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

From: Richard Yang <[email-masked]>
Date: Wed, 1 Aug 2012 05:04:46 -0400

On Wed, Aug 01, 2012 at 04:26:54PM +0800, Gavin Shan wrote:
>On Wed, Aug 01, 2012 at 03:49:41AM -0400, Richard Yang wrote:
>>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().
>>
>
>Thanks, Richard. I think we probablly need remove the following line in pnv_ioda_alloc_pe()
>instead of the line you pointed because pnv_ioda_alloc_pe() might return invalid
>PE number (-1). That will eventually cause data corruption while using "-1" to
>referring phb->ioda.pe_array[], even the situation shouldn't happen for now :-)
>
>	phb->ioda.pe_array[pe].pe_number = pe;

oh, so it is not proper to set pe_number = -1 in the pe_array, right?

>
>Let me change it accordingly in next version. The series of patches is pending
>for the patches against PCI core change. The later one is waiting for Bjorn's
>confirm.
>
>Thanks,
>Gavin
>
>>> 	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
>>>
>>>_______________________________________________
>>>Linuxppc-dev mailing list
>>>[email-masked]
>>>https://lists.ozlabs.org/listinfo/linuxppc-dev
>>
>>-- 
>>Richard Yang
>>Help you, Help me
>
>_______________________________________________
>Linuxppc-dev mailing list
>[email-masked]
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-- 
Richard Yang
Help you, Help me