[v2 PATCH] irqchip/sifive-plic: Add support for multiple PLICs

Atish Patra
2020-02-21T23:23:28Z

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