arch/x86/kernel/vsmp_64.c

   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
  30 static 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 }
  61 static int is_vsmp = -1;
  62
  63 static 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
  76 static 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
  87 static void __init detect_vsmp_box(void)
  88 {
  89 }
  90 static int is_vsmp_box(void)
  91 {
  92         return 0;
  93 }
  94 static void __init set_vsmp_ctl(void)
  95 {
  96 }
  97 #endif
  98
  99 static 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
 133 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
 134 {
 135         return hard_smp_processor_id() >> index_msb;
 136 }
 137
 138 static 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
 144 void __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 }