[Skiboot] [PATCH 2/2] phb3/phb4/p7ioc: Document supported TCE sizes in DT

[Alexey Kardashevskiy]

On 05/02/18 16:07, Russell Currey wrote:
> On Mon, 2018-02-05 at 16:02 +1100, Alexey Kardashevskiy wrote:
>> On 05/02/18 15:00, Russell Currey wrote:
>>> Add a new property, "ibm,supported-tce-sizes", to advertise to
>>> Linux how
>>> big the available TCE sizes are.  Each value is a bit shift, from
>>> smallest to largest.
>>
>> Why would we possibly need such a limit? We already have an example
>> of DDW
>> in sPAPR where possible IOMMU page sizes are fixed and there is no
>> way to
>> have 2M IOMMU pages in the guest, now the same sort of limit is being
>> added
>> to skiboot...
> 
> There are no limits being imposed, this is purely documenting what the
> hardware supports.


Wow. Just found it in the spec. Pls put this kind of information to the
commit log as it is a surprise that now I cannot get 16M IOMMU pages on
P9/hash.




>>
>>
>>>
>>> Signed-off-by: Russell Currey <ruscur at russell.cc>
>>> ---
>>>  hw/p7ioc-phb.c | 5 +++++
>>>  hw/phb3.c      | 5 +++++
>>>  hw/phb4.c      | 5 +++++
>>>  3 files changed, 15 insertions(+)
>>>
>>> diff --git a/hw/p7ioc-phb.c b/hw/p7ioc-phb.c
>>> index 6c074518..b0a26e84 100644
>>> --- a/hw/p7ioc-phb.c
>>> +++ b/hw/p7ioc-phb.c
>>> @@ -2596,6 +2596,11 @@ static void p7ioc_pcie_add_node(struct
>>> p7ioc_phb *p)
>>>  	tkill = reg[0] + PHB_TCE_KILL;
>>>  	dt_add_property_cells(np, "ibm,opal-tce-kill",
>>>  			      hi32(tkill), lo32(tkill));
>>> +	dt_add_property_cells(np, "ibm,supported-tce-sizes",
>>> +			      12, // 4K
>>> +			      16, // 64K
>>> +			      24, // 16M
>>> +			      34); // 16G
>>>  
>>>  	/*
>>>  	 * Linux may use this property to allocate the diag data
>>> buffer, which
>>> diff --git a/hw/phb3.c b/hw/phb3.c
>>> index 0b4c3c32..0c4e1eb3 100644
>>> --- a/hw/phb3.c
>>> +++ b/hw/phb3.c
>>> @@ -4469,6 +4469,11 @@ static void phb3_add_properties(struct phb3
>>> *p)
>>>  	tkill = reg + PHB_TCE_KILL;
>>>  	dt_add_property_cells(np, "ibm,opal-tce-kill",
>>>  			      hi32(tkill), lo32(tkill));
>>> +	dt_add_property_cells(np, "ibm,supported-tce-sizes",
>>> +			      12, // 4K
>>> +			      16, // 64K
>>> +			      24, // 16M
>>> +			      28); // 256M
>>>  
>>>  	/*
>>>  	 * Indicate to Linux that the architected IODA2 MSI EOI
>>> method
>>> diff --git a/hw/phb4.c b/hw/phb4.c
>>> index 0a7e3065..946f9ab6 100644
>>> --- a/hw/phb4.c
>>> +++ b/hw/phb4.c
>>> @@ -4688,6 +4688,11 @@ static void phb4_add_properties(struct phb4
>>> *p)
>>>  	/* M64 ranges start at 1 as MBT0 is used for M32 */
>>>  	dt_add_property_cells(np, "ibm,opal-available-m64-ranges",
>>>  			      1, p->mbt_size - 1);
>>> +	dt_add_property_cells(np, "ibm,supported-tce-sizes",
>>> +			      12, // 4K
>>> +			      16, // 64K
>>> +			      21, // 2M
>>> +			      30); // 1G
>>>  
>>>  	/* Tell Linux about alignment limits for segment splits.
>>>  	 *
>>>
>>
>>


-- 
Alexey