LXR linux/arch/x86/kernel/vsmp

   1/*
   2 * vSMPowered(tm) systems specific initialization
   3 * Copyright (C) 2005 ScaleMP Inc.
   4 *
   5 * Use of this code is subject to the terms and conditions of the
   6 * GNU general public license version 2. See "COPYING" or
   7 * http://www.gnu.org/licenses/gpl.html
   8 *
   9 * Ravikiran Thirumalai <kiran@scalemp.com>,
  10 * Shai Fultheim <shai@scalemp.com>
  11 * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
  12 *                           Ravikiran Thirumalai <kiran@scalemp.com>
  13 */
  14
  15#include <linux/init.h>
  16#include <linux/pci_ids.h>
  17#include <linux/pci_regs.h>
  18#include <linux/smp.h>
  19#include <linux/irq.h>
  20
  21#include <asm/apic.h>
  22#include <asm/pci-direct.h>
  23#include <asm/io.h>
  24#include <asm/paravirt.h>
  25#include <asm/setup.h>
  26
  27#define TOPOLOGY_REGISTER_OFFSET 0x10
  28
  29#ifdef CONFIG_PCI
  30static void __init set_vsmp_ctl(void)
  31{
  32        void __iomem *address;
  33        unsigned int cap, ctl, cfg;
  34
  35        /* set vSMP magic bits to indicate vSMP capable kernel */
  36        cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
  37        address = early_ioremap(cfg, 8);
  38        cap = readl(address);
  39        ctl = readl(address + 4);
  40        printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
  41               cap, ctl);
  42
  43        /* If possible, let the vSMP foundation route the interrupt optimally */
  44#ifdef CONFIG_SMP
  45        if (cap & ctl & BIT(8)) {
  46                ctl &= ~BIT(8);
  47
  48#ifdef CONFIG_PROC_FS
  49                /* Don't let users change irq affinity via procfs */
  50                no_irq_affinity = 1;
  51#endif
  52        }
  53#endif
  54
  55        writel(ctl, address + 4);
  56        ctl = readl(address + 4);
  57        pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
  58
  59        early_iounmap(address, 8);
  60}
  61static int is_vsmp = -1;
  62
  63static void __init detect_vsmp_box(void)
  64{
  65        is_vsmp = 0;
  66
  67        if (!early_pci_allowed())
  68                return;
  69
  70        /* Check if we are running on a ScaleMP vSMPowered box */
  71        if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
  72             (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
  73                is_vsmp = 1;
  74}
  75
  76static int is_vsmp_box(void)
  77{
  78        if (is_vsmp != -1)
  79                return is_vsmp;
  80        else {
  81                WARN_ON_ONCE(1);
  82                return 0;
  83        }
  84}
  85
  86#else
  87static void __init detect_vsmp_box(void)
  88{
  89}
  90static int is_vsmp_box(void)
  91{
  92        return 0;
  93}
  94static void __init set_vsmp_ctl(void)
  95{
  96}
  97#endif
  98
  99static void __init vsmp_cap_cpus(void)
 100{
 101#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
 102        void __iomem *address;
 103        unsigned int cfg, topology, node_shift, maxcpus;
 104
 105        /*
 106         * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
 107         * ones present in the first board, unless explicitly overridden by
 108         * setup_max_cpus
 109         */
 110        if (setup_max_cpus != NR_CPUS)
 111                return;
 112
 113        /* Read the vSMP Foundation topology register */
 114        cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
 115        address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
 116        if (WARN_ON(!address))
 117                return;
 118
 119        topology = readl(address);
 120        node_shift = (topology >> 16) & 0x7;
 121        if (!node_shift)
 122                /* The value 0 should be decoded as 8 */
 123                node_shift = 8;
 124        maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
 125
 126        pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
 127                maxcpus);
 128        setup_max_cpus = maxcpus;
 129        early_iounmap(address, 4);
 130#endif
 131}
 132
 133static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
 134{
 135        return hard_smp_processor_id() >> index_msb;
 136}
 137
 138static void vsmp_apic_post_init(void)
 139{
 140        /* need to update phys_pkg_id */
 141        apic->phys_pkg_id = apicid_phys_pkg_id;
 142}
 143
 144void __init vsmp_init(void)
 145{
 146        detect_vsmp_box();
 147        if (!is_vsmp_box())
 148                return;
 149
 150        x86_platform.apic_post_init = vsmp_apic_post_init;
 151
 152        vsmp_cap_cpus();
 153
 154        set_vsmp_ctl();
 155        return;
 156}
 157