From: Lokesh Vutla <lokeshvutla@ti.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Nishanth Menon <nm@ti.com>,
Device Tree Mailing List <devicetree@vger.kernel.org>,
Grygorii Strashko <grygorii.strashko@ti.com>,
<jason@lakedaemon.net>, Peter Ujfalusi <peter.ujfalusi@ti.com>,
Sekhar Nori <nsekhar@ti.com>, <linux-kernel@vger.kernel.org>,
Tero Kristo <t-kristo@ti.com>, Rob Herring <robh+dt@kernel.org>,
Santosh Shilimkar <ssantosh@kernel.org>, <tglx@linutronix.de>,
Linux ARM Mailing List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 09/10] irqchip: ti-sci-inta: Add support for Interrupt Aggregator driver
Date: Sat, 27 Oct 2018 01:49:41 +0530 [thread overview]
Message-ID: <63ba5353-8470-b4c1-64a8-a1df5bf48614@ti.com> (raw)
In-Reply-To: <b3a71622-7734-04be-0b0c-38e9dc6542d4@ti.com>
Hi Marc,
[..snip..]
>> [...]
>>
>>>>> +/**
>>>>> + * ti_sci_inta_register_event() - Register a event to an interrupt aggregator
>>>>> + * @dev: Device pointer to source generating the event
>>>>> + * @src_id: TISCI device ID of the event source
>>>>> + * @src_index: Event source index within the device.
>>>>> + * @virq: Linux Virtual IRQ number
>>>>> + * @flags: Corresponding IRQ flags
>>>>> + * @ack_needed: If explicit clearing of event is required.
>>>>> + *
>>>>> + * Creates a new irq and attaches to IA domain if virq is not specified
>>>>> + * else attaches the event to vint corresponding to virq.
>>>>> + * When using TISCI within the client drivers, source indexes are always
>>>>> + * generated dynamically and cannot be represented in DT. So client
>>>>> + * drivers should call this API instead of platform_get_irq().
>>>>
>>>> NAK. Either this fits in the standard model, or we adapt the standard
>>>> model to catter for your particular use case. But we don't define a new,
>>>> TI specific API.
>>>>
>>>> I have a hunch that if the IDs are generated dynamically, then the model
>>>> we use for MSIs would fit this thing. I also want to understand what
>>>
>>> hmm..I haven't thought about using MSI. Will try to explore it. But
>>> the "struct msi_msg" is not applicable in this case as device does not
>>> write to a specific location.
>>
>> It doesn't need to. You can perfectly ignore the address field and
>> only be concerned with the data. We already have MSI users that do not
>> need programming of the doorbell address, just the data.
>
Just one more clarification.
First let me explain the IRQ routes a bit deeply. As I said earlier there are
three ways in which IRQ can flow in AM65x SoC
1) Device directly connected to GIC
- Device IRQ --> GIC
2) Device connected to INTR.
- Device IRQ --> INTR --> GIC
3) Devices connected to INTA.
- Device IRQ --> INTA --> INTR --> GIC
1 and 2 are straight forward and we use DT for IRQ representation. Coming to 3
the trickier part is that Input to INTA and output from INTA and dynamically
managed. To be more specific:
- By hardware design there are certain set of physical global events(interrupts)
attached to an INTA. Out of which a certain range are assigned to the current
linux host that can be queried from system-controller.
- Similarly out of all the INTA outputs(referenced as vints) a certain range can
be used by the current linux host.
So for configuring an IRQ route in case 3, the following steps are needed:
- Device id and device resource index for which the interrupt is needed
- A free event id from the range assigned to the INTA in this host context
- A free vint from the range assigned to the INTA in this host context
- A free gic IRQ from the range assigned to the INTR in this host context.
With the above information, linux should send a message to system-controller
using TISCI protocol. After policing the given information, system-controller
does the following:
- Attaches the interrupt(INTA input) to the device resource index
- Muxes the interrupt(INTA input) to corresponding vint(INTA output)
- Muxes the vint(INTR input) to GIC irq(INTR output).
For grouping of interrupts, the same vint number is to be passed to
system-controller for all the requests.
Keeping all the above in mind, I see the following as software IRQ Domain Hierarchy:
1) INTA multi MSI --> 2)INTA -->3) MSI --> 4) INTR -->5) GIC
INTA driver has to set a chained IRQ using virq allocated from its parent MSI.
This is to differentiate the grouped interrupts within INTA.
Inorder to cover the above two MSI domains, a new bus driver has to be created
as I couldn't find a fit with the existing bus drivers.
Does the above approach make sense? Please correct me if i am wrong.
Thanks and regards,
Lokesh
next prev parent reply other threads:[~2018-10-26 20:20 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-18 15:40 [PATCH v2 00/10] Add support for TISCI irqchip drivers Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 01/10] firmware: ti_sci: Add support to get TISCI handle using of_phandle Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 02/10] firmware: ti_sci: Add support for RM core ops Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 03/10] firmware: ti_sci: Add support for IRQ management Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 04/10] firmware: ti_sci: Add RM mapping table for am654 Lokesh Vutla
2018-10-18 20:42 ` Rob Herring
2018-10-18 15:40 ` [PATCH v2 05/10] firmware: ti_sci: Add helper apis to manage resources Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 06/10] dt-bindings: irqchip: Introduce TISCI Interrupt router bindings Lokesh Vutla
2018-10-25 18:45 ` Rob Herring
2018-10-26 6:38 ` Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 07/10] irqchip: ti-sci-intr: Add support for Interrupt Router driver Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 08/10] dt-bindings: irqchip: Introduce TISCI Interrupt Aggregator bindings Lokesh Vutla
2018-10-18 15:40 ` [PATCH v2 09/10] irqchip: ti-sci-inta: Add support for Interrupt Aggregator driver Lokesh Vutla
2018-10-19 15:22 ` Marc Zyngier
2018-10-22 14:35 ` Lokesh Vutla
2018-10-23 13:50 ` Marc Zyngier
2018-10-26 6:39 ` Lokesh Vutla
2018-10-26 20:19 ` Lokesh Vutla [this message]
2018-10-28 13:31 ` Marc Zyngier
2018-10-29 13:04 ` Lokesh Vutla
2018-11-01 7:55 ` Peter Ujfalusi
2018-11-01 9:00 ` Marc Zyngier
2018-11-01 9:14 ` Peter Ujfalusi
2018-11-05 8:08 ` Lokesh Vutla
2018-11-05 15:36 ` Marc Zyngier
2018-11-05 16:20 ` Lokesh Vutla
2018-11-05 16:44 ` Marc Zyngier
2018-11-05 17:56 ` Lokesh Vutla
2018-10-31 16:39 ` Grygorii Strashko
2018-10-31 18:21 ` Marc Zyngier
2018-10-31 18:38 ` Santosh Shilimkar
2018-10-31 18:42 ` Marc Zyngier
2018-10-31 18:48 ` Santosh Shilimkar
2018-10-31 20:33 ` Grygorii Strashko
2018-11-01 14:52 ` Marc Zyngier
2018-11-01 15:36 ` Grygorii Strashko
2018-11-01 9:09 ` Peter Ujfalusi
2018-10-22 10:42 ` Peter Ujfalusi
2018-10-22 10:43 ` Peter Ujfalusi
2018-10-18 15:40 ` [PATCH v2 10/10] soc: ti: am6: Enable interrupt controller drivers Lokesh Vutla
2018-10-22 20:39 ` [PATCH v2 00/10] Add support for TISCI irqchip drivers Santosh Shilimkar
2018-10-23 8:17 ` Lokesh Vutla
2018-10-23 8:27 ` Marc Zyngier
2018-10-23 17:34 ` Santosh Shilimkar
2018-10-26 6:39 ` Lokesh Vutla
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