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Message-ID: <1d693fee-2804-01ec-f0a6-ef5ca1854b46@arm.com>
Date: Mon, 7 Aug 2017 14:21:22 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: Ludovic Barre <ludovic.Barre@...com>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>
Cc: Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...com>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/8] irqchip: stm32: add multi-bank management
On 07/07/17 08:26, Ludovic Barre wrote:
> From: Ludovic Barre <ludovic.barre@...com>
>
> -prepare to manage multi-bank
> -prepare to manage registers offset by compatible
>
> Signed-off-by: Ludovic Barre <ludovic.barre@...com>
> ---
> drivers/irqchip/irq-stm32-exti.c | 137 ++++++++++++++++++++++++++-------------
> 1 file changed, 91 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/irqchip/irq-stm32-exti.c b/drivers/irqchip/irq-stm32-exti.c
> index 491568c..308cef5 100644
> --- a/drivers/irqchip/irq-stm32-exti.c
> +++ b/drivers/irqchip/irq-stm32-exti.c
> @@ -14,27 +14,52 @@
> #include <linux/of_address.h>
> #include <linux/of_irq.h>
>
> -#define EXTI_IMR 0x0
> -#define EXTI_EMR 0x4
> -#define EXTI_RTSR 0x8
> -#define EXTI_FTSR 0xc
> -#define EXTI_SWIER 0x10
> -#define EXTI_PR 0x14
> +struct stm32_exti_bank {
> + u32 imr_ofst;
> + u32 emr_ofst;
> + u32 rtsr_ofst;
> + u32 ftsr_ofst;
> + u32 swier_ofst;
> + u32 pr_ofst;
> +
> + u32 irqs_mask;
> +};
This looks weird. On one hand, you have a set of offsets that are
typical of the HW, and yet you add to it a mask that is read from the HW
(and not hardcoded like the rest).
> +
> +static struct stm32_exti_bank stm32f4xx_exti_b1 = {
> + .imr_ofst = 0x00,
> + .emr_ofst = 0x04,
> + .rtsr_ofst = 0x08,
> + .ftsr_ofst = 0x0C,
> + .swier_ofst = 0x10,
> + .pr_ofst = 0x14,
> +};
And this prevents making this structure const, which it should be.
> +
> +static struct stm32_exti_bank *stm32f4xx_exti_banks[] = {
> + &stm32f4xx_exti_b1,
> +};
>
> static void stm32_irq_handler(struct irq_desc *desc)
> {
> struct irq_domain *domain = irq_desc_get_handler_data(desc);
> - struct irq_chip_generic *gc = domain->gc->gc[0];
> struct irq_chip *chip = irq_desc_get_chip(desc);
> + unsigned int virq, nbanks = domain->gc->num_chips;
> + struct irq_chip_generic *gc;
> + struct stm32_exti_bank *stm32_bank;
> unsigned long pending;
> - int n;
> + int n, i, irq_base = 0;
>
> chained_irq_enter(chip, desc);
>
> - while ((pending = irq_reg_readl(gc, EXTI_PR))) {
> - for_each_set_bit(n, &pending, BITS_PER_LONG) {
> - generic_handle_irq(irq_find_mapping(domain, n));
> - irq_reg_writel(gc, BIT(n), EXTI_PR);
> + for (i = 0; i < nbanks; i++, irq_base += BITS_PER_LONG) {
Are you guaranteed that all the interrupts are organised in a linear
way? No hole between them? Ever?
> + gc = irq_get_domain_generic_chip(domain, irq_base);
> + stm32_bank = gc->private;
> +
> + while ((pending = irq_reg_readl(gc, stm32_bank->pr_ofst))) {
> + for_each_set_bit(n, &pending, BITS_PER_LONG) {
> + virq = irq_find_mapping(domain, irq_base + n);
> + generic_handle_irq(virq);
> + irq_reg_writel(gc, BIT(n), stm32_bank->pr_ofst);
This code doesn't look very good. Since you already have the bank as
part of your gc structure, why don't you add a set of wrappers such as:
static void stm32_irq_write_pr(struct irq_chip_generic *gc, u32 val)
{
struct stm32_exti_bank *bank = gc->private;
irq_reg_writel(gc, val, bank->pr_ofst);
}
Nobody really want to know about this offset business, so just hide it
as much as possible.
> + }
> }
> }
>
> @@ -44,13 +69,14 @@ static void stm32_irq_handler(struct irq_desc *desc)
> static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
> {
> struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> - int pin = data->hwirq;
> + struct stm32_exti_bank *stm32_bank = gc->private;
> + int pin = data->hwirq % BITS_PER_LONG;
> u32 rtsr, ftsr;
>
> irq_gc_lock(gc);
>
> - rtsr = irq_reg_readl(gc, EXTI_RTSR);
> - ftsr = irq_reg_readl(gc, EXTI_FTSR);
> + rtsr = irq_reg_readl(gc, stm32_bank->rtsr_ofst);
> + ftsr = irq_reg_readl(gc, stm32_bank->ftsr_ofst);
>
> switch (type) {
> case IRQ_TYPE_EDGE_RISING:
> @@ -70,8 +96,8 @@ static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
> return -EINVAL;
> }
>
> - irq_reg_writel(gc, rtsr, EXTI_RTSR);
> - irq_reg_writel(gc, ftsr, EXTI_FTSR);
> + irq_reg_writel(gc, rtsr, stm32_bank->rtsr_ofst);
> + irq_reg_writel(gc, ftsr, stm32_bank->ftsr_ofst);
>
> irq_gc_unlock(gc);
>
> @@ -81,17 +107,18 @@ static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
> static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
> {
> struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> - int pin = data->hwirq;
> + struct stm32_exti_bank *stm32_bank = gc->private;
> + int pin = data->hwirq % BITS_PER_LONG;
> u32 emr;
>
> irq_gc_lock(gc);
>
> - emr = irq_reg_readl(gc, EXTI_EMR);
> + emr = irq_reg_readl(gc, stm32_bank->emr_ofst);
> if (on)
> emr |= BIT(pin);
> else
> emr &= ~BIT(pin);
> - irq_reg_writel(gc, emr, EXTI_EMR);
> + irq_reg_writel(gc, emr, stm32_bank->emr_ofst);
>
> irq_gc_unlock(gc);
>
> @@ -101,11 +128,12 @@ static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
> static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
> unsigned int nr_irqs, void *data)
> {
> - struct irq_chip_generic *gc = d->gc->gc[0];
> + struct irq_chip_generic *gc;
> struct irq_fwspec *fwspec = data;
> irq_hw_number_t hwirq;
>
> hwirq = fwspec->param[0];
> + gc = irq_get_domain_generic_chip(d, hwirq);
>
> irq_map_generic_chip(d, virq, hwirq);
> irq_domain_set_info(d, virq, hwirq, &gc->chip_types->chip, gc,
> @@ -129,8 +157,8 @@ struct irq_domain_ops irq_exti_domain_ops = {
> .free = stm32_exti_free,
> };
>
> -static int __init stm32_exti_init(struct device_node *node,
> - struct device_node *parent)
> +static int __init stm32_exti_init(struct stm32_exti_bank **stm32_exti_banks,
> + int bank_nr, struct device_node *node)
> {
> unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
> int nr_irqs, nr_exti, ret, i;
> @@ -144,23 +172,16 @@ static int __init stm32_exti_init(struct device_node *node,
> return -ENOMEM;
> }
>
> - /* Determine number of irqs supported */
> - writel_relaxed(~0UL, base + EXTI_RTSR);
> - nr_exti = fls(readl_relaxed(base + EXTI_RTSR));
> - writel_relaxed(0, base + EXTI_RTSR);
> -
> - pr_info("%s: %d External IRQs detected\n", node->full_name, nr_exti);
> -
> - domain = irq_domain_add_linear(node, nr_exti,
> + domain = irq_domain_add_linear(node, bank_nr * BITS_PER_LONG,
You used to size the domain with the number of *implemented* interrupts.
Now, it becomes something else. Why is that so? Also, is BITS_PER_LONG
the right macro? Shouldn't it be something like "IRQS_PER_BANK", or
something similar? Just in case someone recycles this block on a 64bit
CPU...
> &irq_exti_domain_ops, NULL);
> if (!domain) {
> pr_err("%s: Could not register interrupt domain.\n",
> - node->name);
> + node->name);
> ret = -ENOMEM;
> goto out_unmap;
> }
>
> - ret = irq_alloc_domain_generic_chips(domain, nr_exti, 1, "exti",
> + ret = irq_alloc_domain_generic_chips(domain, BITS_PER_LONG, 1, "exti",
And here, you're not multiplying it by the number of banks. Why?
> handle_edge_irq, clr, 0, 0);
> if (ret) {
> pr_err("%s: Could not allocate generic interrupt chip.\n",
> @@ -168,18 +189,35 @@ static int __init stm32_exti_init(struct device_node *node,
> goto out_free_domain;
> }
>
> - gc = domain->gc->gc[0];
> - gc->reg_base = base;
> - gc->chip_types->type = IRQ_TYPE_EDGE_BOTH;
> - gc->chip_types->chip.name = gc->chip_types[0].chip.name;
> - gc->chip_types->chip.irq_ack = irq_gc_ack_set_bit;
> - gc->chip_types->chip.irq_mask = irq_gc_mask_clr_bit;
> - gc->chip_types->chip.irq_unmask = irq_gc_mask_set_bit;
> - gc->chip_types->chip.irq_set_type = stm32_irq_set_type;
> - gc->chip_types->chip.irq_set_wake = stm32_irq_set_wake;
> - gc->chip_types->regs.ack = EXTI_PR;
> - gc->chip_types->regs.mask = EXTI_IMR;
> - gc->chip_types->handler = handle_edge_irq;
> + for (i = 0; i < bank_nr; i++) {
> + struct stm32_exti_bank *stm32_bank = stm32_exti_banks[i];
> + u32 irqs_mask;
> +
> + gc = irq_get_domain_generic_chip(domain, i * BITS_PER_LONG);
> +
> + gc->reg_base = base;
> + gc->chip_types->type = IRQ_TYPE_EDGE_BOTH;
> + gc->chip_types->chip.name = gc->chip_types[0].chip.name;
> + gc->chip_types->chip.irq_ack = irq_gc_ack_set_bit;
> + gc->chip_types->chip.irq_mask = irq_gc_mask_clr_bit;
> + gc->chip_types->chip.irq_unmask = irq_gc_mask_set_bit;
> + gc->chip_types->chip.irq_set_type = stm32_irq_set_type;
> + gc->chip_types->chip.irq_set_wake = stm32_irq_set_wake;
> + gc->chip_types->regs.ack = stm32_bank->pr_ofst;
> + gc->chip_types->regs.mask = stm32_bank->imr_ofst;
> + gc->chip_types->handler = handle_edge_irq;
> + gc->private = stm32_bank;
> +
> + /* Determine number of irqs supported */
> + writel_relaxed(~0UL, base + stm32_bank->rtsr_ofst);
> + irqs_mask = readl_relaxed(base + stm32_bank->rtsr_ofst);
> + stm32_bank->irqs_mask = irqs_mask;
> + nr_exti = fls(readl_relaxed(base + stm32_bank->rtsr_ofst));
> + writel_relaxed(0, base + stm32_bank->rtsr_ofst);
> +
> + pr_info("%s: bank%d, External IRQs available:%#x\n",
> + node->full_name, i, irqs_mask);
> + }
>
> nr_irqs = of_irq_count(node);
> for (i = 0; i < nr_irqs; i++) {
> @@ -198,4 +236,11 @@ static int __init stm32_exti_init(struct device_node *node,
> return ret;
> }
>
> -IRQCHIP_DECLARE(stm32_exti, "st,stm32-exti", stm32_exti_init);
> +static int __init stm32f4_exti_of_init(struct device_node *np,
> + struct device_node *parent)
> +{
> + return stm32_exti_init(stm32f4xx_exti_banks,
> + ARRAY_SIZE(stm32f4xx_exti_banks), np);
> +}
> +
> +IRQCHIP_DECLARE(stm32f4_exti, "st,stm32-exti", stm32f4_exti_of_init);
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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