Re: [PATCH v2 2/2] irqchip: Add a driver for the Microsemi Ocelot controller

From: Marc Zyngier
Date: Thu Mar 22 2018 - 10:35:54 EST


On Thu, 22 Mar 2018 13:55:42 +0000,
Alexandre Belloni wrote:

Hi Alexandre,

>
> The Microsemi Ocelot SoC has a pretty simple IRQ controller in its ICPU
> block. Add a driver for it.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
> ---
> changes since v1:
> - removed license in favor of SPDX tag
> - reworked style as suggested by Thomas
>
> drivers/irqchip/Kconfig | 5 ++
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-mscc-ocelot.c | 109 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 115 insertions(+)
> create mode 100644 drivers/irqchip/irq-mscc-ocelot.c
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index d913aec85109..0270797765f9 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -286,6 +286,11 @@ config IRQ_MXS
> select IRQ_DOMAIN
> select STMP_DEVICE
>
> +config MSCC_OCELOT_IRQ
> + bool
> + select IRQ_DOMAIN
> + select GENERIC_IRQ_CHIP
> +
> config MVEBU_GICP
> bool
>
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index d27e3e3619e0..63d7bb434c33 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -72,6 +72,7 @@ obj-$(CONFIG_ARCH_SA1100) += irq-sa11x0.o
> obj-$(CONFIG_INGENIC_IRQ) += irq-ingenic.o
> obj-$(CONFIG_IMX_GPCV2) += irq-imx-gpcv2.o
> obj-$(CONFIG_PIC32_EVIC) += irq-pic32-evic.o
> +obj-$(CONFIG_MSCC_OCELOT_IRQ) += irq-mscc-ocelot.o
> obj-$(CONFIG_MVEBU_GICP) += irq-mvebu-gicp.o
> obj-$(CONFIG_MVEBU_ICU) += irq-mvebu-icu.o
> obj-$(CONFIG_MVEBU_ODMI) += irq-mvebu-odmi.o
> diff --git a/drivers/irqchip/irq-mscc-ocelot.c b/drivers/irqchip/irq-mscc-ocelot.c
> new file mode 100644
> index 000000000000..c71094de3cbd
> --- /dev/null
> +++ b/drivers/irqchip/irq-mscc-ocelot.c
> @@ -0,0 +1,109 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Microsemi Ocelot IRQ controller driver
> + *
> + * Copyright (c) 2017 Microsemi Corporation
> + */
> +#include <linux/bitops.h>
> +#include <linux/irq.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/interrupt.h>
> +
> +#define ICPU_CFG_INTR_INTR_STICKY 0x10
> +#define ICPU_CFG_INTR_INTR_ENA 0x18
> +#define ICPU_CFG_INTR_INTR_ENA_CLR 0x1c
> +#define ICPU_CFG_INTR_INTR_ENA_SET 0x20
> +#define ICPU_CFG_INTR_DST_INTR_IDENT(x) (0x38 + 0x4 * (x))
> +#define ICPU_CFG_INTR_INTR_TRIGGER(x) (0x5c + 0x4 * (x))
> +
> +#define OCELOT_NR_IRQ 24
> +
> +static void ocelot_irq_unmask(struct irq_data *data)
> +{
> + struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
> + struct irq_chip_type *ct = irq_data_get_chip_type(data);
> + unsigned int mask = data->mask;
> + u32 val;
> +
> + irq_gc_lock(gc);
> + val = irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(0)) |
> + irq_reg_readl(gc, ICPU_CFG_INTR_INTR_TRIGGER(1));
> + if (!(val & mask))
> + irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_STICKY);
> +
> + *ct->mask_cache &= ~mask;
> + irq_reg_writel(gc, mask, ICPU_CFG_INTR_INTR_ENA_SET);
> + irq_gc_unlock(gc);
> +}
> +
> +static void ocelot_irq_handler(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct irq_domain *d = irq_desc_get_handler_data(desc);
> + struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, 0);
> + u32 reg = irq_reg_readl(gc, ICPU_CFG_INTR_DST_INTR_IDENT(0));
> +
> + chained_irq_enter(chip, desc);
> +
> + while (reg) {
> + u32 hwirq = __fls(reg);
> +
> + generic_handle_irq(irq_find_mapping(d, hwirq));
> + reg &= ~(BIT(hwirq));
> + }
> +
> + chained_irq_exit(chip, desc);
> +}
> +
> +static int __init ocelot_irq_init(struct device_node *node,
> + struct device_node *parent)
> +{
> + struct irq_domain *domain;
> + struct irq_chip_generic *gc;
> + int parent_irq, ret;
> +
> + domain = irq_domain_add_linear(node, OCELOT_NR_IRQ,
> + &irq_generic_chip_ops, NULL);
> + if (!domain) {
> + pr_err("%s: unable to add irq domain\n", node->name);
> + return -ENOMEM;
> + }
> +
> + ret = irq_alloc_domain_generic_chips(domain, OCELOT_NR_IRQ, 1,
> + "icpu", handle_level_irq,
> + 0, 0, 0);
> + if (ret) {
> + pr_err("%s: unable to alloc irq domain gc\n", node->name);
> + return ret;

You're now leaking the allocated domain.

> + }
> +
> + gc = irq_get_domain_generic_chip(domain, 0);
> + gc->reg_base = of_iomap(node, 0);
> + if (!gc->reg_base) {
> + pr_err("%s: unable to map resource\n", node->name);
> + return -ENOMEM;

And here the chip.

> + }
> +
> + gc->chip_types[0].regs.ack = ICPU_CFG_INTR_INTR_STICKY;
> + gc->chip_types[0].regs.mask = ICPU_CFG_INTR_INTR_ENA_CLR;
> + gc->chip_types[0].chip.irq_ack = irq_gc_ack_set_bit;
> + gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
> + gc->chip_types[0].chip.irq_unmask = ocelot_irq_unmask;
> +
> + /* Mask and ack all interrupts */
> + irq_reg_writel(gc, 0, ICPU_CFG_INTR_INTR_ENA);
> + irq_reg_writel(gc, 0xffffffff, ICPU_CFG_INTR_INTR_STICKY);
> +
> + parent_irq = irq_of_parse_and_map(node, 0);
> + if (!parent_irq)

and here the ioremap space. You could also check that parent is
non-NULL early on, just in case...

> + return -EINVAL;
> +
> + irq_set_chained_handler_and_data(parent_irq, ocelot_irq_handler,
> + domain);
> +
> + return 0;
> +}
> +IRQCHIP_DECLARE(ocelot_icpu, "mscc,ocelot-icpu-intr", ocelot_irq_init);
> --
> 2.16.2
>

If you rework the error handling quickly, I'll queue this for 4.17. It
is quite refreshing to see an irqchip with only 3 functions...

Thanks,

M.

--
Jazz is not dead, it just smell funny.