Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbdGEJgc (ORCPT ); Wed, 5 Jul 2017 05:36:32 -0400 Received: from mail-io0-f169.google.com ([209.85.223.169]:35549 "EHLO mail-io0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750867AbdGEJga (ORCPT ); Wed, 5 Jul 2017 05:36:30 -0400 MIME-Version: 1.0 In-Reply-To: <1802aae0-f97b-c437-c00e-5fa7c867286d@sigmadesigns.com> References: <741766e5-cff2-db5f-d40b-6866e08fd966@sigmadesigns.com> <1802aae0-f97b-c437-c00e-5fa7c867286d@sigmadesigns.com> From: Ard Biesheuvel Date: Wed, 5 Jul 2017 10:36:24 +0100 Message-ID: Subject: Re: [PATCH v5 2/3] PCI: Add tango PCIe host bridge support To: Marc Gonzalez Cc: Bjorn Helgaas , Lorenzo Pieralisi , Mason , Marc Zyngier , linux-pci , Thibaud Cornic , Liviu Dudau , LKML , David Laight , Thomas Gleixner , Phuong Nguyen , Robin Murphy , Linux ARM Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7281 Lines: 219 On 31 May 2017 at 13:33, Marc Gonzalez wrote: > This driver is required to work around several hardware bugs > in the PCIe controller. > > NB: Revision 1 does not support legacy interrupts, or IO space. > > Signed-off-by: Marc Gonzalez > --- > drivers/pci/host/Kconfig | 8 +++ > drivers/pci/host/Makefile | 1 + > drivers/pci/host/pcie-tango.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/pci_ids.h | 2 + > 4 files changed, 175 insertions(+) > [...] > diff --git a/drivers/pci/host/pcie-tango.c b/drivers/pci/host/pcie-tango.c > new file mode 100644 > index 000000000000..67aaadcc1c5e > --- /dev/null > +++ b/drivers/pci/host/pcie-tango.c > @@ -0,0 +1,164 @@ > +#include > +#include > +#include > + > +#define MSI_MAX 256 > + > +#define SMP8759_MUX 0x48 > +#define SMP8759_TEST_OUT 0x74 > + > +struct tango_pcie { > + void __iomem *mux; > +}; > + > +/*** HOST BRIDGE SUPPORT ***/ > + > +static int smp8759_config_read(struct pci_bus *bus, > + unsigned int devfn, int where, int size, u32 *val) > +{ > + int ret; > + struct pci_config_window *cfg = bus->sysdata; > + struct tango_pcie *pcie = dev_get_drvdata(cfg->parent); > + > + /* > + * QUIRK #1 > + * Reads in configuration space outside devfn 0 return garbage. > + */ > + if (devfn != 0) > + return PCIBIOS_FUNC_NOT_SUPPORTED; > + Does this mean multi-function devices are not supported? E.g., on my system I have -[0000:00]-+-00.0 Advanced Micro Devices, Inc. [AMD] Device 1a00 +-02.0 Advanced Micro Devices, Inc. [AMD] Device 1a01 +-02.1-[01]----00.0 Renesas Technology Corp. uPD720201 USB 3.0 \-02.2-[02]--+-00.0 NVIDIA Corporation GT218 [GeForce 210] \-00.1 NVIDIA Corporation HD Audio Controller where the HDMI audio is on devfn 00.1 on bus 2 > + /* > + * QUIRK #2 > + * Unfortunately, config and mem spaces are muxed. > + * Linux does not support such a setting, since drivers are free > + * to access mem space directly, at any time. > + * Therefore, we can only PRAY that config and mem space accesses > + * NEVER occur concurrently. > + */ > + writel_relaxed(1, pcie->mux); > + ret = pci_generic_config_read(bus, devfn, where, size, val); > + writel_relaxed(0, pcie->mux); > + > + return ret; > +} > + > +static int smp8759_config_write(struct pci_bus *bus, > + unsigned int devfn, int where, int size, u32 val) > +{ > + int ret; > + struct pci_config_window *cfg = bus->sysdata; > + struct tango_pcie *pcie = dev_get_drvdata(cfg->parent); > + > + writel_relaxed(1, pcie->mux); > + ret = pci_generic_config_write(bus, devfn, where, size, val); > + writel_relaxed(0, pcie->mux); > + > + return ret; > +} > + > +static struct pci_ecam_ops smp8759_ecam_ops = { > + .bus_shift = 20, > + .pci_ops = { > + .map_bus = pci_ecam_map_bus, > + .read = smp8759_config_read, > + .write = smp8759_config_write, > + } > +}; > + > +static const struct of_device_id tango_pcie_ids[] = { > + { .compatible = "sigma,smp8759-pcie" }, > + { /* sentinel */ }, > +}; > + > +static int tango_check_pcie_link(void __iomem *test_out) > +{ > + int i; > + > + writel_relaxed(16, test_out); > + for (i = 0; i < 10; ++i) { > + u32 ltssm_state = readl_relaxed(test_out) >> 8; > + if ((ltssm_state & 0x1f) == 0xf) /* L0 */ > + return 0; > + usleep_range(3000, 4000); > + } > + > + return -ENODEV; > +} > + > +static int smp8759_init(struct tango_pcie *pcie, void __iomem *base) > +{ > + pcie->mux = base + SMP8759_MUX; > + > + return tango_check_pcie_link(base + SMP8759_TEST_OUT); > +} > + > +static int tango_pcie_probe(struct platform_device *pdev) > +{ > + int ret = -EINVAL; > + void __iomem *base; > + struct resource *res; > + struct tango_pcie *pcie; > + struct device *dev = &pdev->dev; > + > + pr_err("MAJOR ISSUE: PCIe config and mem spaces are muxed\n"); > + pr_err("Tainting kernel... Use driver at your own risk\n"); > + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); > + > + pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); > + if (!pcie) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, pcie); > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); > + base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(base)) > + return PTR_ERR(base); > + > + if (of_device_is_compatible(dev->of_node, "sigma,smp8759-pcie")) > + ret = smp8759_init(pcie, base); > + > + if (ret) > + return ret; > + > + return pci_host_common_probe(pdev, &smp8759_ecam_ops); > +} > + > +static struct platform_driver tango_pcie_driver = { > + .probe = tango_pcie_probe, > + .driver = { > + .name = KBUILD_MODNAME, > + .of_match_table = tango_pcie_ids, > + }, > +}; > + > +builtin_platform_driver(tango_pcie_driver); > + > +/* > + * QUIRK #3 > + * The root complex advertizes the wrong device class. > + * Header Type 1 is for PCI-to-PCI bridges. > + */ > +static void tango_fixup_class(struct pci_dev *dev) > +{ > + dev->class = PCI_CLASS_BRIDGE_PCI << 8; > +} > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x24, tango_fixup_class); > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x28, tango_fixup_class); > + > +/* > + * QUIRK #4 > + * The root complex exposes a "fake" BAR, which is used to filter > + * bus-to-system accesses. Only accesses within the range defined > + * by this BAR are forwarded to the host, others are ignored. > + * > + * By default, the DMA framework expects an identity mapping, > + * and DRAM0 is mapped at 0x80000000. > + */ > +static void tango_fixup_bar(struct pci_dev *dev) > +{ > + dev->non_compliant_bars = true; > + pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, 0x80000000); > +} > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x24, tango_fixup_bar); > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x28, tango_fixup_bar); > diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h > index f020ab4079d3..b577dbe46f8f 100644 > --- a/include/linux/pci_ids.h > +++ b/include/linux/pci_ids.h > @@ -1369,6 +1369,8 @@ > #define PCI_DEVICE_ID_TTI_HPT374 0x0008 > #define PCI_DEVICE_ID_TTI_HPT372N 0x0009 /* apparently a 372N variant? */ > > +#define PCI_VENDOR_ID_SIGMA 0x1105 > + > #define PCI_VENDOR_ID_VIA 0x1106 > #define PCI_DEVICE_ID_VIA_8763_0 0x0198 > #define PCI_DEVICE_ID_VIA_8380_0 0x0204 > -- > 2.11.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel