm_v2_cpu_die(int cpu)
+{
+#ifdef CONFIG_PPC_BOOK3E
+	int primary;
+
+	if (threads_per_core == 2) {
+		primary = cpu_first_thread_sibling(cpu);
+		if (cpu_is_offline(primary) && cpu_is_offline(primary + 1)) {
+			/* if both threads are offline, put the cpu in PH20 */
+			rcpm_v2_cpu_enter_state(cpu, E500_PM_PH20);
+		} else {
+			/* if only one thread is offline, disable the thread */
+			qoriq_disable_thread(cpu);
+		}
+	}
+#endif
+
+	if (threads_per_core == 1) {
+		rcpm_v2_cpu_enter_state(cpu, E500_PM_PH20);
+		return;
+	}
+}

That "return;" adds nothing, and it's even more awkward having it on the
one-thread case but not the two-thread case.

+static void rcpm_v1_cpu_up_prepare(int cpu)
+{
+	rcpm_v1_cpu_exit_state(cpu, E500_PM_PH15);
+	rcpm_v1_irq_unmask(cpu);
+}
+
+static void rcpm_v2_cpu_exit_state(int cpu, int state)
+{
+	int hw_cpu = get_hard_smp_processor_id(cpu);
+	u32 mask = 1 << cpu_core_index_of_thread(hw_cpu);

Are you sure cpu_core_index_of_thread() is supposed to take a hardware
cpu id?  The only current user, pseries_energy.c, has the comment
"Convert logical cpu number to core number".

+static const struct of_device_id rcpm_matches[] = {
+	{
+		.compatible = "fsl,qoriq-rcpm-1.0",
+		.data = (void *)&qoriq_rcpm_v1_ops,
+	},
+	{
+		.compatible = "fsl,qoriq-rcpm-2.0",
+		.data = (void *)&qoriq_rcpm_v2_ops,
+	},
+	{
+		.compatible = "fsl,qoriq-rcpm-2.1",
+		.data = (void *)&qoriq_rcpm_v2_ops,
+	},
+	{},
+};

Unnecessary (and const-unsafe) casts.

+
+int __init fsl_rcpm_init(void)
+{
+	struct device_node *np;
+	const struct of_device_id *match;
+	void __iomem *base;
+
+	np = of_find_matching_node_and_match(NULL, rcpm_matches, &match);
+	if (!np) {
+		pr_err("can't find the rcpm node.\n");
+		return -ENODEV;
+	}

It's not an error for the device tree node to not have this.

-Scott