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_device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/pci.h>
  13 #include <linux/export.h>
  14 #include <asm/leon.h>
  15 #include <asm/leon_pci.h>
  16
  17 /* The LEON architecture does not rely on a BIOS or bootloader to setup
  18  * PCI for us. The Linux generic routines are used to setup resources,
  19  * reset values of configuration-space register settings are preserved.
  20  *
  21  * PCI Memory and Prefetchable Memory is direct-mapped. However I/O Space is
  22  * accessed through a Window which is translated to low 64KB in PCI space, the
  23  * first 4KB is not used so 60KB is available.
  24  */
  25 void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
  26 {
  27         LIST_HEAD(resources);
  28         struct pci_bus *root_bus;
  29         struct pci_host_bridge *bridge;
  30         int ret;
  31
  32         bridge = pci_alloc_host_bridge(0);
  33         if (!bridge)
  34                 return;
  35
  36         pci_add_resource_offset(&resources, &info->io_space,
  37                                 info->io_space.start - 0x1000);
  38         pci_add_resource(&resources, &info->mem_space);
  39         info->busn.flags = IORESOURCE_BUS;
  40         pci_add_resource(&resources, &info->busn);
  41
  42         list_splice_init(&resources, &bridge->windows);
  43         bridge->dev.parent = &ofdev->dev;
  44         bridge->sysdata = info;
  45         bridge->busnr = 0;
  46         bridge->ops = info->ops;
  47         bridge->swizzle_irq = pci_common_swizzle;
  48         bridge->map_irq = info->map_irq;
  49
  50         ret = pci_scan_root_bus_bridge(bridge);
  51         if (ret) {
  52                 pci_free_host_bridge(bridge);
  53                 return;
  54         }
  55
  56         root_bus = bridge->bus;
  57
  58         /* Assign devices with resources */
  59         pci_assign_unassigned_resources();
  60         pci_bus_add_devices(root_bus);
  61 }
  62
  63 void pcibios_fixup_bus(struct pci_bus *pbus)
  64 {
  65         struct pci_dev *dev;
  66         int i, has_io, has_mem;
  67         u16 cmd;
  68
  69         list_for_each_entry(dev, &pbus->devices, bus_list) {
  70                 /*
  71                  * We can not rely on that the bootloader has enabled I/O
  72                  * or memory access to PCI devices. Instead we enable it here
  73                  * if the device has BARs of respective type.
  74                  */
  75                 has_io = has_mem = 0;
  76                 for (i = 0; i < PCI_ROM_RESOURCE; i++) {
  77                         unsigned long f = dev->resource[i].flags;
  78                         if (f & IORESOURCE_IO)
  79                                 has_io = 1;
  80                         else if (f & IORESOURCE_MEM)
  81                                 has_mem = 1;
  82                 }
  83                 /* ROM BARs are mapped into 32-bit memory space */
  84                 if (dev->resource[PCI_ROM_RESOURCE].end != 0) {
  85                         dev->resource[PCI_ROM_RESOURCE].flags |=
  86                                                         IORESOURCE_ROM_ENABLE;
  87                         has_mem = 1;
  88                 }
  89                 pci_bus_read_config_word(pbus, dev->devfn, PCI_COMMAND, &cmd);
  90                 if (has_io && !(cmd & PCI_COMMAND_IO)) {
  91 #ifdef CONFIG_PCI_DEBUG
  92                         printk(KERN_INFO "LEONPCI: Enabling I/O for dev %s\n",
  93                                          pci_name(dev));
  94 #endif
  95                         cmd |= PCI_COMMAND_IO;
  96                         pci_bus_write_config_word(pbus, dev->devfn, PCI_COMMAND,
  97                                                                         cmd);
  98                 }
  99                 if (has_mem && !(cmd & PCI_COMMAND_MEMORY)) {
 100 #ifdef CONFIG_PCI_DEBUG
 101                         printk(KERN_INFO "LEONPCI: Enabling MEMORY for dev"
 102                                          "%s\n", pci_name(dev));
 103 #endif
 104                         cmd |= PCI_COMMAND_MEMORY;
 105                         pci_bus_write_config_word(pbus, dev->devfn, PCI_COMMAND,
 106                                                                         cmd);
 107                 }
 108         }
 109 }