arch/x86/kernel/vsmp_64.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * vSMPowered(tm) systems specific initialization
   4  * Copyright (C) 2005 ScaleMP Inc.
   5  *
   6  * Ravikiran Thirumalai <kiran@scalemp.com>,
   7  * Shai Fultheim <shai@scalemp.com>
   8  * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
   9  *                           Ravikiran Thirumalai <kiran@scalemp.com>
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/pci_ids.h>
  14 #include <linux/pci_regs.h>
  15 #include <linux/smp.h>
  16 #include <linux/irq.h>
  17
  18 #include <asm/apic.h>
  19 #include <asm/pci-direct.h>
  20 #include <asm/io.h>
  21 #include <asm/paravirt.h>
  22 #include <asm/setup.h>
  23
  24 #define TOPOLOGY_REGISTER_OFFSET 0x10
  25
  26 #ifdef CONFIG_PCI
  27 static void __init set_vsmp_ctl(void)
  28 {
  29         void __iomem *address;
  30         unsigned int cap, ctl, cfg;
  31
  32         /* set vSMP magic bits to indicate vSMP capable kernel */
  33         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
  34         address = early_ioremap(cfg, 8);
  35         cap = readl(address);
  36         ctl = readl(address + 4);
  37         printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
  38                cap, ctl);
  39
  40         /* If possible, let the vSMP foundation route the interrupt optimally */
  41 #ifdef CONFIG_SMP
  42         if (cap & ctl & BIT(8)) {
  43                 ctl &= ~BIT(8);
  44
  45 #ifdef CONFIG_PROC_FS
  46                 /* Don't let users change irq affinity via procfs */
  47                 no_irq_affinity = 1;
  48 #endif
  49         }
  50 #endif
  51
  52         writel(ctl, address + 4);
  53         ctl = readl(address + 4);
  54         pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
  55
  56         early_iounmap(address, 8);
  57 }
  58 static int is_vsmp = -1;
  59
  60 static void __init detect_vsmp_box(void)
  61 {
  62         is_vsmp = 0;
  63
  64         if (!early_pci_allowed())
  65                 return;
  66
  67         /* Check if we are running on a ScaleMP vSMPowered box */
  68         if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
  69              (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
  70                 is_vsmp = 1;
  71 }
  72
  73 static int is_vsmp_box(void)
  74 {
  75         if (is_vsmp != -1)
  76                 return is_vsmp;
  77         else {
  78                 WARN_ON_ONCE(1);
  79                 return 0;
  80         }
  81 }
  82
  83 #else
  84 static void __init detect_vsmp_box(void)
  85 {
  86 }
  87 static int is_vsmp_box(void)
  88 {
  89         return 0;
  90 }
  91 static void __init set_vsmp_ctl(void)
  92 {
  93 }
  94 #endif
  95
  96 static void __init vsmp_cap_cpus(void)
  97 {
  98 #if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
  99         void __iomem *address;
 100         unsigned int cfg, topology, node_shift, maxcpus;
 101
 102         /*
 103          * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
 104          * ones present in the first board, unless explicitly overridden by
 105          * setup_max_cpus
 106          */
 107         if (setup_max_cpus != NR_CPUS)
 108                 return;
 109
 110         /* Read the vSMP Foundation topology register */
 111         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
 112         address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
 113         if (WARN_ON(!address))
 114                 return;
 115
 116         topology = readl(address);
 117         node_shift = (topology >> 16) & 0x7;
 118         if (!node_shift)
 119                 /* The value 0 should be decoded as 8 */
 120                 node_shift = 8;
 121         maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
 122
 123         pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
 124                 maxcpus);
 125         setup_max_cpus = maxcpus;
 126         early_iounmap(address, 4);
 127 #endif
 128 }
 129
 130 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
 131 {
 132         return hard_smp_processor_id() >> index_msb;
 133 }
 134
 135 static void vsmp_apic_post_init(void)
 136 {
 137         /* need to update phys_pkg_id */
 138         apic->phys_pkg_id = apicid_phys_pkg_id;
 139 }
 140
 141 void __init vsmp_init(void)
 142 {
 143         detect_vsmp_box();
 144         if (!is_vsmp_box())
 145                 return;
 146
 147         x86_platform.apic_post_init = vsmp_apic_post_init;
 148
 149         vsmp_cap_cpus();
 150
 151         set_vsmp_ctl();
 152         return;
 153 }