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// SPDX-License-Identifier: GPL-2.0-only
/*
* vSMPowered(tm) systems specific initialization
* Copyright (C) 2005 ScaleMP Inc.
*
* Ravikiran Thirumalai <kiran@scalemp.com>,
* Shai Fultheim <shai@scalemp.com>
* Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
* Ravikiran Thirumalai <kiran@scalemp.com>
*/
#include <linux/init.h>
#include <linux/pci_ids.h>
#include <linux/pci_regs.h>
#include <linux/smp.h>
#include <linux/irq.h>
#include <asm/apic.h>
#include <asm/pci-direct.h>
#include <asm/io.h>
#include <asm/paravirt.h>
#include <asm/setup.h>
#define TOPOLOGY_REGISTER_OFFSET 0x10
#ifdef CONFIG_PCI
static void __init set_vsmp_ctl(void)
{
void __iomem *address;
unsigned int cap, ctl, cfg;
/* set vSMP magic bits to indicate vSMP capable kernel */
cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
address = early_ioremap(cfg, 8);
cap = readl(address);
ctl = readl(address + 4);
printk(KERN_INFO "vSMP CTL: capabilities:0x%08x control:0x%08x\n",
cap, ctl);
/* If possible, let the vSMP foundation route the interrupt optimally */
#ifdef CONFIG_SMP
if (cap & ctl & BIT(8)) {
ctl &= ~BIT(8);
#ifdef CONFIG_PROC_FS
/* Don't let users change irq affinity via procfs */
no_irq_affinity = 1;
#endif
}
#endif
writel(ctl, address + 4);
ctl = readl(address + 4);
pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
early_iounmap(address, 8);
}
static int is_vsmp = -1;
static void __init detect_vsmp_box(void)
{
is_vsmp = 0;
if (!early_pci_allowed())
return;
/* Check if we are running on a ScaleMP vSMPowered box */
if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
(PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
is_vsmp = 1;
}
static int is_vsmp_box(void)
{
if (is_vsmp != -1)
return is_vsmp;
else {
WARN_ON_ONCE(1);
return 0;
}
}
#else
static void __init detect_vsmp_box(void)
{
}
static int is_vsmp_box(void)
{
return 0;
}
static void __init set_vsmp_ctl(void)
{
}
#endif
static void __init vsmp_cap_cpus(void)
{
#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
void __iomem *address;
unsigned int cfg, topology, node_shift, maxcpus;
/*
* CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
* ones present in the first board, unless explicitly overridden by
* setup_max_cpus
*/
if (setup_max_cpus != NR_CPUS)
return;
/* Read the vSMP Foundation topology register */
cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
if (WARN_ON(!address))
return;
topology = readl(address);
node_shift = (topology >> 16) & 0x7;
if (!node_shift)
/* The value 0 should be decoded as 8 */
node_shift = 8;
maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
maxcpus);
setup_max_cpus = maxcpus;
early_iounmap(address, 4);
#endif
}
void __init vsmp_init(void)
{
detect_vsmp_box();
if (!is_vsmp_box())
return;
vsmp_cap_cpus();
set_vsmp_ctl();
return;
}
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