RE: [PATCH 2/2] irqchip/aspeed-scu-ic: Add support for AST2700 SCU interrupt controllers

[Ryan Chen <ryan_chen@aspeedtech.com>]

> Subject: Re: [PATCH 2/2] irqchip/aspeed-scu-ic: Add support for AST2700 SCU
> interrupt controllers
> 
> On Mon, Aug 04 2025 at 13:34, Ryan Chen wrote:
> > +#define ASPEED_AST2700_SCU_IC0_EN_REG	0x1d0
> > +#define ASPEED_AST2700_SCU_IC0_STS_REG	0x1d4
> > +#define ASPEED_AST2700_SCU_IC0_SHIFT	0
> > +#define ASPEED_AST2700_SCU_IC0_ENABLE	\
> > +	GENMASK(3, ASPEED_AST2700_SCU_IC0_SHIFT)
> 
> Let it stick out, you have 100 characters
Yes, will update to
#define ASPEED_AST2700_SCU_IC0_ENABLE   GENMASK(3, ASPEED_AST2700_SCU_IC0_SHIFT)
And another question, in original code define for AST2600, can I also modify it in this patch? 
or I should be another patch?
#define ASPEED_AST2600_SCU_IC1_ENABLE   \
        GENMASK(5, ASPEED_AST2600_SCU_IC1_SHIFT)
> 
> >  struct aspeed_scu_ic {
> >  	unsigned long irq_enable;
> >  	unsigned long irq_shift;
> >  	unsigned int num_irqs;
> >  	unsigned int reg;
> > +	unsigned int en_reg;
> > +	unsigned int sts_reg;
> > +	bool split_ier_isr;
> 
> Please reformat this struct declaration according to:
> 
> https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#struct-de
> clarations-and-initializers

Will update struct aspeed_scu_ic to following.

struct aspeed_scu_ic {
        unsigned long           irq_enable;
        unsigned long           irq_shift;
        unsigned int            num_irqs;
        unsigned int            reg;
        unsigned int            en_reg;
        unsigned int            sts_reg;
        bool                    split_ier_isr;
        struct regmap           *scu;
        struct irq_domain       *irq_domain;
};
> 
> >  	struct regmap *scu;
> >  	struct irq_domain *irq_domain;
> >  };
> > @@ -52,33 +83,51 @@ static void aspeed_scu_ic_irq_handler(struct
> irq_desc *desc)
> >  	unsigned long status;
> >  	struct aspeed_scu_ic *scu_ic = irq_desc_get_handler_data(desc);
> >  	struct irq_chip *chip = irq_desc_get_chip(desc);
> > -	unsigned int mask = scu_ic->irq_enable <<
> ASPEED_SCU_IC_STATUS_SHIFT;
> > +	unsigned int mask;
> 
> https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#variable-
> declarations

Will update by following.

struct aspeed_scu_ic *scu_ic;
struct irq_chip *chip;
unsigned long bit, enabled, max, status;
unsigned int sts, mask;

scu_ic = irq_desc_get_handler_data(desc);
chip = irq_desc_get_chip(desc);

> 
> >  	chained_irq_enter(chip, desc);
> >
> > -	/*
> > -	 * The SCU IC has just one register to control its operation and read
> > -	 * status. The interrupt enable bits occupy the lower 16 bits of the
> > -	 * register, while the interrupt status bits occupy the upper 16 bits.
> > -	 * The status bit for a given interrupt is always 16 bits shifted from
> > -	 * the enable bit for the same interrupt.
> > -	 * Therefore, perform the IRQ operations in the enable bit space by
> > -	 * shifting the status down to get the mapping and then back up to
> > -	 * clear the bit.
> > -	 */
> > -	regmap_read(scu_ic->scu, scu_ic->reg, &sts);
> > -	enabled = sts & scu_ic->irq_enable;
> > -	status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
> > -
> > -	bit = scu_ic->irq_shift;
> > -	max = scu_ic->num_irqs + bit;
> > -
> > -	for_each_set_bit_from(bit, &status, max) {
> > -		generic_handle_domain_irq(scu_ic->irq_domain,
> > -					  bit - scu_ic->irq_shift);
> > -
> > -		regmap_write_bits(scu_ic->scu, scu_ic->reg, mask,
> > -				  BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
> > +	if (scu_ic->split_ier_isr) {
> > +		mask = scu_ic->irq_enable;
> > +		regmap_read(scu_ic->scu, scu_ic->en_reg, &sts);
> > +		enabled = sts & scu_ic->irq_enable;
> > +		regmap_read(scu_ic->scu, scu_ic->sts_reg, &sts);
> > +		status = sts & enabled;
> > +
> > +		bit = scu_ic->irq_shift;
> > +		max = scu_ic->num_irqs + bit;
> > +
> > +		for_each_set_bit_from(bit, &status, max) {
> > +			generic_handle_domain_irq(scu_ic->irq_domain, bit -
> > +scu_ic->irq_shift);
> > +
> > +			regmap_write_bits(scu_ic->scu, scu_ic->sts_reg, mask, BIT(bit));
> > +		}
> > +	} else {
> > +		mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
> > +		/*
> > +		 * The SCU IC has just one register to control its operation and read
> > +		 * status. The interrupt enable bits occupy the lower 16 bits of the
> > +		 * register, while the interrupt status bits occupy the upper 16 bits.
> > +		 * The status bit for a given interrupt is always 16 bits shifted from
> > +		 * the enable bit for the same interrupt.
> > +		 * Therefore, perform the IRQ operations in the enable bit space by
> > +		 * shifting the status down to get the mapping and then back up to
> > +		 * clear the bit.
> > +		 */
> > +		regmap_read(scu_ic->scu, scu_ic->reg, &sts);
> > +		enabled = sts & scu_ic->irq_enable;
> > +		status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
> > +
> > +		bit = scu_ic->irq_shift;
> > +		max = scu_ic->num_irqs + bit;
> > +
> > +		for_each_set_bit_from(bit, &status, max) {
> > +			generic_handle_domain_irq(scu_ic->irq_domain,
> > +						  bit - scu_ic->irq_shift);
> > +
> > +			regmap_write_bits(scu_ic->scu, scu_ic->reg, mask,
> > +					  BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
> > +		}
> 
> This is horrible, really. Either rework the code so that both chips can share it
> with minimal conditionals or provide seperate handlers. It's not rocket science.

Yes, I will update by separate handlers.

older
static struct irq_chip aspeed_scu_ic_chip = {
	.name			= "aspeed-scu-ic",
	.irq_mask		= aspeed_scu_ic_irq_mask,
	.irq_unmask		= aspeed_scu_ic_irq_unmask,
	.irq_set_affinity	= aspeed_scu_ic_irq_set_affinity,
};
Add new 

static struct irq_chip ast2700_scu_ic_chip = {
	.name			= "aspeed-scu-ic",
	.irq_mask		= ast2700_scu_ic_irq_mask,
	.irq_unmask		= ast2700_scu_ic_irq_unmask,
	.irq_set_affinity	= ast2700_scu_ic_irq_set_affinity,
};

if (scu_ic->split_ier_isr)
    irq_set_chained_handler_and_data(irq, ast2700_scu_ic_irq_handler, scu_ic);
else
    irq_set_chained_handler_and_data(irq, aspeed_scu_ic_irq_handler,, scu_ic);

> 
> >  	chained_irq_exit(chip, desc);
> > @@ -87,30 +136,42 @@ static void aspeed_scu_ic_irq_handler(struct
> > irq_desc *desc)
> 
> >  static void aspeed_scu_ic_irq_mask(struct irq_data *data)  static
> > void aspeed_scu_ic_irq_unmask(struct irq_data *data)
> 
> >  {
> >  	struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
> >  	unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
> > -	unsigned int mask = bit |
> > -		(scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
> > -
> > -	/*
> > -	 * Status bits are cleared by writing 1. In order to prevent the unmask
> > -	 * operation from clearing the status bits, they should be under the
> > -	 * mask and written with 0.
> > -	 */
> > -	regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
> > +	unsigned int mask;
> > +
> > +	if (scu_ic->split_ier_isr) {
> > +		mask = bit;
> > +		regmap_update_bits(scu_ic->scu, scu_ic->en_reg, mask, bit);
> > +	} else {
> > +		mask = bit | (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
> > +
> > +		/*
> > +		 * Status bits are cleared by writing 1. In order to prevent the
> unmask
> > +		 * operation from clearing the status bits, they should be under the
> > +		 * mask and written with 0.
> > +		 */
> > +		regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
> > +	}
> 
> This also wants to be consolidated or seperated.
Yes, will do separated.
> 
> >  }
> >
> > +static int __init aspeed_ast2700_scu_ic0_of_init(struct device_node *node,
> > +						 struct device_node *parent)
> > +{
> > +	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
> > +
> > +	if (!scu_ic)
> > +		return -ENOMEM;
> > +
> > +	scu_ic->irq_enable = ASPEED_AST2700_SCU_IC0_ENABLE;
> > +	scu_ic->irq_shift = ASPEED_AST2700_SCU_IC0_SHIFT;
> > +	scu_ic->num_irqs = ASPEED_AST2700_SCU_IC0_NUM_IRQS;
> > +	scu_ic->split_ier_isr = true;
> > +	scu_ic->en_reg = ASPEED_AST2700_SCU_IC0_EN_REG;
> > +	scu_ic->sts_reg = ASPEED_AST2700_SCU_IC0_STS_REG;
> > +
> > +	return aspeed_scu_ic_of_init_common(scu_ic, node); }
> > +
> > +static int __init aspeed_ast2700_scu_ic1_of_init(struct device_node *node,
> > +						 struct device_node *parent)
> > +{
> > +	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
> > +
> > +	if (!scu_ic)
> > +		return -ENOMEM;
> > +
> > +	scu_ic->irq_enable = ASPEED_AST2700_SCU_IC1_ENABLE;
> > +	scu_ic->irq_shift = ASPEED_AST2700_SCU_IC1_SHIFT;
> > +	scu_ic->num_irqs = ASPEED_AST2700_SCU_IC1_NUM_IRQS;
> > +	scu_ic->split_ier_isr = true;
> > +	scu_ic->en_reg = ASPEED_AST2700_SCU_IC1_EN_REG;
> > +	scu_ic->sts_reg = ASPEED_AST2700_SCU_IC1_STS_REG;
> > +
> > +	return aspeed_scu_ic_of_init_common(scu_ic, node); }
> > +
> > +static int __init aspeed_ast2700_scu_ic2_of_init(struct device_node *node,
> > +						 struct device_node *parent)
> > +{
> > +	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
> > +
> > +	if (!scu_ic)
> > +		return -ENOMEM;
> > +
> > +	scu_ic->irq_enable = ASPEED_AST2700_SCU_IC2_ENABLE;
> > +	scu_ic->irq_shift = ASPEED_AST2700_SCU_IC2_SHIFT;
> > +	scu_ic->num_irqs = ASPEED_AST2700_SCU_IC2_NUM_IRQS;
> > +	scu_ic->split_ier_isr = true;
> > +	scu_ic->en_reg = ASPEED_AST2700_SCU_IC2_EN_REG;
> > +	scu_ic->sts_reg = ASPEED_AST2700_SCU_IC2_STS_REG;
> > +
> > +	return aspeed_scu_ic_of_init_common(scu_ic, node); }
> > +
> > +static int __init aspeed_ast2700_scu_ic3_of_init(struct device_node *node,
> > +						 struct device_node *parent)
> > +{
> > +	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
> > +
> > +	if (!scu_ic)
> > +		return -ENOMEM;
> > +
> > +	scu_ic->irq_enable = ASPEED_AST2700_SCU_IC3_ENABLE;
> > +	scu_ic->irq_shift = ASPEED_AST2700_SCU_IC3_SHIFT;
> > +	scu_ic->num_irqs = ASPEED_AST2700_SCU_IC3_NUM_IRQS;
> > +	scu_ic->split_ier_isr = true;
> > +	scu_ic->en_reg = ASPEED_AST2700_SCU_IC3_EN_REG;
> > +	scu_ic->sts_reg = ASPEED_AST2700_SCU_IC3_STS_REG;
> > +
> > +	return aspeed_scu_ic_of_init_common(scu_ic, node); }
> 
> You seriously have no better idea than this copy & pasta orgy?
> 
> static struct scu_variant variants = {
> 	SCU("aspeed,ast2400-scu-ic", ......, whatever...),
>         ...
> 	SCU("aspeed,ast2700-scu-ic0", 0x1D0, 0x1D4, 0, GENMASK(3, 0),
>             4, whatever...),
>         ...
> 	SCU("aspeed,ast2700-scu-ic3", 0x10C, 0x108, 0, GENMASK(1, 0),
>             2, ......),
> } __initdata;
> 
> static struct scu_variant *find_variant(struct device_node *node) {
>         for (int i = 0; i < ARRAY_SIZE(variant); i++) {
>         	if (!strcmp(variant[i].name, node->name))
>                 	return &variant[i];
> 	}
>         return NULL;
> }
> 
> static int __init ast_scu_of_init(struct device_node *node, struct device_node
> *parent) {
>         struct variant *v = find_variant(node);
> 
>         if (!v)
>           	...
> 
>         scu_ic = kzalloc(...);
>         *scu_ic = v->scu;
>         ...
> 
> You get the idea.
> 
Thanks, I will do rework first, then add AST2700. 

> This rework needs to come first and then you can add your new 2700 muck on
> top.
> 
> Thanks,
> 
>         tglx