[PATCHv3 2/5] arm: mvebu: support for SMP on 98DX3336 SoC

On 06/01/17 19:44, Stephen Boyd wrote:

On 01/06, Chris Packham wrote:

quoted

diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c
index 46c742d3bd41..3c9ab9a008ad 100644
--- a/arch/arm/mach-mvebu/platsmp.c
+++ b/arch/arm/mach-mvebu/platsmp.c

@@ -182,5 +182,48 @@ const struct smp_operations armada_xp_smp_ops __initconst = {
 #endif
 };

+static int mv98dx3236_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	int ret, hw_cpu;
+
+	pr_info("Booting CPU %d\n", cpu);

Doesn't the core already print something when bringing up CPUs?
This message seems redundant.

Copied from armada_xp_boot_secondary but that's no reason to keep it. 
Will remove in v4.

quoted

+
+	hw_cpu = cpu_logical_map(cpu);
+	set_secondary_cpu_clock(hw_cpu);
+	mv98dx3236_resume_set_cpu_boot_addr(hw_cpu,
+					    armada_xp_secondary_startup);
+
+	/*
+	 * This is needed to wake up CPUs in the offline state after
+	 * using CPU hotplug.
+	 */
+	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+	/*
+	 * This is needed to take secondary CPUs out of reset on the
+	 * initial boot.
+	 */
+	ret = mvebu_cpu_reset_deassert(hw_cpu);
+	if (ret) {
+		pr_warn("unable to boot CPU: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+struct smp_operations mv98dx3236_smp_ops __initdata = {

static const __initconst?

Will do.

quoted

+	.smp_init_cpus		= armada_xp_smp_init_cpus,
+	.smp_prepare_cpus	= armada_xp_smp_prepare_cpus,
+	.smp_boot_secondary	= mv98dx3236_boot_secondary,
+	.smp_secondary_init     = armada_xp_secondary_init,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_die		= armada_xp_cpu_die,
+	.cpu_kill               = armada_xp_cpu_kill,
+#endif
+};
+
 CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
 		      &armada_xp_smp_ops);
+CPU_METHOD_OF_DECLARE(mv98dx3236_smp, "marvell,98dx3236-smp",
+		      &mv98dx3236_smp_ops);

diff --git a/arch/arm/mach-mvebu/pmsu-98dx3236.c b/arch/arm/mach-mvebu/pmsu-98dx3236.c
new file mode 100644
index 000000000000..1052674dd439
--- /dev/null
+++ b/arch/arm/mach-mvebu/pmsu-98dx3236.c

@@ -0,0 +1,52 @@
+/**
+ * CPU resume support for 98DX3236 internal CPU (a.k.a. MSYS).
+ */
+
+#define pr_fmt(fmt) "mv98dx3236-resume: " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include "common.h"
+
+static void __iomem *mv98dx3236_resume_base;
+#define MV98DX3236_CPU_RESUME_CTRL_OFFSET	0x08
+#define MV98DX3236_CPU_RESUME_ADDR_OFFSET	0x04
+
+static const struct of_device_id of_mv98dx3236_resume_table[] = {
+	{.compatible = "marvell,98dx3336-resume-ctrl",},
+	{ /* end of list */ },
+};
+
+void mv98dx3236_resume_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
+{
+	WARN_ON(hw_cpu != 1);
+
+	writel(0, mv98dx3236_resume_base + MV98DX3236_CPU_RESUME_CTRL_OFFSET);
+	writel(virt_to_phys(boot_addr), mv98dx3236_resume_base +
+	       MV98DX3236_CPU_RESUME_ADDR_OFFSET);
+}
+
+static int __init mv98dx3236_resume_init(void)
+{
+	struct device_node *np;
+	void __iomem *base;
+
+	np = of_find_matching_node(NULL, of_mv98dx3236_resume_table);
+	if (!np)
+		return 0;

Is there any reason we can't just look for this node from the
smp_ops and map it if it isn't mapped yet? Seems simpler than a
whole new file and initcall.

That's at least 2 votes for rolling it into platsmp.c. The amount of 
code has been significantly reduced so I think I will do it for v4.

quoted

+
+	base = of_io_request_and_map(np, 0, of_node_full_name(np));
+	if (IS_ERR(base)) {
+		pr_err("unable to map registers\n");

Doesn't of_io_request_and_map() spit out an error on failure
already?

Not that I can see. But as has been previously mentioned a CPU failing 
to come online is reasonably obvious already.

quoted

+		of_node_put(np);

This could be done before the if statement and then the duplicate
statement deleted.

Will do.

quoted

+		return PTR_ERR(mv98dx3236_resume_base);

Should be PTR_ERR(base)?

Yes. I decided to add the local variable at the last minute.

quoted

+	}
+
+	mv98dx3236_resume_base = base;
+	of_node_put(np);
+	return 0;
+}