Re: [PATCH v8 08/45] powerpc/powernv: Fix initial IO and M32 segmap

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 04/13/2016 05:53 PM, Gavin Shan wrote:
> On Wed, Apr 13, 2016 at 04:21:07PM +1000, Alexey Kardashevskiy wrote:
>> On 02/17/2016 02:43 PM, Gavin Shan wrote:
>>> There are two arrays for IO and M32 segment maps on every PHB.
>>> The index of the arrays are segment number and the value stored
>>> in the corresponding element is PE number, indicating the segment
>>> is assigned to the PE. Initially, all elements in those two arrays
>>> are zeroes, meaning all segments are assigned to PE#0. It's wrong.
>>>
>>> This fixes the initial values in the elements of those two arrays
>>> to IODA_INVALID_PE, meaning all segments aren't assigned to any
>>> PE.
>>
>> This is ok.
>>
>>> In order to use IODA_INVALID_PE (-1) to represent invalid PE
>>> number, the types of those two arrays are changed from "unsigned int"
>>> to "int".
>>
>> "unsigned" can carry (-1) perfectly fine, just add a type cast to
>> IODA_INVALID_PE:
>>
>> #define IODA_INVALID_PE    (unsigned int)(-1)
>>
>> Using "signed" type for indexes which cannot be negative does not make much
>> sense - instead of checking for the upper boundary, you have to check for "<
>> 0" too.
>>
>> OPAL uses unsigned type for PE (uint64_t or uint32_t or uint16_t - this is
>> quite funny).
>>
>> pnv_ioda_pe::pe_number is "unsigned" and this pe_number is the same thing as
>> I can see in pnv_ioda_setup_dev_PE().
>>
>> Some printk() print the PE number as "%x" (which implies "unsigned").
>>
>
> Yes, I can simply have something like below when PE number as well as
> segment index are represented by "unsigned int" values, right?
>
> #define IODA_INVALID_PE		0xffffffff


This will work too, yes.

>
>>
>> I suggest changing the pci_dn::pe_number type from "int" to "unsigned int" to
>> match pnv_ioda_pe::pe_number, in a separate patch. Or do not touch types for
>> now.
>>
>
> Yes, I will have a separate patch right before this one to address it.
>
>>
>>> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>> ---
>>>   arch/powerpc/platforms/powernv/pci-ioda.c | 9 +++++++--
>>>   arch/powerpc/platforms/powernv/pci.h      | 4 ++--
>>>   2 files changed, 9 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>> index 1d2514f..44cc5f3 100644
>>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>> @@ -3239,7 +3239,7 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
>>>   	unsigned long size, m32map_off, pemap_off, iomap_off = 0;
>>>   	const __be64 *prop64;
>>>   	const __be32 *prop32;
>>> -	int len;
>>> +	int i, len;
>>>   	u64 phb_id;
>>>   	void *aux;
>>>   	long rc;
>>> @@ -3334,8 +3334,13 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
>>>   	aux = memblock_virt_alloc(size, 0);
>>>   	phb->ioda.pe_alloc = aux;
>>>   	phb->ioda.m32_segmap = aux + m32map_off;
>>> -	if (phb->type == PNV_PHB_IODA1)
>>> +	for (i = 0; i < phb->ioda.total_pe_num; i++)
>>> +		phb->ioda.m32_segmap[i] = IODA_INVALID_PE;
>>> +	if (phb->type == PNV_PHB_IODA1) {
>>>   		phb->ioda.io_segmap = aux + iomap_off;
>>> +		for (i = 0; i < phb->ioda.total_pe_num; i++)
>>> +			phb->ioda.io_segmap[i] = IODA_INVALID_PE;
>>> +	}
>>>   	phb->ioda.pe_array = aux + pemap_off;
>>>   	set_bit(phb->ioda.reserved_pe_idx, phb->ioda.pe_alloc);
>>>
>>> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>>> index 784882a..36c4965 100644
>>> --- a/arch/powerpc/platforms/powernv/pci.h
>>> +++ b/arch/powerpc/platforms/powernv/pci.h
>>> @@ -146,8 +146,8 @@ struct pnv_phb {
>>>   		struct pnv_ioda_pe	*pe_array;
>>>
>>>   		/* M32 & IO segment maps */
>>> -		unsigned int		*m32_segmap;
>>> -		unsigned int		*io_segmap;
>>> +		int			*m32_segmap;
>>> +		int			*io_segmap;
>>>
>>>   		/* IRQ chip */
>>>   		int			irq_chip_init;
>>>
>>
>>
>> --
>> Alexey
>>
>


-- 
Alexey