xref: /openbmc/u-boot/arch/x86/cpu/queensbay/tnc.c (revision 103c45fb)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com>
4  */
5 
6 #include <common.h>
7 #include <dm.h>
8 #include <dm/device-internal.h>
9 #include <pci.h>
10 #include <asm/io.h>
11 #include <asm/irq.h>
12 #include <asm/post.h>
13 #include <asm/arch/device.h>
14 #include <asm/arch/tnc.h>
15 #include <asm/fsp/fsp_support.h>
16 #include <asm/processor.h>
17 
disable_igd(void)18 static int __maybe_unused disable_igd(void)
19 {
20 	struct udevice *igd, *sdvo;
21 	int ret;
22 
23 	ret = dm_pci_bus_find_bdf(TNC_IGD, &igd);
24 	if (ret)
25 		return ret;
26 	if (!igd)
27 		return 0;
28 
29 	ret = dm_pci_bus_find_bdf(TNC_SDVO, &sdvo);
30 	if (ret)
31 		return ret;
32 	if (!sdvo)
33 		return 0;
34 
35 	/*
36 	 * According to Atom E6xx datasheet, setting VGA Disable (bit17)
37 	 * of Graphics Controller register (offset 0x50) prevents IGD
38 	 * (D2:F0) from reporting itself as a VGA display controller
39 	 * class in the PCI configuration space, and should also prevent
40 	 * it from responding to VGA legacy memory range and I/O addresses.
41 	 *
42 	 * However test result shows that with just VGA Disable bit set and
43 	 * a PCIe graphics card connected to one of the PCIe controllers on
44 	 * the E6xx, accessing the VGA legacy space still causes system hang.
45 	 * After a number of attempts, it turns out besides VGA Disable bit,
46 	 * the SDVO (D3:F0) device should be disabled to make it work.
47 	 *
48 	 * To simplify, use the Function Disable register (offset 0xc4)
49 	 * to disable both IGD (D2:F0) and SDVO (D3:F0) devices. Now these
50 	 * two devices will be completely disabled (invisible in the PCI
51 	 * configuration space) unless a system reset is performed.
52 	 */
53 	dm_pci_write_config32(igd, IGD_FD, FUNC_DISABLE);
54 	dm_pci_write_config32(sdvo, IGD_FD, FUNC_DISABLE);
55 
56 	/*
57 	 * After setting the function disable bit, IGD and SDVO devices will
58 	 * disappear in the PCI configuration space. This however creates an
59 	 * inconsistent state from a driver model PCI controller point of view,
60 	 * as these two PCI devices are still attached to its parent's child
61 	 * device list as maintained by the driver model. Some driver model PCI
62 	 * APIs like dm_pci_find_class(), are referring to the list to speed up
63 	 * the finding process instead of re-enumerating the whole PCI bus, so
64 	 * it gets the stale cached data which is wrong.
65 	 *
66 	 * Note x86 PCI enueration normally happens twice, in pre-relocation
67 	 * phase and post-relocation. One option might be to call disable_igd()
68 	 * in one of the pre-relocation initialization hooks so that it gets
69 	 * disabled in the first round, and when it comes to the second round
70 	 * driver model PCI will construct a correct list. Unfortunately this
71 	 * does not work as Intel FSP is used on this platform to perform low
72 	 * level initialization, and fsp_init_phase_pci() is called only once
73 	 * in the post-relocation phase. If we disable IGD and SDVO devices,
74 	 * fsp_init_phase_pci() simply hangs and never returns.
75 	 *
76 	 * So the only option we have is to manually remove these two devices.
77 	 */
78 	ret = device_remove(igd, DM_REMOVE_NORMAL);
79 	if (ret)
80 		return ret;
81 	ret = device_unbind(igd);
82 	if (ret)
83 		return ret;
84 	ret = device_remove(sdvo, DM_REMOVE_NORMAL);
85 	if (ret)
86 		return ret;
87 	ret = device_unbind(sdvo);
88 	if (ret)
89 		return ret;
90 
91 	return 0;
92 }
93 
arch_cpu_init(void)94 int arch_cpu_init(void)
95 {
96 	post_code(POST_CPU_INIT);
97 
98 	return x86_cpu_init_f();
99 }
100 
tnc_irq_init(void)101 static void tnc_irq_init(void)
102 {
103 	struct tnc_rcba *rcba;
104 	u32 base;
105 
106 	pci_read_config32(TNC_LPC, LPC_RCBA, &base);
107 	base &= ~MEM_BAR_EN;
108 	rcba = (struct tnc_rcba *)base;
109 
110 	/* Make sure all internal PCI devices are using INTA */
111 	writel(INTA, &rcba->d02ip);
112 	writel(INTA, &rcba->d03ip);
113 	writel(INTA, &rcba->d27ip);
114 	writel(INTA, &rcba->d31ip);
115 	writel(INTA, &rcba->d23ip);
116 	writel(INTA, &rcba->d24ip);
117 	writel(INTA, &rcba->d25ip);
118 	writel(INTA, &rcba->d26ip);
119 
120 	/*
121 	 * Route TunnelCreek PCI device interrupt pin to PIRQ
122 	 *
123 	 * Since PCIe downstream ports received INTx are routed to PIRQ
124 	 * A/B/C/D directly and not configurable, we have to route PCIe
125 	 * root ports' INTx to PIRQ A/B/C/D as well. For other devices
126 	 * on TunneCreek, route them to PIRQ E/F/G/H.
127 	 */
128 	writew(PIRQE, &rcba->d02ir);
129 	writew(PIRQF, &rcba->d03ir);
130 	writew(PIRQG, &rcba->d27ir);
131 	writew(PIRQH, &rcba->d31ir);
132 	writew(PIRQA, &rcba->d23ir);
133 	writew(PIRQB, &rcba->d24ir);
134 	writew(PIRQC, &rcba->d25ir);
135 	writew(PIRQD, &rcba->d26ir);
136 }
137 
arch_early_init_r(void)138 int arch_early_init_r(void)
139 {
140 	int ret = 0;
141 
142 #ifdef CONFIG_DISABLE_IGD
143 	ret = disable_igd();
144 #endif
145 
146 	tnc_irq_init();
147 
148 	return ret;
149 }
150