diff options
Diffstat (limited to 'arch/x86/pci/pcbios.c')
| -rw-r--r-- | arch/x86/pci/pcbios.c | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c new file mode 100644 index 000000000..9c97d8141 --- /dev/null +++ b/arch/x86/pci/pcbios.c @@ -0,0 +1,429 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * BIOS32 and PCI BIOS handling. + */ + +#include <linux/pci.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/uaccess.h> + +#include <asm/pci_x86.h> +#include <asm/e820/types.h> +#include <asm/pci-functions.h> +#include <asm/set_memory.h> + +/* BIOS32 signature: "_32_" */ +#define BIOS32_SIGNATURE (('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24)) + +/* PCI signature: "PCI " */ +#define PCI_SIGNATURE (('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24)) + +/* PCI service signature: "$PCI" */ +#define PCI_SERVICE (('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24)) + +/* PCI BIOS hardware mechanism flags */ +#define PCIBIOS_HW_TYPE1 0x01 +#define PCIBIOS_HW_TYPE2 0x02 +#define PCIBIOS_HW_TYPE1_SPEC 0x10 +#define PCIBIOS_HW_TYPE2_SPEC 0x20 + +int pcibios_enabled; + +/* According to the BIOS specification at: + * http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could + * restrict the x zone to some pages and make it ro. But this may be + * broken on some bios, complex to handle with static_protections. + * We could make the 0xe0000-0x100000 range rox, but this can break + * some ISA mapping. + * + * So we let's an rw and x hole when pcibios is used. This shouldn't + * happen for modern system with mmconfig, and if you don't want it + * you could disable pcibios... + */ +static inline void set_bios_x(void) +{ + pcibios_enabled = 1; + set_memory_x(PAGE_OFFSET + BIOS_BEGIN, (BIOS_END - BIOS_BEGIN) >> PAGE_SHIFT); + if (__supported_pte_mask & _PAGE_NX) + printk(KERN_INFO "PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX.\n"); +} + +/* + * This is the standard structure used to identify the entry point + * to the BIOS32 Service Directory, as documented in + * Standard BIOS 32-bit Service Directory Proposal + * Revision 0.4 May 24, 1993 + * Phoenix Technologies Ltd. + * Norwood, MA + * and the PCI BIOS specification. + */ + +union bios32 { + struct { + unsigned long signature; /* _32_ */ + unsigned long entry; /* 32 bit physical address */ + unsigned char revision; /* Revision level, 0 */ + unsigned char length; /* Length in paragraphs should be 01 */ + unsigned char checksum; /* All bytes must add up to zero */ + unsigned char reserved[5]; /* Must be zero */ + } fields; + char chars[16]; +}; + +/* + * Physical address of the service directory. I don't know if we're + * allowed to have more than one of these or not, so just in case + * we'll make pcibios_present() take a memory start parameter and store + * the array there. + */ + +static struct { + unsigned long address; + unsigned short segment; +} bios32_indirect __initdata = { 0, __KERNEL_CS }; + +/* + * Returns the entry point for the given service, NULL on error + */ + +static unsigned long __init bios32_service(unsigned long service) +{ + unsigned char return_code; /* %al */ + unsigned long address; /* %ebx */ + unsigned long length; /* %ecx */ + unsigned long entry; /* %edx */ + unsigned long flags; + + local_irq_save(flags); + __asm__("lcall *(%%edi); cld" + : "=a" (return_code), + "=b" (address), + "=c" (length), + "=d" (entry) + : "0" (service), + "1" (0), + "D" (&bios32_indirect)); + local_irq_restore(flags); + + switch (return_code) { + case 0: + return address + entry; + case 0x80: /* Not present */ + printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service); + return 0; + default: /* Shouldn't happen */ + printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n", + service, return_code); + return 0; + } +} + +static struct { + unsigned long address; + unsigned short segment; +} pci_indirect __ro_after_init = { + .address = 0, + .segment = __KERNEL_CS, +}; + +static int pci_bios_present __ro_after_init; + +static int __init check_pcibios(void) +{ + u32 signature, eax, ebx, ecx; + u8 status, major_ver, minor_ver, hw_mech; + unsigned long flags, pcibios_entry; + + if ((pcibios_entry = bios32_service(PCI_SERVICE))) { + pci_indirect.address = pcibios_entry + PAGE_OFFSET; + + local_irq_save(flags); + __asm__( + "lcall *(%%edi); cld\n\t" + "jc 1f\n\t" + "xor %%ah, %%ah\n" + "1:" + : "=d" (signature), + "=a" (eax), + "=b" (ebx), + "=c" (ecx) + : "1" (PCIBIOS_PCI_BIOS_PRESENT), + "D" (&pci_indirect) + : "memory"); + local_irq_restore(flags); + + status = (eax >> 8) & 0xff; + hw_mech = eax & 0xff; + major_ver = (ebx >> 8) & 0xff; + minor_ver = ebx & 0xff; + if (pcibios_last_bus < 0) + pcibios_last_bus = ecx & 0xff; + DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n", + status, hw_mech, major_ver, minor_ver, pcibios_last_bus); + if (status || signature != PCI_SIGNATURE) { + printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n", + status, signature); + return 0; + } + printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n", + major_ver, minor_ver, pcibios_entry, pcibios_last_bus); +#ifdef CONFIG_PCI_DIRECT + if (!(hw_mech & PCIBIOS_HW_TYPE1)) + pci_probe &= ~PCI_PROBE_CONF1; + if (!(hw_mech & PCIBIOS_HW_TYPE2)) + pci_probe &= ~PCI_PROBE_CONF2; +#endif + return 1; + } + return 0; +} + +static int pci_bios_read(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *value) +{ + unsigned long result = 0; + unsigned long flags; + unsigned long bx = (bus << 8) | devfn; + u16 number = 0, mask = 0; + + WARN_ON(seg); + if (!value || (bus > 255) || (devfn > 255) || (reg > 255)) + return -EINVAL; + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + switch (len) { + case 1: + number = PCIBIOS_READ_CONFIG_BYTE; + mask = 0xff; + break; + case 2: + number = PCIBIOS_READ_CONFIG_WORD; + mask = 0xffff; + break; + case 4: + number = PCIBIOS_READ_CONFIG_DWORD; + break; + } + + __asm__("lcall *(%%esi); cld\n\t" + "jc 1f\n\t" + "xor %%ah, %%ah\n" + "1:" + : "=c" (*value), + "=a" (result) + : "1" (number), + "b" (bx), + "D" ((long)reg), + "S" (&pci_indirect)); + /* + * Zero-extend the result beyond 8 or 16 bits, do not trust the + * BIOS having done it: + */ + if (mask) + *value &= mask; + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return (int)((result & 0xff00) >> 8); +} + +static int pci_bios_write(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 value) +{ + unsigned long result = 0; + unsigned long flags; + unsigned long bx = (bus << 8) | devfn; + u16 number = 0; + + WARN_ON(seg); + if ((bus > 255) || (devfn > 255) || (reg > 255)) + return -EINVAL; + + raw_spin_lock_irqsave(&pci_config_lock, flags); + + switch (len) { + case 1: + number = PCIBIOS_WRITE_CONFIG_BYTE; + break; + case 2: + number = PCIBIOS_WRITE_CONFIG_WORD; + break; + case 4: + number = PCIBIOS_WRITE_CONFIG_DWORD; + break; + } + + __asm__("lcall *(%%esi); cld\n\t" + "jc 1f\n\t" + "xor %%ah, %%ah\n" + "1:" + : "=a" (result) + : "0" (number), + "c" (value), + "b" (bx), + "D" ((long)reg), + "S" (&pci_indirect)); + + raw_spin_unlock_irqrestore(&pci_config_lock, flags); + + return (int)((result & 0xff00) >> 8); +} + + +/* + * Function table for BIOS32 access + */ + +static const struct pci_raw_ops pci_bios_access = { + .read = pci_bios_read, + .write = pci_bios_write +}; + +/* + * Try to find PCI BIOS. + */ + +static const struct pci_raw_ops *__init pci_find_bios(void) +{ + union bios32 *check; + unsigned char sum; + int i, length; + + /* + * Follow the standard procedure for locating the BIOS32 Service + * directory by scanning the permissible address range from + * 0xe0000 through 0xfffff for a valid BIOS32 structure. + */ + + for (check = (union bios32 *) __va(0xe0000); + check <= (union bios32 *) __va(0xffff0); + ++check) { + long sig; + if (probe_kernel_address(&check->fields.signature, sig)) + continue; + + if (check->fields.signature != BIOS32_SIGNATURE) + continue; + length = check->fields.length * 16; + if (!length) + continue; + sum = 0; + for (i = 0; i < length ; ++i) + sum += check->chars[i]; + if (sum != 0) + continue; + if (check->fields.revision != 0) { + printk("PCI: unsupported BIOS32 revision %d at 0x%p\n", + check->fields.revision, check); + continue; + } + DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check); + if (check->fields.entry >= 0x100000) { + printk("PCI: BIOS32 entry (0x%p) in high memory, " + "cannot use.\n", check); + return NULL; + } else { + unsigned long bios32_entry = check->fields.entry; + DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n", + bios32_entry); + bios32_indirect.address = bios32_entry + PAGE_OFFSET; + set_bios_x(); + if (check_pcibios()) + return &pci_bios_access; + } + break; /* Hopefully more than one BIOS32 cannot happen... */ + } + + return NULL; +} + +/* + * BIOS Functions for IRQ Routing + */ + +struct irq_routing_options { + u16 size; + struct irq_info *table; + u16 segment; +} __attribute__((packed)); + +struct irq_routing_table * pcibios_get_irq_routing_table(void) +{ + struct irq_routing_options opt; + struct irq_routing_table *rt = NULL; + int ret, map; + unsigned long page; + + if (!pci_bios_present) + return NULL; + page = __get_free_page(GFP_KERNEL); + if (!page) + return NULL; + opt.table = (struct irq_info *) page; + opt.size = PAGE_SIZE; + opt.segment = __KERNEL_DS; + + DBG("PCI: Fetching IRQ routing table... "); + __asm__("push %%es\n\t" + "push %%ds\n\t" + "pop %%es\n\t" + "lcall *(%%esi); cld\n\t" + "pop %%es\n\t" + "jc 1f\n\t" + "xor %%ah, %%ah\n" + "1:" + : "=a" (ret), + "=b" (map), + "=m" (opt) + : "0" (PCIBIOS_GET_ROUTING_OPTIONS), + "1" (0), + "D" ((long) &opt), + "S" (&pci_indirect), + "m" (opt) + : "memory"); + DBG("OK ret=%d, size=%d, map=%x\n", ret, opt.size, map); + if (ret & 0xff00) + printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff); + else if (opt.size) { + rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL); + if (rt) { + memset(rt, 0, sizeof(struct irq_routing_table)); + rt->size = opt.size + sizeof(struct irq_routing_table); + rt->exclusive_irqs = map; + memcpy(rt->slots, (void *) page, opt.size); + printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n"); + } + } + free_page(page); + return rt; +} +EXPORT_SYMBOL(pcibios_get_irq_routing_table); + +int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq) +{ + int ret; + + __asm__("lcall *(%%esi); cld\n\t" + "jc 1f\n\t" + "xor %%ah, %%ah\n" + "1:" + : "=a" (ret) + : "0" (PCIBIOS_SET_PCI_HW_INT), + "b" ((dev->bus->number << 8) | dev->devfn), + "c" ((irq << 8) | (pin + 10)), + "S" (&pci_indirect)); + return !(ret & 0xff00); +} +EXPORT_SYMBOL(pcibios_set_irq_routing); + +void __init pci_pcbios_init(void) +{ + if ((pci_probe & PCI_PROBE_BIOS) + && ((raw_pci_ops = pci_find_bios()))) { + pci_bios_present = 1; + } +} + |