2 * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
4 * This is an 64bit optimized version that always keeps the full mmconfig
5 * space mapped. This allows lockless config space operation.
9 #include <linux/init.h>
10 #include <linux/acpi.h>
11 #include <linux/bitmap.h>
16 /* aperture is up to 256MB but BIOS may reserve less */
17 #define MMCONFIG_APER_MIN (2 * 1024*1024)
18 #define MMCONFIG_APER_MAX (256 * 1024*1024)
20 /* Verify the first 16 busses. We assume that systems with more busses
22 #define PCI_MMCFG_MAX_CHECK_BUS 16
24 /* Static virtual mapping of the MMCONFIG aperture */
26 struct acpi_mcfg_allocation *cfg;
29 static struct mmcfg_virt *pci_mmcfg_virt;
31 static char __iomem *get_virt(unsigned int seg, unsigned bus)
34 struct acpi_mcfg_allocation *cfg;
38 if (cfg_num >= pci_mmcfg_config_num)
40 cfg = pci_mmcfg_virt[cfg_num].cfg;
41 if (cfg->pci_segment != seg)
43 if ((cfg->start_bus_number <= bus) &&
44 (cfg->end_bus_number >= bus))
45 return pci_mmcfg_virt[cfg_num].virt;
48 /* Fall back to type 0 */
52 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
55 if (seg == 0 && bus < PCI_MMCFG_MAX_CHECK_BUS &&
56 test_bit(32*bus + PCI_SLOT(devfn), pci_mmcfg_fallback_slots))
58 addr = get_virt(seg, bus);
61 return addr + ((bus << 20) | (devfn << 12));
64 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
65 unsigned int devfn, int reg, int len, u32 *value)
69 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
70 if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
75 addr = pci_dev_base(seg, bus, devfn);
77 return pci_conf1_read(seg,bus,devfn,reg,len,value);
81 *value = readb(addr + reg);
84 *value = readw(addr + reg);
87 *value = readl(addr + reg);
94 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
95 unsigned int devfn, int reg, int len, u32 value)
99 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
100 if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
103 addr = pci_dev_base(seg, bus, devfn);
105 return pci_conf1_write(seg,bus,devfn,reg,len,value);
109 writeb(value, addr + reg);
112 writew(value, addr + reg);
115 writel(value, addr + reg);
122 static struct pci_raw_ops pci_mmcfg = {
123 .read = pci_mmcfg_read,
124 .write = pci_mmcfg_write,
127 static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg)
132 size = (cfg->end_bus_number + 1) << 20;
133 addr = ioremap_nocache(cfg->address, size);
135 printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n",
136 cfg->address, cfg->address + size - 1);
141 int __init pci_mmcfg_arch_init(void)
144 pci_mmcfg_virt = kmalloc(sizeof(*pci_mmcfg_virt) *
145 pci_mmcfg_config_num, GFP_KERNEL);
146 if (pci_mmcfg_virt == NULL) {
147 printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n");
151 for (i = 0; i < pci_mmcfg_config_num; ++i) {
152 pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
153 pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]);
154 if (!pci_mmcfg_virt[i].virt) {
155 printk(KERN_ERR "PCI: Cannot map mmconfig aperture for "
157 pci_mmcfg_config[i].pci_segment);
161 raw_pci_ops = &pci_mmcfg;