Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Received-SPF: Pass (protection.outlook.com: domain of xilinx.com designates
 149.199.60.83 as permitted sender) receiver=protection.outlook.com;
 client-ip=149.199.60.83; helo=xsj-pvapsmtpgw01;
Subject: Re: [PATCH v2] irqchip: xilinx: Add support for multiple instances
To:     Marc Zyngier <maz@kernel.org>,
        Michal Simek <michal.simek@xilinx.com>
Cc:     Mubin Usman Sayyed <mubin.usman.sayyed@xilinx.com>,
        tglx@linutronix.de, jason@lakedaemon.net,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        siva.durga.paladugu@xilinx.com, anirudha.sarangi@xilinx.com
References: <1580911535-19415-1-git-send-email-mubin.usman.sayyed@xilinx.com>
 <b8e7b9120bc6cd306bda3347cde117ff@kernel.org>
 <3d6077c1-2b13-acc6-e8f4-3d1ab23dc159@xilinx.com>
 <8b5c5b5d601856ddc3f4388e267c4cd0@kernel.org>
 <575c6350-139b-65b9-f9e2-2633656baa85@xilinx.com>
 <a3008824af22411034a6172cf09b450f@kernel.org>
From:   Michal Simek <michal.simek@xilinx.com>
Message-ID: <37ff3e76-a188-753e-182c-5c30069b8607@xilinx.com>
Date:   Thu, 6 Feb 2020 10:17:50 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.4.1
MIME-Version: 1.0
In-Reply-To: <a3008824af22411034a6172cf09b450f@kernel.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Feb 2020 09:18:04.4842
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 804e7aa1-f80b-4417-ff5d-08d7aae578c4
X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.83];Helo=[xsj-pvapsmtpgw01]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR02MB2835
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 06. 02. 20 10:15, Marc Zyngier wrote:
> On 2020-02-06 09:11, Michal Simek wrote:
>> On 06. 02. 20 10:09, Marc Zyngier wrote:
>>> On 2020-02-06 07:06, Michal Simek wrote:
>>>> On 05. 02. 20 17:53, Marc Zyngier wrote:
>>>>> On 2020-02-05 14:05, Mubin Usman Sayyed wrote:
>>>
>>> [...]
>>>
>>>>>>  unsigned int xintc_get_irq(void)
>>>>>>  {
>>>>>> -       unsigned int hwirq, irq = -1;
>>>>>> +       int hwirq, irq = -1;
>>>>>>
>>>>>> -       hwirq = xintc_read(IVR);
>>>>>> +       hwirq = xintc_read(primary_intc->base + IVR);
>>>>>>         if (hwirq != -1U)
>>>>>> -               irq = irq_find_mapping(xintc_irqc->root_domain,
>>>>>> hwirq);
>>>>>> +               irq = irq_find_mapping(primary_intc->root_domain,
>>>>>> hwirq);
>>>>>>
>>>>>>         pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);
>>>>>
>>>>> I have the ugly feeling I'm reading the same code twice... Surely you
>>>>> can
>>>>> make these two functions common code.
>>>>
>>>> I have some questions regarding this.
>>>> I have updated one patchset which is adding support for Microblaze SMP.
>>>> And when I was looking at current wiring of this driver I have decided
>>>> to change it.
>>>>
>>>> I have enabled  GENERIC_IRQ_MULTI_HANDLER and HANDLE_DOMAIN_IRQ.
>>>> This driver calls set_handle_irq(xil_intc_handle_irq)
>>>> and MB do_IRQ() call handle_arch_irq()
>>>> and IRQ routine here is using handle_domain_irq().
>>>>
>>>> I would expect that this chained IRQ handler can also use
>>>> handle_domain_irq().
>>>>
>>>> Is that correct understanding?
>>>
>>> handle_domain_irq() implies that you have a set of pt_regs, representing
>>> the context you interrupted. You can't fake that up, so I can't see how
>>> you use it in a chained context.
>>
>> ok. What's your recommendation for chained controller? Just go with
>> irq_find_mapping?
> 
> For now, yes. I have (distant) plans to improve this.

Thanks.
Michal