On Fri, Aug 29, 2025 at 10:51:56PM +0530, ALOK TIWARI wrote:
>
>
> On 8/16/2025 3:50 AM, Frank Li wrote:
> > +int pci_epf_set_inbound_space(struct pci_epf *epf, size_t size,
> > + enum pci_barno bar,
> > + const struct pci_epc_features *epc_features,
> > + enum pci_epc_interface_type type,
> > + bool from_memory,
> > + dma_addr_t inbound_addr)
> > {
> > u64 bar_fixed_size = epc_features->bar[bar].fixed_size;
> > size_t aligned_size, align = epc_features->align;
> > @@ -270,7 +276,32 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
> > dma_addr_t phys_addr;
> > struct pci_epc *epc;
> > struct device *dev;
> > - void *space;
> > + void *space = NULL;
> > + dma_addr_t up;
> > +
> > + up = inbound_addr + size - 1;
> > +
> > + /*
> > + * Bits: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
> > + * Inbound_addr: U U U U U U 0 X X X X X X X X X
> > + * Up: U U U U U U 1 X X X X X X X X X
> > + *
> > + * U means address bits have not change in Range [Inbound_Addr, Up]
> > + * X means bit 0 or 1.
> > + *
> > + * Inbound_addr^Up 0 0 0 0 0 0 1 X X X X X X X X X
> > + * Find first bit 1 pos from MSB, 2 ^ pos windows will cover
> > + * [Inbound_Addr, Up] range.
> > + */
> > + if (!from_memory) {
> > + int pos;
> > +
> > + for (pos = sizeof(dma_addr_t) - 1; pos > 0; pos--)
> > + if ((up ^ inbound_addr) & BIT_ULL(pos))
> > + break;
> > +
>
> sizeof(dma_addr_t) returns bytes, not bits.
> so 7..1 time loop in enough here ?
good find.
Frank
>
> > + size = 1 << pos;
> > + }
> > if (size < 128)
> > size = 128;
> > @@ -283,7 +314,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
> > if (size > bar_fixed_size) {
> > dev_err(&epf->dev,
> > "requested BAR size is larger than fixed size\n");
> > - return NULL;
> > + return -EINVAL;
> > }
> > size = bar_fixed_size;
> > } else {
> > @@ -308,13 +339,25 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
> > }
> > dev = epc->dev.parent;
> > - space = dma_alloc_coherent(dev, aligned_size, &phys_addr, GFP_KERNEL);
> > - if (!space) {
> > - dev_err(dev, "failed to allocate mem space\n");
> > - return NULL;
> > +
> > + if (from_memory) {
> > + space = dma_alloc_coherent(dev, aligned_size,
> > + &phys_addr, GFP_KERNEL);
> > + if (!space) {
> > + dev_err(dev, "failed to allocate mem space\n");
> > + return -ENOMEM;
> > + }
> > + }
> > +
> > + epf_bar[bar].phys_addr = from_memory ?
> > + phys_addr : ALIGN_DOWN(inbound_addr, aligned_size);
> > +
> > + if (!from_memory && (epf_bar[bar].phys_addr + size < up)) {
> > + dev_err(&epf->dev,
> > + "Given bar can't fit required inbound memory region\n");
>
> consider bar -> BAR
>
> > + return -EINVAL;
> > }
>
>
> Thanks,
> Alok
