x86/kernel/vsmp_64.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * vSMPowered(tm) systems specific initialization
0004  * Copyright (C) 2005 ScaleMP Inc.
0005  *
0006  * Ravikiran Thirumalai <kiran@scalemp.com>,
0007  * Shai Fultheim <shai@scalemp.com>
0008  * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
0009  *               Ravikiran Thirumalai <kiran@scalemp.com>
0010  */
0011
0012 #include <linux/init.h>
0013 #include <linux/pci_ids.h>
0014 #include <linux/pci_regs.h>
0015 #include <linux/smp.h>
0016 #include <linux/irq.h>
0017
0018 #include <asm/apic.h>
0019 #include <asm/pci-direct.h>
0020 #include <asm/io.h>
0021 #include <asm/paravirt.h>
0022 #include <asm/setup.h>
0023
0024 #define TOPOLOGY_REGISTER_OFFSET 0x10
0025
0026 #ifdef CONFIG_PCI
0027 static void __init set_vsmp_ctl(void)
0028 {
0029     void __iomem *address;
0030     unsigned int cap, ctl, cfg;
0031
0032     /* set vSMP magic bits to indicate vSMP capable kernel */
0033     cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
0034     address = early_ioremap(cfg, 8);
0035     cap = readl(address);
0036     ctl = readl(address + 4);
0037     printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
0038            cap, ctl);
0039
0040     /* If possible, let the vSMP foundation route the interrupt optimally */
0041 #ifdef CONFIG_SMP
0042     if (cap & ctl & BIT(8)) {
0043         ctl &= ~BIT(8);
0044
0045 #ifdef CONFIG_PROC_FS
0046         /* Don't let users change irq affinity via procfs */
0047         no_irq_affinity = 1;
0048 #endif
0049     }
0050 #endif
0051
0052     writel(ctl, address + 4);
0053     ctl = readl(address + 4);
0054     pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
0055
0056     early_iounmap(address, 8);
0057 }
0058 static int is_vsmp = -1;
0059
0060 static void __init detect_vsmp_box(void)
0061 {
0062     is_vsmp = 0;
0063
0064     if (!early_pci_allowed())
0065         return;
0066
0067     /* Check if we are running on a ScaleMP vSMPowered box */
0068     if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
0069          (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
0070         is_vsmp = 1;
0071 }
0072
0073 static int is_vsmp_box(void)
0074 {
0075     if (is_vsmp != -1)
0076         return is_vsmp;
0077     else {
0078         WARN_ON_ONCE(1);
0079         return 0;
0080     }
0081 }
0082
0083 #else
0084 static void __init detect_vsmp_box(void)
0085 {
0086 }
0087 static int is_vsmp_box(void)
0088 {
0089     return 0;
0090 }
0091 static void __init set_vsmp_ctl(void)
0092 {
0093 }
0094 #endif
0095
0096 static void __init vsmp_cap_cpus(void)
0097 {
0098 #if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
0099     void __iomem *address;
0100     unsigned int cfg, topology, node_shift, maxcpus;
0101
0102     /*
0103      * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
0104      * ones present in the first board, unless explicitly overridden by
0105      * setup_max_cpus
0106      */
0107     if (setup_max_cpus != NR_CPUS)
0108         return;
0109
0110     /* Read the vSMP Foundation topology register */
0111     cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
0112     address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
0113     if (WARN_ON(!address))
0114         return;
0115
0116     topology = readl(address);
0117     node_shift = (topology >> 16) & 0x7;
0118     if (!node_shift)
0119         /* The value 0 should be decoded as 8 */
0120         node_shift = 8;
0121     maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
0122
0123     pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
0124         maxcpus);
0125     setup_max_cpus = maxcpus;
0126     early_iounmap(address, 4);
0127 #endif
0128 }
0129
0130 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
0131 {
0132     return hard_smp_processor_id() >> index_msb;
0133 }
0134
0135 static void vsmp_apic_post_init(void)
0136 {
0137     /* need to update phys_pkg_id */
0138     apic->phys_pkg_id = apicid_phys_pkg_id;
0139 }
0140
0141 void __init vsmp_init(void)
0142 {
0143     detect_vsmp_box();
0144     if (!is_vsmp_box())
0145         return;
0146
0147     x86_platform.apic_post_init = vsmp_apic_post_init;
0148
0149     vsmp_cap_cpus();
0150
0151     set_vsmp_ctl();
0152     return;
0153 }