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

[Marc Zyngier]

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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