Re: [PATCH kernel v9 15/32] powerpc/powernv/ioda/ioda2: Rework TCE invalidation in tce_build()/tce_free()

Alexey Kardashevskiy
2015-04-30T02:58:22Z

On 04/29/2015 01:18 PM, David Gibson wrote:
> On Sat, Apr 25, 2015 at 10:14:39PM +1000, Alexey Kardashevskiy wrote:
>> The pnv_pci_ioda_tce_invalidate() helper invalidates TCE cache. It is
>> supposed to be called on IODA1/2 and not called on p5ioc2. It receives
>> start and end host addresses of TCE table.
>>
>> IODA2 actually needs PCI addresses to invalidate the cache. Those
>> can be calculated from host addresses but since we are going
>> to implement multi-level TCE tables, calculating PCI address from
>> a host address might get either tricky or ugly as TCE table remains flat
>> on PCI bus but not in RAM.
>>
>> This moves pnv_pci_ioda_tce_invalidate() from generic pnv_tce_build/
>> pnt_tce_free and defines IODA1/2-specific callbacks which call generic
>> ones and do PHB-model-specific TCE cache invalidation. P5IOC2 keeps
>> using generic callbacks as before.
>>
>> This changes pnv_pci_ioda2_tce_invalidate() to receives TCE index and
>> number of pages which are PCI addresses shifted by IOMMU page shift.
>>
>> No change in behaviour is expected.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>> Changes:
>> v9:
>> * removed confusing comment from commit log about unintentional calling of
>> pnv_pci_ioda_tce_invalidate()
>> * moved mechanical changes away to "powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table"
>> * fixed bug with broken invalidation in pnv_pci_ioda2_tce_invalidate -
>> @index includes @tbl->it_offset but old code added it anyway which later broke
>> DDW
>> ---
>> arch/powerpc/platforms/powernv/pci-ioda.c | 86 +++++++++++++++++++++----------
>> arch/powerpc/platforms/powernv/pci.c | 17 ++----
>> 2 files changed, 64 insertions(+), 39 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 718d5cc..f070c44 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -1665,18 +1665,20 @@ static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe,
>> }
>> }
>>
>> -static void pnv_pci_ioda1_tce_invalidate(struct pnv_ioda_pe *pe,
>> - struct iommu_table *tbl,
>> - __be64 *startp, __be64 *endp, bool rm)
>> +static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
>> + unsigned long index, unsigned long npages, bool rm)
>> {
>> + struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> + struct pnv_ioda_pe, table_group);
>> __be64 __iomem *invalidate = rm ?
>> (__be64 __iomem *)pe->tce_inval_reg_phys :
>> (__be64 __iomem *)tbl->it_index;
>> unsigned long start, end, inc;
>> const unsigned shift = tbl->it_page_shift;
>>
>> - start = __pa(startp);
>> - end = __pa(endp);
>> + start = __pa((__be64 *)tbl->it_base + index - tbl->it_offset);
>> + end = __pa((__be64 *)tbl->it_base + index - tbl->it_offset +
>> + npages - 1);
>
> This doesn't look right. The arguments to __pa don't appear to be
> addresses (since index and if_offset are in units of (TCE) pages, not
> bytes).

tbl->it_base is an address and it is casted to __be64* which means:

(char*)tbl->it_base + (index - tbl->it_offset)*sizeof(__be64).

Which seems to be correct (I just removed extra braces compared to the old
code), no?

>
>>
>> /* BML uses this case for p6/p7/galaxy2: Shift addr and put in node */
>> if (tbl->it_busno) {
>> @@ -1712,16 +1714,40 @@ static void pnv_pci_ioda1_tce_invalidate(struct pnv_ioda_pe *pe,
>> */
>> }
>>
>> +static int pnv_ioda1_tce_build(struct iommu_table *tbl, long index,
>> + long npages, unsigned long uaddr,
>> + enum dma_data_direction direction,
>> + struct dma_attrs *attrs)
>> +{
>> + long ret = pnv_tce_build(tbl, index, npages, uaddr, direction,
>> + attrs);
>> +
>> + if (!ret && (tbl->it_type & TCE_PCI_SWINV_CREATE))
>> + pnv_pci_ioda1_tce_invalidate(tbl, index, npages, false);
>> +
>> + return ret;
>> +}
>> +
>> +static void pnv_ioda1_tce_free(struct iommu_table *tbl, long index,
>> + long npages)
>> +{
>> + pnv_tce_free(tbl, index, npages);
>> +
>> + if (tbl->it_type & TCE_PCI_SWINV_FREE)
>> + pnv_pci_ioda1_tce_invalidate(tbl, index, npages, false);
>> +}
>> +
>> static struct iommu_table_ops pnv_ioda1_iommu_ops = {
>> - .set = pnv_tce_build,
>> - .clear = pnv_tce_free,
>> + .set = pnv_ioda1_tce_build,
>> + .clear = pnv_ioda1_tce_free,
>> .get = pnv_tce_get,
>> };
>>
>> -static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
>> - struct iommu_table *tbl,
>> - __be64 *startp, __be64 *endp, bool rm)
>> +static void pnv_pci_ioda2_tce_invalidate(struct iommu_table *tbl,
>> + unsigned long index, unsigned long npages, bool rm)
>> {
>> + struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> + struct pnv_ioda_pe, table_group);
>> unsigned long start, end, inc;
>> __be64 __iomem *invalidate = rm ?
>> (__be64 __iomem *)pe->tce_inval_reg_phys :
>> @@ -1734,10 +1760,8 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
>> end = start;
>>
>> /* Figure out the start, end and step */
>> - inc = tbl->it_offset + (((u64)startp - tbl->it_base) / sizeof(u64));
>> - start |= (inc << shift);
>> - inc = tbl->it_offset + (((u64)endp - tbl->it_base) / sizeof(u64));
>> - end |= (inc << shift);
>> + start |= (index << shift);
>> + end |= ((index + npages - 1) << shift);
>> inc = (0x1ull << shift);
>> mb();
>>
>> @@ -1750,22 +1774,32 @@ static void pnv_pci_ioda2_tce_invalidate(struct pnv_ioda_pe *pe,
>> }
>> }
>>
>> -void pnv_pci_ioda_tce_invalidate(struct iommu_table *tbl,
>> - __be64 *startp, __be64 *endp, bool rm)
>> +static int pnv_ioda2_tce_build(struct iommu_table *tbl, long index,
>> + long npages, unsigned long uaddr,
>> + enum dma_data_direction direction,
>> + struct dma_attrs *attrs)
>> {
>> - struct pnv_ioda_pe *pe = container_of(tbl->it_table_group,
>> - struct pnv_ioda_pe, table_group);
>> - struct pnv_phb *phb = pe->phb;
>> -
>> - if (phb->type == PNV_PHB_IODA1)
>> - pnv_pci_ioda1_tce_invalidate(pe, tbl, startp, endp, rm);
>> - else
>> - pnv_pci_ioda2_tce_invalidate(pe, tbl, startp, endp, rm);
>> + long ret = pnv_tce_build(tbl, index, npages, uaddr, direction,
>> + attrs);
>> +
>> + if (!ret && (tbl->it_type & TCE_PCI_SWINV_CREATE))
>> + pnv_pci_ioda2_tce_invalidate(tbl, index, npages, false);
>> +
>> + return ret;
>> +}
>> +
>> +static void pnv_ioda2_tce_free(struct iommu_table *tbl, long index,
>> + long npages)
>> +{
>> + pnv_tce_free(tbl, index, npages);
>> +
>> + if (tbl->it_type & TCE_PCI_SWINV_FREE)
>> + pnv_pci_ioda2_tce_invalidate(tbl, index, npages, false);
>> }
>>
>> static struct iommu_table_ops pnv_ioda2_iommu_ops = {
>> - .set = pnv_tce_build,
>> - .clear = pnv_tce_free,
>> + .set = pnv_ioda2_tce_build,
>> + .clear = pnv_ioda2_tce_free,
>> .get = pnv_tce_get,
>> };
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
>> index 4c3bbb1..84b4ea4 100644
>> --- a/arch/powerpc/platforms/powernv/pci.c
>> +++ b/arch/powerpc/platforms/powernv/pci.c
>> @@ -577,37 +577,28 @@ int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
>> struct dma_attrs *attrs)
>> {
>> u64 proto_tce = iommu_direction_to_tce_perm(direction);
>> - __be64 *tcep, *tces;
>> + __be64 *tcep;
>> u64 rpn;
>>
>> - tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
>> + tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
>> rpn = __pa(uaddr) >> tbl->it_page_shift;
>>
>> while (npages--)
>> *(tcep++) = cpu_to_be64(proto_tce |
>> (rpn++ << tbl->it_page_shift));
>>
>> - /* Some implementations won't cache invalid TCEs and thus may not
>> - * need that flush. We'll probably turn it_type into a bit mask
>> - * of flags if that becomes the case
>> - */
>> - if (tbl->it_type & TCE_PCI_SWINV_CREATE)
>> - pnv_pci_ioda_tce_invalidate(tbl, tces, tcep - 1, false);
>>
>> return 0;
>> }
>>
>> void pnv_tce_free(struct iommu_table *tbl, long index, long npages)
>> {
>> - __be64 *tcep, *tces;
>> + __be64 *tcep;
>>
>> - tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
>> + tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
>>
>> while (npages--)
>> *(tcep++) = cpu_to_be64(0);
>> -
>> - if (tbl->it_type & TCE_PCI_SWINV_FREE)
>> - pnv_pci_ioda_tce_invalidate(tbl, tces, tcep - 1, false);
>> }
>>
>> unsigned long pnv_tce_get(struct iommu_table *tbl, long index)
>

--
Alexey