Re: [PATCH v2] mfd: loongson-se: Add multi-node support

[Huacai Chen]

Hi, Qunqin,

On Mon, Apr 27, 2026 at 4:55 PM Qunqin Zhao <zhaoqunqin@xxxxxxxxxxx> wrote:
>
> On the Loongson platform, each node is equipped with a security engine
> device. However, due to a hardware flaw, only the device on node 0 can
> trigger interrupts. Therefore, interrupts from other nodes are forwarded
> by node 0. We need to check in the interrupt handler of node 0 whether
> this interrupt is intended for other nodes.
Multi-node or multi-package? In my opinion SE has no relationship with
NUMA node, so maybe package?

Huacai

>
> Signed-off-by: Qunqin Zhao <zhaoqunqin@xxxxxxxxxxx>
> ---
> Changes in v2:
>         -Resending due to no feedback for one month.
>         -Rebased on top of latest mainline (7.1-rc1) to ensure the patch
>          applies cleanly.
>         -No functional changes since the previous submission.
>
> Link to v1:
> https://lore.kernel.org/all/20260226102225.19516-1-zhaoqunqin@xxxxxxxxxxx/#t
>
>  drivers/mfd/loongson-se.c       | 38 +++++++++++++++++++++++++++------
>  include/linux/mfd/loongson-se.h |  3 +++
>  2 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mfd/loongson-se.c b/drivers/mfd/loongson-se.c
> index 3902ba377d6..40e18c21268 100644
> --- a/drivers/mfd/loongson-se.c
> +++ b/drivers/mfd/loongson-se.c
> @@ -37,6 +37,9 @@ struct loongson_se_controller_cmd {
>         u32 info[7];
>  };
>
> +static DECLARE_COMPLETION(node0);
> +static struct loongson_se *se_node[SE_MAX_NODES];
> +
>  static int loongson_se_poll(struct loongson_se *se, u32 int_bit)
>  {
>         u32 status;
> @@ -133,8 +136,8 @@ EXPORT_SYMBOL_GPL(loongson_se_init_engine);
>  static irqreturn_t se_irq_handler(int irq, void *dev_id)
>  {
>         struct loongson_se *se = dev_id;
> -       u32 int_status;
> -       int id;
> +       u32 int_status, node_irq = 0;
> +       int id, node;
>
>         spin_lock(&se->dev_lock);
>
> @@ -147,6 +150,11 @@ static irqreturn_t se_irq_handler(int irq, void *dev_id)
>                 writel(SE_INT_CONTROLLER, se->base + SE_S2LINT_CL);
>         }
>
> +       if (int_status & SE_INT_OTHER_NODE) {
> +               int_status &= ~SE_INT_OTHER_NODE;
> +               node_irq = 1;
> +       }
> +
>         /* For engines */
>         while (int_status) {
>                 id = __ffs(int_status);
> @@ -157,6 +165,14 @@ static irqreturn_t se_irq_handler(int irq, void *dev_id)
>
>         spin_unlock(&se->dev_lock);
>
> +       if (node_irq) {
> +               writel(SE_INT_OTHER_NODE, se->base + SE_S2LINT_CL);
> +               for (node = 1; node < SE_MAX_NODES; node++) {
> +                       if (se_node[node])
> +                               se_irq_handler(irq, se_node[node]);
> +               }
> +       }
> +
>         return IRQ_HANDLED;
>  }
>
> @@ -189,6 +205,7 @@ static int loongson_se_probe(struct platform_device *pdev)
>         struct loongson_se *se;
>         int nr_irq, irq, err, i;
>         dma_addr_t paddr;
> +       int node = dev_to_node(dev);
>
>         se = devm_kmalloc(dev, sizeof(*se), GFP_KERNEL);
>         if (!se)
> @@ -213,9 +230,16 @@ static int loongson_se_probe(struct platform_device *pdev)
>
>         writel(SE_INT_ALL, se->base + SE_S2LINT_EN);
>
> -       nr_irq = platform_irq_count(pdev);
> -       if (nr_irq <= 0)
> -               return -ENODEV;
> +       if (node == 0 || node == NUMA_NO_NODE) {
> +               nr_irq = platform_irq_count(pdev);
> +               if (nr_irq <= 0)
> +                       return -ENODEV;
> +       } else {
> +               /* Only the device on node 0 can trigger interrupts */
> +               nr_irq = 0;
> +               wait_for_completion_interruptible(&node0);
> +               se_node[node] = se;
> +       }
>
>         for (i = 0; i < nr_irq; i++) {
>                 irq = platform_get_irq(pdev, i);
> @@ -228,7 +252,9 @@ static int loongson_se_probe(struct platform_device *pdev)
>         if (err)
>                 return err;
>
> -       return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, engines,
> +       complete_all(&node0);
> +
> +       return devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, engines,
>                                     ARRAY_SIZE(engines), NULL, 0, NULL);
>  }
>
> diff --git a/include/linux/mfd/loongson-se.h b/include/linux/mfd/loongson-se.h
> index 07afa0c2524..a80e06eb017 100644
> --- a/include/linux/mfd/loongson-se.h
> +++ b/include/linux/mfd/loongson-se.h
> @@ -20,6 +20,9 @@
>
>  #define SE_INT_ALL                     0xffffffff
>  #define SE_INT_CONTROLLER              BIT(0)
> +#define SE_INT_OTHER_NODE              BIT(31)
> +
> +#define SE_MAX_NODES                   8
>
>  #define SE_ENGINE_MAX                  16
>  #define SE_ENGINE_RNG                  1
>
> base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
> --
> 2.47.2
>
>