Skip to content

Commit

Permalink
irqchip/sifive-plic: Add support for multiple PLICs
Browse files Browse the repository at this point in the history
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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20200302231146.15530-3-atish.patra@wdc.com
  • Loading branch information
Atish Patra authored and Marc Zyngier committed Mar 16, 2020
1 parent ccbe80b commit f1ad113
Showing 1 changed file with 51 additions and 30 deletions.
81 changes: 51 additions & 30 deletions drivers/irqchip/irq-sifive-plic.c
Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,11 @@
#define PLIC_DISABLE_THRESHOLD 0xf
#define PLIC_ENABLE_THRESHOLD 0

static void __iomem *plic_regs;
struct plic_priv {
struct cpumask lmask;
struct irq_domain *irqdomain;
void __iomem *regs;
};

struct plic_handler {
bool present;
Expand All @@ -70,6 +74,7 @@ struct plic_handler {
*/
raw_spinlock_t enable_lock;
void __iomem *enable_base;
struct plic_priv *priv;
};
static DEFINE_PER_CPU(struct plic_handler, plic_handlers);

Expand All @@ -88,49 +93,62 @@ 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_priv *priv = irq_get_chip_data(d->irq);

writel(enable, plic_regs + PRIORITY_BASE + hwirq * PRIORITY_PER_ID);
writel(enable, priv->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->priv->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_priv *priv = irq_get_chip_data(d->irq);

cpumask_and(&amask, &priv->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_priv *priv = irq_get_chip_data(d->irq);

plic_irq_toggle(&priv->lmask, d, 0);
}

#ifdef CONFIG_SMP
static int plic_set_affinity(struct irq_data *d,
const struct cpumask *mask_val, bool force)
{
unsigned int cpu;
struct cpumask amask;
struct plic_priv *priv = irq_get_chip_data(d->irq);

cpumask_and(&amask, &priv->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(&priv->lmask, d, 0);
plic_irq_toggle(cpumask_of(cpu), d, 1);

irq_data_update_effective_affinity(d, cpumask_of(cpu));

Expand Down Expand Up @@ -191,8 +209,6 @@ 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
Expand All @@ -209,7 +225,7 @@ 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->priv->irqdomain, hwirq);

if (unlikely(irq <= 0))
pr_warn_ratelimited("can't find mapping for hwirq %lu\n",
Expand Down Expand Up @@ -265,15 +281,17 @@ static int __init plic_init(struct device_node *node,
{
int error = 0, nr_contexts, nr_handlers = 0, i;
u32 nr_irqs;
struct plic_priv *priv;

if (plic_regs) {
pr_warn("PLIC already present.\n");
return -ENXIO;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;

plic_regs = of_iomap(node, 0);
if (WARN_ON(!plic_regs))
return -EIO;
priv->regs = of_iomap(node, 0);
if (WARN_ON(!priv->regs)) {
error = -EIO;
goto out_free_priv;
}

error = -EINVAL;
of_property_read_u32(node, "riscv,ndev", &nr_irqs);
Expand All @@ -287,9 +305,9 @@ 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))
priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
&plic_irqdomain_ops, priv);
if (WARN_ON(!priv->irqdomain))
goto out_iounmap;

for (i = 0; i < nr_contexts; i++) {
Expand Down Expand Up @@ -334,13 +352,14 @@ static int __init plic_init(struct device_node *node,
goto done;
}

cpumask_set_cpu(cpu, &priv->lmask);
handler->present = true;
handler->hart_base =
plic_regs + CONTEXT_BASE + i * CONTEXT_PER_HART;
priv->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;

priv->regs + ENABLE_BASE + i * ENABLE_PER_HART;
handler->priv = priv;
done:
for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
plic_toggle(handler, hwirq, 0);
Expand All @@ -356,7 +375,9 @@ static int __init plic_init(struct device_node *node,
return 0;

out_iounmap:
iounmap(plic_regs);
iounmap(priv->regs);
out_free_priv:
kfree(priv);
return error;
}

Expand Down

0 comments on commit f1ad113

Please sign in to comment.