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/* Flag below is initialized once during vSMP PCI initialization. */
30static int irq_routing_comply = 1;
31
32#if defined CONFIG_PCI && defined CONFIG_PARAVIRT
33/*
34 * Interrupt control on vSMPowered systems:
35 * ~AC is a shadow of IF.  If IF is 'on' AC should be 'off'
36 * and vice versa.
37 */
38
39asmlinkage __visible unsigned long vsmp_save_fl(void)
40{
41	unsigned long flags = native_save_fl();
42
43	if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
44		flags &= ~X86_EFLAGS_IF;
45	return flags;
46}
47PV_CALLEE_SAVE_REGS_THUNK(vsmp_save_fl);
48
49__visible void vsmp_restore_fl(unsigned long flags)
50{
51	if (flags & X86_EFLAGS_IF)
52		flags &= ~X86_EFLAGS_AC;
53	else
54		flags |= X86_EFLAGS_AC;
55	native_restore_fl(flags);
56}
57PV_CALLEE_SAVE_REGS_THUNK(vsmp_restore_fl);
58
59asmlinkage __visible void vsmp_irq_disable(void)
60{
61	unsigned long flags = native_save_fl();
62
63	native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
64}
65PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_disable);
66
67asmlinkage __visible void vsmp_irq_enable(void)
68{
69	unsigned long flags = native_save_fl();
70
71	native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
72}
73PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_enable);
74
75static unsigned __init_or_module vsmp_patch(u8 type, u16 clobbers, void *ibuf,
76				  unsigned long addr, unsigned len)
77{
78	switch (type) {
79	case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
80	case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
81	case PARAVIRT_PATCH(pv_irq_ops.save_fl):
82	case PARAVIRT_PATCH(pv_irq_ops.restore_fl):
83		return paravirt_patch_default(type, clobbers, ibuf, addr, len);
84	default:
85		return native_patch(type, clobbers, ibuf, addr, len);
86	}
87
88}
89
90static void __init set_vsmp_pv_ops(void)
91{
92	void __iomem *address;
93	unsigned int cap, ctl, cfg;
94
95	/* set vSMP magic bits to indicate vSMP capable kernel */
96	cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
97	address = early_ioremap(cfg, 8);
98	cap = readl(address);
99	ctl = readl(address + 4);
100	printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
101	       cap, ctl);
102
103	/* If possible, let the vSMP foundation route the interrupt optimally */
104#ifdef CONFIG_SMP
105	if (cap & ctl & BIT(8)) {
106		ctl &= ~BIT(8);
107
108		/* Interrupt routing set to ignore */
109		irq_routing_comply = 0;
110
111#ifdef CONFIG_PROC_FS
112		/* Don't let users change irq affinity via procfs */
113		no_irq_affinity = 1;
114#endif
115	}
116#endif
117
118	if (cap & ctl & (1 << 4)) {
119		/* Setup irq ops and turn on vSMP  IRQ fastpath handling */
120		pv_irq_ops.irq_disable = PV_CALLEE_SAVE(vsmp_irq_disable);
121		pv_irq_ops.irq_enable  = PV_CALLEE_SAVE(vsmp_irq_enable);
122		pv_irq_ops.save_fl  = PV_CALLEE_SAVE(vsmp_save_fl);
123		pv_irq_ops.restore_fl  = PV_CALLEE_SAVE(vsmp_restore_fl);
124		pv_init_ops.patch = vsmp_patch;
125		ctl &= ~(1 << 4);
126	}
127	writel(ctl, address + 4);
128	ctl = readl(address + 4);
129	pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
130
131	early_iounmap(address, 8);
132}
133#else
134static void __init set_vsmp_pv_ops(void)
135{
136}
137#endif
138
139#ifdef CONFIG_PCI
140static int is_vsmp = -1;
141
142static void __init detect_vsmp_box(void)
143{
144	is_vsmp = 0;
145
146	if (!early_pci_allowed())
147		return;
148
149	/* Check if we are running on a ScaleMP vSMPowered box */
150	if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
151	     (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
152		is_vsmp = 1;
153}
154
155static int is_vsmp_box(void)
156{
157	if (is_vsmp != -1)
158		return is_vsmp;
159	else {
160		WARN_ON_ONCE(1);
161		return 0;
162	}
163}
164
165#else
166static void __init detect_vsmp_box(void)
167{
168}
169static int is_vsmp_box(void)
170{
171	return 0;
172}
173#endif
174
175static void __init vsmp_cap_cpus(void)
176{
177#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
178	void __iomem *address;
179	unsigned int cfg, topology, node_shift, maxcpus;
180
181	/*
182	 * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
183	 * ones present in the first board, unless explicitly overridden by
184	 * setup_max_cpus
185	 */
186	if (setup_max_cpus != NR_CPUS)
187		return;
188
189	/* Read the vSMP Foundation topology register */
190	cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
191	address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
192	if (WARN_ON(!address))
193		return;
194
195	topology = readl(address);
196	node_shift = (topology >> 16) & 0x7;
197	if (!node_shift)
198		/* The value 0 should be decoded as 8 */
199		node_shift = 8;
200	maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
201
202	pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
203		maxcpus);
204	setup_max_cpus = maxcpus;
205	early_iounmap(address, 4);
206#endif
207}
208
209static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
210{
211	return hard_smp_processor_id() >> index_msb;
212}
213
214/*
215 * In vSMP, all cpus should be capable of handling interrupts, regardless of
216 * the APIC used.
217 */
218static void fill_vector_allocation_domain(int cpu, struct cpumask *retmask,
219					  const struct cpumask *mask)
220{
221	cpumask_setall(retmask);
222}
223
224static void vsmp_apic_post_init(void)
225{
226	/* need to update phys_pkg_id */
227	apic->phys_pkg_id = apicid_phys_pkg_id;
228
229	if (!irq_routing_comply)
230		apic->vector_allocation_domain = fill_vector_allocation_domain;
231}
232
233void __init vsmp_init(void)
234{
235	detect_vsmp_box();
236	if (!is_vsmp_box())
237		return;
238
239	x86_platform.apic_post_init = vsmp_apic_post_init;
240
241	vsmp_cap_cpus();
242
243	set_vsmp_pv_ops();
244	return;
245}
246