Re: [PATCH v6 12/42] powerpc/powernv: Increase PE# capacity

Alexey Kardashevskiy
2015-08-10T09:53:02Z

On 08/06/2015 02:11 PM, Gavin Shan wrote:
> Each PHB maintains an array helping to translate RID (Request
> ID) to PE# with the assumption that PE# takes 8 bits, indicating
> that we can't have more than 256 PEs. However, pci_dn->pe_number
> already had 4-bytes for the PE#.
>
> The patch extends the PE# capacity so that each of them will be
> 4-bytes long. Then we can use IODA_INVALID_PE to check one entry
> in phb->pe_rmap[] is valid or not.
>
> Signed-off-by: Gavin Shan <gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> ---
> arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++--
> arch/powerpc/platforms/powernv/pci.h | 7 +++----
> 2 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 57ba8fd..3094c61 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -786,7 +786,7 @@ static int pnv_ioda_deconfigure_pe(struct pnv_phb *phb, struct pnv_ioda_pe *pe)
>
> /* Clear the reverse map */
> for (rid = pe->rid; rid < rid_end; rid++)
> - phb->ioda.pe_rmap[rid] = 0;
> + phb->ioda.pe_rmap[rid] = IODA_INVALID_PE;
>
> /* Release from all parents PELT-V */
> while (parent) {
> @@ -3134,7 +3134,7 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
> unsigned long size, pemap_off;
> const __be64 *prop64;
> const __be32 *prop32;
> - int len;
> + int len, i;
> u64 phb_id;
> void *aux;
> long rc;
> @@ -3201,6 +3201,10 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
> if (prop32)
> phb->ioda.reserved_pe = be32_to_cpup(prop32);
>
> + /* Invalidate RID to PE# mapping */
> + for (i = 0; i < ARRAY_SIZE(phb->ioda.pe_rmap); ++i)
> + phb->ioda.pe_rmap[i] = IODA_INVALID_PE;
> +
> /* Parse 64-bit MMIO range */
> pnv_ioda_parse_m64_window(phb);
>
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 1dc9578..6f8568e 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -175,11 +175,10 @@ struct pnv_phb {
> struct list_head pe_list;
> struct mutex pe_list_mutex;
>
> - /* Reverse map of PEs, will have to extend if
> - * we are to support more than 256 PEs, indexed
> - * bus { bus, devfn }
> + /* Reverse map of PEs, indexed by
> + * { bus, devfn }
> */
> - unsigned char pe_rmap[0x10000];
> + int pe_rmap[0x10000];

256k seems to be waste when only tiny fraction of it will ever be used.
Using include/linux/hashtable.h makes sense here, and if you use a
hashtable, you won't have to initialize anything with IODA_INVALID_PE.

>
> /* 32-bit TCE tables allocation */
> unsigned long dma32_segcount;
>

--
Alexey
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