MX51: add FIQ support for TZIC

MX51: add FIQ support for TZIC

[Peter Horton]

Add support for FIQ on MX51 TZIC.

(patch is against Sascha's "imx-for-2.6.38" branch)

Signed-off-by: Peter Horton <phorton@bitbox.co.uk>

--

diff --git a/arch/arm/plat-mxc/include/mach/entry-macro.S b/arch/arm/plat-mxc/include/mach/entry-macro.S
index aeb0869..c7dd4a9 100644
--- a/arch/arm/plat-mxc/include/mach/entry-macro.S
+++ b/arch/arm/plat-mxc/include/mach/entry-macro.S
@@ -54,8 +54,18 @@
 #elif defined CONFIG_MXC_TZIC
 	@ Load offset & priority of the highest priority
 	@ interrupt pending.
+	@ 0x080 is INTSEC0 register
 	@ 0xD80 is HIPND0 register
 	mov     \irqnr, #0
+#ifdef CONFIG_FIQ
+1000:
+	add	\irqstat, \base, \irqnr, lsr #3
+	ldr	\tmp, [\irqstat, #0xd80]
+	ldr	\irqstat, [\irqstat, #0x080]
+	ands	\tmp, \tmp, \irqstat
+	bne	1001f
+	add	\irqnr, \irqnr, #32
+#else
 	mov     \irqstat, #0x0D80
 1000:
 	ldr     \tmp,   [\irqstat, \base]
@@ -63,6 +73,7 @@
 	bne     1001f
 	addeq   \irqnr, \irqnr, #32
 	addeq   \irqstat, \irqstat, #4
+#endif
 	cmp     \irqnr, #128
 	blo     1000b
 	b       2001f
diff --git a/arch/arm/plat-mxc/tzic.c b/arch/arm/plat-mxc/tzic.c
index 3703ab2..b648a76 100644
--- a/arch/arm/plat-mxc/tzic.c
+++ b/arch/arm/plat-mxc/tzic.c
@@ -47,6 +47,33 @@
 
 void __iomem *tzic_base; /* Used as irq controller base in entry-macro.S */
 
+#ifdef CONFIG_FIQ
+
+/*
+ * switch interrupt between IRQ and FIQ mode.
+ *
+ * 'type' is true for FIQ mode and false for IRQ mode.
+ */
+int mxc_set_irq_fiq(unsigned int irq, unsigned int type)
+{
+	unsigned int index, mask, value;
+
+	index = irq >> 5;
+	if (unlikely(index >= 4))
+		return -EBUSY;
+	mask = 1U << (irq & 0x1F);
+
+	value = __raw_readl(tzic_base + TZIC_INTSEC0(index));
+	value = (value | mask) ^ (type ? mask : 0);
+	__raw_writel(value, tzic_base + TZIC_INTSEC0(index));
+
+	return 0;
+}
+
+EXPORT_SYMBOL(mxc_set_irq_fiq);
+
+#endif /* CONFIG_FIQ */
+
 /**
  * tzic_mask_irq() - Disable interrupt number "irq" in the TZIC
  *

MX51: add FIQ support for TZIC

[Uwe Kleine-König]

Hello,

On Thu, Nov 25, 2010 at 03:19:09PM +0000, Peter Horton wrote:
> Add support for FIQ on MX51 TZIC.
> 
> (patch is against Sascha's "imx-for-2.6.38" branch)
<nitpick>The comment about which tree this applies to isn't of interest
anymore when the patch is applied, so better write it after the triple
(eww, double?) dash below.  Then it won't make it into git.</nitpick>
 
> Signed-off-by: Peter Horton <phorton@bitbox.co.uk>
> 
> --
> 
Back some time I tried to achieve something similar.  IIRC my patch was
easier.  I definitly didn't patch entry-macro.S.  But OTOH I had some
problems with it so this might have been my problem.  I cannot find it
at the moment, will talk to Sascha tomorrow about it.

> diff --git a/arch/arm/plat-mxc/include/mach/entry-macro.S b/arch/arm/plat-mxc/include/mach/entry-macro.S
> index aeb0869..c7dd4a9 100644
> --- a/arch/arm/plat-mxc/include/mach/entry-macro.S
> +++ b/arch/arm/plat-mxc/include/mach/entry-macro.S
> @@ -54,8 +54,18 @@
>  #elif defined CONFIG_MXC_TZIC
>  	@ Load offset & priority of the highest priority
>  	@ interrupt pending.
> +	@ 0x080 is INTSEC0 register
>  	@ 0xD80 is HIPND0 register
>  	mov     \irqnr, #0
> +#ifdef CONFIG_FIQ
> +1000:
> +	add	\irqstat, \base, \irqnr, lsr #3
> +	ldr	\tmp, [\irqstat, #0xd80]
> +	ldr	\irqstat, [\irqstat, #0x080]
> +	ands	\tmp, \tmp, \irqstat
> +	bne	1001f
> +	add	\irqnr, \irqnr, #32
> +#else
>  	mov     \irqstat, #0x0D80
>  1000:
>  	ldr     \tmp,   [\irqstat, \base]
> @@ -63,6 +73,7 @@
>  	bne     1001f
>  	addeq   \irqnr, \irqnr, #32
>  	addeq   \irqstat, \irqstat, #4
> +#endif
>  	cmp     \irqnr, #128
>  	blo     1000b
>  	b       2001f
> diff --git a/arch/arm/plat-mxc/tzic.c b/arch/arm/plat-mxc/tzic.c
> index 3703ab2..b648a76 100644
> --- a/arch/arm/plat-mxc/tzic.c
> +++ b/arch/arm/plat-mxc/tzic.c
> @@ -47,6 +47,33 @@
>  
>  void __iomem *tzic_base; /* Used as irq controller base in entry-macro.S */
>  
> +#ifdef CONFIG_FIQ
> +
> +/*
> + * switch interrupt between IRQ and FIQ mode.
> + *
> + * 'type' is true for FIQ mode and false for IRQ mode.
> + */
> +int mxc_set_irq_fiq(unsigned int irq, unsigned int type)
> +{
> +	unsigned int index, mask, value;
> +
> +	index = irq >> 5;
> +	if (unlikely(index >= 4))
> +		return -EBUSY;
> +	mask = 1U << (irq & 0x1F);
> +
> +	value = __raw_readl(tzic_base + TZIC_INTSEC0(index));
> +	value = (value | mask) ^ (type ? mask : 0);
> +	__raw_writel(value, tzic_base + TZIC_INTSEC0(index));
Does this result in better code than the straigt forward

	value = __raw_readl(...) & ~mask;
	if (type)
		vale |= mask
	__raw_writel(...);

If not, what is the idea to write it this way?
> +
> +	return 0;
> +}
> +
> +EXPORT_SYMBOL(mxc_set_irq_fiq);
Hmm, I guess this makes it impossible to compile avic.c and tzic.c with
FIQ=y into a single binary.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

MX51: add FIQ support for TZIC

[Peter Horton]

On 25/11/2010 20:38, Uwe Kleine-K?nig wrote:
>
> On Thu, Nov 25, 2010 at 03:19:09PM +0000, Peter Horton wrote:
>> Add support for FIQ on MX51 TZIC.
>>
>> (patch is against Sascha's "imx-for-2.6.38" branch)
> <nitpick>The comment about which tree this applies to isn't of interest
> anymore when the patch is applied, so better write it after the triple
> (eww, double?) dash below.  Then it won't make it into git.</nitpick>
>
>> Signed-off-by: Peter Horton<phorton@bitbox.co.uk>
>>
>> --
>>
> Back some time I tried to achieve something similar.  IIRC my patch was
> easier.  I definitly didn't patch entry-macro.S.  But OTOH I had some
> problems with it so this might have been my problem.  I cannot find it
> at the moment, will talk to Sascha tomorrow about it.
>

There is a tiny window where the interrupt entry code reads the HIPND 
register and can see a pending FIQ. This can cause the interrupt code to 
pick up the FIQ interrupt number rather than the requesting interrupt 
number which results in the kernel's interrupt handler disabling the FIQ 
(as an interrupt without a handler).

When playing audio using the FIQ this happens after a few seconds 
without the attached entry macro fix.

>> diff --git a/arch/arm/plat-mxc/include/mach/entry-macro.S b/arch/arm/plat-mxc/include/mach/entry-macro.S
>> index aeb0869..c7dd4a9 100644
>> --- a/arch/arm/plat-mxc/include/mach/entry-macro.S
>> +++ b/arch/arm/plat-mxc/include/mach/entry-macro.S
>> @@ -54,8 +54,18 @@
>>   #elif defined CONFIG_MXC_TZIC
>>   	@ Load offset&  priority of the highest priority
>>   	@ interrupt pending.
>> +	@ 0x080 is INTSEC0 register
>>   	@ 0xD80 is HIPND0 register
>>   	mov     \irqnr, #0
>> +#ifdef CONFIG_FIQ
>> +1000:
>> +	add	\irqstat, \base, \irqnr, lsr #3
>> +	ldr	\tmp, [\irqstat, #0xd80]
>> +	ldr	\irqstat, [\irqstat, #0x080]
>> +	ands	\tmp, \tmp, \irqstat
>> +	bne	1001f
>> +	add	\irqnr, \irqnr, #32
>> +#else
>>   	mov     \irqstat, #0x0D80
>>   1000:
>>   	ldr     \tmp,   [\irqstat, \base]
>> @@ -63,6 +73,7 @@
>>   	bne     1001f
>>   	addeq   \irqnr, \irqnr, #32
>>   	addeq   \irqstat, \irqstat, #4
>> +#endif
>>   	cmp     \irqnr, #128
>>   	blo     1000b
>>   	b       2001f
>> diff --git a/arch/arm/plat-mxc/tzic.c b/arch/arm/plat-mxc/tzic.c
>> index 3703ab2..b648a76 100644
>> --- a/arch/arm/plat-mxc/tzic.c
>> +++ b/arch/arm/plat-mxc/tzic.c
>> @@ -47,6 +47,33 @@
>>
>>   void __iomem *tzic_base; /* Used as irq controller base in entry-macro.S */
>>
>> +#ifdef CONFIG_FIQ
>> +
>> +/*
>> + * switch interrupt between IRQ and FIQ mode.
>> + *
>> + * 'type' is true for FIQ mode and false for IRQ mode.
>> + */
>> +int mxc_set_irq_fiq(unsigned int irq, unsigned int type)
>> +{
>> +	unsigned int index, mask, value;
>> +
>> +	index = irq>>  5;
>> +	if (unlikely(index>= 4))
>> +		return -EBUSY;
>> +	mask = 1U<<  (irq&  0x1F);
>> +
>> +	value = __raw_readl(tzic_base + TZIC_INTSEC0(index));
>> +	value = (value | mask) ^ (type ? mask : 0);
>> +	__raw_writel(value, tzic_base + TZIC_INTSEC0(index));
> Does this result in better code than the straigt forward
>
> 	value = __raw_readl(...)&  ~mask;
> 	if (type)
> 		vale |= mask
> 	__raw_writel(...);
>
> If not, what is the idea to write it this way?

Write it however you like :)

>> +
>> +	return 0;
>> +}
>> +
>> +EXPORT_SYMBOL(mxc_set_irq_fiq);
> Hmm, I guess this makes it impossible to compile avic.c and tzic.c with
> FIQ=y into a single binary.
>

Fair point.

P.

MX51: add FIQ support for TZIC

[Peter Horton]

On 25/11/2010 20:38, Uwe Kleine-K?nig wrote:
>> +
>> +	return 0;
>> +}
>> +
>> +EXPORT_SYMBOL(mxc_set_irq_fiq);
> Hmm, I guess this makes it impossible to compile avic.c and tzic.c with
> FIQ=y into a single binary.
>

What about adding a local IRQ_TYPE_FAST and implementing 
irq_chip.set_type(), for both the AVIC and the TZIC, to do the switch 
between IRQ and FIQ mode ?

mxc_set_irq_fiq() would then just become a wrapper round irq_set_type().

P.