1 /* 2 * mmconfig.c - Low-level direct PCI config space access via MMCONFIG 3 * 4 * This is an 64bit optimized version that always keeps the full mmconfig 5 * space mapped. This allows lockless config space operation. 6 */ 7 8 #include <linux/pci.h> 9 #include <linux/init.h> 10 #include <linux/acpi.h> 11 #include <linux/bitmap.h> 12 #include <asm/e820.h> 13 14 #include "pci.h" 15 16 /* Static virtual mapping of the MMCONFIG aperture */ 17 struct mmcfg_virt { 18 struct acpi_mcfg_allocation *cfg; 19 char __iomem *virt; 20 }; 21 static struct mmcfg_virt *pci_mmcfg_virt; 22 23 static char __iomem *get_virt(unsigned int seg, unsigned bus) 24 { 25 struct acpi_mcfg_allocation *cfg; 26 int cfg_num; 27 28 for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) { 29 cfg = pci_mmcfg_virt[cfg_num].cfg; 30 if (cfg->pci_segment == seg && 31 (cfg->start_bus_number <= bus) && 32 (cfg->end_bus_number >= bus)) 33 return pci_mmcfg_virt[cfg_num].virt; 34 } 35 36 /* Fall back to type 0 */ 37 return NULL; 38 } 39 40 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn) 41 { 42 char __iomem *addr; 43 44 addr = get_virt(seg, bus); 45 if (!addr) 46 return NULL; 47 return addr + ((bus << 20) | (devfn << 12)); 48 } 49 50 static int pci_mmcfg_read(unsigned int seg, unsigned int bus, 51 unsigned int devfn, int reg, int len, u32 *value) 52 { 53 char __iomem *addr; 54 55 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ 56 if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) { 57 err: *value = -1; 58 return -EINVAL; 59 } 60 61 addr = pci_dev_base(seg, bus, devfn); 62 if (!addr) 63 goto err; 64 65 switch (len) { 66 case 1: 67 *value = mmio_config_readb(addr + reg); 68 break; 69 case 2: 70 *value = mmio_config_readw(addr + reg); 71 break; 72 case 4: 73 *value = mmio_config_readl(addr + reg); 74 break; 75 } 76 77 return 0; 78 } 79 80 static int pci_mmcfg_write(unsigned int seg, unsigned int bus, 81 unsigned int devfn, int reg, int len, u32 value) 82 { 83 char __iomem *addr; 84 85 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ 86 if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) 87 return -EINVAL; 88 89 addr = pci_dev_base(seg, bus, devfn); 90 if (!addr) 91 return -EINVAL; 92 93 switch (len) { 94 case 1: 95 mmio_config_writeb(addr + reg, value); 96 break; 97 case 2: 98 mmio_config_writew(addr + reg, value); 99 break; 100 case 4: 101 mmio_config_writel(addr + reg, value); 102 break; 103 } 104 105 return 0; 106 } 107 108 static struct pci_raw_ops pci_mmcfg = { 109 .read = pci_mmcfg_read, 110 .write = pci_mmcfg_write, 111 }; 112 113 static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg) 114 { 115 void __iomem *addr; 116 u32 size; 117 118 size = (cfg->end_bus_number + 1) << 20; 119 addr = ioremap_nocache(cfg->address, size); 120 if (addr) { 121 printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n", 122 cfg->address, cfg->address + size - 1); 123 } 124 return addr; 125 } 126 127 int __init pci_mmcfg_arch_init(void) 128 { 129 int i; 130 pci_mmcfg_virt = kzalloc(sizeof(*pci_mmcfg_virt) * 131 pci_mmcfg_config_num, GFP_KERNEL); 132 if (pci_mmcfg_virt == NULL) { 133 printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n"); 134 return 0; 135 } 136 137 for (i = 0; i < pci_mmcfg_config_num; ++i) { 138 pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i]; 139 pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]); 140 if (!pci_mmcfg_virt[i].virt) { 141 printk(KERN_ERR "PCI: Cannot map mmconfig aperture for " 142 "segment %d\n", 143 pci_mmcfg_config[i].pci_segment); 144 pci_mmcfg_arch_free(); 145 return 0; 146 } 147 } 148 raw_pci_ext_ops = &pci_mmcfg; 149 return 1; 150 } 151 152 void __init pci_mmcfg_arch_free(void) 153 { 154 int i; 155 156 if (pci_mmcfg_virt == NULL) 157 return; 158 159 for (i = 0; i < pci_mmcfg_config_num; ++i) { 160 if (pci_mmcfg_virt[i].virt) { 161 iounmap(pci_mmcfg_virt[i].virt); 162 pci_mmcfg_virt[i].virt = NULL; 163 pci_mmcfg_virt[i].cfg = NULL; 164 } 165 } 166 167 kfree(pci_mmcfg_virt); 168 pci_mmcfg_virt = NULL; 169 } 170