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Date: Thu, 14 May 2015 13:19:38 +1000
From: Alexey Kardashevskiy <aik@...abs.ru>
To: Gavin Shan <gwshan@...ux.vnet.ibm.com>
CC: linuxppc-dev@...ts.ozlabs.org,
David Gibson <david@...son.dropbear.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Alex Williamson <alex.williamson@...hat.com>,
Wei Yang <weiyang@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH kernel v10 15/34] powerpc/powernv/ioda/ioda2: Rework TCE
invalidation in tce_build()/tce_free()
On 05/14/2015 10:48 AM, Gavin Shan wrote:
> On Tue, May 12, 2015 at 01:39:04AM +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@...abs.ru>
>> Reviewed-by: David Gibson <david@...son.dropbear.id.au>
>
> Reviewed-by: Gavin Shan <gwshan@...ux.vnet.ibm.com>
>
>> ---
>> Changes:
>> v10:
>> * moved before "Switch from iommu_table to new iommu_table_group" as it adds
>> list of groups to iommu_table and tce invalidation depends on it
>>
>> 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 | 81 ++++++++++++++++++++++---------
>> arch/powerpc/platforms/powernv/pci.c | 17 ++-----
>> 2 files changed, 61 insertions(+), 37 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 2924abe..1b43e25 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -1678,18 +1678,19 @@ 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 = tbl->data;
>> __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);
>
> Platform is the only one knowing the TCE table layout and iommu_table_ops->get()
> helps to retrieve TCE entry for the given index. If iommu_table_ops->get() had
> returned the address of the TCE entry, not the content. Here, iommu_table_ops->get()
> can be reused and we hide the platform specific TCE table layout in iommu_table_ops->get()
> backend. However, it's not a big deal and it probably introduces more changes
> than expected. You judge it's worthy to do it or improve it later :-)
This will require a separate patch to convert tce_get() from returning
value to returning address. I could do that, yes. Furthermore there is even
pnv_tce() helper added later in this patchset which can be used for this in
this patch (if I moved that patch earlier). But this would be a bigger
change which is not very much related to what the patch does -
cut-n-pasting invalidate() bits. May be later. The patchset is way too big
already :(
>>
>> /* BML uses this case for p6/p7/galaxy2: Shift addr and put in node */
>> if (tbl->it_busno) {
>> @@ -1725,16 +1726,39 @@ 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);
>
> The return value from pnv_tce_build() is "int" :-)
Oops.
>> +
>> + 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 = tbl->data;
>> unsigned long start, end, inc;
>> __be64 __iomem *invalidate = rm ?
>> (__be64 __iomem *)pe->tce_inval_reg_phys :
>> @@ -1747,10 +1771,8 @@ 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();
>>
>> @@ -1763,21 +1785,32 @@ 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 = tbl->data;
>> - struct pnv_phb *phb = pe->phb;
>> + long ret = pnv_tce_build(tbl, index, npages, uaddr, direction,
>> + attrs);
>
> s/long/int
I better make them all long.
>
>>
>> - 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);
>> + 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)
>> --
>> 2.4.0.rc3.8.gfb3e7d5
>>
>
--
Alexey
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