1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/pci.h>
3 #include <linux/interrupt.h>
4 #include <linux/timer.h>
5 #include <linux/kernel.h>
6 
7 /*
8  * These functions are used early on before PCI scanning is done
9  * and all of the pci_dev and pci_bus structures have been created.
10  */
fake_pci_dev(struct pci_channel * hose,int top_bus,int busnr,int devfn)11 static struct pci_dev *fake_pci_dev(struct pci_channel *hose,
12 	int top_bus, int busnr, int devfn)
13 {
14 	static struct pci_dev dev;
15 	static struct pci_bus bus;
16 
17 	dev.bus = &bus;
18 	dev.sysdata = hose;
19 	dev.devfn = devfn;
20 	bus.number = busnr;
21 	bus.sysdata = hose;
22 	bus.ops = hose->pci_ops;
23 
24 	if(busnr != top_bus)
25 		/* Fake a parent bus structure. */
26 		bus.parent = &bus;
27 	else
28 		bus.parent = NULL;
29 
30 	return &dev;
31 }
32 
33 #define EARLY_PCI_OP(rw, size, type)					\
34 int __init early_##rw##_config_##size(struct pci_channel *hose,		\
35 	int top_bus, int bus, int devfn, int offset, type value)	\
36 {									\
37 	return pci_##rw##_config_##size(				\
38 		fake_pci_dev(hose, top_bus, bus, devfn),		\
39 		offset, value);						\
40 }
41 
EARLY_PCI_OP(read,byte,u8 *)42 EARLY_PCI_OP(read, byte, u8 *)
43 EARLY_PCI_OP(read, word, u16 *)
44 EARLY_PCI_OP(read, dword, u32 *)
45 EARLY_PCI_OP(write, byte, u8)
46 EARLY_PCI_OP(write, word, u16)
47 EARLY_PCI_OP(write, dword, u32)
48 
49 int __init pci_is_66mhz_capable(struct pci_channel *hose,
50 				int top_bus, int current_bus)
51 {
52 	u32 pci_devfn;
53 	unsigned short vid;
54 	int cap66 = -1;
55 	u16 stat;
56 
57 	pr_info("PCI: Checking 66MHz capabilities...\n");
58 
59 	for (pci_devfn = 0; pci_devfn < 0xff; pci_devfn++) {
60 		if (PCI_FUNC(pci_devfn))
61 			continue;
62 		if (early_read_config_word(hose, top_bus, current_bus,
63 					   pci_devfn, PCI_VENDOR_ID, &vid) !=
64 		    PCIBIOS_SUCCESSFUL)
65 			continue;
66 		if (vid == 0xffff)
67 			continue;
68 
69 		/* check 66MHz capability */
70 		if (cap66 < 0)
71 			cap66 = 1;
72 		if (cap66) {
73 			early_read_config_word(hose, top_bus, current_bus,
74 					       pci_devfn, PCI_STATUS, &stat);
75 			if (!(stat & PCI_STATUS_66MHZ)) {
76 				printk(KERN_DEBUG
77 				       "PCI: %02x:%02x not 66MHz capable.\n",
78 				       current_bus, pci_devfn);
79 				cap66 = 0;
80 				break;
81 			}
82 		}
83 	}
84 
85 	return cap66 > 0;
86 }
87 
pcibios_enable_err(struct timer_list * t)88 static void pcibios_enable_err(struct timer_list *t)
89 {
90 	struct pci_channel *hose = from_timer(hose, t, err_timer);
91 
92 	del_timer(&hose->err_timer);
93 	printk(KERN_DEBUG "PCI: re-enabling error IRQ.\n");
94 	enable_irq(hose->err_irq);
95 }
96 
pcibios_enable_serr(struct timer_list * t)97 static void pcibios_enable_serr(struct timer_list *t)
98 {
99 	struct pci_channel *hose = from_timer(hose, t, serr_timer);
100 
101 	del_timer(&hose->serr_timer);
102 	printk(KERN_DEBUG "PCI: re-enabling system error IRQ.\n");
103 	enable_irq(hose->serr_irq);
104 }
105 
pcibios_enable_timers(struct pci_channel * hose)106 void pcibios_enable_timers(struct pci_channel *hose)
107 {
108 	if (hose->err_irq) {
109 		timer_setup(&hose->err_timer, pcibios_enable_err, 0);
110 	}
111 
112 	if (hose->serr_irq) {
113 		timer_setup(&hose->serr_timer, pcibios_enable_serr, 0);
114 	}
115 }
116 
117 /*
118  * A simple handler for the regular PCI status errors, called from IRQ
119  * context.
120  */
pcibios_handle_status_errors(unsigned long addr,unsigned int status,struct pci_channel * hose)121 unsigned int pcibios_handle_status_errors(unsigned long addr,
122 					  unsigned int status,
123 					  struct pci_channel *hose)
124 {
125 	unsigned int cmd = 0;
126 
127 	if (status & PCI_STATUS_REC_MASTER_ABORT) {
128 		printk(KERN_DEBUG "PCI: master abort, pc=0x%08lx\n", addr);
129 		cmd |= PCI_STATUS_REC_MASTER_ABORT;
130 	}
131 
132 	if (status & PCI_STATUS_REC_TARGET_ABORT) {
133 		printk(KERN_DEBUG "PCI: target abort: ");
134 		pcibios_report_status(PCI_STATUS_REC_TARGET_ABORT |
135 				      PCI_STATUS_SIG_TARGET_ABORT |
136 				      PCI_STATUS_REC_MASTER_ABORT, 1);
137 		pr_cont("\n");
138 
139 		cmd |= PCI_STATUS_REC_TARGET_ABORT;
140 	}
141 
142 	if (status & (PCI_STATUS_PARITY | PCI_STATUS_DETECTED_PARITY)) {
143 		printk(KERN_DEBUG "PCI: parity error detected: ");
144 		pcibios_report_status(PCI_STATUS_PARITY |
145 				      PCI_STATUS_DETECTED_PARITY, 1);
146 		pr_cont("\n");
147 
148 		cmd |= PCI_STATUS_PARITY | PCI_STATUS_DETECTED_PARITY;
149 
150 		/* Now back off of the IRQ for awhile */
151 		if (hose->err_irq) {
152 			disable_irq_nosync(hose->err_irq);
153 			hose->err_timer.expires = jiffies + HZ;
154 			add_timer(&hose->err_timer);
155 		}
156 	}
157 
158 	return cmd;
159 }
160