Subject: Re: [RFC PATCH v2 09/11] powerpc: gamecube/wii: flipper interrupt controller support

From: Albert Herranz <[email-masked]>
Date: Tue, 01 Dec 2009 20:48:46 +0100

Segher Boessenkool wrote:
>> Add support for the interrupt controller included in the "Flipper"
>> chipset of the Nintendo GameCube video game console.
>> The same interrupt controller is also present in the "Hollywood" chipset
>> of the Nintendo Wii.
>>
>> Signed-off-by: Albert Herranz <[email-masked]>
> Acked-by: Segher Boessenkool <[email-masked]>
> 
>> ---
>> v1 -> v2
>> - Build always Flipper interrupt controller when GAMECUBE_COMMON and
>>   get rid of FLIPPER_PIC option. Suggestion by Grant Likely.
>> - Use NO_IRQ instead of -1. Suggestion by Benjamin Herrenschmidt.
>> - Write 0xffffffff instead of ~0 to clear interrupts.
>>   Suggestion by Segher Boessenkool.
>> - Use __fls instead of open coded asm. Suggestion by Segher Boessenkool.
>> - Use a write instead of a read/modify/write to ack interrupts.
>>   Suggestion by Segher Boessenkool and Benjamin Herrenschmidt.
>> - Use name instead of typename for struct irq_chip.
>> - Adapt to updated device tree.
>>
>>  arch/powerpc/platforms/embedded6xx/Makefile      |    1 +
>>  arch/powerpc/platforms/embedded6xx/flipper-pic.c |  263
>> ++++++++++++++++++++++
>>  arch/powerpc/platforms/embedded6xx/flipper-pic.h |   25 ++
>>  3 files changed, 289 insertions(+), 0 deletions(-)
>>  create mode 100644 arch/powerpc/platforms/embedded6xx/flipper-pic.c
>>  create mode 100644 arch/powerpc/platforms/embedded6xx/flipper-pic.h
>>
>> diff --git a/arch/powerpc/platforms/embedded6xx/Makefile
>> b/arch/powerpc/platforms/embedded6xx/Makefile
>> index 0ab7492..b80f47c 100644
>> --- a/arch/powerpc/platforms/embedded6xx/Makefile
>> +++ b/arch/powerpc/platforms/embedded6xx/Makefile
>> @@ -8,3 +8,4 @@ obj-$(CONFIG_PPC_HOLLY)        += holly.o
>>  obj-$(CONFIG_PPC_PRPMC2800)    += prpmc2800.o
>>  obj-$(CONFIG_PPC_C2K)        += c2k.o
>>  obj-$(CONFIG_USBGECKO_UDBG)    += usbgecko_udbg.o
>> +obj-$(CONFIG_GAMECUBE_COMMON)    += flipper-pic.o
>> diff --git a/arch/powerpc/platforms/embedded6xx/flipper-pic.c
>> b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
>> new file mode 100644
>> index 0000000..d596328
>> --- /dev/null
>> +++ b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
>> @@ -0,0 +1,263 @@
>> +/*
>> + * arch/powerpc/platforms/embedded6xx/flipper-pic.c
>> + *
>> + * Nintendo GameCube/Wii "Flipper" interrupt controller support.
>> + * Copyright (C) 2004-2009 The GameCube Linux Team
>> + * Copyright (C) 2007,2008,2009 Albert Herranz
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * as published by the Free Software Foundation; either version 2
>> + * of the License, or (at your option) any later version.
>> + *
>> + */
>> +#define DRV_MODULE_NAME "flipper-pic"
>> +#define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/irq.h>
>> +#include <linux/of.h>
>> +#include <asm/io.h>
>> +
>> +#include "flipper-pic.h"
>> +
>> +#define FLIPPER_NR_IRQS        32
>> +
>> +/*
>> + * Each interrupt has a corresponding bit in both
>> + * the Interrupt Cause (ICR) and Interrupt Mask (IMR) registers.
>> + *
>> + * Enabling/disabling an interrupt line involves setting/clearing
>> + * the corresponding bit in IMR.
>> + * Except for the RSW interrupt, all interrupts get deasserted
>> automatically
>> + * when the source deasserts the interrupt.
>> + */
>> +#define FLIPPER_ICR        0x00
>> +#define FLIPPER_ICR_RSS        (1<<16) /* reset switch state */
>> +
>> +#define FLIPPER_IMR        0x04
>> +
>> +#define FLIPPER_RESET        0x24
>> +
>> +
>> +/*
>> + * IRQ chip hooks.
>> + *
>> + */
>> +
>> +static void flipper_pic_mask_and_ack(unsigned int virq)
>> +{
>> +    int irq = virq_to_hw(virq);
>> +    void __iomem *io_base = get_irq_chip_data(virq);
>> +    u32 mask = 1 << irq;
>> +
>> +    clrbits32(io_base + FLIPPER_IMR, mask);
>> +    /* this is at least needed for RSW */
>> +    out_be32(io_base + FLIPPER_ICR, mask);
>> +}
>> +
>> +static void flipper_pic_ack(unsigned int virq)
>> +{
>> +    int irq = virq_to_hw(virq);
>> +    void __iomem *io_base = get_irq_chip_data(virq);
>> +
>> +    /* this is at least needed for RSW */
>> +    out_be32(io_base + FLIPPER_ICR, 1 << irq);
>> +}
>> +
>> +static void flipper_pic_mask(unsigned int virq)
>> +{
>> +    int irq = virq_to_hw(virq);
>> +    void __iomem *io_base = get_irq_chip_data(virq);
>> +
>> +    clrbits32(io_base + FLIPPER_IMR, 1 << irq);
>> +}
>> +
>> +static void flipper_pic_unmask(unsigned int virq)
>> +{
>> +    int irq = virq_to_hw(virq);
>> +    void __iomem *io_base = get_irq_chip_data(virq);
>> +
>> +    setbits32(io_base + FLIPPER_IMR, 1 << irq);
>> +}
>> +
>> +
>> +static struct irq_chip flipper_pic = {
>> +    .name        = "flipper-pic",
>> +    .ack        = flipper_pic_ack,
>> +    .mask_ack    = flipper_pic_mask_and_ack,
>> +    .mask        = flipper_pic_mask,
>> +    .unmask        = flipper_pic_unmask,
>> +};
>> +
>> +/*
>> + * IRQ host hooks.
>> + *
>> + */
>> +
>> +static struct irq_host *flipper_irq_host;
>> +
>> +static int flipper_pic_map(struct irq_host *h, unsigned int virq,
>> +               irq_hw_number_t hwirq)
>> +{
>> +    set_irq_chip_data(virq, h->host_data);
>> +    get_irq_desc(virq)->status |= IRQ_LEVEL;
>> +    set_irq_chip_and_handler(virq, &flipper_pic, handle_level_irq);
>> +    return 0;
>> +}
>> +
>> +static void flipper_pic_unmap(struct irq_host *h, unsigned int irq)
>> +{
>> +    set_irq_chip_data(irq, NULL);
>> +    set_irq_chip(irq, NULL);
>> +}
>> +
>> +static int flipper_pic_match(struct irq_host *h, struct device_node *np)
>> +{
>> +    return 1;
>> +}
>> +
>> +
>> +static struct irq_host_ops flipper_irq_host_ops = {
>> +    .map = flipper_pic_map,
>> +    .unmap = flipper_pic_unmap,
>> +    .match = flipper_pic_match,
>> +};
>> +
>> +/*
>> + * Platform hooks.
>> + *
>> + */
>> +
>> +static void __flipper_quiesce(void __iomem *io_base)
>> +{
>> +    /* mask and ack all IRQs */
>> +    out_be32(io_base + FLIPPER_IMR, 0x00000000);
>> +    out_be32(io_base + FLIPPER_ICR, 0xffffffff);
>> +}
>> +
>> +struct irq_host * __init flipper_pic_init(struct device_node *np)
>> +{
>> +    struct device_node *pi;
>> +    struct irq_host *irq_host = NULL;
>> +    struct resource res;
>> +    void __iomem *io_base;
>> +    int retval;
>> +
>> +    pi = of_get_parent(np);
>> +    if (!pi) {
>> +        pr_err("no parent found\n");
>> +        goto out;
>> +    }
>> +    if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
>> +        pr_err("unexpected parent compatible\n");
>> +        goto out;
>> +    }
>> +
>> +    retval = of_address_to_resource(pi, 0, &res);
>> +    if (retval) {
>> +        pr_err("no io memory range found\n");
>> +        goto out;
>> +    }
>> +    io_base = ioremap(res.start, resource_size(&res));
>> +
>> +    pr_info("controller at 0x%08x mapped to 0x%p\n", res.start,
>> io_base);
>> +
>> +    __flipper_quiesce(io_base);
>> +
>> +    irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, FLIPPER_NR_IRQS,
>> +                  &flipper_irq_host_ops, -1);

This -1 should be NO_IRQ too.
I'll fix this in the next version.

>> +    if (!irq_host) {
>> +        pr_err("failed to allocate irq_host\n");
>> +        return NULL;
>> +    }
>> +
>> +    irq_host->host_data = io_base;
>> +
>> +out:
>> +    return irq_host;
>> +}
>> +
>> +unsigned int flipper_pic_get_irq(void)
>> +{
>> +    void __iomem *io_base = flipper_irq_host->host_data;
>> +    int irq;
>> +    u32 irq_status;
>> +
>> +    irq_status = in_be32(io_base + FLIPPER_ICR) &
>> +             in_be32(io_base + FLIPPER_IMR);
>> +    if (irq_status == 0)
>> +        return NO_IRQ;    /* no more IRQs pending */
>> +
>> +    irq = __ffs(irq_status);
>> +    return irq_linear_revmap(flipper_irq_host, irq);
>> +}
>> +
>> +/*
>> + * Probe function.
>> + *
>> + */
>> +
>> +void __init flipper_pic_probe(void)
>> +{
>> +    struct device_node *np;
>> +
>> +    np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
>> +    BUG_ON(!np);
>> +
>> +    flipper_irq_host = flipper_pic_init(np);
>> +    BUG_ON(!flipper_irq_host);
>> +
>> +    irq_set_default_host(flipper_irq_host);
>> +
>> +    of_node_put(np);
>> +}
>> +
>> +/*
>> + * Misc functions related to the flipper chipset.
>> + *
>> + */
>> +
>> +/**
>> + * flipper_quiesce() - quiesce flipper irq controller
>> + *
>> + * Mask and ack all interrupt sources.
>> + *
>> + */
>> +void flipper_quiesce(void)
>> +{
>> +    void __iomem *io_base = flipper_irq_host->host_data;
>> +
>> +    __flipper_quiesce(io_base);
>> +}
>> +
>> +/*
>> + * Resets the platform.
>> + */
>> +void flipper_platform_reset(void)
>> +{
>> +    void __iomem *io_base;
>> +
>> +    if (flipper_irq_host && flipper_irq_host->host_data) {
>> +        io_base = flipper_irq_host->host_data;
>> +        out_8(io_base + FLIPPER_RESET, 0x00);
>> +    }
>> +}
>> +
>> +/*
>> + * Returns non-zero if the reset button is pressed.
>> + */
>> +int flipper_is_reset_button_pressed(void)
>> +{
>> +    void __iomem *io_base;
>> +    u32 icr;
>> +
>> +    if (flipper_irq_host && flipper_irq_host->host_data) {
>> +        io_base = flipper_irq_host->host_data;
>> +        icr = in_be32(io_base + FLIPPER_ICR);
>> +        return !(icr & FLIPPER_ICR_RSS);
>> +    }
>> +    return 0;
>> +}
>> +
>> diff --git a/arch/powerpc/platforms/embedded6xx/flipper-pic.h
>> b/arch/powerpc/platforms/embedded6xx/flipper-pic.h
>> new file mode 100644
>> index 0000000..e339186
>> --- /dev/null
>> +++ b/arch/powerpc/platforms/embedded6xx/flipper-pic.h
>> @@ -0,0 +1,25 @@
>> +/*
>> + * arch/powerpc/platforms/embedded6xx/flipper-pic.h
>> + *
>> + * Nintendo GameCube/Wii "Flipper" interrupt controller support.
>> + * Copyright (C) 2004-2009 The GameCube Linux Team
>> + * Copyright (C) 2007,2008,2009 Albert Herranz
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU General Public License
>> + * as published by the Free Software Foundation; either version 2
>> + * of the License, or (at your option) any later version.
>> + *
>> + */
>> +
>> +#ifndef __FLIPPER_PIC_H
>> +#define __FLIPPER_PIC_H
>> +
>> +unsigned int flipper_pic_get_irq(void);
>> +void __init flipper_pic_probe(void);
>> +
>> +void flipper_quiesce(void);
>> +void flipper_platform_reset(void);
>> +int flipper_is_reset_button_pressed(void);
>> +
>> +#endif

Cheers,
Albert