![Mike Habeck](/assets/img/avatar_default.png)
The Linux kernel assigns BARs that a BIOS did not assign, most likely to handle broken BIOSes that didn't enumerate the devices correctly. On UV the BIOS purposely doesn't assign I/O BARs for certain devices/ drivers we know don't use them (examples, LSI SAS, Qlogic FC, ...). We purposely don't assign these I/O BARs because I/O Space is a very limited resource. There is only 64k of I/O Space, and in a PCIe topology that space gets divided up into 4k chucks (this is due to the fact that a pci-to-pci bridge's I/O decoder is aligned at 4k)... Thus a system can have at most 16 cards with I/O BARs: (64k / 4k = 16) SGI needs to scale to >16 devices with I/O BARs. So by not assigning I/O BARs on devices we know don't use them, we can do that (iff the kernel doesn't go and assign these BARs that the BIOS purposely didn't assign). This patch will not assign a resource to a device BAR if that BAR was not assigned by the BIOS, and the kernel cmdline option 'pci=nobar' was specified. This patch is closely modeled after the 'pci=norom' option that currently exists in the tree. Signed-off-by: Mike Habeck <habeck@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
201 lines
5.1 KiB
C
201 lines
5.1 KiB
C
/*
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* Low-Level PCI Access for i386 machines.
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*
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* (c) 1999 Martin Mares <mj@ucw.cz>
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*/
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#undef DEBUG
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#ifdef DEBUG
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#define DBG(x...) printk(x)
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#else
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#define DBG(x...)
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#endif
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#define PCI_PROBE_BIOS 0x0001
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#define PCI_PROBE_CONF1 0x0002
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#define PCI_PROBE_CONF2 0x0004
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#define PCI_PROBE_MMCONF 0x0008
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#define PCI_PROBE_MASK 0x000f
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#define PCI_PROBE_NOEARLY 0x0010
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#define PCI_NO_CHECKS 0x0400
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#define PCI_USE_PIRQ_MASK 0x0800
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#define PCI_ASSIGN_ROMS 0x1000
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#define PCI_BIOS_IRQ_SCAN 0x2000
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#define PCI_ASSIGN_ALL_BUSSES 0x4000
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#define PCI_CAN_SKIP_ISA_ALIGN 0x8000
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#define PCI_USE__CRS 0x10000
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#define PCI_CHECK_ENABLE_AMD_MMCONF 0x20000
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#define PCI_HAS_IO_ECS 0x40000
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#define PCI_NOASSIGN_ROMS 0x80000
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#define PCI_ROOT_NO_CRS 0x100000
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#define PCI_NOASSIGN_BARS 0x200000
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extern unsigned int pci_probe;
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extern unsigned long pirq_table_addr;
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enum pci_bf_sort_state {
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pci_bf_sort_default,
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pci_force_nobf,
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pci_force_bf,
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pci_dmi_bf,
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};
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/* pci-i386.c */
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extern unsigned int pcibios_max_latency;
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void pcibios_resource_survey(void);
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/* pci-pc.c */
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extern int pcibios_last_bus;
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extern struct pci_bus *pci_root_bus;
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extern struct pci_ops pci_root_ops;
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void pcibios_scan_specific_bus(int busn);
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/* pci-irq.c */
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struct irq_info {
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u8 bus, devfn; /* Bus, device and function */
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struct {
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u8 link; /* IRQ line ID, chipset dependent,
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0 = not routed */
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u16 bitmap; /* Available IRQs */
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} __attribute__((packed)) irq[4];
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u8 slot; /* Slot number, 0=onboard */
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u8 rfu;
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} __attribute__((packed));
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struct irq_routing_table {
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u32 signature; /* PIRQ_SIGNATURE should be here */
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u16 version; /* PIRQ_VERSION */
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u16 size; /* Table size in bytes */
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u8 rtr_bus, rtr_devfn; /* Where the interrupt router lies */
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u16 exclusive_irqs; /* IRQs devoted exclusively to
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PCI usage */
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u16 rtr_vendor, rtr_device; /* Vendor and device ID of
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interrupt router */
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u32 miniport_data; /* Crap */
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u8 rfu[11];
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u8 checksum; /* Modulo 256 checksum must give 0 */
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struct irq_info slots[0];
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} __attribute__((packed));
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extern unsigned int pcibios_irq_mask;
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extern raw_spinlock_t pci_config_lock;
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extern int (*pcibios_enable_irq)(struct pci_dev *dev);
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extern void (*pcibios_disable_irq)(struct pci_dev *dev);
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struct pci_raw_ops {
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int (*read)(unsigned int domain, unsigned int bus, unsigned int devfn,
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int reg, int len, u32 *val);
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int (*write)(unsigned int domain, unsigned int bus, unsigned int devfn,
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int reg, int len, u32 val);
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};
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extern struct pci_raw_ops *raw_pci_ops;
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extern struct pci_raw_ops *raw_pci_ext_ops;
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extern struct pci_raw_ops pci_direct_conf1;
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extern bool port_cf9_safe;
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/* arch_initcall level */
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extern int pci_direct_probe(void);
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extern void pci_direct_init(int type);
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extern void pci_pcbios_init(void);
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extern void __init dmi_check_pciprobe(void);
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extern void __init dmi_check_skip_isa_align(void);
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/* some common used subsys_initcalls */
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extern int __init pci_acpi_init(void);
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extern void __init pcibios_irq_init(void);
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extern int __init pcibios_init(void);
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extern int pci_legacy_init(void);
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extern void pcibios_fixup_irqs(void);
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/* pci-mmconfig.c */
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/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
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#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
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struct pci_mmcfg_region {
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struct list_head list;
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struct resource res;
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u64 address;
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char __iomem *virt;
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u16 segment;
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u8 start_bus;
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u8 end_bus;
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char name[PCI_MMCFG_RESOURCE_NAME_LEN];
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};
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extern int __init pci_mmcfg_arch_init(void);
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extern void __init pci_mmcfg_arch_free(void);
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extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
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extern struct list_head pci_mmcfg_list;
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#define PCI_MMCFG_BUS_OFFSET(bus) ((bus) << 20)
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/*
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* AMD Fam10h CPUs are buggy, and cannot access MMIO config space
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* on their northbrige except through the * %eax register. As such, you MUST
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* NOT use normal IOMEM accesses, you need to only use the magic mmio-config
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* accessor functions.
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* In fact just use pci_config_*, nothing else please.
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*/
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static inline unsigned char mmio_config_readb(void __iomem *pos)
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{
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u8 val;
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asm volatile("movb (%1),%%al" : "=a" (val) : "r" (pos));
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return val;
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}
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static inline unsigned short mmio_config_readw(void __iomem *pos)
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{
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u16 val;
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asm volatile("movw (%1),%%ax" : "=a" (val) : "r" (pos));
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return val;
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}
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static inline unsigned int mmio_config_readl(void __iomem *pos)
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{
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u32 val;
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asm volatile("movl (%1),%%eax" : "=a" (val) : "r" (pos));
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return val;
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}
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static inline void mmio_config_writeb(void __iomem *pos, u8 val)
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{
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asm volatile("movb %%al,(%1)" : : "a" (val), "r" (pos) : "memory");
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}
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static inline void mmio_config_writew(void __iomem *pos, u16 val)
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{
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asm volatile("movw %%ax,(%1)" : : "a" (val), "r" (pos) : "memory");
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}
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static inline void mmio_config_writel(void __iomem *pos, u32 val)
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{
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asm volatile("movl %%eax,(%1)" : : "a" (val), "r" (pos) : "memory");
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}
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#ifdef CONFIG_PCI
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# ifdef CONFIG_ACPI
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# define x86_default_pci_init pci_acpi_init
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# else
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# define x86_default_pci_init pci_legacy_init
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# endif
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# define x86_default_pci_init_irq pcibios_irq_init
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# define x86_default_pci_fixup_irqs pcibios_fixup_irqs
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#else
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# define x86_default_pci_init NULL
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# define x86_default_pci_init_irq NULL
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# define x86_default_pci_fixup_irqs NULL
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#endif
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