lantiq: kernel 4.14: don't use CPU interrupt controller IPI IRQ domain support

This reverts kernel commit 1eed40043579 ("MIPS: smp-mt: Use CPU interrupt
controller IPI IRQ domain support"). With the patch applied, the kernel
hangs during boot if SMP is active.

The Lantiq IRQ controller gets registered first and it directly handles
the MIPS native SW1/2 and HW0 - HW5 IRQs. It looks like this controller
already registers IRQ 0 - 7 and the generic driver only gets the following
IRQs starting later.

The upstream discussion can be found at
https://www.linux-mips.org/archives/linux-mips/2017-05/msg00059.html.

Signed-off-by: Mathias Kresin <dev@kresin.me>

1 files changed, 271 insertions, 0 deletions

diff --git a/target/linux/lantiq/patches-4.14/0400-Revert-MIPS-smp-mt-Use-CPU-interrupt-controller-IPI-.patch b/target/linux/lantiq/patches-4.14/0400-Revert-MIPS-smp-mt-Use-CPU-interrupt-controller-IPI-.patch
new file mode 100644
index 0000000..7c2deb1
--- /dev/null
+++ b/target/linux/lantiq/patches-4.14/0400-Revert-MIPS-smp-mt-Use-CPU-interrupt-controller-IPI-.patch
@@ -0,0 +1,271 @@
+From 8fe9821b478e5c61fef4786b7ec96b6766af196d Mon Sep 17 00:00:00 2001
+From: Mathias Kresin <dev@kresin.me>
+Date: Mon, 8 Jan 2018 23:04:57 +0100
+Subject: [PATCH] Revert "MIPS: smp-mt: Use CPU interrupt controller IPI IRQ
+ domain support"
+
+The problem is that the Lantiq IRQ controller gets registered first and
+it directly handles the MIPS native SW1/2 and HW0 - HW5 IRQs. It looks
+like this controller already registers IRQ 0 - 7 and the generic driver
+only gets the following IRQs starting later.
+
+The upstream discussion can be found at https://www.linux-mips.org/archives/linux-mips/2017-05/msg00059.html
+
+This reverts kernel commit 1eed40043579 ("MIPS: smp-mt: Use CPU interrupt
+controller IPI IRQ domain support").
+
+Signed-off-by: Mathias Kresin <dev@kresin.me>
+
+---
+ arch/mips/kernel/smp-mt.c       | 49 ++++++++++++++++++++++--
+ arch/mips/lantiq/irq.c          | 52 ++++++++++++++++++++++++++
+ arch/mips/mti-malta/malta-int.c | 83 +++++++++++++++++++++++++++++++++++++++--
+ 3 files changed, 176 insertions(+), 8 deletions(-)
+
+--- a/arch/mips/kernel/smp-mt.c
++++ b/arch/mips/kernel/smp-mt.c
+@@ -83,8 +83,6 @@ static unsigned int __init smvp_vpe_init
+ 	if (tc != 0)
+ 		smvp_copy_vpe_config();
+ 
+-	cpu_set_vpe_id(&cpu_data[ncpu], tc);
+-
+ 	return ncpu;
+ }
+ 
+@@ -116,6 +114,49 @@ static void __init smvp_tc_init(unsigned
+ 	write_tc_c0_tchalt(TCHALT_H);
+ }
+ 
++static void vsmp_send_ipi_single(int cpu, unsigned int action)
++{
++	int i;
++	unsigned long flags;
++	int vpflags;
++
++#ifdef CONFIG_MIPS_GIC
++	if (gic_present) {
++		mips_smp_send_ipi_single(cpu, action);
++		return;
++	}
++#endif
++	local_irq_save(flags);
++
++	vpflags = dvpe();	/* can't access the other CPU's registers whilst MVPE enabled */
++
++	switch (action) {
++	case SMP_CALL_FUNCTION:
++		i = C_SW1;
++		break;
++
++	case SMP_RESCHEDULE_YOURSELF:
++	default:
++		i = C_SW0;
++		break;
++	}
++
++	/* 1:1 mapping of vpe and tc... */
++	settc(cpu);
++	write_vpe_c0_cause(read_vpe_c0_cause() | i);
++	evpe(vpflags);
++
++	local_irq_restore(flags);
++}
++
++static void vsmp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
++{
++	unsigned int i;
++
++	for_each_cpu(i, mask)
++		vsmp_send_ipi_single(i, action);
++}
++
+ static void vsmp_init_secondary(void)
+ {
+ 	/* This is Malta specific: IPI,performance and timer interrupts */
+@@ -240,8 +281,8 @@ static void __init vsmp_prepare_cpus(uns
+ }
+ 
+ const struct plat_smp_ops vsmp_smp_ops = {
+-	.send_ipi_single	= mips_smp_send_ipi_single,
+-	.send_ipi_mask		= mips_smp_send_ipi_mask,
++	.send_ipi_single	= vsmp_send_ipi_single,
++	.send_ipi_mask		= vsmp_send_ipi_mask,
+ 	.init_secondary		= vsmp_init_secondary,
+ 	.smp_finish		= vsmp_smp_finish,
+ 	.boot_secondary		= vsmp_boot_secondary,
+--- a/arch/mips/lantiq/irq.c
++++ b/arch/mips/lantiq/irq.c
+@@ -272,6 +272,47 @@ static void ltq_hw_irq_handler(struct ir
+ 	ltq_hw_irqdispatch(irq_desc_get_irq(desc) - 2);
+ }
+ 
++#ifdef CONFIG_MIPS_MT_SMP
++void __init arch_init_ipiirq(int irq, struct irqaction *action)
++{
++	setup_irq(irq, action);
++	irq_set_handler(irq, handle_percpu_irq);
++}
++
++static void ltq_sw0_irqdispatch(void)
++{
++	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_RESCHED_IRQ);
++}
++
++static void ltq_sw1_irqdispatch(void)
++{
++	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_CALL_IRQ);
++}
++static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
++{
++	scheduler_ipi();
++	return IRQ_HANDLED;
++}
++
++static irqreturn_t ipi_call_interrupt(int irq, void *dev_id)
++{
++	generic_smp_call_function_interrupt();
++	return IRQ_HANDLED;
++}
++
++static struct irqaction irq_resched = {
++	.handler	= ipi_resched_interrupt,
++	.flags		= IRQF_PERCPU,
++	.name		= "IPI_resched"
++};
++
++static struct irqaction irq_call = {
++	.handler	= ipi_call_interrupt,
++	.flags		= IRQF_PERCPU,
++	.name		= "IPI_call"
++};
++#endif
++
+ asmlinkage void plat_irq_dispatch(void)
+ {
+ 	unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
+@@ -359,6 +400,17 @@ int __init icu_of_init(struct device_nod
+ 		(MAX_IM * INT_NUM_IM_OFFSET) + MIPS_CPU_IRQ_CASCADE,
+ 		&irq_domain_ops, 0);
+ 
++#if defined(CONFIG_MIPS_MT_SMP)
++	if (cpu_has_vint) {
++		pr_info("Setting up IPI vectored interrupts\n");
++		set_vi_handler(MIPS_CPU_IPI_RESCHED_IRQ, ltq_sw0_irqdispatch);
++		set_vi_handler(MIPS_CPU_IPI_CALL_IRQ, ltq_sw1_irqdispatch);
++	}
++	arch_init_ipiirq(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_RESCHED_IRQ,
++		&irq_resched);
++	arch_init_ipiirq(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_CALL_IRQ, &irq_call);
++#endif
++
+ #ifndef CONFIG_MIPS_MT_SMP
+ 	set_c0_status(IE_IRQ0 | IE_IRQ1 | IE_IRQ2 |
+ 		IE_IRQ3 | IE_IRQ4 | IE_IRQ5);
+--- a/arch/mips/mti-malta/malta-int.c
++++ b/arch/mips/mti-malta/malta-int.c
+@@ -144,6 +144,56 @@ static irqreturn_t corehi_handler(int ir
+ 	return IRQ_HANDLED;
+ }
+ 
++#ifdef CONFIG_MIPS_MT_SMP
++
++#define MIPS_CPU_IPI_RESCHED_IRQ 0	/* SW int 0 for resched */
++#define C_RESCHED C_SW0
++#define MIPS_CPU_IPI_CALL_IRQ 1		/* SW int 1 for resched */
++#define C_CALL C_SW1
++static int cpu_ipi_resched_irq, cpu_ipi_call_irq;
++
++static void ipi_resched_dispatch(void)
++{
++	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_RESCHED_IRQ);
++}
++
++static void ipi_call_dispatch(void)
++{
++	do_IRQ(MIPS_CPU_IRQ_BASE + MIPS_CPU_IPI_CALL_IRQ);
++}
++
++static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
++{
++#ifdef CONFIG_MIPS_VPE_APSP_API_CMP
++	if (aprp_hook)
++		aprp_hook();
++#endif
++
++	scheduler_ipi();
++
++	return IRQ_HANDLED;
++}
++
++static irqreturn_t ipi_call_interrupt(int irq, void *dev_id)
++{
++	generic_smp_call_function_interrupt();
++
++	return IRQ_HANDLED;
++}
++
++static struct irqaction irq_resched = {
++	.handler	= ipi_resched_interrupt,
++	.flags		= IRQF_PERCPU,
++	.name		= "IPI_resched"
++};
++
++static struct irqaction irq_call = {
++	.handler	= ipi_call_interrupt,
++	.flags		= IRQF_PERCPU,
++	.name		= "IPI_call"
++};
++#endif /* CONFIG_MIPS_MT_SMP */
++
+ static struct irqaction corehi_irqaction = {
+ 	.handler = corehi_handler,
+ 	.name = "CoreHi",
+@@ -171,6 +221,12 @@ static msc_irqmap_t msc_eicirqmap[] __in
+ 
+ static int msc_nr_eicirqs __initdata = ARRAY_SIZE(msc_eicirqmap);
+ 
++void __init arch_init_ipiirq(int irq, struct irqaction *action)
++{
++	setup_irq(irq, action);
++	irq_set_handler(irq, handle_percpu_irq);
++}
++
+ void __init arch_init_irq(void)
+ {
+ 	int corehi_irq;
+@@ -216,11 +272,30 @@ void __init arch_init_irq(void)
+ 
+ 	if (mips_gic_present()) {
+ 		corehi_irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_COREHI;
+-	} else if (cpu_has_veic) {
+-		set_vi_handler(MSC01E_INT_COREHI, corehi_irqdispatch);
+-		corehi_irq = MSC01E_INT_BASE + MSC01E_INT_COREHI;
+ 	} else {
+-		corehi_irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_COREHI;
++#if defined(CONFIG_MIPS_MT_SMP)
++		/* set up ipi interrupts */
++		if (cpu_has_veic) {
++			set_vi_handler (MSC01E_INT_SW0, ipi_resched_dispatch);
++			set_vi_handler (MSC01E_INT_SW1, ipi_call_dispatch);
++			cpu_ipi_resched_irq = MSC01E_INT_SW0;
++			cpu_ipi_call_irq = MSC01E_INT_SW1;
++		} else {
++			cpu_ipi_resched_irq = MIPS_CPU_IRQ_BASE +
++				MIPS_CPU_IPI_RESCHED_IRQ;
++			cpu_ipi_call_irq = MIPS_CPU_IRQ_BASE +
++				MIPS_CPU_IPI_CALL_IRQ;
++		}
++		arch_init_ipiirq(cpu_ipi_resched_irq, &irq_resched);
++		arch_init_ipiirq(cpu_ipi_call_irq, &irq_call);
++#endif
++		if (cpu_has_veic) {
++			set_vi_handler(MSC01E_INT_COREHI,
++				       corehi_irqdispatch);
++			corehi_irq = MSC01E_INT_BASE + MSC01E_INT_COREHI;
++		} else {
++			corehi_irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_COREHI;
++		}
+ 	}
+ 
+ 	setup_irq(corehi_irq, &corehi_irqaction);