xref: /openbmc/linux/arch/x86/kernel/vsmp_64.c (revision 22246614)
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 <asm/pci-direct.h>
19 #include <asm/io.h>
20 #include <asm/paravirt.h>
21 
22 #if defined CONFIG_PCI && defined CONFIG_PARAVIRT
23 /*
24  * Interrupt control on vSMPowered systems:
25  * ~AC is a shadow of IF.  If IF is 'on' AC should be 'off'
26  * and vice versa.
27  */
28 
29 static unsigned long vsmp_save_fl(void)
30 {
31 	unsigned long flags = native_save_fl();
32 
33 	if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
34 		flags &= ~X86_EFLAGS_IF;
35 	return flags;
36 }
37 
38 static void vsmp_restore_fl(unsigned long flags)
39 {
40 	if (flags & X86_EFLAGS_IF)
41 		flags &= ~X86_EFLAGS_AC;
42 	else
43 		flags |= X86_EFLAGS_AC;
44 	native_restore_fl(flags);
45 }
46 
47 static void vsmp_irq_disable(void)
48 {
49 	unsigned long flags = native_save_fl();
50 
51 	native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
52 }
53 
54 static void vsmp_irq_enable(void)
55 {
56 	unsigned long flags = native_save_fl();
57 
58 	native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
59 }
60 
61 static unsigned __init vsmp_patch(u8 type, u16 clobbers, void *ibuf,
62 				  unsigned long addr, unsigned len)
63 {
64 	switch (type) {
65 	case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
66 	case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
67 	case PARAVIRT_PATCH(pv_irq_ops.save_fl):
68 	case PARAVIRT_PATCH(pv_irq_ops.restore_fl):
69 		return paravirt_patch_default(type, clobbers, ibuf, addr, len);
70 	default:
71 		return native_patch(type, clobbers, ibuf, addr, len);
72 	}
73 
74 }
75 
76 static void __init set_vsmp_pv_ops(void)
77 {
78 	void *address;
79 	unsigned int cap, ctl, cfg;
80 
81 	/* set vSMP magic bits to indicate vSMP capable kernel */
82 	cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
83 	address = early_ioremap(cfg, 8);
84 	cap = readl(address);
85 	ctl = readl(address + 4);
86 	printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
87 	       cap, ctl);
88 	if (cap & ctl & (1 << 4)) {
89 		/* Setup irq ops and turn on vSMP  IRQ fastpath handling */
90 		pv_irq_ops.irq_disable = vsmp_irq_disable;
91 		pv_irq_ops.irq_enable  = vsmp_irq_enable;
92 		pv_irq_ops.save_fl  = vsmp_save_fl;
93 		pv_irq_ops.restore_fl  = vsmp_restore_fl;
94 		pv_init_ops.patch = vsmp_patch;
95 
96 		ctl &= ~(1 << 4);
97 		writel(ctl, address + 4);
98 		ctl = readl(address + 4);
99 		printk(KERN_INFO "vSMP CTL: control set to:0x%08x\n", ctl);
100 	}
101 
102 	early_iounmap(address, 8);
103 }
104 #else
105 static void __init set_vsmp_pv_ops(void)
106 {
107 }
108 #endif
109 
110 #ifdef CONFIG_PCI
111 static int is_vsmp = -1;
112 
113 static void __init detect_vsmp_box(void)
114 {
115 	is_vsmp = 0;
116 
117 	if (!early_pci_allowed())
118 		return;
119 
120 	/* Check if we are running on a ScaleMP vSMPowered box */
121 	if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
122 	     (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
123 		is_vsmp = 1;
124 }
125 
126 int is_vsmp_box(void)
127 {
128 	if (is_vsmp != -1)
129 		return is_vsmp;
130 	else {
131 		WARN_ON_ONCE(1);
132 		return 0;
133 	}
134 }
135 #else
136 static void __init detect_vsmp_box(void)
137 {
138 }
139 int is_vsmp_box(void)
140 {
141 	return 0;
142 }
143 #endif
144 
145 void __init vsmp_init(void)
146 {
147 	detect_vsmp_box();
148 	if (!is_vsmp_box())
149 		return;
150 
151 	set_vsmp_pv_ops();
152 	return;
153 }
154