Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/x86/pci/mmconfig_64.c
10818 views
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
#include <asm/pci_x86.h>

14


15
#define PREFIX "PCI: "

16


17
static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)

18
{

19
	struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);

20


21
	if (cfg && cfg->virt)

22
		return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));

23
	return NULL;

24
}

25


26
static int pci_mmcfg_read(unsigned int seg, unsigned int bus,

27
			  unsigned int devfn, int reg, int len, u32 *value)

28
{

29
	char __iomem *addr;

30


31
	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */

32
	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {

33
err:		*value = -1;

34
		return -EINVAL;

35
	}

36


37
	addr = pci_dev_base(seg, bus, devfn);

38
	if (!addr)

39
		goto err;

40


41
	switch (len) {

42
	case 1:

43
		*value = mmio_config_readb(addr + reg);

44
		break;

45
	case 2:

46
		*value = mmio_config_readw(addr + reg);

47
		break;

48
	case 4:

49
		*value = mmio_config_readl(addr + reg);

50
		break;

51
	}

52


53
	return 0;

54
}

55


56
static int pci_mmcfg_write(unsigned int seg, unsigned int bus,

57
			   unsigned int devfn, int reg, int len, u32 value)

58
{

59
	char __iomem *addr;

60


61
	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */

62
	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))

63
		return -EINVAL;

64


65
	addr = pci_dev_base(seg, bus, devfn);

66
	if (!addr)

67
		return -EINVAL;

68


69
	switch (len) {

70
	case 1:

71
		mmio_config_writeb(addr + reg, value);

72
		break;

73
	case 2:

74
		mmio_config_writew(addr + reg, value);

75
		break;

76
	case 4:

77
		mmio_config_writel(addr + reg, value);

78
		break;

79
	}

80


81
	return 0;

82
}

83


84
static struct pci_raw_ops pci_mmcfg = {

85
	.read =		pci_mmcfg_read,

86
	.write =	pci_mmcfg_write,

87
};

88


89
static void __iomem * __init mcfg_ioremap(struct pci_mmcfg_region *cfg)

90
{

91
	void __iomem *addr;

92
	u64 start, size;

93
	int num_buses;

94


95
	start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus);

96
	num_buses = cfg->end_bus - cfg->start_bus + 1;

97
	size = PCI_MMCFG_BUS_OFFSET(num_buses);

98
	addr = ioremap_nocache(start, size);

99
	if (addr)

100
		addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus);

101
	return addr;

102
}

103


104
int __init pci_mmcfg_arch_init(void)

105
{

106
	struct pci_mmcfg_region *cfg;

107


108
	list_for_each_entry(cfg, &pci_mmcfg_list, list) {

109
		cfg->virt = mcfg_ioremap(cfg);

110
		if (!cfg->virt) {

111
			printk(KERN_ERR PREFIX "can't map MMCONFIG at %pR\n",

112
			       &cfg->res);

113
			pci_mmcfg_arch_free();

114
			return 0;

115
		}

116
	}

117
	raw_pci_ext_ops = &pci_mmcfg;

118
	return 1;

119
}

120


121
void __init pci_mmcfg_arch_free(void)

122
{

123
	struct pci_mmcfg_region *cfg;

124


125
	list_for_each_entry(cfg, &pci_mmcfg_list, list) {

126
		if (cfg->virt) {

127
			iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus));

128
			cfg->virt = NULL;

129
		}

130
	}

131
}

132


133