Re: [PATCH 2/4] PCI: add driver for Cortina Gemini Host Bridge

Arnd Bergmann
2017-02-01T11:11:57Z

On Saturday, January 28, 2017 9:48:37 PM CET Linus Walleij wrote:
> +static int gemini_pci_read_config(struct pci_bus *bus, unsigned int fn,
> + int config, int size, u32 *value)
> +{
> + struct gemini_pci *p = bus->sysdata;
> + unsigned long irq_flags;
> +
> + spin_lock_irqsave(&p->lock, irq_flags);
> +
> + writel(PCI_CONF_BUS(bus->number) |
> + PCI_CONF_DEVICE(PCI_SLOT(fn)) |
> + PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
> + PCI_CONF_WHERE(config) |
> + PCI_CONF_ENABLE,
> + p->base + PCI_CONFIG);
> +
> + *value = readl(p->base + PCI_DATA);
> +
> + if (size == 1)
> + *value = (*value >> (8 * (config & 3))) & 0xFF;
> + else if (size == 2)
> + *value = (*value >> (8 * (config & 3))) & 0xFFFF;
> +
> + spin_unlock_irqrestore(&p->lock, irq_flags);

The read_config/write_config functions are called under a spinlock,
no need for another one.

> + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + p->base = devm_ioremap_resource(dev, regs);
> + if (IS_ERR(p->base))
> + return PTR_ERR(p->base);
> +
> + ret = of_pci_get_host_bridge_resources(dev->of_node, 0, 0xff,
> + &res, &io_base);
> + if (ret)
> + return ret;
> +
> + ret = devm_request_pci_bus_resources(dev, &res);
> + if (ret)
> + return ret;
> +
> + /* No clue what these do */
> + pcibios_min_io = 0x100;
> + pcibios_min_mem = 0;

Don't touch these

> + /* setup I/O space to 1MB size */
> + writel(GEMINI_PCI_IOSIZE_1M, p->base + PCI_IOSIZE);

Maybe get the size from the resource instead? Note that pci_remap_iospace
only registers 64K of I/O space, so you could also use that.

> + /* setup hostbridge */
> + val = readl(p->base + PCI_CTRL);
> + val |= PCI_COMMAND_IO;
> + val |= PCI_COMMAND_MEMORY;
> + val |= PCI_COMMAND_MASTER;
> + writel(val, p->base + PCI_CTRL);
> +
> + /* Get the I/O and memory ranges from DT */
> + resource_list_for_each_entry(win, &res) {
> + switch (resource_type(win->res)) {
> + case IORESOURCE_IO:
> + io = win->res;
> + io->name = "Gemini PCI I/O";
> + ret = pci_remap_iospace(io, io_base);
> + if (ret) {
> + dev_warn(dev, "error %d: failed to map resource %pR\n",
> + ret, io);
> + continue;
> + }
> + break;
> + case IORESOURCE_MEM:
> + mem = win->res;
> + mem->name = "Gemini PCI MEM";
> + break;
> + case IORESOURCE_BUS:
> + break;
> + default:
> + break;
> + }
> + }
> +
> + bus = pci_scan_root_bus(&pdev->dev, 0, &gemini_pci_ops, p, &res);

Can you try using the new pci_register_host_bridge() API?

Arnd