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WDCIronportException: Internal
From:   Atish Patra <atish.patra@wdc.com>
To:     linux-kernel@vger.kernel.org
Cc:     Atish Patra <atish.patra@wdc.com>,
        Jason Cooper <jason@lakedaemon.net>,
        linux-riscv@lists.infradead.org, Marc Zyngier <maz@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: [v2 PATCH] irqchip/sifive-plic: Add support for multiple PLICs
Date:   Fri, 21 Feb 2020 15:22:46 -0800
Message-Id: <20200221232246.9176-1-atish.patra@wdc.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Current, PLIC driver can support only 1 PLIC on the board. However,
there can be multiple PLICs present on a two socket systems in RISC-V.

Modify the driver so that each PLIC handler can have a information
about individual PLIC registers and an irqdomain associated with it.

Tested on two socket RISC-V system based on VCU118 FPGA connected via
OmniXtend protocol.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
This patch is rebased on top of 5.6-rc2 and following plic fix from
hotplug series.

https://lkml.org/lkml/2020/2/20/1220

Changes from v1->v2:
1. Use irq_chip_get_data to retrieve host_data
2. Renamed plic_hw to plic_node_ctx
---
 drivers/irqchip/irq-sifive-plic.c | 82 ++++++++++++++++++++-----------
 1 file changed, 52 insertions(+), 30 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 7c7f37393f99..9b9b6f4def4f 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -59,7 +59,11 @@
 #define	PLIC_DISABLE_THRESHOLD		0xf
 #define	PLIC_ENABLE_THRESHOLD		0
 
-static void __iomem *plic_regs;
+struct plic_node_ctx {
+	struct cpumask lmask;
+	struct irq_domain *irqdomain;
+	void __iomem *regs;
+};
 
 struct plic_handler {
 	bool			present;
@@ -70,6 +74,7 @@ struct plic_handler {
 	 */
 	raw_spinlock_t		enable_lock;
 	void __iomem		*enable_base;
+	struct plic_node_ctx		*node_ctx;
 };
 static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
 
@@ -88,31 +93,41 @@ static inline void plic_toggle(struct plic_handler *handler,
 }
 
 static inline void plic_irq_toggle(const struct cpumask *mask,
-				   int hwirq, int enable)
+				   struct irq_data *d, int enable)
 {
 	int cpu;
+	struct plic_node_ctx *node_ctx = irq_get_chip_data(d->irq);
 
-	writel(enable, plic_regs + PRIORITY_BASE + hwirq * PRIORITY_PER_ID);
+	writel(enable,
+	       node_ctx->regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID);
 	for_each_cpu(cpu, mask) {
 		struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
 
-		if (handler->present)
-			plic_toggle(handler, hwirq, enable);
+		if (handler->present &&
+		    cpumask_test_cpu(cpu, &handler->node_ctx->lmask))
+			plic_toggle(handler, d->hwirq, enable);
 	}
 }
 
 static void plic_irq_unmask(struct irq_data *d)
 {
-	unsigned int cpu = cpumask_any_and(irq_data_get_affinity_mask(d),
-					   cpu_online_mask);
+	struct cpumask amask;
+	unsigned int cpu;
+	struct plic_node_ctx *node_ctx = irq_get_chip_data(d->irq);
+
+	cpumask_and(&amask, &node_ctx->lmask, cpu_online_mask);
+	cpu = cpumask_any_and(irq_data_get_affinity_mask(d),
+					   &amask);
 	if (WARN_ON_ONCE(cpu >= nr_cpu_ids))
 		return;
-	plic_irq_toggle(cpumask_of(cpu), d->hwirq, 1);
+	plic_irq_toggle(cpumask_of(cpu), d, 1);
 }
 
 static void plic_irq_mask(struct irq_data *d)
 {
-	plic_irq_toggle(cpu_possible_mask, d->hwirq, 0);
+	struct plic_node_ctx *node_ctx = irq_get_chip_data(d->irq);
+
+	plic_irq_toggle(&node_ctx->lmask, d, 0);
 }
 
 #ifdef CONFIG_SMP
@@ -120,17 +135,21 @@ static int plic_set_affinity(struct irq_data *d,
 			     const struct cpumask *mask_val, bool force)
 {
 	unsigned int cpu;
+	struct cpumask amask;
+	struct plic_node_ctx *node_ctx = irq_get_chip_data(d->irq);
+
+	cpumask_and(&amask, &node_ctx->lmask, mask_val);
 
 	if (force)
-		cpu = cpumask_first(mask_val);
+		cpu = cpumask_first(&amask);
 	else
-		cpu = cpumask_any_and(mask_val, cpu_online_mask);
+		cpu = cpumask_any_and(&amask, cpu_online_mask);
 
 	if (cpu >= nr_cpu_ids)
 		return -EINVAL;
 
-	plic_irq_toggle(cpu_possible_mask, d->hwirq, 0);
-	plic_irq_toggle(cpumask_of(cpu), d->hwirq, 1);
+	plic_irq_toggle(&node_ctx->lmask, d, 0);
+	plic_irq_toggle(cpumask_of(cpu), d, 1);
 
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));
 
@@ -191,8 +210,6 @@ static const struct irq_domain_ops plic_irqdomain_ops = {
 	.free		= irq_domain_free_irqs_top,
 };
 
-static struct irq_domain *plic_irqdomain;
-
 /*
  * Handling an interrupt is a two-step process: first you claim the interrupt
  * by reading the claim register, then you complete the interrupt by writing
@@ -209,7 +226,7 @@ static void plic_handle_irq(struct pt_regs *regs)
 
 	csr_clear(CSR_IE, IE_EIE);
 	while ((hwirq = readl(claim))) {
-		int irq = irq_find_mapping(plic_irqdomain, hwirq);
+		int irq = irq_find_mapping(handler->node_ctx->irqdomain, hwirq);
 
 		if (unlikely(irq <= 0))
 			pr_warn_ratelimited("can't find mapping for hwirq %lu\n",
@@ -265,15 +282,17 @@ static int __init plic_init(struct device_node *node,
 {
 	int error = 0, nr_contexts, nr_handlers = 0, i;
 	u32 nr_irqs;
+	struct plic_node_ctx *node_ctx;
 
-	if (plic_regs) {
-		pr_warn("PLIC already present.\n");
-		return -ENXIO;
-	}
+	node_ctx = kzalloc(sizeof(*node_ctx), GFP_KERNEL);
+	if (!node_ctx)
+		return -ENOMEM;
 
-	plic_regs = of_iomap(node, 0);
-	if (WARN_ON(!plic_regs))
-		return -EIO;
+	node_ctx->regs = of_iomap(node, 0);
+	if (WARN_ON(!node_ctx->regs)) {
+		error = -EIO;
+		goto out_free_nctx;
+	}
 
 	error = -EINVAL;
 	of_property_read_u32(node, "riscv,ndev", &nr_irqs);
@@ -287,9 +306,9 @@ static int __init plic_init(struct device_node *node,
 		goto out_iounmap;
 
 	error = -ENOMEM;
-	plic_irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
-			&plic_irqdomain_ops, NULL);
-	if (WARN_ON(!plic_irqdomain))
+	node_ctx->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
+			&plic_irqdomain_ops, node_ctx);
+	if (WARN_ON(!node_ctx->irqdomain))
 		goto out_iounmap;
 
 	for (i = 0; i < nr_contexts; i++) {
@@ -334,13 +353,14 @@ static int __init plic_init(struct device_node *node,
 			goto done;
 		}
 
+		cpumask_set_cpu(cpu, &node_ctx->lmask);
 		handler->present = true;
 		handler->hart_base =
-			plic_regs + CONTEXT_BASE + i * CONTEXT_PER_HART;
+			node_ctx->regs + CONTEXT_BASE + i * CONTEXT_PER_HART;
 		raw_spin_lock_init(&handler->enable_lock);
 		handler->enable_base =
-			plic_regs + ENABLE_BASE + i * ENABLE_PER_HART;
-
+			node_ctx->regs + ENABLE_BASE + i * ENABLE_PER_HART;
+		handler->node_ctx = node_ctx;
 done:
 		for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
 			plic_toggle(handler, hwirq, 0);
@@ -356,7 +376,9 @@ static int __init plic_init(struct device_node *node,
 	return 0;
 
 out_iounmap:
-	iounmap(plic_regs);
+	iounmap(node_ctx->regs);
+out_free_nctx:
+	kfree(node_ctx);
 	return error;
 }
 
-- 
2.25.0