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Date:   Mon, 30 Mar 2020 09:45:10 +0100
From:   Marc Zyngier <maz@kernel.org>
To:     Michal Simek <michal.simek@xilinx.com>
Cc:     linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Stefan Asserhall <stefan.asserhall@xilinx.com>,
        x86 <x86@kernel.org>, Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [tip: irq/core] irqchip/xilinx: Enable generic irq multi handler
In-Reply-To: <083ad708-ea4d-ed53-598e-84d911ca4177@xilinx.com>
References: <20200317125600.15913-4-mubin.usman.sayyed@xilinx.com>
 <158551357076.28353.1716269552245308352.tip-bot2@tip-bot2>
 <083ad708-ea4d-ed53-598e-84d911ca4177@xilinx.com>
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On 2020-03-30 09:32, Michal Simek wrote:
> Hi Thomas and Marc,
> 
> On 29. 03. 20 22:26, tip-bot2 for Michal Simek wrote:
>> The following commit has been merged into the irq/core branch of tip:
>> 
>> Commit-ID:     a0789993bf8266e62fea6b4613945ba081c71e7d
>> Gitweb:        
>> https://git.kernel.org/tip/a0789993bf8266e62fea6b4613945ba081c71e7d
>> Author:        Michal Simek <michal.simek@xilinx.com>
>> AuthorDate:    Tue, 17 Mar 2020 18:25:59 +05:30
>> Committer:     Marc Zyngier <maz@kernel.org>
>> CommitterDate: Sun, 22 Mar 2020 11:52:53
>> 
>> irqchip/xilinx: Enable generic irq multi handler
>> 
>> Register default arch handler via driver instead of directly pointing 
>> to
>> xilinx intc controller. This patch makes architecture code more 
>> generic.
>> 
>> Driver calls generic domain specific irq handler which does the most 
>> of
>> things self. Also get rid of concurrent_irq counting which hasn't been
>> exported anywhere.
>> Based on this loop was also optimized by using do/while loop instead 
>> of
>> goto loop.
>> 
>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> Reviewed-by: Stefan Asserhall <stefan.asserhall@xilinx.com>
>> Link: 
>> https://lore.kernel.org/r/20200317125600.15913-4-mubin.usman.sayyed@xilinx.com
>> ---
>>  arch/microblaze/Kconfig           |  2 ++-
>>  arch/microblaze/include/asm/irq.h |  3 +---
>>  arch/microblaze/kernel/irq.c      | 21 +-------------------
>>  drivers/irqchip/irq-xilinx-intc.c | 34 +++++++++++++++++-------------
>>  4 files changed, 23 insertions(+), 37 deletions(-)
>> 
>> diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
>> index 6a331bd..242f58e 100644
>> --- a/arch/microblaze/Kconfig
>> +++ b/arch/microblaze/Kconfig
>> @@ -47,6 +47,8 @@ config MICROBLAZE
>>  	select CPU_NO_EFFICIENT_FFS
>>  	select MMU_GATHER_NO_RANGE if MMU
>>  	select SPARSE_IRQ
>> +	select GENERIC_IRQ_MULTI_HANDLER
>> +	select HANDLE_DOMAIN_IRQ
>> 
>>  # Endianness selection
>>  choice
>> diff --git a/arch/microblaze/include/asm/irq.h 
>> b/arch/microblaze/include/asm/irq.h
>> index eac2fb4..5166f08 100644
>> --- a/arch/microblaze/include/asm/irq.h
>> +++ b/arch/microblaze/include/asm/irq.h
>> @@ -14,7 +14,4 @@
>>  struct pt_regs;
>>  extern void do_IRQ(struct pt_regs *regs);
>> 
>> -/* should be defined in each interrupt controller driver */
>> -extern unsigned int xintc_get_irq(void);
>> -
>>  #endif /* _ASM_MICROBLAZE_IRQ_H */
>> diff --git a/arch/microblaze/kernel/irq.c 
>> b/arch/microblaze/kernel/irq.c
>> index 903dad8..0b37dde 100644
>> --- a/arch/microblaze/kernel/irq.c
>> +++ b/arch/microblaze/kernel/irq.c
>> @@ -20,29 +20,10 @@
>>  #include <linux/irqchip.h>
>>  #include <linux/of_irq.h>
>> 
>> -static u32 concurrent_irq;
>> -
>>  void __irq_entry do_IRQ(struct pt_regs *regs)
>>  {
>> -	unsigned int irq;
>> -	struct pt_regs *old_regs = set_irq_regs(regs);
>>  	trace_hardirqs_off();
>> -
>> -	irq_enter();
>> -	irq = xintc_get_irq();
>> -next_irq:
>> -	BUG_ON(!irq);
>> -	generic_handle_irq(irq);
>> -
>> -	irq = xintc_get_irq();
>> -	if (irq != -1U) {
>> -		pr_debug("next irq: %d\n", irq);
>> -		++concurrent_irq;
>> -		goto next_irq;
>> -	}
>> -
>> -	irq_exit();
>> -	set_irq_regs(old_regs);
>> +	handle_arch_irq(regs);
>>  	trace_hardirqs_on();
>>  }
>> 
>> diff --git a/drivers/irqchip/irq-xilinx-intc.c 
>> b/drivers/irqchip/irq-xilinx-intc.c
>> index 1d3d273..ea74181 100644
>> --- a/drivers/irqchip/irq-xilinx-intc.c
>> +++ b/drivers/irqchip/irq-xilinx-intc.c
>> @@ -124,20 +124,6 @@ static unsigned int xintc_get_irq_local(struct 
>> xintc_irq_chip *irqc)
>>  	return irq;
>>  }
>> 
>> -unsigned int xintc_get_irq(void)
>> -{
>> -	unsigned int irq = -1;
>> -	u32 hwirq;
>> -
>> -	hwirq = xintc_read(primary_intc, IVR);
>> -	if (hwirq != -1U)
>> -		irq = irq_find_mapping(primary_intc->root_domain, hwirq);
>> -
>> -	pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);
>> -
>> -	return irq;
>> -}
>> -
>>  static int xintc_map(struct irq_domain *d, unsigned int irq, 
>> irq_hw_number_t hw)
>>  {
>>  	struct xintc_irq_chip *irqc = d->host_data;
>> @@ -177,6 +163,25 @@ static void xil_intc_irq_handler(struct irq_desc 
>> *desc)
>>  	chained_irq_exit(chip, desc);
>>  }
>> 
>> +static void xil_intc_handle_irq(struct pt_regs *regs)
>> +{
>> +	u32 hwirq;
>> +	struct xintc_irq_chip *irqc = primary_intc;
>> +
>> +	do {
>> +		hwirq = xintc_read(irqc, IVR);
>> +		if (likely(hwirq != -1U)) {
>> +			int ret;
>> +
>> +			ret = handle_domain_irq(irqc->root_domain, hwirq, regs);
>> +			WARN_ONCE(ret, "Unhandled HWIRQ %d\n", hwirq);
>> +			continue;
>> +		}
>> +
>> +		break;
>> +	} while (1);
>> +}
>> +
>>  static int __init xilinx_intc_of_init(struct device_node *intc,
>>  					     struct device_node *parent)
>>  {
>> @@ -246,6 +251,7 @@ static int __init xilinx_intc_of_init(struct 
>> device_node *intc,
>>  	} else {
>>  		primary_intc = irqc;
>>  		irq_set_default_host(primary_intc->root_domain);
>> +		set_handle_irq(xil_intc_handle_irq);
>>  	}
>> 
>>  	return 0;
>> 
> 
> Stephen reported compilation issue when this patch is applied because 
> of
> removal of xintc_get_irq() which is also used by ancient ppc405/ppc440
> xilinx platforms. I have reported this twice to Marc already last week.

Did you? I can't possibly find these emails.

> On Friday I have also send v1 of removal of that platforms (need to 
> send v2)
> https://lore.kernel.org/alsa-devel/cover.1585311091.git.michal.simek@xilinx.com/

You want to remove exising platforms two days before the start of the 
merge window?
I don't think this is acceptable with such short notice.

> That's why please really consider next steps and let us know.

I think the only option is to revert (at least partially) the Xilinx 
series.

         M.
-- 
Jazz is not dead. It just smells funny...