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 int pcibios_enable_device(struct pci_dev *dev, int mask) 64 { 65 u16 cmd, oldcmd; 66 int i; 67 68 pci_read_config_word(dev, PCI_COMMAND, &cmd); 69 oldcmd = cmd; 70 71 for (i = 0; i < PCI_NUM_RESOURCES; i++) { 72 struct resource *res = &dev->resource[i]; 73 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 } 90