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 MAX_CHECK_BUS 16
24 static DECLARE_BITMAP(fallback_slots
, 32*MAX_CHECK_BUS
);
26 /* Static virtual mapping of the MMCONFIG aperture */
28 struct acpi_table_mcfg_config
*cfg
;
31 static struct mmcfg_virt
*pci_mmcfg_virt
;
33 static char __iomem
*get_virt(unsigned int seg
, unsigned bus
)
36 struct acpi_table_mcfg_config
*cfg
;
40 if (cfg_num
>= pci_mmcfg_config_num
)
42 cfg
= pci_mmcfg_virt
[cfg_num
].cfg
;
43 if (cfg
->pci_segment_group_number
!= seg
)
45 if ((cfg
->start_bus_number
<= bus
) &&
46 (cfg
->end_bus_number
>= bus
))
47 return pci_mmcfg_virt
[cfg_num
].virt
;
50 /* Handle more broken MCFG tables on Asus etc.
51 They only contain a single entry for bus 0-0. Assume
52 this applies to all busses. */
53 cfg
= &pci_mmcfg_config
[0];
54 if (pci_mmcfg_config_num
== 1 &&
55 cfg
->pci_segment_group_number
== 0 &&
56 (cfg
->start_bus_number
| cfg
->end_bus_number
) == 0)
57 return pci_mmcfg_virt
[0].virt
;
59 /* Fall back to type 0 */
63 static char __iomem
*pci_dev_base(unsigned int seg
, unsigned int bus
, unsigned int devfn
)
66 if (seg
== 0 && bus
< MAX_CHECK_BUS
&&
67 test_bit(32*bus
+ PCI_SLOT(devfn
), fallback_slots
))
69 addr
= get_virt(seg
, bus
);
72 return addr
+ ((bus
<< 20) | (devfn
<< 12));
75 static int pci_mmcfg_read(unsigned int seg
, unsigned int bus
,
76 unsigned int devfn
, int reg
, int len
, u32
*value
)
80 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
81 if (unlikely((bus
> 255) || (devfn
> 255) || (reg
> 4095))) {
86 addr
= pci_dev_base(seg
, bus
, devfn
);
88 return pci_conf1_read(seg
,bus
,devfn
,reg
,len
,value
);
92 *value
= readb(addr
+ reg
);
95 *value
= readw(addr
+ reg
);
98 *value
= readl(addr
+ reg
);
105 static int pci_mmcfg_write(unsigned int seg
, unsigned int bus
,
106 unsigned int devfn
, int reg
, int len
, u32 value
)
110 /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
111 if (unlikely((bus
> 255) || (devfn
> 255) || (reg
> 4095)))
114 addr
= pci_dev_base(seg
, bus
, devfn
);
116 return pci_conf1_write(seg
,bus
,devfn
,reg
,len
,value
);
120 writeb(value
, addr
+ reg
);
123 writew(value
, addr
+ reg
);
126 writel(value
, addr
+ reg
);
133 static struct pci_raw_ops pci_mmcfg
= {
134 .read
= pci_mmcfg_read
,
135 .write
= pci_mmcfg_write
,
138 /* K8 systems have some devices (typically in the builtin northbridge)
139 that are only accessible using type1
140 Normally this can be expressed in the MCFG by not listing them
141 and assigning suitable _SEGs, but this isn't implemented in some BIOS.
142 Instead try to discover all devices on bus 0 that are unreachable using MM
143 and fallback for them. */
144 static __init
void unreachable_devices(void)
147 /* Use the max bus number from ACPI here? */
148 for (k
= 0; k
< MAX_CHECK_BUS
; k
++) {
149 for (i
= 0; i
< 32; i
++) {
153 pci_conf1_read(0, k
, PCI_DEVFN(i
,0), 0, 4, &val1
);
154 if (val1
== 0xffffffff)
156 addr
= pci_dev_base(0, k
, PCI_DEVFN(i
, 0));
157 if (addr
== NULL
|| readl(addr
) != val1
) {
158 set_bit(i
+ 32*k
, fallback_slots
);
159 printk(KERN_NOTICE
"PCI: No mmconfig possible"
160 " on device %02x:%02x\n", k
, i
);
166 void __init
pci_mmcfg_init(int type
)
170 if ((pci_probe
& PCI_PROBE_MMCONF
) == 0)
173 acpi_table_parse(ACPI_MCFG
, acpi_parse_mcfg
);
174 if ((pci_mmcfg_config_num
== 0) ||
175 (pci_mmcfg_config
== NULL
) ||
176 (pci_mmcfg_config
[0].base_address
== 0))
179 /* Only do this check when type 1 works. If it doesn't work
180 assume we run on a Mac and always use MCFG */
181 if (type
== 1 && !e820_all_mapped(pci_mmcfg_config
[0].base_address
,
182 pci_mmcfg_config
[0].base_address
+ MMCONFIG_APER_MIN
,
184 printk(KERN_ERR
"PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
185 pci_mmcfg_config
[0].base_address
);
186 printk(KERN_ERR
"PCI: Not using MMCONFIG.\n");
190 pci_mmcfg_virt
= kmalloc(sizeof(*pci_mmcfg_virt
) * pci_mmcfg_config_num
, GFP_KERNEL
);
191 if (pci_mmcfg_virt
== NULL
) {
192 printk(KERN_ERR
"PCI: Can not allocate memory for mmconfig structures\n");
195 for (i
= 0; i
< pci_mmcfg_config_num
; ++i
) {
196 pci_mmcfg_virt
[i
].cfg
= &pci_mmcfg_config
[i
];
197 pci_mmcfg_virt
[i
].virt
= ioremap_nocache(pci_mmcfg_config
[i
].base_address
,
199 if (!pci_mmcfg_virt
[i
].virt
) {
200 printk(KERN_ERR
"PCI: Cannot map mmconfig aperture for "
202 pci_mmcfg_config
[i
].pci_segment_group_number
);
205 printk(KERN_INFO
"PCI: Using MMCONFIG at %x\n", pci_mmcfg_config
[i
].base_address
);
208 unreachable_devices();
210 raw_pci_ops
= &pci_mmcfg
;
211 pci_probe
= (pci_probe
& ~PCI_PROBE_MASK
) | PCI_PROBE_MMCONF
;