diff options
Diffstat (limited to 'arch/x86/pci/direct.c')
-rw-r--r-- | arch/x86/pci/direct.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/arch/x86/pci/direct.c b/arch/x86/pci/direct.c new file mode 100644 index 0000000000..a51074c559 --- /dev/null +++ b/arch/x86/pci/direct.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * direct.c - Low-level direct PCI config space access + */ + +#include <linux/pci.h> +#include <linux/init.h> +#include <linux/dmi.h> +#include <asm/pci_x86.h> + +/* + * Functions for accessing PCI base (first 256 bytes) and extended + * (4096 bytes per PCI function) configuration space with type 1 + * accesses. + */ + +#define PCI_CONF1_ADDRESS(bus, devfn, reg) \ + (0x80000000 | ((reg & 0xF00) << 16) | (bus << 16) \ + | (devfn << 8) | (reg & 0xFC)) + +static int pci_conf1_read(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *value) +{ + unsigned long flags; + + if (seg || (bus > 255) || (devfn > 255) || (reg > 4095)) { + *value = -1; + return -EINVAL; + } + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8); + + switch (len) { + case 1: + *value = inb(0xCFC + (reg & 3)); + break; + case 2: + *value = inw(0xCFC + (reg & 2)); + break; + case 4: + *value = inl(0xCFC); + break; + } + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return 0; +} + +static int pci_conf1_write(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 value) +{ + unsigned long flags; + + if (seg || (bus > 255) || (devfn > 255) || (reg > 4095)) + return -EINVAL; + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8); + + switch (len) { + case 1: + outb((u8)value, 0xCFC + (reg & 3)); + break; + case 2: + outw((u16)value, 0xCFC + (reg & 2)); + break; + case 4: + outl((u32)value, 0xCFC); + break; + } + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return 0; +} + +#undef PCI_CONF1_ADDRESS + +const struct pci_raw_ops pci_direct_conf1 = { + .read = pci_conf1_read, + .write = pci_conf1_write, +}; + + +/* + * Functions for accessing PCI configuration space with type 2 accesses + */ + +#define PCI_CONF2_ADDRESS(dev, reg) (u16)(0xC000 | (dev << 8) | reg) + +static int pci_conf2_read(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *value) +{ + unsigned long flags; + int dev, fn; + + WARN_ON(seg); + if ((bus > 255) || (devfn > 255) || (reg > 255)) { + *value = -1; + return -EINVAL; + } + + dev = PCI_SLOT(devfn); + fn = PCI_FUNC(devfn); + + if (dev & 0x10) + return PCIBIOS_DEVICE_NOT_FOUND; + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + outb((u8)(0xF0 | (fn << 1)), 0xCF8); + outb((u8)bus, 0xCFA); + + switch (len) { + case 1: + *value = inb(PCI_CONF2_ADDRESS(dev, reg)); + break; + case 2: + *value = inw(PCI_CONF2_ADDRESS(dev, reg)); + break; + case 4: + *value = inl(PCI_CONF2_ADDRESS(dev, reg)); + break; + } + + outb(0, 0xCF8); + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return 0; +} + +static int pci_conf2_write(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 value) +{ + unsigned long flags; + int dev, fn; + + WARN_ON(seg); + if ((bus > 255) || (devfn > 255) || (reg > 255)) + return -EINVAL; + + dev = PCI_SLOT(devfn); + fn = PCI_FUNC(devfn); + + if (dev & 0x10) + return PCIBIOS_DEVICE_NOT_FOUND; + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + outb((u8)(0xF0 | (fn << 1)), 0xCF8); + outb((u8)bus, 0xCFA); + + switch (len) { + case 1: + outb((u8)value, PCI_CONF2_ADDRESS(dev, reg)); + break; + case 2: + outw((u16)value, PCI_CONF2_ADDRESS(dev, reg)); + break; + case 4: + outl((u32)value, PCI_CONF2_ADDRESS(dev, reg)); + break; + } + + outb(0, 0xCF8); + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return 0; +} + +#undef PCI_CONF2_ADDRESS + +static const struct pci_raw_ops pci_direct_conf2 = { + .read = pci_conf2_read, + .write = pci_conf2_write, +}; + + +/* + * Before we decide to use direct hardware access mechanisms, we try to do some + * trivial checks to ensure it at least _seems_ to be working -- we just test + * whether bus 00 contains a host bridge (this is similar to checking + * techniques used in XFree86, but ours should be more reliable since we + * attempt to make use of direct access hints provided by the PCI BIOS). + * + * This should be close to trivial, but it isn't, because there are buggy + * chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID. + */ +static int __init pci_sanity_check(const struct pci_raw_ops *o) +{ + u32 x = 0; + int devfn; + + if (pci_probe & PCI_NO_CHECKS) + return 1; + /* Assume Type 1 works for newer systems. + This handles machines that don't have anything on PCI Bus 0. */ + if (dmi_get_bios_year() >= 2001) + return 1; + + for (devfn = 0; devfn < 0x100; devfn++) { + if (o->read(0, 0, devfn, PCI_CLASS_DEVICE, 2, &x)) + continue; + if (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA) + return 1; + + if (o->read(0, 0, devfn, PCI_VENDOR_ID, 2, &x)) + continue; + if (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ) + return 1; + } + + DBG(KERN_WARNING "PCI: Sanity check failed\n"); + return 0; +} + +static int __init pci_check_type1(void) +{ + unsigned long flags; + unsigned int tmp; + int works = 0; + + local_irq_save(flags); + + outb(0x01, 0xCFB); + tmp = inl(0xCF8); + outl(0x80000000, 0xCF8); + if (inl(0xCF8) == 0x80000000 && pci_sanity_check(&pci_direct_conf1)) { + works = 1; + } + outl(tmp, 0xCF8); + local_irq_restore(flags); + + return works; +} + +static int __init pci_check_type2(void) +{ + unsigned long flags; + int works = 0; + + local_irq_save(flags); + + outb(0x00, 0xCFB); + outb(0x00, 0xCF8); + outb(0x00, 0xCFA); + if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00 && + pci_sanity_check(&pci_direct_conf2)) { + works = 1; + } + + local_irq_restore(flags); + + return works; +} + +void __init pci_direct_init(int type) +{ + if (type == 0) + return; + printk(KERN_INFO "PCI: Using configuration type %d for base access\n", + type); + if (type == 1) { + raw_pci_ops = &pci_direct_conf1; + if (raw_pci_ext_ops) + return; + if (!(pci_probe & PCI_HAS_IO_ECS)) + return; + printk(KERN_INFO "PCI: Using configuration type 1 " + "for extended access\n"); + raw_pci_ext_ops = &pci_direct_conf1; + return; + } + raw_pci_ops = &pci_direct_conf2; +} + +int __init pci_direct_probe(void) +{ + if ((pci_probe & PCI_PROBE_CONF1) == 0) + goto type2; + if (!request_region(0xCF8, 8, "PCI conf1")) + goto type2; + + if (pci_check_type1()) { + raw_pci_ops = &pci_direct_conf1; + port_cf9_safe = true; + return 1; + } + release_region(0xCF8, 8); + + type2: + if ((pci_probe & PCI_PROBE_CONF2) == 0) + return 0; + if (!request_region(0xCF8, 4, "PCI conf2")) + return 0; + if (!request_region(0xC000, 0x1000, "PCI conf2")) + goto fail2; + + if (pci_check_type2()) { + raw_pci_ops = &pci_direct_conf2; + port_cf9_safe = true; + return 2; + } + + release_region(0xC000, 0x1000); + fail2: + release_region(0xCF8, 4); + return 0; +} |