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

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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@xxxxxxxxxxxxxxxxxx>
---
  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
--
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