/* * mmconfig.c - Low-level direct PCI config space access via MMCONFIG * * This is an 64bit optimized version that always keeps the full mmconfig * space mapped. This allows lockless config space operation. */ #include <linux/pci.h> #include <linux/init.h> #include <linux/acpi.h> #include "pci.h" #define MMCONFIG_APER_SIZE (256*1024*1024) /* Static virtual mapping of the MMCONFIG aperture */ struct mmcfg_virt { struct acpi_table_mcfg_config *cfg; char *virt; }; static struct mmcfg_virt *pci_mmcfg_virt; static char *get_virt(unsigned int seg, int bus) { int cfg_num = -1; struct acpi_table_mcfg_config *cfg; while (1) { ++cfg_num; if (cfg_num >= pci_mmcfg_config_num) { /* something bad is going on, no cfg table is found. */ /* so we fall back to the old way we used to do this */ /* and just rely on the first entry to be correct. */ return pci_mmcfg_virt[0].virt; } cfg = pci_mmcfg_virt[cfg_num].cfg; if (cfg->pci_segment_group_number != seg) continue; if ((cfg->start_bus_number <= bus) && (cfg->end_bus_number >= bus)) return pci_mmcfg_virt[cfg_num].virt; } } static inline char *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn) { return get_virt(seg, bus) + ((bus << 20) | (devfn << 12)); } static int pci_mmcfg_read(unsigned int seg, unsigned int bus, unsigned int devfn, int reg, int len, u32 *value) { char *addr = pci_dev_base(seg, bus, devfn); if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095))) return -EINVAL; switch (len) { case 1: *value = readb(addr + reg); break; case 2: *value = readw(addr + reg); break; case 4: *value = readl(addr + reg); break; } return 0; } static int pci_mmcfg_write(unsigned int seg, unsigned int bus, unsigned int devfn, int reg, int len, u32 value) { char *addr = pci_dev_base(seg, bus, devfn); if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) return -EINVAL; switch (len) { case 1: writeb(value, addr + reg); break; case 2: writew(value, addr + reg); break; case 4: writel(value, addr + reg); break; } return 0; } static struct pci_raw_ops pci_mmcfg = { .read = pci_mmcfg_read, .write = pci_mmcfg_write, }; static int __init pci_mmcfg_init(void) { int i; if ((pci_probe & PCI_PROBE_MMCONF) == 0) return 0; acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg); if ((pci_mmcfg_config_num == 0) || (pci_mmcfg_config == NULL) || (pci_mmcfg_config[0].base_address == 0)) return 0; /* RED-PEN i386 doesn't do _nocache right now */ pci_mmcfg_virt = kmalloc(sizeof(*pci_mmcfg_virt) * pci_mmcfg_config_num, GFP_KERNEL); if (pci_mmcfg_virt == NULL) { printk("PCI: Can not allocate memory for mmconfig structures\n"); return 0; } for (i = 0; i < pci_mmcfg_config_num; ++i) { pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i]; pci_mmcfg_virt[i].virt = ioremap_nocache(pci_mmcfg_config[i].base_address, MMCONFIG_APER_SIZE); if (!pci_mmcfg_virt[i].virt) { printk("PCI: Cannot map mmconfig aperture for segment %d\n", pci_mmcfg_config[i].pci_segment_group_number); return 0; } printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_config[i].base_address); } raw_pci_ops = &pci_mmcfg; pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF; return 0; } arch_initcall(pci_mmcfg_init);