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Message-ID: <CAAhV-H6+GYjbJbZjKUVvHJ7sTnRhMqBOun149OqO8WEL7xF8Aw@mail.gmail.com>
Date: Wed, 28 Aug 2024 21:56:53 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Bibo Mao <maobibo@...ngson.cn>
Cc: Jianmin Lv <lvjianmin@...ngson.cn>, WANG Xuerui <kernel@...0n.name>,
Thomas Gleixner <tglx@...utronix.de>, loongarch@...ts.linux.dev,
linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org
Subject: Re: [RFC v2 2/2] irqchip/loongson-eiointc: Add multiple interrupt pin
routing support
Hi, Bibo,
On Wed, Aug 28, 2024 at 3:06 PM Bibo Mao <maobibo@...ngson.cn> wrote:
>
> Eiointc interrupt controller support 256 interrupt vectors at most,
> and irq handler gets interrupt status from base register group
> EIOINTC_REG_ISR plus specific offset. It needs to read register group
> EIOINTC_REG_ISR four times to get all 256 interrupt vectors status.
>
> Eiointc registers including EIOINTC_REG_ISR is software emulated for
> VMs, there will be VM-exits when accessing eiointc registers. Here one
> method is introduced so that eiointc interrupt controller can route
> to different cpu interrupt pins for every 64 interrupt vectors. So
> irq handler needs read only relative 64 interrupt vector, it reduces
> VM-exits.
>
> Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
> ---
> drivers/irqchip/irq-loongson-eiointc.c | 72 ++++++++++++++++++++++----
> 1 file changed, 63 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
> index e9ec63d85ee8..c6bcb6625e6d 100644
> --- a/drivers/irqchip/irq-loongson-eiointc.c
> +++ b/drivers/irqchip/irq-loongson-eiointc.c
> @@ -30,11 +30,20 @@
> #define VEC_REG_IDX(irq_id) ((irq_id) / VEC_COUNT_PER_REG)
> #define VEC_REG_BIT(irq_id) ((irq_id) % VEC_COUNT_PER_REG)
> #define EIOINTC_ALL_ENABLE 0xffffffff
> +#define EIOINTC_ROUTE_MULTIPLE_IP BIT(0)
>
> #define MAX_EIO_NODES (NR_CPUS / CORES_PER_EIO_NODE)
>
> static int nr_pics;
>
> +struct eiointc_priv;
> +struct eiointc_ip_route {
> + struct eiointc_priv *priv;
> + /* Routed destination IP offset */
> + int start;
> + int end;
> +};
> +
> struct eiointc_priv {
> u32 node;
> u32 vec_count;
> @@ -43,6 +52,8 @@ struct eiointc_priv {
> struct fwnode_handle *domain_handle;
> struct irq_domain *eiointc_domain;
> int parent_hwirq;
> + int flags;
> + struct eiointc_ip_route route_info[4];
> };
>
> static struct eiointc_priv *eiointc_priv[MAX_IO_PICS];
> @@ -145,12 +156,20 @@ static int eiointc_router_init(unsigned int cpu)
> uint32_t data;
> uint32_t node = cpu_to_eio_node(cpu);
> int index = eiointc_index(node);
> + int hwirq, mask;
>
> if (index < 0) {
> pr_err("Error: invalid nodemap!\n");
> return -1;
> }
>
> + /* Enable cpu interrupt pin routed from eiointc */
> + hwirq = eiointc_priv[index]->parent_hwirq;
> + mask = BIT(hwirq);
> + if (eiointc_priv[index]->flags & EIOINTC_ROUTE_MULTIPLE_IP)
> + mask |= BIT(hwirq + 1) | BIT(hwirq + 2) | BIT(hwirq + 3);
> + set_csr_ecfg(mask);
> +
> if ((cpu_logical_map(cpu) % CORES_PER_EIO_NODE) == 0) {
> eiointc_enable();
>
> @@ -161,12 +180,23 @@ static int eiointc_router_init(unsigned int cpu)
>
> for (i = 0; i < eiointc_priv[0]->vec_count / 32 / 4; i++) {
> /*
> - * Route to interrupt pin, using offset minus INT_HWI0
> - * Offset 0 means IP0 and so on
> - * Every 32 vector routing to one interrupt pin
> + * Route to interrupt pin, minus INT_HWI0 as offset
> + * Offset 0 means IP0 and so on, every 32 vector
> + * routing to one interrupt pin
> + *
> + * If flags is set with EIOINTC_ROUTE_MULTIPLE_IP,
> + * every 64 vector routes to different consecutive
> + * IPs, otherwise all vector routes to the same IP
> */
> - bit = BIT(eiointc_priv[index]->parent_hwirq - INT_HWI0);
> - data = bit | (bit << 8) | (bit << 16) | (bit << 24);
> + if (eiointc_priv[index]->flags & EIOINTC_ROUTE_MULTIPLE_IP) {
> + bit = BIT(hwirq++ - INT_HWI0);
> + data = bit | (bit << 8);
> + bit = BIT(hwirq++ - INT_HWI0);
> + data |= (bit << 16) | (bit << 24);
> + } else {
> + bit = BIT(hwirq - INT_HWI0);
> + data = bit | (bit << 8) | (bit << 16) | (bit << 24);
> + }
> iocsr_write32(data, EIOINTC_REG_IPMAP + i * 4);
> }
>
> @@ -197,11 +227,18 @@ static void eiointc_irq_dispatch(struct irq_desc *desc)
> u64 pending;
> bool handled = false;
> struct irq_chip *chip = irq_desc_get_chip(desc);
> - struct eiointc_priv *priv = irq_desc_get_handler_data(desc);
> + struct eiointc_ip_route *info = irq_desc_get_handler_data(desc);
>
> chained_irq_enter(chip, desc);
>
> - for (i = 0; i < eiointc_priv[0]->vec_count / VEC_COUNT_PER_REG; i++) {
> + /*
> + * If EIOINTC_ROUTE_MULTIPLE_IP is set, every 64 interrupt vectors in
> + * eiointc interrupt controller routes to different cpu interrupt pins
> + *
> + * Every cpu interrupt pin has its own irq handler, it is ok to
> + * read ISR for these 64 interrupt vectors rather than all vectors
> + */
> + for (i = info->start; i < info->end; i++) {
> pending = iocsr_read64(EIOINTC_REG_ISR + (i << 3));
>
> /* Skip handling if pending bitmap is zero */
> @@ -214,7 +251,7 @@ static void eiointc_irq_dispatch(struct irq_desc *desc)
> int bit = __ffs(pending);
> int irq = bit + VEC_COUNT_PER_REG * i;
>
> - generic_handle_domain_irq(priv->eiointc_domain, irq);
> + generic_handle_domain_irq(info->priv->eiointc_domain, irq);
> pending &= ~BIT(bit);
> handled = true;
> }
> @@ -397,8 +434,25 @@ static int __init eiointc_init(struct eiointc_priv *priv, int parent_irq,
> }
>
> eiointc_priv[nr_pics++] = priv;
> + if (cpu_has_hypervisor) {
> + priv->parent_hwirq = INT_HWI0;
> + for (i = 0; i < priv->vec_count / VEC_COUNT_PER_REG; i++) {
> + priv->route_info[i].start = priv->parent_hwirq - INT_HWI0 + i;
> + priv->route_info[i].end = priv->route_info[i].start + 1;
> + priv->route_info[i].priv = priv;
> + parent_irq = get_percpu_irq(priv->parent_hwirq + i);
> + irq_set_chained_handler_and_data(parent_irq, eiointc_irq_dispatch,
> + &priv->route_info[i]);
> + }
> + priv->flags |= EIOINTC_ROUTE_MULTIPLE_IP;
Can real machines also use EIOINTC_ROUTE_MULTIPLE_IP?
Huacai
> + } else {
> + priv->route_info[0].start = 0;
> + priv->route_info[0].end = priv->vec_count / VEC_COUNT_PER_REG;
> + priv->route_info[0].priv = priv;
> + irq_set_chained_handler_and_data(parent_irq, eiointc_irq_dispatch,
> + &priv->route_info[0]);
> + }
> eiointc_router_init(0);
> - irq_set_chained_handler_and_data(parent_irq, eiointc_irq_dispatch, priv);
>
> if (nr_pics == 1) {
> register_syscore_ops(&eiointc_syscore_ops);
> --
> 2.39.3
>
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