Re: [PATCH] PCI: Add MCFG quirks for Tegra194 host controllers

[Bjorn Helgaas]

On Fri, Jan 3, 2020 at 11:50 AM Vidya Sagar <vidyas@xxxxxxxxxx> wrote:
>
> The PCIe controller in Tegra194 SoC is not completely ECAM-compliant.

What is the plan for making these SoCs ECAM-compliant?  When was
Tegra194 designed?  Is it shipping to end customers, i.e., would I be
able to buy one?

I do not want to add these quirks indefinitely, and the first quirks
were added over three years ago.

> With the current hardware design limitations in place, ECAM can be enabled
> only for one controller (C5 controller to be precise) with bus numbers
> starting from 160 instead of 0. A different approach is taken to avoid this
> abnormal way of enabling ECAM  for just one controller and to also enable
> configuration space access for all the other controllers. In this approach,
> MCFG quirks are added for each controller with a 30MB PCIe aperture
> resource for each controller in the disguise of ECAM region. But, this
> region actually contains DesignWare core's internal Address Translation
> Unit (iATU) using which the ECAM ops access configuration space in the
> otherwise standard way of programming iATU registers in DesignWare core
> based IPs for a respective B:D:F.
>
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> ---
>  drivers/acpi/pci_mcfg.c                    | 13 +++
>  drivers/pci/controller/dwc/pcie-tegra194.c | 95 ++++++++++++++++++++++
>  include/linux/pci-ecam.h                   |  1 +
>  3 files changed, 109 insertions(+)
>
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> index 6b347d9920cc..a42918ecc19a 100644
> --- a/drivers/acpi/pci_mcfg.c
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -116,6 +116,19 @@ static struct mcfg_fixup mcfg_quirks[] = {
>         THUNDER_ECAM_QUIRK(2, 12),
>         THUNDER_ECAM_QUIRK(2, 13),
>
> +       { "NVIDIA", "TEGRA194", 1, 0, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x38200000, (30 * SZ_1M))},
> +       { "NVIDIA", "TEGRA194", 1, 1, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x30200000, (30 * SZ_1M))},
> +       { "NVIDIA", "TEGRA194", 1, 2, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x32200000, (30 * SZ_1M))},
> +       { "NVIDIA", "TEGRA194", 1, 3, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x34200000, (30 * SZ_1M))},
> +       { "NVIDIA", "TEGRA194", 1, 4, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x36200000, (30 * SZ_1M))},
> +       { "NVIDIA", "TEGRA194", 1, 5, MCFG_BUS_ANY, &tegra194_pcie_ops,
> +         DEFINE_RES_MEM(0x3a200000, (30 * SZ_1M))},
> +
>  #define XGENE_V1_ECAM_MCFG(rev, seg) \
>         {"APM   ", "XGENE   ", rev, seg, MCFG_BUS_ANY, \
>                 &xgene_v1_pcie_ecam_ops }
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index cbe95f0ea0ca..91496978deb7 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -21,6 +21,8 @@
>  #include <linux/of_irq.h>
>  #include <linux/of_pci.h>
>  #include <linux/pci.h>
> +#include <linux/pci-acpi.h>
> +#include <linux/pci-ecam.h>
>  #include <linux/phy/phy.h>
>  #include <linux/pinctrl/consumer.h>
>  #include <linux/platform_device.h>
> @@ -895,6 +897,99 @@ static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
>         .set_num_vectors = tegra_pcie_set_msi_vec_num,
>  };
>
> +#if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
> +struct tegra194_pcie_acpi  {
> +       void __iomem *dbi_base;
> +       void __iomem *iatu_base;
> +};
> +
> +static int tegra194_acpi_init(struct pci_config_window *cfg)
> +{
> +       struct device *dev = cfg->parent;
> +       struct tegra194_pcie_acpi *pcie;
> +
> +       pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +       if (!pcie)
> +               return -ENOMEM;
> +
> +       pcie->dbi_base = cfg->win;
> +       pcie->iatu_base = cfg->win + SZ_256K;
> +       cfg->priv = pcie;
> +
> +       return 0;
> +}
> +
> +static inline void atu_reg_write(struct tegra194_pcie_acpi *pcie, int index,
> +                                u32 val, u32 reg)
> +{
> +       u32 offset = PCIE_GET_ATU_OUTB_UNR_REG_OFFSET(index);
> +
> +       writel(val, pcie->iatu_base + offset + reg);
> +}
> +
> +static void program_outbound_atu(struct tegra194_pcie_acpi *pcie, int index,
> +                                int type, u64 cpu_addr, u64 pci_addr, u64 size)
> +{
> +       atu_reg_write(pcie, index, lower_32_bits(cpu_addr),
> +                     PCIE_ATU_LOWER_BASE);
> +       atu_reg_write(pcie, index, upper_32_bits(cpu_addr),
> +                     PCIE_ATU_UPPER_BASE);
> +       atu_reg_write(pcie, index, lower_32_bits(pci_addr),
> +                     PCIE_ATU_LOWER_TARGET);
> +       atu_reg_write(pcie, index, lower_32_bits(cpu_addr + size - 1),
> +                     PCIE_ATU_LIMIT);
> +       atu_reg_write(pcie, index, upper_32_bits(pci_addr),
> +                     PCIE_ATU_UPPER_TARGET);
> +       atu_reg_write(pcie, index, type, PCIE_ATU_CR1);
> +       atu_reg_write(pcie, index, PCIE_ATU_ENABLE, PCIE_ATU_CR2);
> +}
> +
> +static void __iomem *tegra194_map_bus(struct pci_bus *bus,
> +                                     unsigned int devfn, int where)
> +{
> +       struct pci_config_window *cfg = bus->sysdata;
> +       struct tegra194_pcie_acpi *pcie = cfg->priv;
> +       u32 busdev;
> +       int type;
> +
> +       if (bus->number < cfg->busr.start || bus->number > cfg->busr.end)
> +               return NULL;
> +
> +       if (bus->number == cfg->busr.start) {
> +               if (PCI_SLOT(devfn) == 0)
> +                       return pcie->dbi_base + where;
> +               else
> +                       return NULL;
> +       }
> +
> +       busdev = PCIE_ATU_BUS(bus->number) | PCIE_ATU_DEV(PCI_SLOT(devfn)) |
> +                PCIE_ATU_FUNC(PCI_FUNC(devfn));
> +
> +       if (bus->parent->number == cfg->busr.start) {
> +               if (PCI_SLOT(devfn) == 0)
> +                       type = PCIE_ATU_TYPE_CFG0;
> +               else
> +                       return NULL;
> +       } else {
> +               type = PCIE_ATU_TYPE_CFG1;
> +       }
> +
> +       program_outbound_atu(pcie, PCIE_ATU_REGION_INDEX0, type,
> +                            cfg->res.start + SZ_128K, busdev, SZ_128K);
> +       return (void __iomem *)(pcie->dbi_base + SZ_128K + where);
> +}
> +
> +struct pci_ecam_ops tegra194_pcie_ops = {
> +       .bus_shift      = 20,
> +       .init           = tegra194_acpi_init,
> +       .pci_ops        = {
> +               .map_bus        = tegra194_map_bus,
> +               .read           = pci_generic_config_read,
> +               .write          = pci_generic_config_write,
> +       }
> +};
> +#endif /* defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS) */
> +
>  static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
>  {
>         unsigned int phy_count = pcie->phy_count;
> diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
> index a73164c85e78..6156140dcbb6 100644
> --- a/include/linux/pci-ecam.h
> +++ b/include/linux/pci-ecam.h
> @@ -57,6 +57,7 @@ extern struct pci_ecam_ops pci_thunder_ecam_ops; /* Cavium ThunderX 1.x */
>  extern struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 */
>  extern struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */
>  extern struct pci_ecam_ops al_pcie_ops; /* Amazon Annapurna Labs PCIe */
> +extern struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */
>  #endif
>
>  #ifdef CONFIG_PCI_HOST_COMMON
> --
> 2.17.1
>