1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * DMA translation between STA2x11 AMBA memory mapping and the x86 memory mapping
4 *
5 * ST Microelectronics ConneXt (STA2X11/STA2X10)
6 *
7 * Copyright (c) 2010-2011 Wind River Systems, Inc.
8 */
9
10 #include <linux/pci.h>
11 #include <linux/pci_ids.h>
12 #include <linux/export.h>
13 #include <linux/list.h>
14 #include <linux/dma-map-ops.h>
15 #include <linux/swiotlb.h>
16 #include <asm/iommu.h>
17
18 #define STA2X11_SWIOTLB_SIZE (4*1024*1024)
19
20 /*
21 * We build a list of bus numbers that are under the ConneXt. The
22 * main bridge hosts 4 busses, which are the 4 endpoints, in order.
23 */
24 #define STA2X11_NR_EP 4 /* 0..3 included */
25 #define STA2X11_NR_FUNCS 8 /* 0..7 included */
26 #define STA2X11_AMBA_SIZE (512 << 20)
27
28 struct sta2x11_ahb_regs { /* saved during suspend */
29 u32 base, pexlbase, pexhbase, crw;
30 };
31
32 struct sta2x11_mapping {
33 int is_suspended;
34 struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
35 };
36
37 struct sta2x11_instance {
38 struct list_head list;
39 int bus0;
40 struct sta2x11_mapping map[STA2X11_NR_EP];
41 };
42
43 static LIST_HEAD(sta2x11_instance_list);
44
45 /* At probe time, record new instances of this bridge (likely one only) */
sta2x11_new_instance(struct pci_dev * pdev)46 static void sta2x11_new_instance(struct pci_dev *pdev)
47 {
48 struct sta2x11_instance *instance;
49
50 instance = kzalloc(sizeof(*instance), GFP_ATOMIC);
51 if (!instance)
52 return;
53 /* This has a subordinate bridge, with 4 more-subordinate ones */
54 instance->bus0 = pdev->subordinate->number + 1;
55
56 if (list_empty(&sta2x11_instance_list)) {
57 int size = STA2X11_SWIOTLB_SIZE;
58 /* First instance: register your own swiotlb area */
59 dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
60 if (swiotlb_init_late(size, GFP_DMA, NULL))
61 dev_emerg(&pdev->dev, "init swiotlb failed\n");
62 }
63 list_add(&instance->list, &sta2x11_instance_list);
64 }
65 DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
66
67 /*
68 * Utility functions used in this file from below
69 */
sta2x11_pdev_to_instance(struct pci_dev * pdev)70 static struct sta2x11_instance *sta2x11_pdev_to_instance(struct pci_dev *pdev)
71 {
72 struct sta2x11_instance *instance;
73 int ep;
74
75 list_for_each_entry(instance, &sta2x11_instance_list, list) {
76 ep = pdev->bus->number - instance->bus0;
77 if (ep >= 0 && ep < STA2X11_NR_EP)
78 return instance;
79 }
80 return NULL;
81 }
82
sta2x11_pdev_to_ep(struct pci_dev * pdev)83 static int sta2x11_pdev_to_ep(struct pci_dev *pdev)
84 {
85 struct sta2x11_instance *instance;
86
87 instance = sta2x11_pdev_to_instance(pdev);
88 if (!instance)
89 return -1;
90
91 return pdev->bus->number - instance->bus0;
92 }
93
94 /* This is exported, as some devices need to access the MFD registers */
sta2x11_get_instance(struct pci_dev * pdev)95 struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
96 {
97 return sta2x11_pdev_to_instance(pdev);
98 }
99 EXPORT_SYMBOL(sta2x11_get_instance);
100
101 /* At setup time, we use our own ops if the device is a ConneXt one */
sta2x11_setup_pdev(struct pci_dev * pdev)102 static void sta2x11_setup_pdev(struct pci_dev *pdev)
103 {
104 struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
105
106 if (!instance) /* either a sta2x11 bridge or another ST device */
107 return;
108
109 /* We must enable all devices as master, for audio DMA to work */
110 pci_set_master(pdev);
111 }
112 DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_setup_pdev);
113
114 /*
115 * At boot we must set up the mappings for the pcie-to-amba bridge.
116 * It involves device access, and the same happens at suspend/resume time
117 */
118
119 #define AHB_MAPB 0xCA4
120 #define AHB_CRW(i) (AHB_MAPB + 0 + (i) * 0x10)
121 #define AHB_CRW_SZMASK 0xfffffc00UL
122 #define AHB_CRW_ENABLE (1 << 0)
123 #define AHB_CRW_WTYPE_MEM (2 << 1)
124 #define AHB_CRW_ROE (1UL << 3) /* Relax Order Ena */
125 #define AHB_CRW_NSE (1UL << 4) /* No Snoop Enable */
126 #define AHB_BASE(i) (AHB_MAPB + 4 + (i) * 0x10)
127 #define AHB_PEXLBASE(i) (AHB_MAPB + 8 + (i) * 0x10)
128 #define AHB_PEXHBASE(i) (AHB_MAPB + 12 + (i) * 0x10)
129
130 /* At probe time, enable mapping for each endpoint, using the pdev */
sta2x11_map_ep(struct pci_dev * pdev)131 static void sta2x11_map_ep(struct pci_dev *pdev)
132 {
133 struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
134 struct device *dev = &pdev->dev;
135 u32 amba_base, max_amba_addr;
136 int i, ret;
137
138 if (!instance)
139 return;
140
141 pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
142 max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
143
144 ret = dma_direct_set_offset(dev, 0, amba_base, STA2X11_AMBA_SIZE);
145 if (ret)
146 dev_err(dev, "sta2x11: could not set DMA offset\n");
147
148 dev->bus_dma_limit = max_amba_addr;
149 dma_set_mask_and_coherent(&pdev->dev, max_amba_addr);
150
151 /* Configure AHB mapping */
152 pci_write_config_dword(pdev, AHB_PEXLBASE(0), 0);
153 pci_write_config_dword(pdev, AHB_PEXHBASE(0), 0);
154 pci_write_config_dword(pdev, AHB_CRW(0), STA2X11_AMBA_SIZE |
155 AHB_CRW_WTYPE_MEM | AHB_CRW_ENABLE);
156
157 /* Disable all the other windows */
158 for (i = 1; i < STA2X11_NR_FUNCS; i++)
159 pci_write_config_dword(pdev, AHB_CRW(i), 0);
160
161 dev_info(&pdev->dev,
162 "sta2x11: Map EP %i: AMBA address %#8x-%#8x\n",
163 sta2x11_pdev_to_ep(pdev), amba_base, max_amba_addr);
164 }
165 DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_map_ep);
166
167 #ifdef CONFIG_PM /* Some register values must be saved and restored */
168
sta2x11_pdev_to_mapping(struct pci_dev * pdev)169 static struct sta2x11_mapping *sta2x11_pdev_to_mapping(struct pci_dev *pdev)
170 {
171 struct sta2x11_instance *instance;
172 int ep;
173
174 instance = sta2x11_pdev_to_instance(pdev);
175 if (!instance)
176 return NULL;
177 ep = sta2x11_pdev_to_ep(pdev);
178 return instance->map + ep;
179 }
180
suspend_mapping(struct pci_dev * pdev)181 static void suspend_mapping(struct pci_dev *pdev)
182 {
183 struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
184 int i;
185
186 if (!map)
187 return;
188
189 if (map->is_suspended)
190 return;
191 map->is_suspended = 1;
192
193 /* Save all window configs */
194 for (i = 0; i < STA2X11_NR_FUNCS; i++) {
195 struct sta2x11_ahb_regs *regs = map->regs + i;
196
197 pci_read_config_dword(pdev, AHB_BASE(i), ®s->base);
198 pci_read_config_dword(pdev, AHB_PEXLBASE(i), ®s->pexlbase);
199 pci_read_config_dword(pdev, AHB_PEXHBASE(i), ®s->pexhbase);
200 pci_read_config_dword(pdev, AHB_CRW(i), ®s->crw);
201 }
202 }
203 DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, suspend_mapping);
204
resume_mapping(struct pci_dev * pdev)205 static void resume_mapping(struct pci_dev *pdev)
206 {
207 struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
208 int i;
209
210 if (!map)
211 return;
212
213
214 if (!map->is_suspended)
215 goto out;
216 map->is_suspended = 0;
217
218 /* Restore all window configs */
219 for (i = 0; i < STA2X11_NR_FUNCS; i++) {
220 struct sta2x11_ahb_regs *regs = map->regs + i;
221
222 pci_write_config_dword(pdev, AHB_BASE(i), regs->base);
223 pci_write_config_dword(pdev, AHB_PEXLBASE(i), regs->pexlbase);
224 pci_write_config_dword(pdev, AHB_PEXHBASE(i), regs->pexhbase);
225 pci_write_config_dword(pdev, AHB_CRW(i), regs->crw);
226 }
227 out:
228 pci_set_master(pdev); /* Like at boot, enable master on all devices */
229 }
230 DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, resume_mapping);
231
232 #endif /* CONFIG_PM */
233