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

From: Gavin Shan <[email-masked]>
Date: Tue, 11 Aug 2015 10:39:30 +1000

On Mon, Aug 10, 2015 at 08:02:20PM +1000, Alexey Kardashevskiy wrote:
>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.
>

Fair enough. I'll change the commit log accordingly.

>>
>>Signed-off-by: Gavin Shan <[email-masked]>
>>---
>>  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);
>>

Thanks,
Gavin