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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <gpxe/tables.h>
#include <gpxe/device.h>
#include <gpxe/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|PCI_BASE_ADDRESS_MEM_TYPE_MASK) )
             == (PCI_BASE_ADDRESS_SPACE_MEMORY|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 {
                                DBG ( "Unhandled 64-bit BAR %08x%08x\n",
                                      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) == PCI_BASE_ADDRESS_SPACE_MEMORY ){
                return ( bar & PCI_BASE_ADDRESS_MEM_MASK );
        } else {
                return ( bar & PCI_BASE_ADDRESS_IO_MASK );
        }
}

/**
 * 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;

        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 ) {
                DBG ( "PCI BIOS has not enabled device %02x:%02x.%x! "
                      "Updating PCI command %04x->%04x\n", pci->bus,
                      PCI_SLOT ( pci->devfn ), PCI_FUNC ( pci->devfn ),
                      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 ) {
                DBG ( "PCI device %02x:%02x.%x latency timer is unreasonably "
                      "low at %d. Setting to 32.\n", pci->bus,
                      PCI_SLOT ( pci->devfn ), PCI_FUNC ( pci->devfn ),
                      pci_latency );
                pci_write_config_byte ( pci, PCI_LATENCY_TIMER, 32);
        }
}

/**
 * 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.
 */
static int pci_probe ( struct pci_device *pci ) {
        struct pci_driver *driver;
        struct pci_device_id *id;
        unsigned int i;
        int rc;

        DBG ( "Adding PCI device %02x:%02x.%x (%04x:%04x mem %lx io %lx "
              "irq %d)\n", pci->bus, PCI_SLOT ( pci->devfn ),
              PCI_FUNC ( pci->devfn ), pci->vendor, pci->device,
              pci->membase, pci->ioaddr, pci->irq );

        for_each_table_entry ( driver, PCI_DRIVERS ) {
                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->driver = driver;
                        pci->driver_name = id->name;
                        DBG ( "...using driver %s\n", pci->driver_name );
                        if ( ( rc = driver->probe ( pci, id ) ) != 0 ) {
                                DBG ( "......probe failed\n" );
                                continue;
                        }
                        return 0;
                }
        }

        DBG ( "...no driver found\n" );
        return -ENOTTY;
}

/**
 * Remove a PCI device
 *
 * @v pci               PCI device
 */
static void pci_remove ( struct pci_device *pci ) {
        pci->driver->remove ( pci );
        DBG ( "Removed PCI device %02x:%02x.%x\n", pci->bus,
              PCI_SLOT ( pci->devfn ), PCI_FUNC ( pci->devfn ) );
}

/**
 * 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;
        unsigned int max_bus;
        unsigned int bus;
        unsigned int devfn;
        uint8_t hdrtype = 0;
        uint32_t tmp;
        int rc;

        max_bus = pci_max_bus();
        for ( bus = 0 ; bus <= max_bus ; bus++ ) {
                for ( devfn = 0 ; devfn <= 0xff ; devfn++ ) {

                        /* Allocate struct pci_device */
                        if ( ! pci )
                                pci = malloc ( sizeof ( *pci ) );
                        if ( ! pci ) {
                                rc = -ENOMEM;
                                goto err;
                        }
                        memset ( pci, 0, sizeof ( *pci ) );
                        pci->bus = bus;
                        pci->devfn = devfn;
                        
                        /* Skip all but the first function on
                         * non-multifunction cards
                         */
                        if ( PCI_FUNC ( devfn ) == 0 ) {
                                pci_read_config_byte ( pci, PCI_HEADER_TYPE,
                                                       &hdrtype );
                        } else if ( ! ( hdrtype & 0x80 ) ) {
                                        continue;
                        }

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

                        /* Add to device hierarchy */
                        snprintf ( pci->dev.name, sizeof ( pci->dev.name ),
                                   "PCI%02x:%02x.%x", bus,
                                   PCI_SLOT ( devfn ), PCI_FUNC ( devfn ) );
                        pci->dev.desc.bus_type = BUS_TYPE_PCI;
                        pci->dev.desc.location = PCI_BUSDEVFN (bus, devfn);
                        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;
                        pci->dev.parent = &rootdev->dev;
                        list_add ( &pci->dev.siblings, &rootdev->dev.children);
                        INIT_LIST_HEAD ( &pci->dev.children );
                        
                        /* Look for a driver */
                        if ( 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 );
                        }
                }
        }

        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,
};