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SubjectRE: [PATCH V3 2/2] drivers/irqchip: add NXP INTMUX interrupt multiplexer support
Date

> -----Original Message-----
> From: Marc Zyngier <maz@kernel.org>
> Sent: 2019年12月20日 18:49
> To: Joakim Zhang <qiangqing.zhang@nxp.com>
> Cc: tglx@linutronix.de; jason@lakedaemon.net; robh+dt@kernel.org;
> mark.rutland@arm.com; shawnguo@kernel.org; s.hauer@pengutronix.de;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>;
> linux-kernel@vger.kernel.org; Andy Duan <fugang.duan@nxp.com>;
> linux-arm-kernel@lists.infradead.org; S.j. Wang <shengjiu.wang@nxp.com>
> Subject: Re: [PATCH V3 2/2] drivers/irqchip: add NXP INTMUX interrupt
> multiplexer support
>
> On 2019-12-20 07:37, Joakim Zhang wrote:
> > The Interrupt Multiplexer (INTMUX) expands the number of peripherals
> > that can interrupt the core:
> > * The INTMUX has 8 channels that are assigned to 8 NVIC interrupt
> > slots.
> > * Each INTMUX channel can receive up to 32 interrupt sources and has
> > 1
> > interrupt output.
> > * The INTMUX routes the interrupt sources to the interrupt outputs.
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> > ---
> > drivers/irqchip/Kconfig | 6 +
> > drivers/irqchip/Makefile | 1 +
> > drivers/irqchip/irq-imx-intmux.c | 311
> > +++++++++++++++++++++++++++++++
> > 3 files changed, 318 insertions(+)
> > create mode 100644 drivers/irqchip/irq-imx-intmux.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index
> > ba152954324b..7e2b1e9d0b45 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -457,6 +457,12 @@ config IMX_IRQSTEER
> > help
> > Support for the i.MX IRQSTEER interrupt multiplexer/remapper.
> >
> > +config IMX_INTMUX
> > + def_bool y if ARCH_MXC
> > + select IRQ_DOMAIN
> > + help
> > + Support for the i.MX INTMUX interrupt multiplexer.
> > +
> > config LS1X_IRQ
> > bool "Loongson-1 Interrupt Controller"
> > depends on MACH_LOONGSON32
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index
> > e806dda690ea..af976a79d1fb 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -100,6 +100,7 @@ obj-$(CONFIG_CSKY_MPINTC) +=
> irq-csky-mpintc.o
> > obj-$(CONFIG_CSKY_APB_INTC) += irq-csky-apb-intc.o
> > obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
> > obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
> > +obj-$(CONFIG_IMX_INTMUX) += irq-imx-intmux.o
> > obj-$(CONFIG_MADERA_IRQ) += irq-madera.o
> > obj-$(CONFIG_LS1X_IRQ) += irq-ls1x.o
> > obj-$(CONFIG_TI_SCI_INTR_IRQCHIP) += irq-ti-sci-intr.o
> > diff --git a/drivers/irqchip/irq-imx-intmux.c
> > b/drivers/irqchip/irq-imx-intmux.c
> > new file mode 100644
> > index 000000000000..94c67fdd7163
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-imx-intmux.c
> > @@ -0,0 +1,311 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright 2017 NXP
> > +
> > +/* INTMUX Block Diagram
> > + *
> > + * ________________
> > + * interrupt source # 0 +---->| |
> > + * | | |
> > + * interrupt source # 1 +++-->| |
> > + * ... | | | channel # 0
> > |--------->interrupt out # 0
> > + * ... | | | |
> > + * ... | | | |
> > + * interrupt source # X-1 +++-->|________________|
> > + * | | |
> > + * | | |
> > + * | | | ________________
> > + * +---->| |
> > + * | | | | |
> > + * | +-->| |
> > + * | | | | channel # 1
> > |--------->interrupt out # 1
> > + * | | +>| |
> > + * | | | | |
> > + * | | | |________________|
> > + * | | |
> > + * | | |
> > + * | | | ...
> > + * | | | ...
> > + * | | |
> > + * | | | ________________
> > + * +---->| |
> > + * | | | |
> > + * +-->| |
> > + * | | channel # N
> > |--------->interrupt out # N
> > + * +>| |
> > + * | |
> > + * |________________|
> > + *
> > + *
> > + * N: Interrupt Channel Instance Number (N=7)
> > + * X: Interrupt Source Number for each channel (X=32)
> > + *
> > + * The INTMUX interrupt multiplexer has 8 channels, each channel
> > receives 32
> > + * interrupt sources and generates 1 interrupt output.
> > + *
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip/chained_irq.h> #include <linux/irqdomain.h>
> > +#include <linux/kernel.h> #include <linux/of_irq.h> #include
> > +<linux/of_platform.h> #include <linux/spinlock.h>
> > +
> > +#define CHANIER(n) (0x10 + (0x40 * n))
> > +#define CHANIPR(n) (0x20 + (0x40 * n))
> > +
> > +#define CHAN_MAX_NUM 0x8
> > +
> > +struct intmux_irqchip_data {
> > + int chanidx;
> > + int irq;
> > + struct irq_domain *domain;
> > +};
> > +
> > +struct intmux_data {
> > + raw_spinlock_t lock;
> > + void __iomem *regs;
> > + struct clk *ipg_clk;
> > + int channum;
> > + struct intmux_irqchip_data irqchip_data[];
> > +};
> > +
> > +static void imx_intmux_irq_mask(struct irq_data *d) {
> > + struct intmux_irqchip_data *irqchip_data = d->chip_data;
> > + int idx = irqchip_data->chanidx;
> > + struct intmux_data *data = container_of(irqchip_data, struct
> > intmux_data,
> > + irqchip_data[idx]);
> > + unsigned long flags;
> > + void __iomem *reg;
> > + u32 val;
> > +
> > + raw_spin_lock_irqsave(&data->lock, flags);
> > + reg = data->regs + CHANIER(idx);
> > + val = readl_relaxed(reg);
> > + /* disable the interrupt source of this channel */
> > + val &= ~BIT(d->hwirq);
> > + writel_relaxed(val, reg);
> > + raw_spin_unlock_irqrestore(&data->lock, flags); }
> > +
> > +static void imx_intmux_irq_unmask(struct irq_data *d) {
> > + struct intmux_irqchip_data *irqchip_data = d->chip_data;
> > + int idx = irqchip_data->chanidx;
> > + struct intmux_data *data = container_of(irqchip_data, struct
> > intmux_data,
> > + irqchip_data[idx]);
> > + unsigned long flags;
> > + void __iomem *reg;
> > + u32 val;
> > +
> > + raw_spin_lock_irqsave(&data->lock, flags);
> > + reg = data->regs + CHANIER(idx);
> > + val = readl_relaxed(reg);
> > + /* enable the interrupt source of this channel */
> > + val |= BIT(d->hwirq);
> > + writel_relaxed(val, reg);
> > + raw_spin_unlock_irqrestore(&data->lock, flags); }
> > +
> > +static struct irq_chip imx_intmux_irq_chip = {
> > + .name = "intmux",
> > + .irq_mask = imx_intmux_irq_mask,
> > + .irq_unmask = imx_intmux_irq_unmask,
> > +};
> > +
> > +static int imx_intmux_irq_map(struct irq_domain *h, unsigned int
> > irq,
> > + irq_hw_number_t hwirq)
> > +{
> > + irq_set_status_flags(irq, IRQ_LEVEL);
>
> You shouldn't need to do this if you had it right in the xlate callback, see below.
Yes.

> > + irq_set_chip_data(irq, h->host_data);
> > + irq_set_chip_and_handler(irq, &imx_intmux_irq_chip,
> > handle_level_irq);
> > +
> > + return 0;
> > +}
> > +
> > +static int imx_intmux_irq_xlate(struct irq_domain *d, struct
> > device_node *node,
> > + const u32 *intspec, unsigned int intsize,
> > + unsigned long *out_hwirq, unsigned int *out_type) {
> > + struct intmux_irqchip_data *irqchip_data = d->host_data;
> > + int idx = irqchip_data->chanidx;
> > + struct intmux_data *data = container_of(irqchip_data, struct
> > intmux_data,
> > + irqchip_data[idx]);
> > +
> > + /* two cells needed in interrupt specifier:
> > + * the 1st cell: hw interrupt number
> > + * the 2nd cell: channel index
> > + */
>
> The comment format is:
>
> /*
> * comments
> */
Go it.

> > + if (WARN_ON(intsize != 2))
> > + return -EINVAL;
> > +
> > + if (WARN_ON(intspec[1] >= data->channum))
> > + return -EINVAL;
> > +
> > + *out_hwirq = intspec[0];
> > + *out_type = IRQ_TYPE_NONE;
>
> Why NONE? Your interrupts are all level, if I trust the map function.
It is all level, I will correct it.

> > +
> > + return 0;
> > +}
> > +
> > +static int imx_intmux_irq_select(struct irq_domain *d, struct
> > irq_fwspec *fwspec,
> > + enum irq_domain_bus_token bus_token) {
> > + struct intmux_irqchip_data *irqchip_data = d->host_data;
> > +
> > + /* Not for us */
> > + if (fwspec->fwnode != d->fwnode)
> > + return false;
> > +
> > + if (irqchip_data->chanidx == fwspec->param[1])
> > + return true;
> > + else
> > + return false;
>
>
> This is trivially simplified as
>
> return irqchip_data->chanidx == fwspec->param[1];
Got it.

> > +}
> > +
> > +static const struct irq_domain_ops imx_intmux_domain_ops = {
> > + .map = imx_intmux_irq_map,
> > + .xlate = imx_intmux_irq_xlate,
> > + .select = imx_intmux_irq_select,
> > +};
> > +
> > +static void imx_intmux_irq_handler(struct irq_desc *desc) {
> > + struct intmux_irqchip_data *irqchip_data =
> > irq_desc_get_handler_data(desc);
> > + int idx = irqchip_data->chanidx;
> > + struct intmux_data *data = container_of(irqchip_data, struct
> > intmux_data,
> > + irqchip_data[idx]);
> > + unsigned long irqstat;
> > + int pos, virq;
> > +
> > + chained_irq_enter(irq_desc_get_chip(desc), desc);
> > +
> > + /* read the interrupt source pending status of this channel */
> > + irqstat = readl_relaxed(data->regs + CHANIPR(idx));
> > +
> > + for_each_set_bit(pos, &irqstat, 32) {
> > + virq = irq_find_mapping(irqchip_data->domain, pos);
> > + if (virq)
> > + generic_handle_irq(virq);
> > + }
> > +
> > + chained_irq_exit(irq_desc_get_chip(desc), desc); }
> > +
> > +static int imx_intmux_probe(struct platform_device *pdev) {
> > + struct device_node *np = pdev->dev.of_node;
> > + struct intmux_data *data;
> > + int channum;
> > + int i, ret;
> > +
> > + ret = of_property_read_u32(np, "fsl,intmux_chans", &channum);
> > + if (ret) {
> > + channum = 1;
> > + } else if (channum > CHAN_MAX_NUM) {
> > + dev_err(&pdev->dev, "supports up to %d multiplex channels\n",
> > + CHAN_MAX_NUM);
> > + return -EINVAL;
> > + }
> > +
> > + data = devm_kzalloc(&pdev->dev, sizeof(*data) +
> > + channum * sizeof(data->irqchip_data[0]), GFP_KERNEL);
> > + if (!data)
> > + return -ENOMEM;
> > +
> > + data->regs = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(data->regs)) {
> > + dev_err(&pdev->dev, "failed to initialize reg\n");
> > + return PTR_ERR(data->regs);
> > + }
> > +
> > + data->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
> > + if (IS_ERR(data->ipg_clk)) {
> > + ret = PTR_ERR(data->ipg_clk);
> > + if (ret != -EPROBE_DEFER)
> > + dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + data->channum = channum;
> > + raw_spin_lock_init(&data->lock);
> > +
> > + ret = clk_prepare_enable(data->ipg_clk);
> > + if (ret) {
> > + dev_err(&pdev->dev, "failed to enable ipg clk: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + for (i = 0; i < channum; i++) {
> > + data->irqchip_data[i].chanidx = i;
> > +
> > + data->irqchip_data[i].irq = irq_of_parse_and_map(np, i);
> > + if (data->irqchip_data[i].irq <= 0) {
> > + ret = -EINVAL;
> > + dev_err(&pdev->dev, "failed to get irq\n");
> > + goto out;
> > + }
> > +
> > + data->irqchip_data[i].domain =
> > + irq_domain_add_linear(np, 32, &imx_intmux_domain_ops,
> > + &data->irqchip_data[i]);
>
> Same problem as before. If the line is too long, use an intermediate variable. Or
> leave the assignment as a single long line. Don't split assignment like this.
Got it.

> > + if (!data->irqchip_data[i].domain) {
> > + ret = -ENOMEM;
> > + dev_err(&pdev->dev, "failed to create IRQ domain\n");
> > + goto out;
> > + }
> > +
> > + irq_set_chained_handler_and_data(data->irqchip_data[i].irq,
> > + imx_intmux_irq_handler,
> > + &data->irqchip_data[i]);
> > +
> > + /* disable interrupt sources of this channel firstly */
> > + writel_relaxed(0, data->regs + CHANIER(i));
>
> So you disable interrupts *after* enabling the mux interrupt. If you have
> screaming interrupts, this will lockup. You really need to do it *before* enabling
> the chained interrupt.
Make sense. Thanks.

> > + }
> > +
> > + platform_set_drvdata(pdev, data);
> > +
> > + return 0;
> > +out:
> > + clk_disable_unprepare(data->ipg_clk);
> > + return ret;
> > +}
> > +
> > +static int imx_intmux_remove(struct platform_device *pdev) {
> > + struct intmux_data *data = platform_get_drvdata(pdev);
> > + int i;
> > +
> > + for (i = 0; i < data->channum; i++) {
> > + /* clear interrupt sources pending status of this channel */
> > + writel_relaxed(0, data->regs + CHANIPR(i));
>
> If these are level interrupts, this won't do a thing. You need to actively
> *disable* them.
Yes.

Thanks for your kindly review, Marc :-)

Best Regards,
Joakim Zhang
> > +
> > + irq_set_chained_handler_and_data(data->irqchip_data[i].irq,
> > + NULL, NULL);
> > +
> > + irq_domain_remove(data->irqchip_data[i].domain);
> > + }
> > +
> > + clk_disable_unprepare(data->ipg_clk);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id imx_intmux_id[] = {
> > + { .compatible = "fsl,imx-intmux", },
> > + { /* sentinel */ },
> > +};
> > +
> > +static struct platform_driver imx_intmux_driver = {
> > + .driver = {
> > + .name = "imx-intmux",
> > + .of_match_table = imx_intmux_id,
> > + },
> > + .probe = imx_intmux_probe,
> > + .remove = imx_intmux_remove,
> > +};
> > +builtin_platform_driver(imx_intmux_driver);
>
> M.
> --
> Jazz is not dead. It just smells funny...
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