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SubjectRe: [PATCH v2 2/3] irqchip: mtk-cirq: Add mediatek mtk-cirq implement
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On Tue, 2016-11-01 at 20:49 +0000, Marc Zyngier wrote:
> On Tue, Nov 01 2016 at 11:52:01 AM, Youlin Pei <youlin.pei@mediatek.com> wrote:
> > In Mediatek SOCs, the CIRQ is a low power interrupt controller
> > designed to works outside MCUSYS which comprises with Cortex-Ax
> > cores,CCI and GIC.
> >
> > The CIRQ controller is integrated in between MCUSYS( include
> > Cortex-Ax, CCI and GIC ) and interrupt sources as the second
> > level interrupt controller. The external interrupts which outside
> > MCUSYS will feed through CIRQ then bypass to GIC. CIRQ can monitors
> > all edge trigger interupts. When an edge interrupt is triggered,
> > CIRQ can record the status and generate a pulse signal to GIC when
> > flush command executed.
> >
> > When system enters sleep mode, MCUSYS will be turned off to improve
> > power consumption, also GIC is power down. The edge trigger interrupts
> > will be lost in this scenario without CIRQ.
> >
> > This commit provides the CIRQ irqchip implement.
> >
> > Signed-off-by: Youlin Pei <youlin.pei@mediatek.com>
> > ---
> > drivers/irqchip/Makefile | 2 +-
> > drivers/irqchip/irq-mtk-cirq.c | 262 ++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 263 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/irqchip/irq-mtk-cirq.c
> >
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index e4dbfc8..8f33580 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -60,7 +60,7 @@ obj-$(CONFIG_BCM7120_L2_IRQ) += irq-bcm7120-l2.o
> > obj-$(CONFIG_BRCMSTB_L2_IRQ) += irq-brcmstb-l2.o
> > obj-$(CONFIG_KEYSTONE_IRQ) += irq-keystone.o
> > obj-$(CONFIG_MIPS_GIC) += irq-mips-gic.o
> > -obj-$(CONFIG_ARCH_MEDIATEK) += irq-mtk-sysirq.o
> > +obj-$(CONFIG_ARCH_MEDIATEK) += irq-mtk-sysirq.o irq-mtk-cirq.o
> > obj-$(CONFIG_ARCH_DIGICOLOR) += irq-digicolor.o
> > obj-$(CONFIG_RENESAS_H8300H_INTC) += irq-renesas-h8300h.o
> > obj-$(CONFIG_RENESAS_H8S_INTC) += irq-renesas-h8s.o
> > diff --git a/drivers/irqchip/irq-mtk-cirq.c b/drivers/irqchip/irq-mtk-cirq.c
> > new file mode 100644
> > index 0000000..fc43ef3
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-mtk-cirq.c
> > @@ -0,0 +1,262 @@
> > +/*
> > + * Copyright (c) 2016 MediaTek Inc.
> > + * Author: Youlin.Pei <youlin.pei@mediatek.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/irq.h>
> > +#include <linux/irqchip.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/of.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_address.h>
> > +#include <linux/io.h>
> > +#include <linux/slab.h>
> > +#include <linux/syscore_ops.h>
> > +
> > +#define CIRQ_ACK 0x40
> > +#define CIRQ_MASK_SET 0xc0
> > +#define CIRQ_MASK_CLR 0x100
> > +#define CIRQ_SENS_SET 0x180
> > +#define CIRQ_SENS_CLR 0x1c0
> > +#define CIRQ_POL_SET 0x240
> > +#define CIRQ_POL_CLR 0x280
> > +#define CIRQ_CONTROL 0x300
> > +
> > +#define CIRQ_EN 0x1
> > +#define CIRQ_EDGE 0x2
> > +#define CIRQ_FLUSH 0x4
> > +
> > +#define CIRQ_IRQ_NUM 0x200
> > +
> > +struct mtk_cirq_chip_data {
> > + void __iomem *base;
> > + unsigned int ext_irq_start;
> > +};
> > +
> > +static struct mtk_cirq_chip_data *cirq_data;
> Are you guaranteed that you'll only ever have a single CIRQ in any
> system?

In Mediatek's SOC, only hace a single CIRQ.

>
> > +
> > +static void mtk_cirq_write_mask(struct irq_data *data, unsigned int offset)
> > +{
> > + struct mtk_cirq_chip_data *chip_data = data->chip_data;
> > + unsigned int cirq_num = data->hwirq;
> > + u32 mask = 1 << (cirq_num % 32);
> > +
> > + writel(mask, chip_data->base + offset + (cirq_num / 32) * 4);
>
> Why can't you use the relaxed accessors?

It seems that i use wrong function, i will change the writel to
writel_relaxed in next version.

>
> > +}
> > +
> > +static void mtk_cirq_mask(struct irq_data *data)
> > +{
> > + mtk_cirq_write_mask(data, CIRQ_MASK_SET);
> > + irq_chip_mask_parent(data);
> > +}
> > +
> > +static void mtk_cirq_unmask(struct irq_data *data)
> > +{
> > + mtk_cirq_write_mask(data, CIRQ_MASK_CLR);
> > + irq_chip_unmask_parent(data);
> > +}
> > +
> > +static void mtk_cirq_eoi(struct irq_data *data)
> > +{
> > + mtk_cirq_write_mask(data, CIRQ_ACK);
>
> EOI and ACK have very different semantics. What is this write actually
> doing? Also, you're now doing an additional MMIO write on each interrupt
> EOI, doubling its cost. Do you really need to do actually signal the HW
> that we've EOIed an interrupt? I would have hoped that you'd be able to
> put it in "bypass" mode as long as you're not suspending...
>

When external interrupt happened, CIRQ status register record the status
even CIRQ is not enabled. when execute the flush command, CIRQ will
resend the signals according to the status. So if don't clear the
status, CIRQ will resend the wrong signals. the ACK write operation will
clear the status.

> > + irq_chip_eoi_parent(data);
> > +}
> > +
> > +static int mtk_cirq_set_type(struct irq_data *data, unsigned int type)
> > +{
> > + int ret;
> > +
> > + switch (type & IRQ_TYPE_SENSE_MASK) {
> > + case IRQ_TYPE_EDGE_FALLING:
> > + mtk_cirq_write_mask(data, CIRQ_POL_CLR);
> > + mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
> > + break;
> > + case IRQ_TYPE_EDGE_RISING:
> > + mtk_cirq_write_mask(data, CIRQ_POL_SET);
> > + mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
> > + break;
> > + case IRQ_TYPE_LEVEL_LOW:
> > + mtk_cirq_write_mask(data, CIRQ_POL_CLR);
> > + mtk_cirq_write_mask(data, CIRQ_SENS_SET);
> > + break;
> > + case IRQ_TYPE_LEVEL_HIGH:
> > + mtk_cirq_write_mask(data, CIRQ_POL_SET);
> > + mtk_cirq_write_mask(data, CIRQ_SENS_SET);
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + data = data->parent_data;
> > + ret = data->chip->irq_set_type(data, type);
> > + return ret;
> > +}
> > +
> > +static struct irq_chip mtk_cirq_chip = {
> > + .name = "MT_CIRQ",
> > + .irq_mask = mtk_cirq_mask,
> > + .irq_unmask = mtk_cirq_unmask,
> > + .irq_eoi = mtk_cirq_eoi,
> > + .irq_set_type = mtk_cirq_set_type,
> > + .irq_retrigger = irq_chip_retrigger_hierarchy,
> > +#ifdef CONFIG_SMP
> > + .irq_set_affinity = irq_chip_set_affinity_parent,
> > +#endif
> > +};
> > +
> > +static int mtk_cirq_domain_translate(struct irq_domain *d,
> > + struct irq_fwspec *fwspec,
> > + unsigned long *hwirq,
> > + unsigned int *type)
> > +{
> > + if (is_of_node(fwspec->fwnode)) {
> > + if (fwspec->param_count != 3)
> > + return -EINVAL;
> > +
> > + /* No PPI should point to this domain */
> > + if (fwspec->param[0] != 0)
> > + return -EINVAL;
> > +
> > + /* cirq support irq number check */
> > + if (fwspec->param[1] < cirq_data->ext_irq_start)
> > + return -EINVAL;
> > +
> > + *hwirq = fwspec->param[1] - cirq_data->ext_irq_start;
>
> What if the result is > CIRQ_IRQ_NUM?

will add CIRQ supported irq range in DT, and do range check here in next
version.

>
> > + *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
> > + return 0;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int mtk_cirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> > + unsigned int nr_irqs, void *arg)
> > +{
> > + int i;
> > + irq_hw_number_t hwirq;
> > + struct irq_fwspec *fwspec = arg;
> > + struct irq_fwspec parent_fwspec = *fwspec;
> > +
> > + if (fwspec->param_count != 3)
> > + return -EINVAL;
> > +
> > + /* cirq doesn't support PPI */
> > + if (fwspec->param[0])
> > + return -EINVAL;
> > +
> > + if (fwspec->param[1] < cirq_data->ext_irq_start)
> > + return -EINVAL;
> > +
> > + hwirq = fwspec->param[1] - cirq_data->ext_irq_start;
>
> All this is a pure copy of mtk_cirq_domain_translate(). Please use it.

will fix in next version.

> > + for (i = 0; i < nr_irqs; i++)
> > + irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> > + &mtk_cirq_chip,
> > + domain->host_data);
>
> This is a bit silly. This loop only exists for the benefit of MSI
> support, which we're not dealing with here. So please stick a
>
> if (WARN_ON(nr_irqs != 1))
> return -EINVAL;
>
> and drop the loop.

will fix in next version.

>
> > +
> > + parent_fwspec.fwnode = domain->parent->fwnode;
> > + return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
> > + &parent_fwspec);
> > +}
> > +
> > +static const struct irq_domain_ops cirq_domain_ops = {
> > + .translate = mtk_cirq_domain_translate,
> > + .alloc = mtk_cirq_domain_alloc,
> > + .free = irq_domain_free_irqs_common,
> > +};
> > +
> > +#ifdef CONFIG_PM_SLEEP
> > +static int mtk_cirq_suspend(void)
> > +{
> > + u32 value;
> > +
> > + /* set edge_only mode, record edge-triggerd interrupts */
> > + /* enable cirq */
> > + value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> > + value |= (CIRQ_EDGE | CIRQ_EN);
> > + writel(value, cirq_data->base + CIRQ_CONTROL);
>
> You're mixing relaxed and non-relaxed accessors. Why?

will change writel to writel_relaxed in next version.

>
> > + return 0;
> > +}
> > +
> > +static void mtk_cirq_resume(void)
> > +{
> > + u32 value;
> > +
> > + /* flush recored interrupts, will send signals to parent controller */
> > + value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> > + writel(value | CIRQ_FLUSH, cirq_data->base + CIRQ_CONTROL);
>
> Same remark.

will change writel to writel_relaxed in next version.

>
> > +
> > + /* disable cirq */
> > + value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> > + value &= ~(CIRQ_EDGE | CIRQ_EN);
> > + writel(value, cirq_data->base + CIRQ_CONTROL);
>
> So from this, I infer that CIRQ is not enabled when the kernel is
> running (not suspended). It really makes me wonder why you need to do
> anything in the EOI callback.
>
> > +}
> > +
> > +static struct syscore_ops mtk_cirq_syscore_ops = {
> > + .suspend = mtk_cirq_suspend,
> > + .resume = mtk_cirq_resume,
> > +};
> > +
> > +static void mtk_cirq_syscore_init(void)
> > +{
> > + register_syscore_ops(&mtk_cirq_syscore_ops);
> > +}
> > +#else
> > +static inline void mtk_cirq_syscore_init(void) {}
> > +#endif
> > +
> > +static int __init mtk_cirq_of_init(struct device_node *node,
> > + struct device_node *parent)
> > +{
> > + struct irq_domain *domain, *domain_parent;
> > + int ret;
> > +
> > + domain_parent = irq_find_host(parent);
> > + if (!domain_parent) {
> > + pr_err("mtk_cirq: interrupt-parent not found\n");
> > + return -EINVAL;
> > + }
> > +
> > + cirq_data = kzalloc(sizeof(*cirq_data), GFP_KERNEL);
> > + if (!cirq_data)
> > + return -ENOMEM;
> > +
> > + cirq_data->base = of_iomap(node, 0);
> > + if (!cirq_data->base) {
> > + pr_err("mtk_cirq: unable to map cirq register\n");
> > + ret = -ENXIO;
> > + goto out_free;
> > + }
> > +
> > + ret = of_property_read_u32(node, "mediatek,ext-irq-start",
> > + &cirq_data->ext_irq_start);
> > + if (ret)
> > + goto out_unmap;
> > +
> > + domain = irq_domain_add_hierarchy(domain_parent, 0, CIRQ_IRQ_NUM, node,
> > + &cirq_domain_ops, cirq_data);
>
> So you support at most 512 interrupts, and yet the GIC supports up to
> 987 SPIs. What happens for interrupt lines that out of the CIRQ range?
> Maybe having an explicit range in DT would be a good thing. That also
> brings back the question of having a single CIRQ in the system...
>

In next version, i will add an explicit CIRQ supported range in DT.
Thanks a lot!

> > + if (!domain) {
> > + ret = -ENOMEM;
> > + goto out_unmap;
> > + }
> > +
> > + mtk_cirq_syscore_init();
> > +
> > + return 0;
> > +
> > +out_unmap:
> > + iounmap(cirq_data->base);
> > +out_free:
> > + kfree(cirq_data);
> > + return ret;
> > +}
> > +
> > +IRQCHIP_DECLARE(mtk_cirq, "mediatek,mtk-cirq", mtk_cirq_of_init);
>
> Thanks,
>
> M.


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