[PATCH v11 4/5] clocksource/timer-econet-en751221: Support EN751627 without percpu IRQ

[Caleb James DeLisle <cjd@cjdns.fr>]

EN751627 is based on the 1004Kc which uses a different interrupt number
for each CPU timer. Support both this and the EN751221 which uses a
single percpu interrupt.

CPU hotplug path is intentionally unsupported because this CPU timer
is part of a legacy MIPS CPU which never had support for it.

Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
---
 drivers/clocksource/timer-econet-en751221.c | 131 ++++++++++++++++----
 1 file changed, 108 insertions(+), 23 deletions(-)

diff --git a/drivers/clocksource/timer-econet-en751221.c b/drivers/clocksource/timer-econet-en751221.c
index f2c4c1ee0a56..edb3db3125ce 100644
--- a/drivers/clocksource/timer-econet-en751221.c
+++ b/drivers/clocksource/timer-econet-en751221.c
@@ -24,7 +24,9 @@
 
 static struct {
 	void __iomem	*membase[ECONET_NUM_BLOCKS];
-	int		irq;
+	int		*irqs;
+	int		num_irqs;
+	bool		is_percpu;
 	u32		freq_hz;
 } econet_timer __ro_after_init;
 
@@ -102,6 +104,25 @@ static int cevt_init_cpu(uint cpu)
 	struct clock_event_device *cd = &per_cpu(econet_timer_pcpu, cpu);
 	u32 reg;
 
+	if (!reg_ctl(cpu)) {
+		pr_err("%s: missing address resource for CPU %d\n", cd->name,
+		       cpu);
+		return -EINVAL;
+	}
+	if (cd->irq <= 0) {
+		pr_err("%s: missing IRQ for CPU %d\n", cd->name, cpu);
+		return -EINVAL;
+	}
+	if (!econet_timer.is_percpu) {
+		int ret = irq_force_affinity(cd->irq, cpumask_of(cpu));
+
+		if (ret) {
+			pr_err("%s: failed to set IRQ affinity to CPU %d: %pe\n",
+			       cd->name, cpu, ERR_PTR(ret));
+			return ret;
+		}
+	}
+
 	pr_debug("%s: Setting up clockevent for CPU %d\n", cd->name, cpu);
 
 	reg = ioread32(reg_ctl(cpu)) | ctl_bit_enabled(cpu);
@@ -110,7 +131,10 @@ static int cevt_init_cpu(uint cpu)
 	clockevents_config_and_register(cd, econet_timer.freq_hz,
 					ECONET_MIN_DELTA, ECONET_MAX_DELTA);
 
-	enable_percpu_irq(cd->irq, IRQ_TYPE_NONE);
+	if (econet_timer.is_percpu)
+		enable_percpu_irq(cd->irq, IRQ_TYPE_NONE);
+	else
+		enable_irq(cd->irq);
 
 	return 0;
 }
@@ -141,19 +165,52 @@ static void __init cevt_init(struct device_node *np)
 					  CLOCK_EVT_FEAT_C3STOP |
 					  CLOCK_EVT_FEAT_PERCPU;
 		cd->set_next_event	= cevt_set_next_event;
-		cd->irq			= econet_timer.irq;
 		cd->cpumask		= cpumask_of(i);
 		cd->name		= np->name;
 
-		cevt_dev_init(i);
+		/*
+		 * If not enough IRQs were specified for the CPUs, leave IRQ -1
+		 * and error in cevt_init_cpu
+		 */
+		if (econet_timer.is_percpu)
+			cd->irq = econet_timer.irqs[0];
+		else if (i < econet_timer.num_irqs)
+			cd->irq = econet_timer.irqs[i];
+		else
+			cd->irq = -1;
+
+		/*
+		 * Tolerate CPUs that could exist but don't.
+		 * Fail in cevt_init_cpu when they try to start.
+		 */
+		if (reg_ctl(i) && cd->irq > -1)
+			cevt_dev_init(i);
 	}
 }
 
 static int __init timer_init(struct device_node *np)
 {
-	int num_blocks = DIV_ROUND_UP(num_possible_cpus(), 2);
+	int num_blocks = of_address_count(np);
+	int num_irqs = of_irq_count(np);
 	struct clk *clk;
-	int ret;
+	int ret, i;
+
+	econet_timer.is_percpu = of_device_is_compatible(np, "econet,en751221-timer");
+
+	if (econet_timer.is_percpu && num_irqs != 1) {
+		pr_err("%pOFn: EN751221 clock must have 1 IRQ not %d\n", np,
+		       num_irqs);
+		return -EINVAL;
+	}
+	if (num_blocks > ARRAY_SIZE(econet_timer.membase)) {
+		pr_err("%pOFn: Too many regs: max %zd got %d\n", np,
+		       ARRAY_SIZE(econet_timer.membase), num_blocks);
+		return -EINVAL;
+	}
+	if (num_blocks == 0) {
+		pr_err("%pOFn: At least one reg block must be provided\n", np);
+		return -EINVAL;
+	}
 
 	clk = of_clk_get(np, 0);
 	if (IS_ERR(clk)) {
@@ -164,7 +221,13 @@ static int __init timer_init(struct device_node *np)
 	econet_timer.freq_hz = clk_get_rate(clk);
 	clk_put(clk);
 
-	for (int i = 0; i < num_blocks; i++) {
+	econet_timer.num_irqs = num_irqs;
+	econet_timer.irqs = kcalloc(num_irqs, sizeof(*econet_timer.irqs),
+				    GFP_KERNEL);
+	if (!econet_timer.irqs)
+		return -ENOMEM;
+
+	for (i = 0; i < num_blocks; i++) {
 		econet_timer.membase[i] = of_iomap(np, i);
 		if (!econet_timer.membase[i]) {
 			pr_err("%pOFn: failed to map register [%d]\n", np, i);
@@ -173,22 +236,32 @@ static int __init timer_init(struct device_node *np)
 		}
 	}
 
-	econet_timer.irq = irq_of_parse_and_map(np, 0);
-	if (econet_timer.irq <= 0) {
-		pr_err("%pOFn: irq_of_parse_and_map failed\n", np);
-		ret = -EINVAL;
-		goto out_membase;
+	for (i = 0; i < num_irqs; i++) {
+		econet_timer.irqs[i] = irq_of_parse_and_map(np, i);
+		if (econet_timer.irqs[i] <= 0) {
+			pr_err("%pOFn: failed mapping irq %d\n", np, i);
+			ret = -EINVAL;
+			goto out_irq_mapping;
+		}
 	}
 
-	irq_set_status_flags(econet_timer.irq, IRQ_NOAUTOEN);
-
-	ret = request_percpu_irq(econet_timer.irq, cevt_interrupt, np->name,
-				 &econet_timer_pcpu);
-
-	if (ret < 0) {
-		pr_err("%pOFn: IRQ %d setup failed (%d)\n", np,
-		       econet_timer.irq, ret);
-		goto out_irq_mapping;
+	for (i = 0; i < num_irqs; i++) {
+		irq_set_status_flags(econet_timer.irqs[i], IRQ_NOAUTOEN);
+
+		if (econet_timer.is_percpu)
+			ret = request_percpu_irq(econet_timer.irqs[i],
+						 cevt_interrupt, np->name,
+						 &econet_timer_pcpu);
+		else
+			ret = request_irq(econet_timer.irqs[i], cevt_interrupt,
+					  IRQF_TIMER | IRQF_NOBALANCING,
+					  np->name, NULL);
+
+		if (ret < 0) {
+			pr_err("%pOFn: IRQ %d setup failed: %pe\n", np,
+			       i, ERR_PTR(ret));
+			goto out_irq_free;
+		}
 	}
 
 	cevt_init(np);
@@ -220,9 +293,17 @@ static int __init timer_init(struct device_node *np)
 	return 0;
 
 out_irq_free:
-	free_percpu_irq(econet_timer.irq, &econet_timer_pcpu);
+	while (--i >= 0) {
+		if (econet_timer.is_percpu)
+			free_percpu_irq(econet_timer.irqs[i], &econet_timer_pcpu);
+		else
+			free_irq(econet_timer.irqs[i], NULL);
+	}
 out_irq_mapping:
-	irq_dispose_mapping(econet_timer.irq);
+	for (i = 0; i < num_irqs; i++) {
+		if (econet_timer.irqs[i] > 0)
+			irq_dispose_mapping(econet_timer.irqs[i]);
+	}
 out_membase:
 	for (int i = 0; i < ARRAY_SIZE(econet_timer.membase); i++) {
 		if (econet_timer.membase[i]) {
@@ -231,7 +312,11 @@ static int __init timer_init(struct device_node *np)
 		}
 	}
 
+	kfree(econet_timer.irqs);
+	econet_timer.irqs = NULL;
+
 	return ret;
 }
 
 TIMER_OF_DECLARE(econet_timer_hpt, "econet,en751221-timer", timer_init);
+TIMER_OF_DECLARE(econet_timer_en751627, "econet,en751627-timer", timer_init);
-- 
2.39.5