From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from exprod5og109.obsmtp.com ([64.18.0.188]:35392 "EHLO mail-pd0-f180.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755378AbbFMAgO (ORCPT ); Fri, 12 Jun 2015 20:36:14 -0400 Received: by pdjm12 with SMTP id m12so33038633pdj.3 for ; Fri, 12 Jun 2015 17:36:14 -0700 (PDT) From: Duc Dang To: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ian Campbell , Marcin Juszkiewicz , Tanmay Inamdar , patches@apm.com, Duc Dang Subject: [PATCH v2 1/1] PCI: X-Gene: Disable Configuration Request Retry Status for X-Gene v1 PCIe Date: Fri, 12 Jun 2015 17:35:57 -0700 Message-Id: <017c1ec8e3f43f86a947eaddb30c9389e0b1053b.1434154377.git.dhdang@apm.com> In-Reply-To: References: Sender: linux-pci-owner@vger.kernel.org List-ID: X-Gene v1 PCIe controller has a bug in Configuration Request Retry Status (CRS) logic: When CPU tries to read Vendor ID and Device ID of not-existed remote device, the controller returns 0xFFFF0001 instead of 0xFFFFFFFF; this will add significant delay in boot time as pci_bus_read_dev_vendor_id will wait for 60 seconds before giving up. So for X-Gene v1 PCIe controllers, disable CRS capability advertisement by clearing CRS Software Visibility bit before returning the Root Capability value to the callers. This is done by implementing X-Gene PCIe specific xgene_pcie_config_read32 for CFG read accesses to replace the generic default pci_generic_config_read32 function. v2 changes: Use pci_generic_config_read32 to implement xgene_pcie_config_read32 Signed-off-by: Duc Dang Tested-by: Ian Campbell Tested-by: Marcin Juszkiewicz --- drivers/pci/host/pci-xgene.c | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c index e6c8864..7e3cf28 100644 --- a/drivers/pci/host/pci-xgene.c +++ b/drivers/pci/host/pci-xgene.c @@ -59,6 +59,12 @@ #define SZ_1T (SZ_1G*1024ULL) #define PIPE_PHY_RATE_RD(src) ((0xc000 & (u32)(src)) >> 0xe) +#define ROOT_CAP_AND_CTRL 0x5C + +/* PCIe IP version */ +#define XGENE_PCIE_IP_VER_UNKN 0 +#define XGENE_PCIE_IP_VER_1 1 + struct xgene_pcie_port { struct device_node *node; struct device *dev; @@ -67,6 +73,7 @@ struct xgene_pcie_port { void __iomem *cfg_base; unsigned long cfg_addr; bool link_up; + u32 version; }; static inline u32 pcie_bar_low_val(u32 addr, u32 flags) @@ -140,9 +147,39 @@ static void __iomem *xgene_pcie_map_bus(struct pci_bus *bus, unsigned int devfn, return xgene_pcie_get_cfg_base(bus) + offset; } +int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn, + int where, int size, u32 *val) +{ + struct xgene_pcie_port *port = bus->sysdata; + + if (pci_generic_config_read32(bus, devfn, where & ~0x3, 4, val) != + PCIBIOS_SUCCESSFUL) + return PCIBIOS_DEVICE_NOT_FOUND; + /* + * X-Gene v1 PCIe controller has a bug in Configuration Request + * Retry Status (CRS) logic: + * When CPU tries to read Vendor ID and Device ID of not-existed + * remote device, the controller returns 0xFFFF0001 instead of + * 0xFFFFFFFF; this will add significant delay in boot time as + * pci_bus_read_dev_vendor_id will wait for 60 seconds before + * giving up. + * So for X-Gene v1 PCIe controllers, disable CRS capability + * advertisement by clearing CRS Software Visibility bit before + * returning the Root Capability value to the callers. + */ + if (pci_is_root_bus(bus) && (port->version == XGENE_PCIE_IP_VER_1) && + ((where & ~0x3) == ROOT_CAP_AND_CTRL)) + *val &= ~(PCI_EXP_RTCAP_CRSVIS << 16); + + if (size <= 2) + *val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1); + + return PCIBIOS_SUCCESSFUL; +} + static struct pci_ops xgene_pcie_ops = { .map_bus = xgene_pcie_map_bus, - .read = pci_generic_config_read32, + .read = xgene_pcie_config_read32, .write = pci_generic_config_write32, }; @@ -500,6 +537,10 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev) port->node = of_node_get(pdev->dev.of_node); port->dev = &pdev->dev; + port->version = XGENE_PCIE_IP_VER_UNKN; + if (of_device_is_compatible(port->node, "apm,xgene-pcie")) + port->version = XGENE_PCIE_IP_VER_1; + ret = xgene_pcie_map_reg(port, pdev); if (ret) return ret; -- 1.9.1