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SubjectRe: [PATCH 2/2] irqchip: ti-sci-intr: Add support for Interrupt Router driver
Date
Hi Marc,

On 10/6/2018 3:25 PM, Marc Zyngier wrote:
> Hi Lokesh,
>
> On Sat, 06 Oct 2018 08:28:12 +0100,
> Lokesh Vutla <lokeshvutla@ti.com> wrote:
>>
>> Texas Instruments' K3 generation SoCs has an IP Interrupt Router
>> that does allows for multiplexing 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.
>
> I assume that this co-processor only deals with the routing itself,
> and doesn't need to be talked to during interrupt processing, right?

Yes, that's right.

>
>>
>> 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 | 325 ++++++++++++++++++++++++++++++
>> 4 files changed, 338 insertions(+)
>> create mode 100644 drivers/irqchip/irq-ti-sci-intr.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index a23778b68d74..cf3c834f8cee 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -14626,6 +14626,7 @@ 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
>>
>> THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
>> M: Hans Verkuil <hverkuil@xs4all.nl>
>> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
>> index 96451b581452..9a965fe22043 100644
>> --- a/drivers/irqchip/Kconfig
>> +++ b/drivers/irqchip/Kconfig
>> @@ -374,6 +374,17 @@ config QCOM_PDC
>> Power Domain Controller driver to manage and configure wakeup
>> IRQs for Qualcomm Technologies Inc (QTI) mobile chips.
>>
>> +config TI_SCI_INTR_IRQCHIP
>> + tristate "TISCI based Interrupt Router irqchip driver"
>> + 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.
>
> I don't really see the point of making this user-selectable. If you're
> compiling support for a given platform, this platform configuration
> fragment should itself select the necessary dependencies for the
> system to work as expected. Here, you are leaving the choice to the
> user, with a 50% chance of getting a system that doesn't boot...

There are 2 reasons why I made it tristate:
- Not all interrupts go through this irqchip(At least in the AM6 SoC
using this). Most of the legacy peripherals still are directly connected
to GIC
- TI_SCI_PROTOCOL is defined as tristate.

If you still feel I should not make it user-selectable, I can drop it.

>
>> +
>> endmenu
>>
>> config SIFIVE_PLIC
>> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
>> index b822199445ff..44bf65606d60 100644
>> --- a/drivers/irqchip/Makefile
>> +++ b/drivers/irqchip/Makefile
>> @@ -89,3 +89,4 @@ obj-$(CONFIG_GOLDFISH_PIC) += irq-goldfish-pic.o
>> obj-$(CONFIG_NDS32) += irq-ativic32.o
>> obj-$(CONFIG_QCOM_PDC) += qcom-pdc.o
>> obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.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..f04fe6da1b09
>> --- /dev/null
>> +++ b/drivers/irqchip/irq-ti-sci-intr.c
>> @@ -0,0 +1,325 @@
>> +// 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_IS_EVENT_IRQ BIT(31)
>> +
>> +#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))
>
> nit: s/(HWIRQ)/(hwirq)/g

okay.

>
>> +
>> +/**
>> + * 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;
>> +};
>> +
>> +/**
>> + * struct ti_sci_intr_irq_desc - Description of an Interrupt Router IRQ
>> + * @src_id: TISCI device ID of the IRQ source
>> + * @src_index: IRQ source index within the device.
>> + * @dst_irq: Destination host IRQ.
>> + */
>> +struct ti_sci_intr_irq_desc {
>> + u16 src_id;
>> + u16 src_index;
>> + u16 dst_irq;
>> +};
>
> Oh great. So this is reinventing the GICv3 ITS, only for SPIs. :-(
>
> Now, this structure seems completely useless, see below.
>
>> +
>> +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 != 3)
>> + return -EINVAL;
>> +
>> + *hwirq = ((fwspec->param[0] & TI_SCI_DEV_ID_MASK) <<
>> + TI_SCI_DEV_ID_SHIFT) |
>> + (fwspec->param[1] & TI_SCI_IRQ_ID_MASK);
>
> Maybe it would make sense to have a macro that hides this:

okay.

>
> *hwirq = FWSPEC_TO_HWIRQ(fwspec);
>
>> + *type = fwspec->param[2];
>> +
>> + return 0;
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static inline void ti_sci_intr_delete_desc(struct ti_sci_intr_irq_domain *intr,
>> + struct ti_sci_intr_irq_desc *desc)
>> +{
>> + intr->sci->ops.rm_irq_ops.free_direct_irq(intr->sci, desc->src_id,
>> + desc->src_index,
>> + intr->dst_id, desc->dst_irq);
>
> This looks horrible. Why doesn't your firmware interface have a helper
> functions that hides this? Something like:
>
> ti_sci_free_direct_irq(intr, src_id, src_index, dst_irq);
>
> and you could even add some error checking.

All existing TISCI users follow the same convention, so I did not bother adding
any such wrapper. Will update TISCI with these wrappers and see what firmware
maintainer says.

>
>> + pr_debug("%s: IRQ deleted from src = %d, src_index = %d, to dst = %d, dst_irq = %d\n",
>> + __func__, desc->src_id, desc->src_index, intr->dst_id,
>> + desc->dst_irq);
>
> And put this where it belongs (in the helper function).
>
>> +}
>> +
>> +/**
>> + * 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 ti_sci_intr_irq_desc *desc;
>> + struct irq_data *data;
>> + int i;
>> +
>> + intr = domain->host_data;
>> +
>> + for (i = 0; i < nr_irqs; i++) {
>> + data = irq_domain_get_irq_data(domain, virq + i);
>> +
>> + desc = irq_data_get_irq_chip_data(data);
>> +
>> + ti_sci_intr_delete_desc(intr, desc);
>> + irq_domain_free_irqs_parent(domain, virq, 1);
>> + irq_domain_reset_irq_data(data);
>> + ti_sci_release_resource(intr->dst_irq, desc->dst_irq);
>> + kfree(desc);
>> + }
>> +}
>> +
>> +/**
>> + * 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
>> + *
>> + * Returns pointer to irq descriptor if all went well else appropriate
>> + * error pointer.
>> + */
>> +static struct ti_sci_intr_irq_desc *allocate_gic_irq(struct irq_domain *domain,
>> + unsigned int virq,
>> + u16 dev, u16 irq,
>> + u32 flags)
>> +{
>> + struct ti_sci_intr_irq_domain *intr = domain->host_data;
>> + struct ti_sci_intr_irq_desc *desc;
>> + struct irq_fwspec fwspec;
>> + int err;
>> +
>> + if (!irq_domain_get_of_node(domain->parent))
>> + return ERR_PTR(-EINVAL);
>> +
>> + desc = kzalloc(sizeof(*desc), GFP_KERNEL);
>> + if (!desc)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + desc->src_id = dev;
>> + desc->src_index = irq;
>> + desc->dst_irq = ti_sci_get_free_resource(intr->dst_irq);
>
> I don't think this structure serves any purpose. src_id and src_index
> are just a decomposition of hwirq. dst_irq is the GIC interrupt, which
> is stored... by the GIC driver. Also, it is worth realising that
> you're allocating per-interrupt data, but none of the per-interrupt
> callbacks are using it. In my book, that's a sure sign that this
> structure is pointless.

hmm..you are right, these 3 fields can be dropped completely.

>
> Am I missing anything here? >
>> +
>> + fwspec.fwnode = domain->parent->fwnode;
>> + fwspec.param_count = 3;
>> + fwspec.param[0] = 0; /* SPI */
>> + fwspec.param[1] = desc->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;
>> +
>> + pr_debug("%s: IRQ requested from src = %d, src_index = %d, to dst = %d, dst_irq = %d\n",
>> + __func__, desc->src_id, desc->src_index, intr->dst_id,
>> + desc->dst_irq);
>> +
>> + err = intr->sci->ops.rm_irq_ops.set_direct_irq(intr->sci, desc->src_id,
>> + desc->src_index,
>> + intr->dst_id,
>> + desc->dst_irq);
>
> Same remarks about the horrible interface.
>
>> + if (err) {
>> + pr_err("%s: IRQ allocation failed from src = %d, src_index = %d to dst_id = %d, dst_irq = %d",
>> + __func__, desc->src_id, desc->src_index, intr->dst_id,
>> + desc->dst_irq);
>> + goto err_msg;
>> + }
>> +
>> + return desc;
>> +
>> +err_msg:
>> + irq_domain_free_irqs_parent(domain, virq, 1);
>> +err_irqs:
>> + ti_sci_release_resource(intr->dst_irq, desc->dst_irq);
>> + kfree(desc);
>> + return ERR_PTR(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;
>> + struct ti_sci_intr_irq_desc *desc;
>> + unsigned long hwirq;
>> + u16 src_id, src_index;
>> + 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);
>> +
>> + for (i = 0; i < nr_irqs; i++) {
>> + desc = allocate_gic_irq(domain, virq + i, src_id, src_index + i,
>> + type);
>> + if (IS_ERR(desc))
>> + /* ToDO: Clean already allocated IRQs */
>> + return PTR_ERR(desc);
>
> Please address this. But it also worth realising that this code will
> never be called with nr_irqs!=1 (that's only for things like PCI
> Multi-MSI).

will fix it in v2.

>
>> +
>> + err = irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
>> + &ti_sci_intr_irq_chip,
>> + desc);
>> + if (err)
>> + return err;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static const struct irq_domain_ops ti_sci_intr_irq_domain_ops = {
>> + .alloc = ti_sci_intr_irq_domain_alloc,
>> + .free = ti_sci_intr_irq_domain_free,
>> + .translate = ti_sci_intr_irq_domain_translate,
>> +};
>> +
>> +static int ti_sci_intr_irq_domain_probe(struct platform_device *pdev)
>> +{
>> + struct irq_domain *parent_domain, *domain;
>> + struct ti_sci_intr_irq_domain *intr;
>> + struct device_node *parent_node;
>> + struct device *dev = &pdev->dev;
>> + int ret;
>> +
>> + parent_node = of_irq_find_parent(dev_of_node(dev));
>> + if (!parent_node) {
>> + dev_err(dev, "Failed to get IRQ parent node\n");
>> + return -ENODEV;
>> + }
>> +
>> + parent_domain = irq_find_host(parent_node);
>> + if (!parent_domain) {
>> + dev_err(dev, "Failed to find IRQ parent domain\n");
>> + return -ENODEV;
>> + }
>> +
>> + intr = devm_kzalloc(dev, sizeof(*intr), GFP_KERNEL);
>> + if (!intr)
>> + return -ENOMEM;
>> +
>> + intr->sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
>> + if (IS_ERR(intr->sci)) {
>> + ret = PTR_ERR(intr->sci);
>> + if (ret != -EPROBE_DEFER)
>> + dev_err(dev, "ti,sci read fail %d\n", ret);
>> + intr->sci = NULL;
>> + return ret;
>> + }
>> +
>> + intr->dst_irq = devm_ti_sci_get_of_resource(intr->sci, dev,
>> + "ti,sci-rm-range-girq");
>> + if (IS_ERR(intr->dst_irq)) {
>> + dev_err(dev, "Destination irq resource allocation failed\n");
>> + return PTR_ERR(intr->dst_irq);
>> + }
>> +
>> + ret = of_property_read_u32(dev_of_node(dev), "ti,sci-dst-id",
>> + (u32 *)&intr->dst_id);
>> + if (ret) {
>> + dev_err(dev, "missing 'ti,sci-dst-id' property\n");
>> + return -EINVAL;
>> + }
>
> Do you expect other drivers to require similar resource request? If
> so, It might be worth getting the firmware interface to do that
> work. Specially the "give me my SCI" part.

I tried to consolidate sci resource part under devm_ti_sci_get_of_resource() api
but dst-id is something that is used by irqchip driver. So couldn't consolidate
it and had to get it from dt in the driver probe.

Thanks and regards,
Lokesh

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