Subject: [PATCH 4/4] irqchip, gicv3-its: Implement Cavium ThunderX errata 22375, 24313

From: [email-masked] (Marc Zyngier)
Date: Wed, 01 Jul 2015 16:18:41 +0100

On 01/07/15 14:36, Pavel Fedin wrote:
>  Hello!
> 
>> This implements two gicv3-its errata for ThunderX. Both with small
>> impact affecting only ITS table allocation.
>>
>>  erratum 22375: only alloc 8MB table size
> 
>  I have a simpler solution to this one:
> ---
> For some reason on ThunderX GITS_BASER reports entry size == 8 for ITT,
> while real size, reported by GITS_TYPER is 4. Consequently, allocated
> table size appears twice bigger than expected. And, if we set
> GITS_BASER.SIZE accordingly (the value appears to be 0xFF instead of 0x7F)
> the ITS will not work.
> 
> Signed-off-by: Pavel Fedin <[email-masked]>
> ---
>  drivers/irqchip/irq-gic-v3-its.c   | 3 ++-
>  include/linux/irqchip/arm-gic-v3.h | 2 ++
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index ed70163..c420f17 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -827,6 +827,7 @@ static int its_alloc_tables(struct its_node *its)
>  		if (type == GITS_BASER_TYPE_DEVICE) {
>  			u64 typer = readq_relaxed(its->base + GITS_TYPER);
>  			u32 ids = GITS_TYPER_DEVBITS(typer);
> +			u32 itte_size = GITS_TYPER_ITTE_SIZE(typer);
>  
>  			/*
>  			 * 'order' was initialized earlier to the default page
> @@ -834,7 +835,7 @@ static int its_alloc_tables(struct its_node *its)
>  			 * smaller than that.  If the requested allocation
>  			 * is smaller, round up to the default page granule.
>  			 */
> -			order = max(get_order((1UL << ids) * entry_size),
> +			order = max(get_order((1UL << ids) * itte_size),

What makes you think that an entry in the device table is the same size
as a translation entry? Just because one contains a pointer to the other
doesn't imply they have the same size.

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