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SubjectRe: [PATCH v4 07/13] irqchip: ti-sci-intr: Add support for Interrupt Router driver
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Hi Marc,

On 16/01/19 10:46 PM, Marc Zyngier wrote:
> [Still in the process of sorting out my email - don't ask]
>
> On 27/12/2018 06:13, Lokesh Vutla wrote:
>> Texas Instruments' K3 generation SoCs has an IP Interrupt Router
>> that does allows for redirection of input interrupts to host
>> interrupt controller. Interrupt Router inputs are either from a
>> peripheral or from an Interrupt Aggregator which is another
>> interrupt controller.
>>
>> Configuration of the interrupt router registers can only be done by
>> a system co-processor and the driver needs to send a message to this
>> co processor over TISCI protocol.
>>
>> Add support for Interrupt Router driver over TISCI protocol.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>> MAINTAINERS | 1 +
>> drivers/irqchip/Kconfig | 11 ++
>> drivers/irqchip/Makefile | 1 +
>> drivers/irqchip/irq-ti-sci-intr.c | 310 ++++++++++++++++++++++++++++++
>> 4 files changed, 323 insertions(+)
>> create mode 100644 drivers/irqchip/irq-ti-sci-intr.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 8c7513b02d50..4480eb2fe851 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -15024,6 +15024,7 @@ F: Documentation/devicetree/bindings/clock/ti,sci-clk.txt
>> F: drivers/clk/keystone/sci-clk.c
>> F: drivers/reset/reset-ti-sci.c
>> F: Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>> +F: drivers/irqchip/irq-ti-sci-intr.c
>>
>> Texas Instruments ASoC drivers
>> M: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
>> index 3d1e60779078..a8d9bed0254b 100644
>> --- a/drivers/irqchip/Kconfig
>> +++ b/drivers/irqchip/Kconfig
>> @@ -406,6 +406,17 @@ config IMX_IRQSTEER
>> help
>> Support for the i.MX IRQSTEER interrupt multiplexer/remapper.
>>
>> +config TI_SCI_INTR_IRQCHIP
>> + bool
>> + depends on TI_SCI_PROTOCOL && ARCH_K3
>> + select IRQ_DOMAIN
>> + select IRQ_DOMAIN_HIERARCHY
>> + help
>> + This enables the irqchip driver support for K3 Interrupt router
>> + over TI System Control Interface available on some new TI's SoCs.
>> + If you wish to use interrupt router irq resources managed by the
>> + TI System Controller, say Y here. Otherwise, say N.
>> +
>> endmenu
>>
>> config SIFIVE_PLIC
>> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
>> index c93713d24b86..b4ff376a08ef 100644
>> --- a/drivers/irqchip/Makefile
>> +++ b/drivers/irqchip/Makefile
>> @@ -94,3 +94,4 @@ obj-$(CONFIG_CSKY_APB_INTC) += irq-csky-apb-intc.o
>> obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
>> obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
>> obj-$(CONFIG_MADERA_IRQ) += irq-madera.o
>> +obj-$(CONFIG_TI_SCI_INTR_IRQCHIP) += irq-ti-sci-intr.o
>> diff --git a/drivers/irqchip/irq-ti-sci-intr.c b/drivers/irqchip/irq-ti-sci-intr.c
>> new file mode 100644
>> index 000000000000..a5396e08412c
>> --- /dev/null
>> +++ b/drivers/irqchip/irq-ti-sci-intr.c
>> @@ -0,0 +1,310 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Texas Instruments' K3 Interrupt Router irqchip driver
>> + *
>> + * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
>> + * Lokesh Vutla <lokeshvutla@ti.com>
>> + */
>> +
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/irqchip.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/module.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/irqdomain.h>
>> +#include <linux/soc/ti/ti_sci_protocol.h>
>> +
>> +#define TI_SCI_DEV_ID_MASK 0xffff
>> +#define TI_SCI_DEV_ID_SHIFT 16
>> +#define TI_SCI_IRQ_ID_MASK 0xffff
>> +#define TI_SCI_IRQ_ID_SHIFT 0
>> +#define TI_SCI_EVENT_IRQ BIT(0)
>> +
>> +#define HWIRQ_TO_DEVID(hwirq) (((hwirq) >> (TI_SCI_DEV_ID_SHIFT)) & \
>> + (TI_SCI_DEV_ID_MASK))
>> +#define HWIRQ_TO_IRQID(hwirq) ((hwirq) & (TI_SCI_IRQ_ID_MASK))
>> +#define FWSPEC_TO_HWIRQ(fwspec) (((fwspec->param[0] & TI_SCI_DEV_ID_MASK) << \
>> + TI_SCI_DEV_ID_SHIFT) | \
>> + (fwspec->param[1] & TI_SCI_IRQ_ID_MASK))
>> +
>> +/**
>> + * struct ti_sci_intr_irq_domain - Structure representing a TISCI based
>> + * Interrupt Router IRQ domain.
>> + * @sci: Pointer to TISCI handle
>> + * @dst_irq: TISCI resource pointer representing destination irq controller.
>> + * @dst_id: TISCI device ID of the destination irq controller.
>> + */
>> +struct ti_sci_intr_irq_domain {
>> + const struct ti_sci_handle *sci;
>> + struct ti_sci_resource *dst_irq;
>> + u16 dst_id;
>> +};
>> +
>> +static struct irq_chip ti_sci_intr_irq_chip = {
>> + .name = "INTR",
>> + .irq_eoi = irq_chip_eoi_parent,
>> + .irq_mask = irq_chip_mask_parent,
>> + .irq_unmask = irq_chip_unmask_parent,
>> + .irq_retrigger = irq_chip_retrigger_hierarchy,
>> + .irq_set_type = irq_chip_set_type_parent,
>> + .irq_set_affinity = irq_chip_set_affinity_parent,
>> +};
>> +
>> +/**
>> + * ti_sci_intr_irq_domain_translate() - Retrieve hwirq and type from
>> + * IRQ firmware specific handler.
>> + * @domain: Pointer to IRQ domain
>> + * @fwspec: Pointer to IRQ specific firmware structure
>> + * @hwirq: IRQ number identified by hardware
>> + * @type: IRQ type
>> + *
>> + * Return 0 if all went ok else appropriate error.
>> + */
>> +static int ti_sci_intr_irq_domain_translate(struct irq_domain *domain,
>> + struct irq_fwspec *fwspec,
>> + unsigned long *hwirq,
>> + unsigned int *type)
>> +{
>> + if (is_of_node(fwspec->fwnode)) {
>> + if (fwspec->param_count != 4)
>> + return -EINVAL;
>> +
>> + *hwirq = FWSPEC_TO_HWIRQ(fwspec);
>> + *type = fwspec->param[2];
>> +
>> + return 0;
>> + }
>
> From what I can see in the code used by this platform, there is
> absolutely no chance this will ever support any firmware interface other
> than DT. So I think you can loose the is_of_node check here.

Sure will drop it in next version.

>
> Another thing is that you do not seem to use the 4th parameter to the
> intspec. So what is it used for here?
>
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static inline void ti_sci_intr_delete_desc(struct ti_sci_intr_irq_domain *intr,
>
> So this is called "delete desc". What is desc? It seems to free an irq
> in the resource manager, so please call it something that matches what
> this does.

will change it to delete_irq.

>
>> + u16 src_id, u16 src_index,
>> + u16 dst_irq)
>> +{
>> + intr->sci->ops.rm_irq_ops.free_direct_irq(intr->sci, src_id, src_index,
>> + intr->dst_id, dst_irq);
>> +}
>> +
>> +/**
>> + * ti_sci_intr_irq_domain_free() - Free the specified IRQs from the domain.
>> + * @domain: Domain to which the irqs belong
>> + * @virq: Linux virtual IRQ to be freed.
>> + * @nr_irqs: Number of continuous irqs to be freed
>> + */
>> +static void ti_sci_intr_irq_domain_free(struct irq_domain *domain,
>> + unsigned int virq, unsigned int nr_irqs)
>> +{
>> + struct ti_sci_intr_irq_domain *intr = domain->host_data;
>> + struct irq_data *data, *parent_data;
>> + u64 flags;
>> + int i;
>> +
>> + intr = domain->host_data;
>> +
>> + for (i = 0; i < nr_irqs; i++) {
>> + data = irq_domain_get_irq_data(domain, virq + i);
>> + flags = (u64)irq_data_get_irq_chip_data(data);
>
> Are you guaranteed that this will only exist on a 64bit architecture?

most likely yes. But will use phys_addr_t to be more specific

>
>> + parent_data = irq_domain_get_irq_data(domain->parent, virq + i);
>> +
>> + if (!(flags & TI_SCI_EVENT_IRQ))
>> + ti_sci_intr_delete_desc(intr,
>> + HWIRQ_TO_DEVID(data->hwirq),
>> + HWIRQ_TO_IRQID(data->hwirq),
>> + parent_data->hwirq);
>> + ti_sci_release_resource(intr->dst_irq, parent_data->hwirq);
>> + irq_domain_free_irqs_parent(domain, virq + i, 1);
>
> Couldn't this be moved out of the loop so that you free nr_irqs directly
> since you seem to be assuming that they are continuous? But are they?
>
> Also, and depending on the context this is called from, it is pretty
> unlikely that you'll see nr_irqs!=1, the only case I know about being
> the PCI Multi-MSI train-wreck.

okay, ill drop the loop and consider only the case nr_irqs == 1

>
>> + irq_domain_reset_irq_data(data);
>> + }
>> +}
>> +
>> +/**
>> + * ti_sci_intr_allocate_gic_irq() - Allocate GIC specific IRQ
>> + * @domain: Point to the interrupt router IRQ domain
>> + * @dev: TISCI device IRQ generating the IRQ
>> + * @irq: IRQ offset within the device
>> + * @flags: Corresponding flags to the IRQ
>> + * @event_irq: Flag to tell if requested irq is from interrupt aggregator.
>> + *
>> + * Returns 0 if all went well else appropriate error pointer.
>> + */
>> +static int ti_sci_intr_allocate_gic_irq(struct irq_domain *domain,
>> + unsigned int virq, u16 dev, u16 irq,
>> + u32 flags, u8 event_irq)
>> +{
>> + struct ti_sci_intr_irq_domain *intr = domain->host_data;
>> + struct irq_fwspec fwspec;
>> + u16 dst_irq;
>> + int err;
>> +
>> + if (!irq_domain_get_of_node(domain->parent))
>> + return -EINVAL;
>> +
>> + dst_irq = ti_sci_get_free_resource(intr->dst_irq);
>> + if (dst_irq == TI_SCI_RESOURCE_NULL)
>> + return -EINVAL;
>> +
>> + fwspec.fwnode = domain->parent->fwnode;
>> + fwspec.param_count = 3;
>> + fwspec.param[0] = 0; /* SPI */
>> + fwspec.param[1] = dst_irq - 32; /* SPI offset */
>> + fwspec.param[2] = flags & IRQ_TYPE_SENSE_MASK;
>> +
>> + err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
>> + if (err)
>> + goto err_irqs;
>> +
>> + /* If event is requested then return */
>> + if (event_irq == TI_SCI_EVENT_IRQ)
>> + return 0;
>> +
>> + err = intr->sci->ops.rm_irq_ops.set_direct_irq(intr->sci, dev, irq,
>> + intr->dst_id, dst_irq);
>> + if (err) {
>> + pr_err("%s: IRQ allocation failed from src = %d, src_index = %d to dst_id = %d, dst_irq = %d",
>> + __func__, dev, irq, intr->dst_id, dst_irq);
>
> Do we really needs this error message? It doesn't seem to provide any
> useful information at this stage. I'd rather the terrible callback does
> the screaming if required.

okay will drop this error message.

>
>> + goto err_msg;
>> + }
>> +
>> + return 0;
>> +
>> +err_msg:
>> + irq_domain_free_irqs_parent(domain, virq, 1);
>> +err_irqs:
>> + ti_sci_release_resource(intr->dst_irq, dst_irq);
>> + return err;
>> +}
>> +
>> +/**
>> + * ti_sci_intr_irq_domain_alloc() - Allocate Interrupt router IRQs
>> + * @domain: Point to the interrupt router IRQ domain
>> + * @virq: Corresponding Linux virtual IRQ number
>> + * @nr_irqs: Continuous irqs to be allocated
>> + * @data: Pointer to firmware specifier
>> + *
>> + * Return 0 if all went well else appropriate error value.
>> + */
>> +static int ti_sci_intr_irq_domain_alloc(struct irq_domain *domain,
>> + unsigned int virq, unsigned int nr_irqs,
>> + void *data)
>> +{
>> + struct irq_fwspec *fwspec = data;
>> + u16 src_id, src_index;
>> + unsigned long hwirq;
>> + u8 event_irq;
>> + int i, err;
>> + u32 type;
>> +
>> + err = ti_sci_intr_irq_domain_translate(domain, fwspec, &hwirq, &type);
>> + if (err)
>> + return err;
>> +
>> + src_id = HWIRQ_TO_DEVID(hwirq);
>> + src_index = HWIRQ_TO_IRQID(hwirq);
>> + event_irq = fwspec->param[3];
>
> Ah, so this is where it is used. You could perform some sanitization,
> given that you're feeding this to other part of the system.

sure will add a check for fwspec->param[3].

Thanks and regards,
Lokesh

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