Re: [PATCH v6 15/42] powerpc/powernv: PE oriented during configuration

Alexey Kardashevskiy
2015-08-10T10:02:20Z

On 08/06/2015 02:11 PM, Gavin Shan wrote:
> Several functions used to configure PE take pe_number to indentify
> PE instance. As the pe_number is included in PE instance after it
> is reserved or allocated. It's convienent for those functions to
> return PE instance which includes the required pe_number.

This is a description for the half of the patch but this patch also adds a
return value to functions which did not have it before and I am not sure
you need all of them to return something. It would be cleaner if you added
"return" when/where you really need it, not just because it seems that it
may be convenient later.

>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> ---
> arch/powerpc/platforms/powernv/pci-ioda.c | 51 ++++++++++++++++---------------
> arch/powerpc/platforms/powernv/pci.h | 2 +-
> 2 files changed, 27 insertions(+), 26 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 3094c61..9f53682 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -132,12 +132,12 @@ static inline bool pnv_pci_is_mem_pref_64(unsigned long flags)
> (IORESOURCE_MEM_64 | IORESOURCE_PREFETCH));
> }
>
> -static void pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no)
> +static struct pnv_ioda_pe *pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no)
> {
> if (!(pe_no >= 0 && pe_no < phb->ioda.total_pe)) {
> pr_warn("%s: Invalid PE %d on PHB#%x\n",
> __func__, pe_no, phb->hose->global_number);
> - return;
> + return NULL;
> }
>
> if (test_and_set_bit(pe_no, phb->ioda.pe_alloc))
> @@ -146,9 +146,11 @@ static void pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no)
>
> phb->ioda.pe_array[pe_no].phb = phb;
> phb->ioda.pe_array[pe_no].pe_number = pe_no;
> +
> + return &phb->ioda.pe_array[pe_no];
> }
>
> -static int pnv_ioda_alloc_pe(struct pnv_phb *phb)
> +static struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb)
> {
> unsigned long pe;
>
> @@ -156,12 +158,12 @@ static int pnv_ioda_alloc_pe(struct pnv_phb *phb)
> pe = find_next_zero_bit(phb->ioda.pe_alloc,
> phb->ioda.total_pe, 0);
> if (pe >= phb->ioda.total_pe)
> - return IODA_INVALID_PE;
> + return NULL;
> } while(test_and_set_bit(pe, phb->ioda.pe_alloc));
>
> phb->ioda.pe_array[pe].phb = phb;
> phb->ioda.pe_array[pe].pe_number = pe;
> - return pe;
> + return &phb->ioda.pe_array[pe];
> }
>
> static void pnv_ioda_free_pe(struct pnv_phb *phb, int pe)
> @@ -334,7 +336,7 @@ static void pnv_ioda_reserve_m64_pe(struct pci_bus *bus,
> }
> }
>
> -static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
> +static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
> {
> struct pci_controller *hose = pci_bus_to_host(bus);
> struct pnv_phb *phb = hose->private_data;
> @@ -344,7 +346,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
>
> /* Root bus shouldn't use M64 */
> if (pci_is_root_bus(bus))
> - return IODA_INVALID_PE;
> + return NULL;
>
> /* Allocate bitmap */
> size = _ALIGN_UP(phb->ioda.total_pe / 8, sizeof(unsigned long));
> @@ -352,7 +354,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
> if (!pe_alloc) {
> pr_warn("%s: Out of memory !\n",
> __func__);
> - return IODA_INVALID_PE;
> + return NULL;
> }
>
> /* Figure out reserved PE numbers by the PE */
> @@ -365,7 +367,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
> */
> if (bitmap_empty(pe_alloc, phb->ioda.total_pe)) {
> kfree(pe_alloc);
> - return IODA_INVALID_PE;
> + return NULL;
> }
>
> /*
> @@ -416,7 +418,7 @@ static int pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
> }
>
> kfree(pe_alloc);
> - return master_pe->pe_number;
> + return master_pe;
> }
>
> static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
> @@ -1069,28 +1071,26 @@ static void pnv_ioda_setup_same_PE(struct pci_bus *bus, struct pnv_ioda_pe *pe)
> * subordinate PCI devices and buses. The second type of PE is normally
> * orgiriated by PCIe-to-PCI bridge or PLX switch downstream ports.
> */
> -static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
> +static struct pnv_ioda_pe *pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
> {
> struct pci_controller *hose = pci_bus_to_host(bus);
> struct pnv_phb *phb = hose->private_data;
> - struct pnv_ioda_pe *pe;
> - int pe_num = IODA_INVALID_PE;
> + struct pnv_ioda_pe *pe = NULL;
>
> /* Check if PE is determined by M64 */
> if (phb->pick_m64_pe)
> - pe_num = phb->pick_m64_pe(bus, all);
> + pe = phb->pick_m64_pe(bus, all);
>
> /* The PE number isn't pinned by M64 */
> - if (pe_num == IODA_INVALID_PE)
> - pe_num = pnv_ioda_alloc_pe(phb);
> + if (!pe)
> + pe = pnv_ioda_alloc_pe(phb);
>
> - if (pe_num == IODA_INVALID_PE) {
> - pr_warning("%s: Not enough PE# available for PCI bus %04x:%02x\n",
> + if (!pe) {
> + pr_warning("%s: No enough PE# for PCI bus %04x:%02x\n",
> __func__, pci_domain_nr(bus), bus->number);
> - return;
> + return NULL;
> }
>
> - pe = &phb->ioda.pe_array[pe_num];
> pe->flags |= (all ? PNV_IODA_PE_BUS_ALL : PNV_IODA_PE_BUS);
> pe->pbus = bus;
> pe->pdev = NULL;
> @@ -1101,17 +1101,16 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
>
> if (all)
> pe_info(pe, "Secondary bus %d..%d associated with PE#%d\n",
> - bus->busn_res.start, bus->busn_res.end, pe_num);
> + bus->busn_res.start, bus->busn_res.end, pe->pe_number);
> else
> pe_info(pe, "Secondary bus %d associated with PE#%d\n",
> - bus->busn_res.start, pe_num);
> + bus->busn_res.start, pe->pe_number);
>
> if (pnv_ioda_configure_pe(phb, pe)) {
> /* XXX What do we do here ? */
> - if (pe_num)
> - pnv_ioda_free_pe(phb, pe_num);
> + pnv_ioda_free_pe(phb, pe->pe_number);
> pe->pbus = NULL;
> - return;
> + return NULL;
> }
>
> /* Associate it with all child devices */
> @@ -1122,6 +1121,8 @@ static void pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
>
> /* Link the PE */
> pnv_ioda_link_pe_by_weight(phb, pe);
> +
> + return pe;
> }
>
> static void pnv_ioda_setup_PEs(struct pci_bus *bus)
> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
> index 6f8568e..c0bc57f 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -121,7 +121,7 @@ struct pnv_phb {
> int (*init_m64)(struct pnv_phb *phb);
> void (*reserve_m64_pe)(struct pci_bus *bus,
> unsigned long *pe_bitmap, bool all);
> - int (*pick_m64_pe)(struct pci_bus *bus, bool all);
> + struct pnv_ioda_pe* (*pick_m64_pe)(struct pci_bus *bus, bool all);
> int (*get_pe_state)(struct pnv_phb *phb, int pe_no);
> void (*freeze_pe)(struct pnv_phb *phb, int pe_no);
> int (*unfreeze_pe)(struct pnv_phb *phb, int pe_no, int opt);
>

--
Alexey