leon_pci.c
// SPDX-License-Identifier: GPL-2.0
/*
* leon_pci.c: LEON Host PCI support
*
* Copyright (C) 2011 Aeroflex Gaisler AB, Daniel Hellstrom
*
* Code is partially derived from pcic.c
*/
#include <linux/of_device.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/export.h>
#include <asm/leon.h>
#include <asm/leon_pci.h>
/* The LEON architecture does not rely on a BIOS or bootloader to setup
* PCI for us. The Linux generic routines are used to setup resources,
* reset values of configuration-space register settings are preserved.
*
* PCI Memory and Prefetchable Memory is direct-mapped. However I/O Space is
* accessed through a Window which is translated to low 64KB in PCI space, the
* first 4KB is not used so 60KB is available.
*/
void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info)
{
LIST_HEAD(resources);
struct pci_bus *root_bus;
struct pci_host_bridge *bridge;
int ret;
bridge = pci_alloc_host_bridge(0);
if (!bridge)
return;
pci_add_resource_offset(&resources, &info->io_space,
info->io_space.start - 0x1000);
pci_add_resource(&resources, &info->mem_space);
info->busn.flags = IORESOURCE_BUS;
pci_add_resource(&resources, &info->busn);
list_splice_init(&resources, &bridge->windows);
bridge->dev.parent = &ofdev->dev;
bridge->sysdata = info;
bridge->busnr = 0;
bridge->ops = info->ops;
bridge->swizzle_irq = pci_common_swizzle;
bridge->map_irq = info->map_irq;
ret = pci_scan_root_bus_bridge(bridge);
if (ret) {
pci_free_host_bridge(bridge);
return;
}
root_bus = bridge->bus;
/* Assign devices with resources */
pci_assign_unassigned_resources();
pci_bus_add_devices(root_bus);
}
int pcibios_enable_device(struct pci_dev *dev, int mask)
{
u16 cmd, oldcmd;
int i;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
oldcmd = cmd;
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *res = &dev->resource[i];
/* Only set up the requested stuff */
if (!(mask & (1<<i)))
continue;
if (res->flags & IORESOURCE_IO)
cmd |= PCI_COMMAND_IO;
if (res->flags & IORESOURCE_MEM)
cmd |= PCI_COMMAND_MEMORY;
}
if (cmd != oldcmd) {
pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd);
pci_write_config_word(dev, PCI_COMMAND, cmd);
}
return 0;
}