pci.c

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/*
 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * Based in part on pci.c from Etherboot 5.4, by Ken Yap and David
 * Munro, in turn based on the Linux kernel's PCI implementation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <ipxe/tables.h>
#include <ipxe/device.h>
#include <ipxe/pci.h>

/** @file
 *
 * PCI bus
 *
 */

static void pcibus_remove ( struct root_device *rootdev );

/**
 * Read PCI BAR
 *
 * @v pci               PCI device
 * @v reg               PCI register number
 * @ret bar             Base address register
 *
 * Reads the specified PCI base address register, including the flags
 * portion.  64-bit BARs will be handled automatically.  If the value
 * of the 64-bit BAR exceeds the size of an unsigned long (i.e. if the
 * high dword is non-zero on a 32-bit platform), then the value
 * returned will be zero plus the flags for a 64-bit BAR.  Unreachable
 * 64-bit BARs are therefore returned as uninitialised 64-bit BARs.
 */
static unsigned long pci_bar ( struct pci_device *pci, unsigned int reg ) {
        uint32_t low;
        uint32_t high;

        pci_read_config_dword ( pci, reg, &low );
        if ( ( low & (PCI_BASE_ADDRESS_SPACE_IO|PCI_BASE_ADDRESS_MEM_TYPE_MASK))
             == PCI_BASE_ADDRESS_MEM_TYPE_64 ) {
                pci_read_config_dword ( pci, reg + 4, &high );
                if ( high ) {
                        if ( sizeof ( unsigned long ) > sizeof ( uint32_t ) ) {
                                return ( ( ( uint64_t ) high << 32 ) | low );
                        } else {
                                DBGC ( pci, PCI_FMT " unhandled 64-bit BAR "
                                       "%08x%08x\n",
                                       PCI_ARGS ( pci ), high, low );
                                return PCI_BASE_ADDRESS_MEM_TYPE_64;
                        }
                }
        }
        return low;
}

/**
 * Find the start of a PCI BAR
 *
 * @v pci               PCI device
 * @v reg               PCI register number
 * @ret start           BAR start address
 *
 * Reads the specified PCI base address register, and returns the
 * address portion of the BAR (i.e. without the flags).
 *
 * If the address exceeds the size of an unsigned long (i.e. if a
 * 64-bit BAR has a non-zero high dword on a 32-bit machine), the
 * return value will be zero.
 */
unsigned long pci_bar_start ( struct pci_device *pci, unsigned int reg ) {
        unsigned long bar;

        bar = pci_bar ( pci, reg );
        if ( bar & PCI_BASE_ADDRESS_SPACE_IO ) {
                return ( bar & ~PCI_BASE_ADDRESS_IO_MASK );
        } else {
                return ( bar & ~PCI_BASE_ADDRESS_MEM_MASK );
        }
}

/**
 * Set the start of a PCI BAR
 *
 * @v pci               PCI device
 * @v reg               PCI register number
 * @v start             BAR start address
 */
void pci_bar_set ( struct pci_device *pci, unsigned int reg,
                   unsigned long start ) {
        unsigned int type;
        uint32_t low;
        uint32_t high;
        uint16_t cmd;

        /* Save the original command register and disable decoding */
        pci_read_config_word ( pci, PCI_COMMAND, &cmd );
        pci_write_config_word ( pci, PCI_COMMAND,
                                ( cmd & ~( PCI_COMMAND_MEM |
                                           PCI_COMMAND_IO ) ) );

        /* Check for a 64-bit BAR */
        pci_read_config_dword ( pci, reg, &low );
        type = ( low & ( PCI_BASE_ADDRESS_SPACE_IO |
                         PCI_BASE_ADDRESS_MEM_TYPE_MASK ) );

        /* Write low 32 bits */
        low = start;
        pci_write_config_dword ( pci, reg, low );

        /* Write high 32 bits, if applicable */
        if ( type == PCI_BASE_ADDRESS_MEM_TYPE_64 ) {
                if ( sizeof ( unsigned long ) > sizeof ( uint32_t ) ) {
                        high = ( ( ( uint64_t ) start ) >> 32 );
                } else {
                        high = 0;
                }
                pci_write_config_dword ( pci, reg + 4, high );
        }

        /* Restore the original command register */
        pci_write_config_word ( pci, PCI_COMMAND, cmd );
}

/**
 * Get the size of a PCI BAR
 *
 * @v pci               PCI device
 * @v reg               PCI register number
 * @ret size            BAR size
 *
 * Most drivers should not need to call this function.  It is not
 * necessary to map the whole PCI BAR, only the portion that will be
 * used for register access.  Since register offsets are almost always
 * fixed by hardware design, the length of the mapped portion will
 * almost always be a compile-time constant.
 */
unsigned long pci_bar_size ( struct pci_device *pci, unsigned int reg ) {
        unsigned long start;
        unsigned long size;
        uint16_t cmd;

        /* Save the original command register and disable decoding */
        pci_read_config_word ( pci, PCI_COMMAND, &cmd );
        pci_write_config_word ( pci, PCI_COMMAND,
                                ( cmd & ~( PCI_COMMAND_MEM |
                                           PCI_COMMAND_IO ) ) );

        /* Save the original start address */
        start = pci_bar_start ( pci, reg );

        /* Set all possible bits */
        pci_bar_set ( pci, reg, -1UL );

        /* Determine size by finding lowest set bit */
        size = pci_bar_start ( pci, reg );
        size &= ( -size );

        /* Restore the original start address */
        pci_bar_set ( pci, reg, start );

        /* Restore the original command register */
        pci_write_config_word ( pci, PCI_COMMAND, cmd );

        return size;
}

/**
 * Read membase and ioaddr for a PCI device
 *
 * @v pci               PCI device
 *
 * This scans through all PCI BARs on the specified device.  The first
 * valid memory BAR is recorded as pci_device::membase, and the first
 * valid IO BAR is recorded as pci_device::ioaddr.
 *
 * 64-bit BARs are handled automatically.  On a 32-bit platform, if a
 * 64-bit BAR has a non-zero high dword, it will be regarded as
 * invalid.
 */
static void pci_read_bases ( struct pci_device *pci ) {
        unsigned long bar;
        int reg;

        /* Clear any existing base addresses */
        pci->ioaddr = 0;
        pci->membase = 0;

        /* Get first memory and I/O BAR addresses */
        for ( reg = PCI_BASE_ADDRESS_0; reg <= PCI_BASE_ADDRESS_5; reg += 4 ) {
                bar = pci_bar ( pci, reg );
                if ( bar & PCI_BASE_ADDRESS_SPACE_IO ) {
                        if ( ! pci->ioaddr )
                                pci->ioaddr = 
                                        ( bar & ~PCI_BASE_ADDRESS_IO_MASK );
                } else {
                        if ( ! pci->membase )
                                pci->membase =
                                        ( bar & ~PCI_BASE_ADDRESS_MEM_MASK );
                        /* Skip next BAR if 64-bit */
                        if ( bar & PCI_BASE_ADDRESS_MEM_TYPE_64 )
                                reg += 4;
                }
        }
}

/**
 * Enable PCI device
 *
 * @v pci               PCI device
 *
 * Set device to be a busmaster in case BIOS neglected to do so.  Also
 * adjust PCI latency timer to a reasonable value, 32.
 */
void adjust_pci_device ( struct pci_device *pci ) {
        unsigned short new_command, pci_command;
        unsigned char pci_latency;

        pci_read_config_word ( pci, PCI_COMMAND, &pci_command );
        new_command = ( pci_command | PCI_COMMAND_MASTER |
                        PCI_COMMAND_MEM | PCI_COMMAND_IO );
        if ( pci_command != new_command ) {
                DBGC ( pci, PCI_FMT " device not enabled by BIOS! Updating "
                       "PCI command %04x->%04x\n",
                       PCI_ARGS ( pci ), pci_command, new_command );
                pci_write_config_word ( pci, PCI_COMMAND, new_command );
        }

        pci_read_config_byte ( pci, PCI_LATENCY_TIMER, &pci_latency);
        if ( pci_latency < 32 ) {
                DBGC ( pci, PCI_FMT " latency timer is unreasonably low at "
                       "%d. Setting to 32.\n", PCI_ARGS ( pci ), pci_latency );
                pci_write_config_byte ( pci, PCI_LATENCY_TIMER, 32);
        }
}

/**
 * Read PCI device configuration
 *
 * @v pci               PCI device
 * @ret rc              Return status code
 */
int pci_read_config ( struct pci_device *pci ) {
        uint32_t busdevfn;
        uint8_t hdrtype;
        uint32_t tmp;

        /* Ignore all but the first function on non-multifunction devices */
        if ( PCI_FUNC ( pci->busdevfn ) != 0 ) {
                busdevfn = pci->busdevfn;
                pci->busdevfn = PCI_FIRST_FUNC ( pci->busdevfn );
                pci_read_config_byte ( pci, PCI_HEADER_TYPE, &hdrtype );
                pci->busdevfn = busdevfn;
                if ( ! ( hdrtype & PCI_HEADER_TYPE_MULTI ) )
                        return -ENODEV;
        }

        /* Check for physical device presence */
        pci_read_config_dword ( pci, PCI_VENDOR_ID, &tmp );
        if ( ( tmp == 0xffffffff ) || ( tmp == 0 ) )
                return -ENODEV;

        /* Populate struct pci_device */
        pci->vendor = ( tmp & 0xffff );
        pci->device = ( tmp >> 16 );
        pci_read_config_dword ( pci, PCI_REVISION, &tmp );
        pci->class = ( tmp >> 8 );
        pci_read_config_byte ( pci, PCI_INTERRUPT_LINE, &pci->irq );
        pci_read_config_byte ( pci, PCI_HEADER_TYPE, &pci->hdrtype );
        pci_read_bases ( pci );

        /* Initialise generic device component */
        snprintf ( pci->dev.name, sizeof ( pci->dev.name ), "%04x:%02x:%02x.%x",
                   PCI_SEG ( pci->busdevfn ), PCI_BUS ( pci->busdevfn ),
                   PCI_SLOT ( pci->busdevfn ), PCI_FUNC ( pci->busdevfn ) );
        pci->dev.desc.bus_type = BUS_TYPE_PCI;
        pci->dev.desc.location = pci->busdevfn;
        pci->dev.desc.vendor = pci->vendor;
        pci->dev.desc.device = pci->device;
        pci->dev.desc.class = pci->class;
        pci->dev.desc.ioaddr = pci->ioaddr;
        pci->dev.desc.irq = pci->irq;
        INIT_LIST_HEAD ( &pci->dev.siblings );
        INIT_LIST_HEAD ( &pci->dev.children );

        return 0;
}

/**
 * Find next device on PCI bus
 *
 * @v pci               PCI device to fill in
 * @v busdevfn          Starting bus:dev.fn address
 * @ret busdevfn        Bus:dev.fn address of next PCI device
 * @ret rc              Return status code
 */
int pci_find_next ( struct pci_device *pci, uint32_t *busdevfn ) {
        static struct pci_range range;
        uint8_t hdrtype;
        uint8_t sub;
        uint32_t end;
        unsigned int count;
        int rc;

        /* Find next PCI device, if any */
        do {
                /* Find next PCI bus:dev.fn address range, if necessary */
                if ( ( *busdevfn - range.start ) >= range.count ) {
                        pci_discover ( *busdevfn, &range );
                        if ( *busdevfn < range.start )
                                *busdevfn = range.start;
                        if ( ( *busdevfn - range.start ) >= range.count )
                                break;
                }

                /* Check for PCI device existence */
                memset ( pci, 0, sizeof ( *pci ) );
                pci_init ( pci, *busdevfn );
                if ( ( rc = pci_read_config ( pci ) ) != 0 )
                        continue;

                /* If device is a bridge, expand the PCI bus:dev.fn
                 * address range as needed.
                 */
                pci_read_config_byte ( pci, PCI_HEADER_TYPE, &hdrtype );
                hdrtype &= PCI_HEADER_TYPE_MASK;
                if ( hdrtype == PCI_HEADER_TYPE_BRIDGE ) {
                        pci_read_config_byte ( pci, PCI_SUBORDINATE, &sub );
                        end = PCI_BUSDEVFN ( PCI_SEG ( *busdevfn ),
                                             ( sub + 1 ), 0, 0 );
                        count = ( end - range.start );
                        if ( count > range.count ) {
                                DBGC ( pci, PCI_FMT " found subordinate bus "
                                       "%#02x\n", PCI_ARGS ( pci ), sub );
                                range.count = count;
                        }
                }

                /* Return this device */
                return 0;

        } while ( ++(*busdevfn) );

        return -ENODEV;
}

/**
 * Find driver for PCI device
 *
 * @v pci               PCI device
 * @ret rc              Return status code
 */
int pci_find_driver ( struct pci_device *pci ) {
        struct pci_driver *driver;
        struct pci_device_id *id;
        unsigned int i;

        for_each_table_entry ( driver, PCI_DRIVERS ) {
                if ( ( driver->class.class ^ pci->class ) & driver->class.mask )
                        continue;
                for ( i = 0 ; i < driver->id_count ; i++ ) {
                        id = &driver->ids[i];
                        if ( ( id->vendor != PCI_ANY_ID ) &&
                             ( id->vendor != pci->vendor ) )
                                continue;
                        if ( ( id->device != PCI_ANY_ID ) &&
                             ( id->device != pci->device ) )
                                continue;
                        pci_set_driver ( pci, driver, id );
                        return 0;
                }
        }
        return -ENOENT;
}

/**
 * Probe a PCI device
 *
 * @v pci               PCI device
 * @ret rc              Return status code
 *
 * Searches for a driver for the PCI device.  If a driver is found,
 * its probe() routine is called.
 */
int pci_probe ( struct pci_device *pci ) {
        int rc;

        DBGC ( pci, PCI_FMT " (%04x:%04x) has driver \"%s\"\n",
               PCI_ARGS ( pci ), pci->vendor, pci->device, pci->id->name );
        DBGC ( pci, PCI_FMT " has mem %lx io %lx irq %d\n",
               PCI_ARGS ( pci ), pci->membase, pci->ioaddr, pci->irq );

        if ( ( rc = pci->driver->probe ( pci ) ) != 0 ) {
                DBGC ( pci, PCI_FMT " probe failed: %s\n",
                       PCI_ARGS ( pci ), strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Remove a PCI device
 *
 * @v pci               PCI device
 */
void pci_remove ( struct pci_device *pci ) {
        pci->driver->remove ( pci );
        DBGC ( pci, PCI_FMT " removed\n", PCI_ARGS ( pci ) );
}

/**
 * Probe PCI root bus
 *
 * @v rootdev           PCI bus root device
 *
 * Scans the PCI bus for devices and registers all devices it can
 * find.
 */
static int pcibus_probe ( struct root_device *rootdev ) {
        struct pci_device *pci = NULL;
        uint32_t busdevfn = 0;
        int rc;

        do {
                /* Allocate struct pci_device */
                if ( ! pci )
                        pci = malloc ( sizeof ( *pci ) );
                if ( ! pci ) {
                        rc = -ENOMEM;
                        goto err;
                }

                /* Find next PCI device, if any */
                if ( ( rc = pci_find_next ( pci, &busdevfn ) ) != 0 )
                        break;

                /* Skip automatic probing if prohibited */
                if ( ! pci_can_probe ( pci ) )
                        continue;

                /* Look for a driver */
                if ( ( rc = pci_find_driver ( pci ) ) != 0 ) {
                        DBGC ( pci, PCI_FMT " (%04x:%04x class %06x) has no "
                               "driver\n", PCI_ARGS ( pci ), pci->vendor,
                               pci->device, pci->class );
                        continue;
                }

                /* Add to device hierarchy */
                pci->dev.parent = &rootdev->dev;
                list_add ( &pci->dev.siblings, &rootdev->dev.children );

                /* Look for a driver */
                if ( ( rc = pci_probe ( pci ) ) == 0 ) {
                        /* pcidev registered, we can drop our ref */
                        pci = NULL;
                } else {
                        /* Not registered; re-use struct pci_device */
                        list_del ( &pci->dev.siblings );
                }

        } while ( ++busdevfn );

        free ( pci );
        return 0;

 err:
        free ( pci );
        pcibus_remove ( rootdev );
        return rc;
}

/**
 * Remove PCI root bus
 *
 * @v rootdev           PCI bus root device
 */
static void pcibus_remove ( struct root_device *rootdev ) {
        struct pci_device *pci;
        struct pci_device *tmp;

        list_for_each_entry_safe ( pci, tmp, &rootdev->dev.children,
                                   dev.siblings ) {
                pci_remove ( pci );
                list_del ( &pci->dev.siblings );
                free ( pci );
        }
}

/** PCI bus root device driver */
static struct root_driver pci_root_driver = {
        .probe = pcibus_probe,
        .remove = pcibus_remove,
};

/** PCI bus root device */
struct root_device pci_root_device __root_device = {
        .dev = { .name = "PCI" },
        .driver = &pci_root_driver,
};

/* Drag in objects via pcibus_probe() */
REQUIRING_SYMBOL ( pcibus_probe );

/* Drag in PCI configuration */
REQUIRE_OBJECT ( config_pci );