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SubjectRe: [PATCH V5 09/10] irqchip: Add Loongson Extended I/O interrupt controller support
Hi, Marc,

On Fri, Oct 1, 2021 at 12:21 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Thu, 16 Sep 2021 13:31:37 +0100,
> Huacai Chen <chenhuacai@loongson.cn> wrote:
> >
> > We are preparing to add new Loongson (based on LoongArch, not compatible
> > with old MIPS-based Loongson) support. This patch add Loongson Extended
> > I/O CPU interrupt controller support.
> >
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> > drivers/irqchip/Kconfig | 10 +
> > drivers/irqchip/Makefile | 1 +
> > drivers/irqchip/irq-loongson-eiointc.c | 373 +++++++++++++++++++++++++
> > include/linux/cpuhotplug.h | 1 +
> > 4 files changed, 385 insertions(+)
> > create mode 100644 drivers/irqchip/irq-loongson-eiointc.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index 443c3a7a0cc1..aff08ad824c9 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -547,6 +547,16 @@ config LOONGSON_LIOINTC
> > help
> > Support for the Loongson Local I/O Interrupt Controller.
> >
> > +config LOONGSON_EIOINTC
> > + bool "Loongson Extend I/O Interrupt Controller"
> > + depends on LOONGARCH
> > + depends on MACH_LOONGSON64
> > + default MACH_LOONGSON64
> > + select IRQ_DOMAIN_HIERARCHY
> > + select GENERIC_IRQ_CHIP
> > + help
> > + Support for the Loongson3 Extend I/O Interrupt Vector Controller.
> > +
> > config LOONGSON_HTPIC
> > bool "Loongson3 HyperTransport PIC Controller"
> > depends on (MACH_LOONGSON64 && MIPS)
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index 4e34eebe180b..eb3fdc6fe808 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -107,6 +107,7 @@ obj-$(CONFIG_TI_SCI_INTA_IRQCHIP) += irq-ti-sci-inta.o
> > obj-$(CONFIG_TI_PRUSS_INTC) += irq-pruss-intc.o
> > obj-$(CONFIG_IRQ_LOONGARCH_CPU) += irq-loongarch-cpu.o
> > obj-$(CONFIG_LOONGSON_LIOINTC) += irq-loongson-liointc.o
> > +obj-$(CONFIG_LOONGSON_EIOINTC) += irq-loongson-eiointc.o
> > obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
> > obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
> > obj-$(CONFIG_LOONGSON_PCH_PIC) += irq-loongson-pch-pic.o
> > diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
> > new file mode 100644
> > index 000000000000..353c91ea5ad2
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-loongson-eiointc.c
> > @@ -0,0 +1,373 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Loongson Extend I/O Interrupt Controller support
> > + *
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#define pr_fmt(fmt) "eiointc: " fmt
> > +
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/irqchip/chained_irq.h>
> > +#include <linux/kernel.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/syscore_ops.h>
> > +
> > +#define EIOINTC_REG_NODEMAP 0x14a0
> > +#define EIOINTC_REG_IPMAP 0x14c0
> > +#define EIOINTC_REG_ENABLE 0x1600
> > +#define EIOINTC_REG_BOUNCE 0x1680
> > +#define EIOINTC_REG_ISR 0x1800
> > +#define EIOINTC_REG_ROUTE 0x1c00
> > +
> > +#define VEC_REG_COUNT 4
> > +#define VEC_COUNT_PER_REG 64
> > +#define VEC_COUNT (VEC_REG_COUNT * VEC_COUNT_PER_REG)
> > +#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_DEF_ENABLE 0xffffffff
> > +
> > +static int nr_pics;
> > +
> > +struct eiointc_priv {
> > + u32 node;
> > + nodemask_t node_map;
> > + cpumask_t cpuspan_map;
> > + struct fwnode_handle *domain_handle;
> > + struct irq_domain *eiointc_domain;
> > +};
> > +
> > +struct eiointc_priv *eiointc_priv[2];
> > +
> > +int eiointc_get_node(int id)
> > +{
> > + return eiointc_priv[id]->node;
> > +}
>
> Why aren't these static?
Emm, eiointc_priv should be static, but eiointc_get_node() is used by arch code.

>
> > +
> > +static void eiointc_set_irq_route(int pos, unsigned int cpu, unsigned int mnode, nodemask_t *node_map)
> > +{
> > + int node, cpu_node, route_node;
> > + unsigned char coremap[MAX_NUMNODES];
> > + uint32_t pos_off, data, data_byte, data_mask;
> > +
> > + pos_off = pos & ~3;
> > + data_byte = pos & 3;
> > + data_mask = ~BIT_MASK(data_byte) & 0xf;
> > +
> > + memset(coremap, 0, sizeof(unsigned char) * MAX_NUMNODES);
> > +
> > + /* Calculate node and coremap of target irq */
> > + cpu_node = cpu_to_node(cpu);
> > + coremap[cpu_node] |= (1 << (topology_core_id(cpu)));
>
> BIT()?
OK, thanks.

>
> > +
> > + for_each_online_node(node) {
> > + if (!node_isset(node, *node_map))
> > + continue;
> > +
> > + /* Node 0 is in charge of inter-node interrupt dispatch */
> > + route_node = (node == mnode) ? cpu_node : node;
> > + data = ((coremap[node] | (route_node << 4)) << (data_byte * 8));
> > + csr_any_send(EIOINTC_REG_ROUTE + pos_off, data, data_mask, node);
> > + }
> > +}
> > +
> > +static DEFINE_SPINLOCK(affinity_lock);
> > +
> > +static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *affinity, bool force)
> > +{
> > + unsigned int cpu;
> > + unsigned long flags;
> > + uint32_t vector, pos_off;
> > + struct cpumask intersect_affinity;
> > + struct eiointc_priv *priv = (struct eiointc_priv *)d->domain->host_data;
>
> Drop the cast.
OK, thanks.

>
> > +
> > + if (!IS_ENABLED(CONFIG_SMP))
> > + return -EPERM;
> > +
> > + spin_lock_irqsave(&affinity_lock, flags);
>
> This must be a raw spinlock.
OK, thanks.

>
> > +
> > + cpumask_and(&intersect_affinity, affinity, cpu_online_mask);
> > + cpumask_and(&intersect_affinity, &intersect_affinity, &priv->cpuspan_map);
> > +
> > + if (cpumask_empty(&intersect_affinity)) {
> > + spin_unlock_irqrestore(&affinity_lock, flags);
> > + return -EINVAL;
> > + }
> > + cpu = cpumask_first(&intersect_affinity);
> > +
> > + /*
> > + * Control interrupt enable or disalbe through cpu 0
> > + * which is reponsible for dispatching interrupts.
> > + */
> > + if (!d->parent_data)
> > + vector = d->hwirq;
> > + else
> > + vector = d->parent_data->hwirq;
> > +
> > + pos_off = vector >> 5;
> > +
> > + csr_any_send(EIOINTC_REG_ENABLE + (pos_off << 2),
> > + EIOINTC_DEF_ENABLE & (~((1 << (vector & 0x1F)))), 0x0, 0);
> > + eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
> > + csr_any_send(EIOINTC_REG_ENABLE + (pos_off << 2), EIOINTC_DEF_ENABLE, 0x0, 0);
>
> These bit shifts are undecipherable. At the very least, explain what
> this is doing.
OK, this will be improved.

>
> > +
> > + irq_data_update_effective_affinity(d, cpumask_of(cpu));
> > +
> > + spin_unlock_irqrestore(&affinity_lock, flags);
> > +
> > + return IRQ_SET_MASK_OK;
> > +}
> > +
> > +static int eiointc_index(int node)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < nr_pics; i++) {
> > + if (node_isset(node, eiointc_priv[i]->node_map))
> > + return i;
> > + }
> > +
> > + return -1;
> > +}
> > +
> > +static int eiointc_router_init(unsigned int cpu)
> > +{
> > + int i, bit;
> > + uint32_t data;
> > + uint32_t node = cpu_to_node(cpu);
> > + uint32_t index = eiointc_index(node);
> > +
> > + if (index < 0) {
> > + pr_err("Error: invalid nodemap!\n");
> > + return -1;
> > + }
> > +
> > + if (cpu == cpumask_first(cpumask_of_node(node))) {
> > + eiointc_enable();
> > +
> > + for (i = 0; i < VEC_COUNT / 32; i++) {
> > + data = (((1 << (i * 2 + 1)) << 16) | (1 << (i * 2)));
> > + iocsr_writel(data, EIOINTC_REG_NODEMAP + i * 4);
> > + }
> > +
> > + for (i = 0; i < VEC_COUNT / 32 / 4; i++) {
> > + bit = BIT(1 + index); /* Route to IP[1 + index] */
> > + data = bit | (bit << 8) | (bit << 16) | (bit << 24);
> > + iocsr_writel(data, EIOINTC_REG_IPMAP + i * 4);
> > + }
> > +
> > + for (i = 0; i < VEC_COUNT / 4; i++) {
> > + /* Route to Node-0 Core-0 */
> > + if (index == 0)
> > + bit = BIT(cpu_logical_map(0));
> > + else
> > + bit = (eiointc_priv[index]->node << 4) | 1;
> > +
> > + data = bit | (bit << 8) | (bit << 16) | (bit << 24);
> > + iocsr_writel(data, EIOINTC_REG_ROUTE + i * 4);
> > + }
> > +
> > + for (i = 0; i < VEC_COUNT / 32; i++) {
> > + data = 0xffffffff;
> > + iocsr_writel(data, EIOINTC_REG_ENABLE + i * 4);
> > + iocsr_writel(data, EIOINTC_REG_BOUNCE + i * 4);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void eiointc_irq_dispatch(struct irq_desc *desc)
> > +{
> > + int i;
> > + u64 pending;
> > + bool handled = false;
> > + struct irq_chip *chip = irq_desc_get_chip(desc);
> > + struct eiointc_priv *priv = irq_desc_get_handler_data(desc);
> > +
> > + chained_irq_enter(chip, desc);
> > +
> > + for (i = 0; i < VEC_REG_COUNT; i++) {
> > + pending = iocsr_readq(EIOINTC_REG_ISR + (i << 3));
> > + iocsr_writeq(pending, EIOINTC_REG_ISR + (i << 3));
> > + while (pending) {
> > + int bit = __ffs(pending);
> > + int irq = bit + VEC_COUNT_PER_REG * i;
> > +
> > + generic_handle_domain_irq(priv->eiointc_domain, irq);
> > + pending &= ~BIT(bit);
> > + handled = true;
> > + }
> > + }
> > +
> > + if (!handled)
> > + spurious_interrupt();
> > +
> > + chained_irq_exit(chip, desc);
> > +}
> > +
> > +static void eiointc_ack_irq(struct irq_data *d)
> > +{
> > +}
> > +
> > +static void eiointc_mask_irq(struct irq_data *d)
> > +{
> > +}
> > +
> > +static void eiointc_unmask_irq(struct irq_data *d)
> > +{
> > +}
> > +
> > +static struct irq_chip eiointc_irq_chip = {
> > + .name = "EIOINTC",
> > + .irq_ack = eiointc_ack_irq,
> > + .irq_mask = eiointc_mask_irq,
> > + .irq_unmask = eiointc_unmask_irq,
> > + .irq_set_affinity = eiointc_set_irq_affinity,
>
> If this is only routing interrupts, why isn't this a hierarchical
> interrupt controller that passes all the callbacks directly to the
> parent?
OK, this will be improved.

>
> > +};
> > +
> > +static int eiointc_domain_alloc(struct irq_domain *domain, unsigned int virq,
> > + unsigned int nr_irqs, void *arg)
> > +{
> > + int ret;
> > + unsigned int i, type;
> > + unsigned long hwirq = 0;
> > + struct eiointc *priv = domain->host_data;
> > +
> > + ret = irq_domain_translate_onecell(domain, arg, &hwirq, &type);
> > + if (ret)
> > + return ret;
> > +
> > + for (i = 0; i < nr_irqs; i++) {
> > + irq_domain_set_info(domain, virq + i, hwirq + i, &eiointc_irq_chip,
> > + priv, handle_edge_irq, NULL, NULL);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void eiointc_domain_free(struct irq_domain *domain, unsigned int virq,
> > + unsigned int nr_irqs)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < nr_irqs; i++) {
> > + struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
> > +
> > + irq_set_handler(virq + i, NULL);
> > + irq_domain_reset_irq_data(d);
> > + }
> > +}
> > +
> > +static const struct irq_domain_ops eiointc_domain_ops = {
> > + .translate = irq_domain_translate_onecell,
> > + .alloc = eiointc_domain_alloc,
> > + .free = eiointc_domain_free,
> > +};
> > +
> > +static int eiointc_suspend(void)
> > +{
> > + return 0;
> > +}
> > +
> > +static bool is_eiointc_irq(struct irq_data *irq_data)
> > +{
> > + int i;
> > + struct irq_domain *parent;
> > +
> > + for (parent = irq_data->domain; parent; parent = parent->parent) {
> > + for (i = 0; i < nr_pics; i++) {
> > + if (parent == eiointc_priv[i]->eiointc_domain)
> > + return true;
> > + }
> > + }
> > +
> > + return false;
> > +}
> > +
> > +static void eiointc_resume(void)
> > +{
> > + int i;
> > + struct irq_desc *desc;
> > + struct irq_data *irq_data;
> > +
> > + eiointc_router_init(0);
> > +
> > + for (i = 0; i < NR_IRQS; i++) {
>
> No. Never.
>
> > + desc = irq_to_desc(i);
> > + if (desc && desc->handle_irq && desc->handle_irq != handle_bad_irq) {
> > + irq_data = &desc->irq_data;
> > + if (!is_eiointc_irq(irq_data))
> > + continue;
> > +
> > + eiointc_set_irq_affinity(irq_data, irq_data->common->affinity, 0);
> > + }
>
> If you need to restore some state, track the interrupts that actually
> matter. But this is... just not on.
OK, let me try to improve.

Huacai
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.

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