On Wed, Dec 20, 2017 at 09:36:07PM +0100, Thierry Reding wrote:
> From: Vidya Sagar <vidyas@xxxxxxxxxx>
>
> Use only 4 KiB space from the available 1 GiB PCIe aperture to access
> endpoint configuration space by dynamically moving the AFI_FPCI_BAR base
> address. This frees more space for mapping endpoint device BARs on some
> Tegra platforms.
>
> The ->add_bus() and ->remove_bus() callbacks are now no longer needed,
> so they can be removed.
>
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> [treding@xxxxxxxxxx: various cleanups, update commit message]
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/pci/host/pci-tegra.c | 148 +++++++++----------------------------------
Applied to pci/tegra for v4.16.
Thanks,
Lorenzo
> 1 file changed, 30 insertions(+), 118 deletions(-)
>
> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
> index f2214ca1ad17..56434aa44b60 100644
> --- a/drivers/pci/host/pci-tegra.c
> +++ b/drivers/pci/host/pci-tegra.c
> @@ -269,11 +269,10 @@ struct tegra_pcie {
>
> void __iomem *pads;
> void __iomem *afi;
> + void __iomem *cfg;
> int irq;
>
> - struct list_head buses;
> - struct resource *cs;
> -
> + struct resource cs;
> struct resource io;
> struct resource pio;
> struct resource mem;
> @@ -322,7 +321,6 @@ struct tegra_pcie_port {
> };
>
> struct tegra_pcie_bus {
> - struct vm_struct *area;
> struct list_head list;
> unsigned int nr;
> };
> @@ -362,100 +360,19 @@ static inline u32 pads_readl(struct tegra_pcie *pcie, unsigned long offset)
> *
> * Mapping the whole extended configuration space would require 256 MiB of
> * virtual address space, only a small part of which will actually be used.
> - * To work around this, a 1 MiB of virtual addresses are allocated per bus
> - * when the bus is first accessed. When the physical range is mapped, the
> - * the bus number bits are hidden so that the extended register number bits
> - * appear as bits [19:16]. Therefore the virtual mapping looks like this:
> - *
> - * [19:16] extended register number
> - * [15:11] device number
> - * [10: 8] function number
> - * [ 7: 0] register number
> *
> - * This is achieved by stitching together 16 chunks of 64 KiB of physical
> - * address space via the MMU.
> + * To work around this, a 4 KiB region is used to generate the required
> + * configuration transaction with relevant B:D:F and register offset values.
> + * This is achieved by dynamically programming base address and size of
> + * AFI_AXI_BAR used for end point config space mapping to make sure that the
> + * address (access to which generates correct config transaction) falls in
> + * this 4 KiB region.
> */
> -static unsigned long tegra_pcie_conf_offset(unsigned int devfn, int where)
> -{
> - return ((where & 0xf00) << 8) | (PCI_SLOT(devfn) << 11) |
> - (PCI_FUNC(devfn) << 8) | (where & 0xfc);
> -}
> -
> -static struct tegra_pcie_bus *tegra_pcie_bus_alloc(struct tegra_pcie *pcie,
> - unsigned int busnr)
> +static unsigned int tegra_pcie_conf_offset(u8 bus, unsigned int devfn,
> + unsigned int where)
> {
> - struct device *dev = pcie->dev;
> - pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
> - phys_addr_t cs = pcie->cs->start;
> - struct tegra_pcie_bus *bus;
> - unsigned int i;
> - int err;
> -
> - bus = kzalloc(sizeof(*bus), GFP_KERNEL);
> - if (!bus)
> - return ERR_PTR(-ENOMEM);
> -
> - INIT_LIST_HEAD(&bus->list);
> - bus->nr = busnr;
> -
> - /* allocate 1 MiB of virtual addresses */
> - bus->area = get_vm_area(SZ_1M, VM_IOREMAP);
> - if (!bus->area) {
> - err = -ENOMEM;
> - goto free;
> - }
> -
> - /* map each of the 16 chunks of 64 KiB each */
> - for (i = 0; i < 16; i++) {
> - unsigned long virt = (unsigned long)bus->area->addr +
> - i * SZ_64K;
> - phys_addr_t phys = cs + i * SZ_16M + busnr * SZ_64K;
> -
> - err = ioremap_page_range(virt, virt + SZ_64K, phys, prot);
> - if (err < 0) {
> - dev_err(dev, "ioremap_page_range() failed: %d\n", err);
> - goto unmap;
> - }
> - }
> -
> - return bus;
> -
> -unmap:
> - vunmap(bus->area->addr);
> -free:
> - kfree(bus);
> - return ERR_PTR(err);
> -}
> -
> -static int tegra_pcie_add_bus(struct pci_bus *bus)
> -{
> - struct pci_host_bridge *host = pci_find_host_bridge(bus);
> - struct tegra_pcie *pcie = pci_host_bridge_priv(host);
> - struct tegra_pcie_bus *b;
> -
> - b = tegra_pcie_bus_alloc(pcie, bus->number);
> - if (IS_ERR(b))
> - return PTR_ERR(b);
> -
> - list_add_tail(&b->list, &pcie->buses);
> -
> - return 0;
> -}
> -
> -static void tegra_pcie_remove_bus(struct pci_bus *child)
> -{
> - struct pci_host_bridge *host = pci_find_host_bridge(child);
> - struct tegra_pcie *pcie = pci_host_bridge_priv(host);
> - struct tegra_pcie_bus *bus, *tmp;
> -
> - list_for_each_entry_safe(bus, tmp, &pcie->buses, list) {
> - if (bus->nr == child->number) {
> - vunmap(bus->area->addr);
> - list_del(&bus->list);
> - kfree(bus);
> - break;
> - }
> - }
> + return ((where & 0xf00) << 16) | (bus << 16) | (PCI_SLOT(devfn) << 11) |
> + (PCI_FUNC(devfn) << 8) | (where & 0xff);
> }
>
> static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
> @@ -464,7 +381,6 @@ static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
> {
> struct pci_host_bridge *host = pci_find_host_bridge(bus);
> struct tegra_pcie *pcie = pci_host_bridge_priv(host);
> - struct device *dev = pcie->dev;
> void __iomem *addr = NULL;
>
> if (bus->number == 0) {
> @@ -478,19 +394,17 @@ static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
> }
> }
> } else {
> - struct tegra_pcie_bus *b;
> + unsigned int offset;
> + u32 base;
>
> - list_for_each_entry(b, &pcie->buses, list)
> - if (b->nr == bus->number)
> - addr = (void __iomem *)b->area->addr;
> + offset = tegra_pcie_conf_offset(bus->number, devfn, where);
>
> - if (!addr) {
> - dev_err(dev, "failed to map cfg. space for bus %u\n",
> - bus->number);
> - return NULL;
> - }
> + /* move 4 KiB window to offset within the FPCI region */
> + base = 0xfe100000 + ((offset & ~(SZ_4K - 1)) >> 8);
> + afi_writel(pcie, base, AFI_FPCI_BAR0);
>
> - addr += tegra_pcie_conf_offset(devfn, where);
> + /* move to correct offset within the 4 KiB page */
> + addr = pcie->cfg + (offset & (SZ_4K - 1));
> }
>
> return addr;
> @@ -517,8 +431,6 @@ static int tegra_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
> }
>
> static struct pci_ops tegra_pcie_ops = {
> - .add_bus = tegra_pcie_add_bus,
> - .remove_bus = tegra_pcie_remove_bus,
> .map_bus = tegra_pcie_map_bus,
> .read = tegra_pcie_config_read,
> .write = tegra_pcie_config_write,
> @@ -743,12 +655,9 @@ static void tegra_pcie_setup_translations(struct tegra_pcie *pcie)
> u32 fpci_bar, size, axi_address;
>
> /* Bar 0: type 1 extended configuration space */
> - fpci_bar = 0xfe100000;
> - size = resource_size(pcie->cs);
> - axi_address = pcie->cs->start;
> - afi_writel(pcie, axi_address, AFI_AXI_BAR0_START);
> + size = resource_size(&pcie->cs);
> + afi_writel(pcie, pcie->cs.start, AFI_AXI_BAR0_START);
> afi_writel(pcie, size >> 12, AFI_AXI_BAR0_SZ);
> - afi_writel(pcie, fpci_bar, AFI_FPCI_BAR0);
>
> /* Bar 1: downstream IO bar */
> fpci_bar = 0xfdfc0000;
> @@ -1353,10 +1262,14 @@ static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
> goto poweroff;
> }
>
> - pcie->cs = devm_request_mem_region(dev, res->start,
> - resource_size(res), res->name);
> - if (!pcie->cs) {
> - err = -EADDRNOTAVAIL;
> + pcie->cs = *res;
> +
> + /* constrain configuration space to 4 KiB */
> + pcie->cs.end = pcie->cs.start + SZ_4K - 1;
> +
> + pcie->cfg = devm_ioremap_resource(dev, &pcie->cs);
> + if (IS_ERR(pcie->cfg)) {
> + err = PTR_ERR(pcie->cfg);
> goto poweroff;
> }
>
> @@ -2376,7 +2289,6 @@ static int tegra_pcie_probe(struct platform_device *pdev)
> pcie = pci_host_bridge_priv(host);
>
> pcie->soc = of_device_get_match_data(dev);
> - INIT_LIST_HEAD(&pcie->buses);
> INIT_LIST_HEAD(&pcie->ports);
> pcie->dev = dev;
>
> --
> 2.15.1
>
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