arch/sparc/kernel/leon_pci.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * leon_pci.c: LEON Host PCI support
   4  *
   5  * Copyright (C) 2011 Aeroflex Gaisler AB, Daniel Hellstrom
   6  *
   7  * Code is partially derived from pcic.c
   8  */
   9
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/pci.h>
  14 #include <linux/export.h>
  15 #include <asm/leon.h>
  16 #include <asm/leon_pci.h>
  17
  18 /* The LEON architecture does not rely on a BIOS or bootloader to setup
  19  * PCI for us. The Linux generic routines are used to setup resources,
  20  * reset values of configuration-space register settings are preserved.
  21  *
  22  * PCI Memory and Prefetchable Memory is direct-mapped. However I/O Space is
  23  * accessed through a Window which is translated to low 64KB in PCI space, the
  24  * first 4KB is not used so 60KB is available.
  25  */
  26 void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
  27 {
  28         LIST_HEAD(resources);
  29         struct pci_bus *root_bus;
  30         struct pci_host_bridge *bridge;
  31         int ret;
  32
  33         bridge = pci_alloc_host_bridge(0);
  34         if (!bridge)
  35                 return;
  36
  37         pci_add_resource_offset(&resources, &info->io_space,
  38                                 info->io_space.start - 0x1000);
  39         pci_add_resource(&resources, &info->mem_space);
  40         info->busn.flags = IORESOURCE_BUS;
  41         pci_add_resource(&resources, &info->busn);
  42
  43         list_splice_init(&resources, &bridge->windows);
  44         bridge->dev.parent = &ofdev->dev;
  45         bridge->sysdata = info;
  46         bridge->busnr = 0;
  47         bridge->ops = info->ops;
  48         bridge->swizzle_irq = pci_common_swizzle;
  49         bridge->map_irq = info->map_irq;
  50
  51         ret = pci_scan_root_bus_bridge(bridge);
  52         if (ret) {
  53                 pci_free_host_bridge(bridge);
  54                 return;
  55         }
  56
  57         root_bus = bridge->bus;
  58
  59         /* Assign devices with resources */
  60         pci_assign_unassigned_resources();
  61         pci_bus_add_devices(root_bus);
  62 }
  63
  64 int pcibios_enable_device(struct pci_dev *dev, int mask)
  65 {
  66         struct resource *res;
  67         u16 cmd, oldcmd;
  68         int i;
  69
  70         pci_read_config_word(dev, PCI_COMMAND, &cmd);
  71         oldcmd = cmd;
  72
  73         pci_dev_for_each_resource(dev, res, i) {
  74                 /* Only set up the requested stuff */
  75                 if (!(mask & (1<<i)))
  76                         continue;
  77
  78                 if (res->flags & IORESOURCE_IO)
  79                         cmd |= PCI_COMMAND_IO;
  80                 if (res->flags & IORESOURCE_MEM)
  81                         cmd |= PCI_COMMAND_MEMORY;
  82         }
  83
  84         if (cmd != oldcmd) {
  85                 pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
  86                 pci_write_config_word(dev, PCI_COMMAND, cmd);
  87         }
  88         return 0;
  89 }