Subject: Re: [PATCH 1/8] ppc/pnv: create bus sensitive PEs

From: Richard Yang <[email-masked]>
Date: Wed, 1 Aug 2012 03:49:41 -0400

On Mon, Jun 25, 2012 at 11:43:14PM +0800, Gavin Shan wrote:
>Basically, there're 2 types of PCI bus sensitive PEs: (A) The PE
>includes single PCI bus. (B) The PE includes the PCI bus and all
>the subordinate PCI buses. At present, we'd like to put PCI bus
>originated by PCI-e link to form PE that contains single PCI bus,
>and the PCIe-to-PCI bridge will form the 2nd type of PE. We don't
>figure out to detect PLX bridge yet. Once we can detect PLX bridge
>some day, we have to put PCI buses originated from the downstream
>port of PLX bridge to the 2nd type of PE.
>
>The patch changes the original implementation for a little bit
>to support 2 types of PCI bus sensitive PEs described as above.
>Also, the function used to retrieve the corresponding PE according
>to the given PCI device has been changed based on that because each
>PCI device should trace the directly associated PE.
>
>Signed-off-by: Gavin Shan <[email-masked]>
>Reviewed-by: Ram Pai <[email-masked]>
>Reviewed-by: Richard Yang <[email-masked]>
>---
> arch/powerpc/platforms/powernv/pci-ioda.c |   97 +++++++++++++++++------------
> arch/powerpc/platforms/powernv/pci.h      |   10 +--
> 2 files changed, 63 insertions(+), 44 deletions(-)
>
>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>index fbdd74d..1504795 100644
>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>@@ -548,7 +548,7 @@ static void __devinit pnv_ioda_free_pe(struct pnv_phb *phb, int pe)
>  * but in the meantime, we need to protect them to avoid warnings
>  */
> #ifdef CONFIG_PCI_MSI
>-static struct pnv_ioda_pe * __devinit __pnv_ioda_get_one_pe(struct pci_dev *dev)
>+static struct pnv_ioda_pe * __devinit pnv_ioda_get_pe(struct pci_dev *dev)
> {
> 	struct pci_controller *hose = pci_bus_to_host(dev->bus);
> 	struct pnv_phb *phb = hose->private_data;
>@@ -560,19 +560,6 @@ static struct pnv_ioda_pe * __devinit __pnv_ioda_get_one_pe(struct pci_dev *dev)
> 		return NULL;
> 	return &phb->ioda.pe_array[pdn->pe_number];
> }
>-
>-static struct pnv_ioda_pe * __devinit pnv_ioda_get_pe(struct pci_dev *dev)
>-{
>-	struct pnv_ioda_pe *pe = __pnv_ioda_get_one_pe(dev);
>-
>-	while (!pe && dev->bus->self) {
>-		dev = dev->bus->self;
>-		pe = __pnv_ioda_get_one_pe(dev);
>-		if (pe)
>-			pe = pe->bus_pe;
>-	}
>-	return pe;
>-}
> #endif /* CONFIG_PCI_MSI */
>
> static int __devinit pnv_ioda_configure_pe(struct pnv_phb *phb,
>@@ -589,7 +576,11 @@ static int __devinit pnv_ioda_configure_pe(struct pnv_phb *phb,
> 		dcomp = OPAL_IGNORE_RID_DEVICE_NUMBER;
> 		fcomp = OPAL_IGNORE_RID_FUNCTION_NUMBER;
> 		parent = pe->pbus->self;
>-		count = pe->pbus->subordinate - pe->pbus->secondary + 1;
>+		if (pe->flags & PNV_IODA_PE_BUS_ALL)
>+			count = pe->pbus->subordinate - pe->pbus->secondary + 1;
>+		else
>+			count = 1;
>+
> 		switch(count) {
> 		case  1: bcomp = OpalPciBusAll;		break;
> 		case  2: bcomp = OpalPciBus7Bits;	break;
>@@ -699,6 +690,7 @@ static unsigned int pnv_ioda_dma_weight(struct pci_dev *dev)
> 	return 10;
> }
>
>+#if 0
> static struct pnv_ioda_pe * __devinit pnv_ioda_setup_dev_PE(struct pci_dev *dev)
> {
> 	struct pci_controller *hose = pci_bus_to_host(dev->bus);
>@@ -767,6 +759,7 @@ static struct pnv_ioda_pe * __devinit pnv_ioda_setup_dev_PE(struct pci_dev *dev)
>
> 	return pe;
> }
>+#endif /* Useful for SRIOV case */
>
> static void pnv_ioda_setup_same_PE(struct pci_bus *bus, struct pnv_ioda_pe *pe)
> {
>@@ -784,43 +777,47 @@ static void pnv_ioda_setup_same_PE(struct pci_bus *bus, struct pnv_ioda_pe *pe)
> 		pdn->pcidev = dev;
> 		pdn->pe_number = pe->pe_number;
> 		pe->dma_weight += pnv_ioda_dma_weight(dev);
>-		if (dev->subordinate)
>+		if ((pe->flags & PNV_IODA_PE_BUS_ALL) && dev->subordinate)
> 			pnv_ioda_setup_same_PE(dev->subordinate, pe);
> 	}
> }
>
>-static void __devinit pnv_ioda_setup_bus_PE(struct pci_dev *dev,
>-					    struct pnv_ioda_pe *ppe)
>+/*
>+ * There're 2 types of PCI bus sensitive PEs: One that is compromised of
>+ * single PCI bus. Another one that contains the primary PCI bus and its
>+ * 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 __devinit pnv_ioda_setup_bus_PE(struct pci_bus *bus, int all)
> {
>-	struct pci_controller *hose = pci_bus_to_host(dev->bus);
>+	struct pci_controller *hose = pci_bus_to_host(bus);
> 	struct pnv_phb *phb = hose->private_data;
>-	struct pci_bus *bus = dev->subordinate;
> 	struct pnv_ioda_pe *pe;
> 	int pe_num;
>
>-	if (!bus) {
>-		pr_warning("%s: Bridge without a subordinate bus !\n",
>-			   pci_name(dev));
>-		return;
>-	}
> 	pe_num = pnv_ioda_alloc_pe(phb);
> 	if (pe_num == IODA_INVALID_PE) {
>-		pr_warning("%s: Not enough PE# available, disabling bus\n",
>-			   pci_name(dev));
>+		pr_warning("%s: Not enough PE# available for PCI bus %04x:%02x\n",
>+			__func__, pci_domain_nr(bus), bus->number);
> 		return;
> 	}
>
> 	pe = &phb->ioda.pe_array[pe_num];
>-	ppe->bus_pe = pe;
>+	pe->flags = (all ? PNV_IODA_PE_BUS_ALL : PNV_IODA_PE_BUS);
> 	pe->pbus = bus;
>+	pe->pe_number = pe_num;

Gavin, 

Sorry for the late reply. I am not sure I a replying on the latest code. If
not, please point me out. 

I think we don't need to add this line. the pe->pe_number is already set in
pnv_ioda_alloc_pe().

> 	pe->pdev = NULL;
> 	pe->tce32_seg = -1;
> 	pe->mve_number = -1;
> 	pe->rid = bus->secondary << 8;
> 	pe->dma_weight = 0;
>
>-	pe_info(pe, "Secondary busses %d..%d associated with PE\n",
>-		bus->secondary, bus->subordinate);
>+	if (all)
>+		pe_info(pe, "Secondary busses %d..%d associated with PE#%d\n",
>+			bus->secondary, bus->subordinate, pe_num);
>+	else
>+		pe_info(pe, "Secondary busses %d associated with PE#%d\n",
>+			bus->secondary, pe_num);
>
> 	if (pnv_ioda_configure_pe(phb, pe)) {
> 		/* XXX What do we do here ? */
>@@ -848,17 +845,33 @@ static void __devinit pnv_ioda_setup_bus_PE(struct pci_dev *dev,
> static void __devinit pnv_ioda_setup_PEs(struct pci_bus *bus)
> {
> 	struct pci_dev *dev;
>-	struct pnv_ioda_pe *pe;
>+
>+	pnv_ioda_setup_bus_PE(bus, 0);
>
> 	list_for_each_entry(dev, &bus->devices, bus_list) {
>-		pe = pnv_ioda_setup_dev_PE(dev);
>-		if (pe == NULL)
>-			continue;
>-		/* Leaving the PCIe domain ... single PE# */
>-		if (dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE)
>-			pnv_ioda_setup_bus_PE(dev, pe);
>-		else if (dev->subordinate)
>-			pnv_ioda_setup_PEs(dev->subordinate);
>+		if (dev->subordinate) {
>+			if (dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE)
>+				pnv_ioda_setup_bus_PE(dev->subordinate, 1);
>+			else
>+				pnv_ioda_setup_PEs(dev->subordinate);
>+		}
>+	}
>+}
>+
>+/*
>+ * Configure PEs so that the downstream PCI buses and devices
>+ * could have their associated PE#. Unfortunately, we didn't
>+ * figure out the way to identify the PLX bridge yet. So we
>+ * simply put the PCI bus and the subordinate behind the root
>+ * port to PE# here. The game rule here is expected to be changed
>+ * as soon as we can detected PLX bridge correctly.
>+ */
>+static void __devinit pnv_pci_ioda_setup_PEs(void)
>+{
>+	struct pci_controller *hose, *tmp;
>+
>+	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
>+		pnv_ioda_setup_PEs(hose->bus);
> 	}
> }
>
>@@ -1139,6 +1152,11 @@ static void __devinit pnv_pci_ioda_fixup_phb(struct pci_controller *hose)
> 	}
> }
>
>+static void __devinit pnv_pci_ioda_fixup(void)
>+{
>+	pnv_pci_ioda_setup_PEs();
>+}
>+
> /* Prevent enabling devices for which we couldn't properly
>  * assign a PE
>  */
>@@ -1305,6 +1323,7 @@ void __init pnv_pci_init_ioda1_phb(struct device_node *np)
> 	 * ourselves here
> 	 */
> 	ppc_md.pcibios_fixup_phb = pnv_pci_ioda_fixup_phb;
>+	ppc_md.pcibios_fixup = pnv_pci_ioda_fixup;
> 	ppc_md.pcibios_enable_device_hook = pnv_pci_enable_device_hook;
> 	pci_add_flags(PCI_PROBE_ONLY | PCI_REASSIGN_ALL_RSRC);
>
>diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>index 8bc4796..0cb760c 100644
>--- a/arch/powerpc/platforms/powernv/pci.h
>+++ b/arch/powerpc/platforms/powernv/pci.h
>@@ -17,9 +17,14 @@ enum pnv_phb_model {
> };
>
> #define PNV_PCI_DIAG_BUF_SIZE	4096
>+#define PNV_IODA_PE_DEV		(1 << 0)	/* PE has single PCI device	*/
>+#define PNV_IODA_PE_BUS		(1 << 1)	/* PE has primary PCI bus	*/
>+#define PNV_IODA_PE_BUS_ALL	(1 << 2)	/* PE has subordinate buses	*/
>
> /* Data associated with a PE, including IOMMU tracking etc.. */
> struct pnv_ioda_pe {
>+	unsigned long		flags;
>+
> 	/* A PE can be associated with a single device or an
> 	 * entire bus (& children). In the former case, pdev
> 	 * is populated, in the later case, pbus is.
>@@ -40,11 +45,6 @@ struct pnv_ioda_pe {
> 	 */
> 	unsigned int		dma_weight;
>
>-	/* This is a PCI-E -> PCI-X bridge, this points to the
>-	 * corresponding bus PE
>-	 */
>-	struct pnv_ioda_pe	*bus_pe;
>-
> 	/* "Base" iommu table, ie, 4K TCEs, 32-bit DMA */
> 	int			tce32_seg;
> 	int			tce32_segcount;
>-- 
>1.7.9.5
>
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-- 
Richard Yang
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