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SubjectRe: [PATCH 2/3] drivers/irqchip: add NXP INTMUX interrupt multiplexer support
Date
From
On 2019-12-18 07:20, Joakim Zhang wrote:
> From: Shengjiu Wang <shengjiu.wang@nxp.com>
>
> The intmux module is used to output internal interrupt in subsystem
> to system with 32-to-8 configuration. It has several multiplex
> channels depends on system.
>
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> ---
> drivers/irqchip/irq-imx-intmux.c | 220
> +++++++++++++++++++++++++++++++
> 1 file changed, 220 insertions(+)
> create mode 100644 drivers/irqchip/irq-imx-intmux.c
>
> diff --git a/drivers/irqchip/irq-imx-intmux.c
> b/drivers/irqchip/irq-imx-intmux.c
> new file mode 100644
> index 000000000000..fa24b968f30b
> --- /dev/null
> +++ b/drivers/irqchip/irq-imx-intmux.c
> @@ -0,0 +1,220 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright 2017 NXP
> +
> +#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/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/spinlock.h>
> +
> +#define CHANCSR(n) (0x0 + 0x40 * n)
> +#define CHANVEC(n) (0x4 + 0x40 * n)

These two macros are unused.

> +#define CHANIER(n) (0x10 + (0x40 * n))
> +#define CHANIPR(n) (0x20 + (0x40 * n))
> +
> +struct intmux_irqchip_data {
> + int chanidx;
> + int irq;
> + struct irq_domain *domain;
> + unsigned int irqstat;

It would make things a bit readable if you aligned the various fields:

struct intmux_irqchip_data {
int chanidx;
int irq;
struct irq_domain *domain;
[...]
};

> +};
> +
> +struct intmux_data {
> + spinlock_t lock;
> + struct platform_device *pdev;
> + 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;
> + u32 idx = irqchip_data->chanidx;
> + struct intmux_data *intmux_data = container_of(irqchip_data,
> + struct intmux_data, irqchip_data[idx]);
> + void __iomem *reg;
> + u32 val;
> +
> + spin_lock(&intmux_data->lock);

This is racy. you could take an interrupt while executing
disable_irq(),
which calls this. In turn, the interrupt handler will try to acquire
this
lock -> deadlock.

Please turn this into its _irqsave version.

> + reg = intmux_data->regs + CHANIER(idx);
> + val = readl_relaxed(reg);
> + /* disable the interrupt source of this channel */
> + val &= ~(1 << d->hwirq);

val &= ~BIT(d->hwirq);

> + writel_relaxed(val, reg);
> + spin_unlock(&intmux_data->lock);
> +}
> +
> +static void imx_intmux_irq_unmask(struct irq_data *d)
> +{
> + struct intmux_irqchip_data *irqchip_data = d->chip_data;
> + u32 idx = irqchip_data->chanidx;
> + struct intmux_data *intmux_data = container_of(irqchip_data,
> + struct intmux_data, irqchip_data[idx]);
> + void __iomem *reg;
> + u32 val;
> +
> + spin_lock(&intmux_data->lock);
> + reg = intmux_data->regs + CHANIER(idx);
> + val = readl_relaxed(reg);
> + /* enable the interrupt source of this channel */
> + val |= 1 << d->hwirq;
> + writel_relaxed(val, reg);
> + spin_unlock(&intmux_data->lock);
> +}
> +
> +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);
> + irq_set_chip_data(irq, h->host_data);
> + irq_set_chip_and_handler(irq, &imx_intmux_irq_chip,
> handle_level_irq);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops imx_intmux_domain_ops = {
> + .map = imx_intmux_irq_map,
> + .xlate = irq_domain_xlate_onecell,
> +};
> +
> +static void imx_intmux_update_irqstat(struct intmux_irqchip_data
> *irqchip_data)
> +{
> + int i = irqchip_data->chanidx;
> + struct intmux_data *intmux_data = container_of(irqchip_data,
> + struct intmux_data, irqchip_data[i]);
> +
> + /* read the interrupt source pending status of this channel */
> + irqchip_data->irqstat = readl_relaxed(intmux_data->regs +
> CHANIPR(i));

Why does it need to be stored into the data structure, instead of
sinply being returned by the function?

> +}
> +
> +static void imx_intmux_irq_handler(struct irq_desc *desc)
> +{
> + struct intmux_irqchip_data *irqchip_data =
> irq_desc_get_handler_data(desc);
> + int pos, virq;
> +
> + chained_irq_enter(irq_desc_get_chip(desc), desc);
> +
> + imx_intmux_update_irqstat(irqchip_data);
> +
> + for_each_set_bit(pos, (unsigned long *)&irqchip_data->irqstat, 32)
> {

This is broken on big-endian. Never cast a smaller type into unsigned
long
if you're going to use any of the bit iterators.

> + 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 *intmux_data;
> + int channum;
> + int i, ret;
> +
> + ret = of_property_read_u32(np, "fsl,intmux_chans", &channum);
> + if (ret)
> + channum = 1;
> +
> + intmux_data = devm_kzalloc(&pdev->dev, sizeof(*intmux_data) +
> + channum * sizeof(intmux_data->irqchip_data[0]),
> + GFP_KERNEL);
> + if (!intmux_data)
> + return -ENOMEM;
> +
> + intmux_data->regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(intmux_data->regs)) {
> + dev_err(&pdev->dev, "failed to initialize reg\n");
> + return PTR_ERR(intmux_data->regs);
> + }
> +
> + intmux_data->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
> + if (IS_ERR(intmux_data->ipg_clk)) {
> + ret = PTR_ERR(intmux_data->ipg_clk);
> + dev_err(&pdev->dev, "failed to get ipg clk: %d\n", ret);
> + return ret;
> + }
> +
> + intmux_data->channum = channum;
> + intmux_data->pdev = pdev;

What is the point of keeping track of this? The only instance where you
go from MUX to device is just below, and you already have the device
at hand.

> + spin_lock_init(&intmux_data->lock);
> +
> + ret = clk_prepare_enable(intmux_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++) {
> + intmux_data->irqchip_data[i].chanidx = i;
> + intmux_data->irqchip_data[i].irq = platform_get_irq(pdev, i);
> + if (intmux_data->irqchip_data[i].irq <= 0) {
> + dev_err(&pdev->dev, "failed to get irq\n");
> + return -ENODEV;
> + }
> +
> + intmux_data->irqchip_data[i].domain = irq_domain_add_linear(
> + np,
> + 32,
> + &imx_intmux_domain_ops,
> + &intmux_data->irqchip_data[i]);

Please indent this in a readable manner. If you need an intermediate
variable,
so be it. Or have a long line if you want, but don't write things like
this.

> + if (!intmux_data->irqchip_data[i].domain) {
> + dev_err(&intmux_data->pdev->dev,
> + "failed to create IRQ domain\n");
> + return -ENOMEM;
> + }
> +
> + irq_set_chained_handler_and_data(intmux_data->irqchip_data[i].irq,
> + imx_intmux_irq_handler,
> + &intmux_data->irqchip_data[i]);

Shouldn't you initialize the HW to some sane state here? Like having
having all interrupts masked?

> + }
> +
> + platform_set_drvdata(pdev, intmux_data);
> +
> + return 0;
> +}
> +
> +static int imx_intmux_remove(struct platform_device *pdev)
> +{
> + struct intmux_data *intmux_data = platform_get_drvdata(pdev);
> + int i;
> +
> + for (i = 0; i < intmux_data->channum; i++) {
> + irq_set_chained_handler_and_data(intmux_data->irqchip_data[i].irq,
> + NULL, NULL);

Same thing here. Shouldn't you make sure that no interrupt can fire
anymore?

> +
> + irq_domain_remove(intmux_data->irqchip_data[i].domain);
> + }
> +
> + platform_set_drvdata(pdev, NULL);
> + clk_disable_unprepare(intmux_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);

Thanks,

M.
--
Jazz is not dead. It just smells funny...

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