Re: [PATCH v3 2/6] irqchip: Add interrupt controller support for Realtek DHC SoCs

Thomas Gleixner
2023-12-08T15:31:13Z

On Wed, Nov 29 2023 at 13:43, James Tai wrote:
> Realtek DHC (Digital Home Center) SoCs share a common interrupt controller
> design. This universal interrupt controller driver provides support for
> various variants within the Realtek DHC SoC family.
>
> Each DHC SoC features two sets of extended interrupt controllers, each
> capable of handling up to 32 interrupts. These expansion controllers are
> connected to the GIC (Generic Interrupt Controller).
>
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <error27@gmail.com>
> Closes: https://lore.kernel.org/r/202311201929.2FpvMRlg-lkp@intel.com/

These tags are pointless as they are not related to anything in
tree. You addressed review comments and 0-day fallout, but neither Dan
nor 0-day reported that the interrupt controller for Realtek DHC SoCs is
missing.

> +#include "irq-realtek-intc-common.h"
> +
> +struct realtek_intc_data;

struct realtek_intc_data is declared in irq-realtek-intc-common.h, so
what's the point of this forward declaration?

> +static inline unsigned int realtek_intc_get_ints(struct realtek_intc_data *data)
> +{
> + return readl(data->base + data->info->isr_offset);
> +}
> +
> +static inline void realtek_intc_clear_ints_bit(struct realtek_intc_data *data, int bit)
> +{
> + writel(BIT(bit) & ~1, data->base + data->info->isr_offset);

That '& ~1' solves what aside of preventing bit 0 from being written?

> +static int realtek_intc_domain_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
> +{
> + struct realtek_intc_data *data = d->host_data;
> +
> + irq_set_chip_and_handler(irq, &realtek_intc_chip, handle_level_irq);
> + irq_set_chip_data(irq, data);
> + irq_set_probe(irq);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops realtek_intc_domain_ops = {
> + .xlate = irq_domain_xlate_onecell,
> + .map = realtek_intc_domain_map,

.xlate = irq_domain_xlate_onecell,
.map = realtek_intc_domain_map,

Please.

> +};
> +
> +static int realtek_intc_subset(struct device_node *node, struct realtek_intc_data *data, int index)
> +{
> + struct realtek_intc_subset_data *subset_data = &data->subset_data[index];
> + const struct realtek_intc_subset_cfg *cfg = &data->info->cfg[index];
> + int irq;
> +
> + irq = irq_of_parse_and_map(node, index);

irq_of_parse_and_map() returns an 'unsigned int' where 0 is fail.

> + if (irq <= 0)
> + return irq;
> +
> + subset_data->common = data;
> + subset_data->cfg = cfg;
> + subset_data->parent_irq = irq;
> + irq_set_chained_handler_and_data(irq, realtek_intc_handler, subset_data);
> +
> + return 0;
> +}
> +
> +int realtek_intc_probe(struct platform_device *pdev, const struct realtek_intc_info *info)
> +{
> + struct realtek_intc_data *data;
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + int ret, i;
> +
> + data = devm_kzalloc(dev, struct_size(data, subset_data, info->cfg_num), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->base = of_iomap(node, 0);
> + if (!data->base) {
> + ret = -ENOMEM;
> + goto out_cleanup;

devm_kzalloc() is automatically cleaned up when the probe function
fails, so 'return -ENOMEM;' is sufficient.

> + }
> +
> + data->info = info;
> +
> + raw_spin_lock_init(&data->lock);
> +
> + data->domain = irq_domain_add_linear(node, 32, &realtek_intc_domain_ops, data);
> + if (!data->domain) {
> + ret = -ENOMEM;

This 'ret = -ENOMEM;' is pointless as the only error code returned in this
function is -ENOMEM. So you can just return -ENOMEM in the error path, no?

> + goto out_cleanup;
> + }
> +
> + data->subset_data_num = info->cfg_num;
> + for (i = 0; i < info->cfg_num; i++) {
> + ret = realtek_intc_subset(node, data, i);
> + if (ret) {
> + WARN(ret, "failed to init subset %d: %d", i, ret);
> + ret = -ENOMEM;
> + goto out_cleanup;

if (WARN(ret, "....."))
goto cleanup;

> + }
> + }
> +
> + platform_set_drvdata(pdev, data);
> +
> + return 0;
> +
> +out_cleanup:
> +
> + if (data->base)
> + iounmap(data->base);

Leaks the irqdomain.

> +
> + devm_kfree(dev, data);

Pointless exercise.

> + return ret;
> +}
> +EXPORT_SYMBOL(realtek_intc_probe);

EXPORT_SYMBOL_GPL

> +/**
> + * realtek_intc_subset_cfg - subset interrupt mask
> + * @ints_mask: inetrrupt mask
> + */
> +struct realtek_intc_subset_cfg {
> + unsigned int ints_mask;
> +};

The value of a struct wrapping a single 'unsigned int' is? What's wrong
with using unsigned int (actually you want u32 as this represents a
hardware mask) directly? Not enough obfuscation, right?

> +/**
> + * realtek_intc_info - interrupt controller data.
> + * @isr_offset: interrupt status register offset.
> + * @umsk_isr_offset: unmask interrupt status register offset.
> + * @scpu_int_en_offset: interrupt enable register offset.
> + * @cfg: cfg of the subset.
> + * @cfg_num: number of cfg.

* @isr_offset: interrupt status register offset
* @umsk_isr_offset: unmask interrupt status register offset
* @scpu_int_en_offset: interrupt enable register offset

Can you spot the difference?

Please fix all over the place.

> + */
> +struct realtek_intc_info {
> + const struct realtek_intc_subset_cfg *cfg;
> + unsigned int isr_offset;
> + unsigned int umsk_isr_offset;
> + unsigned int scpu_int_en_offset;
> + const u32 *isr_to_scpu_int_en_mask;
> + int cfg_num;
> +};
> +
> +/**
> + * realtek_intc_subset_data - handler of a interrupt source only handles ints
> + * bits in the mask.
> + * @cfg: cfg of the subset.

Seriously. 'cfg of'? This is a description, so can you spell the words
out? This is really neither space constraint nor subject to Xitter
rules. Fix this all over the place please.

> + * @common: common data.
> + * @parent_irq: interrupt source.
> + */
> +struct realtek_intc_subset_data {
> + const struct realtek_intc_subset_cfg *cfg;
> + struct realtek_intc_data *common;
> + int parent_irq;
> +};
> +
> +/**
> + * realtek_intc_data - configuration data for realtek interrupt controller driver.
> + * @base: base of interrupt register
> + * @info: info of intc
> + * @domain: interrupt domain
> + * @lock: lock
> + * @saved_en: status of interrupt enable
> + * @subset_data_num: number of subset data
> + * @subset_data: subset data
> + */
> +struct realtek_intc_data {
> + void __iomem *base;
> + const struct realtek_intc_info *info;
> + struct irq_domain *domain;
> + struct raw_spinlock lock;
> + unsigned int saved_en;
> + int subset_data_num;
> + struct realtek_intc_subset_data subset_data[];
> +};
> +
> +#define IRQ_ALWAYS_ENABLED U32_MAX
> +#define DISABLE_INTC (0)
> +#define CLEAN_INTC_STATUS GENMASK(31, 1)

#define IRQ_ALWAYS_ENABLED U32_MAX
#define DISABLE_INTC (0)
#define CLEAN_INTC_STATUS GENMASK(31, 1)

Please, as that makes this readable.

Thanks,

tglx