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Message-ID: <874jrv1cuu.wl-maz@kernel.org>
Date: Thu, 09 Feb 2023 08:07:05 +0000
From: Marc Zyngier <maz@...nel.org>
To: Mason Huo <mason.huo@...rfivetech.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Palmer Dabbelt <palmer@...belt.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
<linux-kernel@...r.kernel.org>, <linux-riscv@...ts.infradead.org>,
Ley Foon Tan <leyfoon.tan@...rfivetech.com>,
Sia Jee Heng <jeeheng.sia@...rfivetech.com>
Subject: Re: [PATCH v2] irqchip/irq-sifive-plic: Add syscore callbacks for hibernation
On Thu, 09 Feb 2023 03:43:22 +0000,
Mason Huo <mason.huo@...rfivetech.com> wrote:
>
> The priority and enable registers of plic will be reset
> during hibernation power cycle in poweroff mode,
> add the syscore callbacks to save/restore those registers.
>
> Signed-off-by: Mason Huo <mason.huo@...rfivetech.com>
> Reviewed-by: Ley Foon Tan <leyfoon.tan@...rfivetech.com>
> Reviewed-by: Sia Jee Heng <jeeheng.sia@...rfivetech.com>
> ---
> drivers/irqchip/irq-sifive-plic.c | 94 ++++++++++++++++++++++++++++++-
> 1 file changed, 92 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index ff47bd0dec45..4683e49d90ad 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -17,6 +17,7 @@
> #include <linux/of_irq.h>
> #include <linux/platform_device.h>
> #include <linux/spinlock.h>
> +#include <linux/syscore_ops.h>
> #include <asm/smp.h>
>
> /*
> @@ -67,6 +68,8 @@ struct plic_priv {
> struct irq_domain *irqdomain;
> void __iomem *regs;
> unsigned long plic_quirks;
> + unsigned int nr_irqs;
> + unsigned long *priority_reg;
This isn't a pointer to registers. This is a save area for the
values. Please fix the naming.
> };
>
> struct plic_handler {
> @@ -78,11 +81,13 @@ struct plic_handler {
> */
> raw_spinlock_t enable_lock;
> void __iomem *enable_base;
> + u32 *enable_reg;
Same thing here.
> struct plic_priv *priv;
> };
> static int plic_parent_irq __ro_after_init;
> static bool plic_cpuhp_setup_done __ro_after_init;
> static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
> +static struct plic_priv *priv_data;
>
> static int plic_irq_set_type(struct irq_data *d, unsigned int type);
>
> @@ -229,6 +234,68 @@ static int plic_irq_set_type(struct irq_data *d, unsigned int type)
> return IRQ_SET_MASK_OK;
> }
>
> +static int plic_irq_suspend(void)
> +{
> + unsigned int i, cpu;
> + u32 __iomem *reg;
> +
> + for (i = 0; i < priv_data->nr_irqs; i++)
> + if (readl(priv_data->regs + PRIORITY_BASE + i * PRIORITY_PER_ID))
> + __set_bit(i, priv_data->priority_reg);
> + else
> + __clear_bit(i, priv_data->priority_reg);
> +
> + for_each_cpu(cpu, cpu_present_mask) {
> + struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
> +
> + if (!handler->present)
> + continue;
> +
> + raw_spin_lock(&handler->enable_lock);
> + for (i = 0; i < DIV_ROUND_UP(priv_data->nr_irqs, 32); i++) {
> + reg = handler->enable_base + i * sizeof(u32);
> + handler->enable_reg[i] = readl(reg);
> + }
> + raw_spin_unlock(&handler->enable_lock);
> + }
> +
> + return 0;
> +}
> +
> +static void plic_irq_resume(void)
> +{
> + unsigned int i, cpu;
> + u32 __iomem *reg;
> +
> + for (i = 0; i < priv_data->nr_irqs; i++)
> + writel(test_bit(i, priv_data->priority_reg),
> + priv_data->regs + PRIORITY_BASE + i * PRIORITY_PER_ID);
I suggest you write the priority value instead of the result of
test_bit(). Yes, they are the same for now. They may change in the
future.
> +
> + for_each_cpu(cpu, cpu_present_mask) {
> + struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
> +
> + if (!handler->present)
> + continue;
> +
> + raw_spin_lock(&handler->enable_lock);
> + for (i = 0; i < DIV_ROUND_UP(priv_data->nr_irqs, 32); i++) {
> + reg = handler->enable_base + i * sizeof(u32);
> + writel(handler->enable_reg[i], reg);
> + }
> + raw_spin_unlock(&handler->enable_lock);
> + }
> +}
> +
> +static struct syscore_ops plic_irq_syscore_ops = {
> + .suspend = plic_irq_suspend,
> + .resume = plic_irq_resume,
> +};
> +
> +static void plic_irq_pm_init(void)
> +{
> + register_syscore_ops(&plic_irq_syscore_ops);
> +}
I think we can live without this single line helper.
> +
> static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
> irq_hw_number_t hwirq)
> {
> @@ -345,12 +412,14 @@ static int __init __plic_init(struct device_node *node,
> u32 nr_irqs;
> struct plic_priv *priv;
> struct plic_handler *handler;
> + unsigned int cpu;
>
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
>
> priv->plic_quirks = plic_quirks;
> + priv_data = priv;
And what happens if you have more than a single PLIC in the system, as
described in [1]?
You also already have this pointer in each per-CPU handler structure.
Why do you need a global one?
>
> priv->regs = of_iomap(node, 0);
> if (WARN_ON(!priv->regs)) {
> @@ -363,15 +432,23 @@ static int __init __plic_init(struct device_node *node,
> if (WARN_ON(!nr_irqs))
> goto out_iounmap;
>
> + priv->nr_irqs = nr_irqs;
> +
> + priv->priority_reg = kcalloc(DIV_ROUND_UP(nr_irqs,
> + sizeof(unsigned long) * 8),
> + sizeof(unsigned long), GFP_KERNEL);
Is this trying to be a substitute to bitmap_alloc()?
> + if (!priv->priority_reg)
> + goto out_free_priority_reg;
> +
> nr_contexts = of_irq_count(node);
> if (WARN_ON(!nr_contexts))
> - goto out_iounmap;
> + goto out_free_priority_reg;
>
> error = -ENOMEM;
> priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
> &plic_irqdomain_ops, priv);
> if (WARN_ON(!priv->irqdomain))
> - goto out_iounmap;
> + goto out_free_priority_reg;
>
> for (i = 0; i < nr_contexts; i++) {
> struct of_phandle_args parent;
> @@ -441,6 +518,11 @@ static int __init __plic_init(struct device_node *node,
> handler->enable_base = priv->regs + CONTEXT_ENABLE_BASE +
> i * CONTEXT_ENABLE_SIZE;
> handler->priv = priv;
> +
> + handler->enable_reg = kcalloc(DIV_ROUND_UP(nr_irqs, 32),
> + 32, GFP_KERNEL);
nit: either you write this on a single line, or you align the second
line with the opening bracket of the previous one.
> + if (!handler->enable_reg)
> + goto out_free_enable_reg;
> done:
> for (hwirq = 1; hwirq <= nr_irqs; hwirq++) {
> plic_toggle(handler, hwirq, 0);
> @@ -461,11 +543,19 @@ static int __init __plic_init(struct device_node *node,
> plic_starting_cpu, plic_dying_cpu);
> plic_cpuhp_setup_done = true;
> }
> + plic_irq_pm_init();
>
> pr_info("%pOFP: mapped %d interrupts with %d handlers for"
> " %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
> return 0;
>
> +out_free_enable_reg:
> + for_each_cpu(cpu, cpu_present_mask) {
> + handler = per_cpu_ptr(&plic_handlers, cpu);
> + kfree(handler->enable_reg);
> + }
> +out_free_priority_reg:
> + kfree(priv->priority_reg);
> out_iounmap:
> iounmap(priv->regs);
> out_free_priv:
M.
[1] https://patchwork.kernel.org/project/linux-riscv/patch/20200302231146.15530-3-atish.patra@wdc.com/
--
Without deviation from the norm, progress is not possible.
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