Re: [PATCH v9 3/4] irqchip:create irq domain for each mbigen device

From: Marc Zyngier
Date: Thu Dec 03 2015 - 11:25:59 EST


On 23/11/15 03:15, MaJun wrote:
> From: Ma Jun <majun258@xxxxxxxxxx>
>
> For peripheral devices which connect to mbigen,mbigen is a interrupt
> controller. So, we create irq domain for each mbigen device and add
> mbigen irq domain into irq hierarchy structure.
>
> Signed-off-by: Ma Jun <majun258@xxxxxxxxxx>
> ---
> drivers/irqchip/irq-mbigen.c | 119 ++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 119 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/irqchip/irq-mbigen.c b/drivers/irqchip/irq-mbigen.c
> index 9f036c2..81ae61f 100644
> --- a/drivers/irqchip/irq-mbigen.c
> +++ b/drivers/irqchip/irq-mbigen.c
> @@ -16,13 +16,36 @@
> * along with this program. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#include <linux/interrupt.h>
> +#include <linux/irqchip.h>
> #include <linux/module.h>
> +#include <linux/msi.h>
> #include <linux/of_address.h>
> #include <linux/of_irq.h>
> #include <linux/of_platform.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
>
> +/* Interrupt numbers per mbigen node supported */
> +#define IRQS_PER_MBIGEN_NODE 128
> +
> +/* 64 irqs (Pin0-pin63) are reserved for each mbigen chip */
> +#define RESERVED_IRQ_PER_MBIGEN_CHIP 64
> +
> +/**
> + * In mbigen vector register
> + * bit[21:12]: event id value
> + * bit[11:0]: device id
> + */
> +#define IRQ_EVENT_ID_SHIFT 12
> +#define IRQ_EVENT_ID_MASK 0x3ff
> +
> +/* register range of each mbigen node */
> +#define MBIGEN_NODE_OFFSET 0x1000
> +
> +/* offset of vector register in mbigen node */
> +#define REG_MBIGEN_VEC_OFFSET 0x200
> +
> /**
> * struct mbigen_device - holds the information of mbigen device.
> *
> @@ -34,10 +57,94 @@ struct mbigen_device {
> void __iomem *base;
> };
>
> +static inline unsigned int get_mbigen_vec_reg(irq_hw_number_t hwirq)
> +{
> + unsigned int nid, pin;
> +
> + hwirq -= RESERVED_IRQ_PER_MBIGEN_CHIP;
> + nid = hwirq / IRQS_PER_MBIGEN_NODE + 1;
> + pin = hwirq % IRQS_PER_MBIGEN_NODE;
> +
> + return pin * 4 + nid * MBIGEN_NODE_OFFSET
> + + REG_MBIGEN_VEC_OFFSET;
> +}
> +
> +static struct irq_chip mbigen_irq_chip = {
> + .name = "mbigen-v2",
> +};
> +
> +static void mbigen_write_msg(struct msi_desc *desc, struct msi_msg *msg)
> +{
> + struct irq_data *d = irq_get_irq_data(desc->irq);
> + void __iomem *base = d->chip_data;
> + u32 val;
> +
> + base += get_mbigen_vec_reg(d->hwirq);
> + val = readl_relaxed(base);
> +
> + val &= ~(IRQ_EVENT_ID_MASK << IRQ_EVENT_ID_SHIFT);
> + val |= (msg->data << IRQ_EVENT_ID_SHIFT);
> +
> + writel_relaxed(val, base);

nit: It would be good to have a comment explaining why you do not need
to program the address of the doorbell...

> +}
> +
> +static int mbigen_domain_translate(struct irq_domain *d,
> + struct irq_fwspec *fwspec,
> + unsigned long *hwirq,
> + unsigned int *type)
> +{
> + if (is_of_node(fwspec->fwnode)) {
> + if (fwspec->param_count != 2)
> + return -EINVAL;
> +
> + *hwirq = fwspec->param[0];
> + *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> +
> + return 0;
> + }
> + return -EINVAL;
> +}
> +
> +static int mbigen_irq_domain_alloc(struct irq_domain *domain,
> + unsigned int virq,
> + unsigned int nr_irqs,
> + void *args)
> +{
> + struct irq_fwspec *fwspec = args;
> + irq_hw_number_t hwirq;
> + unsigned int type;
> + struct mbigen_device *mgn_chip;
> + int i, err;
> +
> + err = mbigen_domain_translate(domain, fwspec, &hwirq, &type);
> + if (err)
> + return err;
> +
> + err = platform_msi_domain_alloc(domain, virq, nr_irqs);
> + if (err)
> + return err;
> +
> + mgn_chip = platform_msi_get_host_data(domain);
> +
> + for (i = 0; i < nr_irqs; i++)
> + irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> + &mbigen_irq_chip, mgn_chip->base);
> +
> + return 0;
> +}
> +
> +static struct irq_domain_ops mbigen_domain_ops = {
> + .translate = mbigen_domain_translate,
> + .alloc = mbigen_irq_domain_alloc,
> + .free = irq_domain_free_irqs_common,
> +};
> +
> static int mbigen_device_probe(struct platform_device *pdev)
> {
> struct mbigen_device *mgn_chip;
> struct resource *res;
> + struct irq_domain *domain;
> + u32 num_msis;
>
> mgn_chip = devm_kzalloc(&pdev->dev, sizeof(*mgn_chip), GFP_KERNEL);
> if (!mgn_chip)
> @@ -50,6 +157,18 @@ static int mbigen_device_probe(struct platform_device *pdev)
> if (IS_ERR(mgn_chip->base))
> return PTR_ERR(mgn_chip->base);
>
> + /* If there is no "num-msis" property, assume 64... */
> + if (of_property_read_u32(pdev->dev.of_node, "num-msis", &num_msis) < 0)
> + num_msis = 64;

nit: Is that always true? This has been lifted from my dummy example, so
I wonder if that's what you actually want to do.

> +
> + domain = platform_msi_create_device_domain(&pdev->dev, num_msis,
> + mbigen_write_msg,
> + &mbigen_domain_ops,
> + mgn_chip);
> +
> + if (!domain)
> + return -ENOMEM;
> +
> platform_set_drvdata(pdev, mgn_chip);
>
> return 0;
>

Apart for the two above point,

Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>

M.
--
Jazz is not dead. It just smells funny...
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