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#include <asm/sta2x11.h>
18
19#define STA2X11_SWIOTLB_SIZE (4*1024*1024)
20
21/*
22 * We build a list of bus numbers that are under the ConneXt. The
23 * main bridge hosts 4 busses, which are the 4 endpoints, in order.
24 */
25#define STA2X11_NR_EP		4	/* 0..3 included */
26#define STA2X11_NR_FUNCS	8	/* 0..7 included */
27#define STA2X11_AMBA_SIZE	(512 << 20)
28
29struct sta2x11_ahb_regs { /* saved during suspend */
30	u32 base, pexlbase, pexhbase, crw;
31};
32
33struct sta2x11_mapping {
34	int is_suspended;
35	struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
36};
37
38struct sta2x11_instance {
39	struct list_head list;
40	int bus0;
41	struct sta2x11_mapping map[STA2X11_NR_EP];
42};
43
44static LIST_HEAD(sta2x11_instance_list);
45
46/* At probe time, record new instances of this bridge (likely one only) */
47static void sta2x11_new_instance(struct pci_dev *pdev)
48{
49	struct sta2x11_instance *instance;
50
51	instance = kzalloc(sizeof(*instance), GFP_ATOMIC);
52	if (!instance)
53		return;
54	/* This has a subordinate bridge, with 4 more-subordinate ones */
55	instance->bus0 = pdev->subordinate->number + 1;
56
57	if (list_empty(&sta2x11_instance_list)) {
58		int size = STA2X11_SWIOTLB_SIZE;
59		/* First instance: register your own swiotlb area */
60		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
61		if (swiotlb_init_late(size, GFP_DMA, NULL))
62			dev_emerg(&pdev->dev, "init swiotlb failed\n");
63	}
64	list_add(&instance->list, &sta2x11_instance_list);
65}
66DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
67
68/*
69 * Utility functions used in this file from below
70 */
71static struct sta2x11_instance *sta2x11_pdev_to_instance(struct pci_dev *pdev)
72{
73	struct sta2x11_instance *instance;
74	int ep;
75
76	list_for_each_entry(instance, &sta2x11_instance_list, list) {
77		ep = pdev->bus->number - instance->bus0;
78		if (ep >= 0 && ep < STA2X11_NR_EP)
79			return instance;
80	}
81	return NULL;
82}
83
84static int sta2x11_pdev_to_ep(struct pci_dev *pdev)
85{
86	struct sta2x11_instance *instance;
87
88	instance = sta2x11_pdev_to_instance(pdev);
89	if (!instance)
90		return -1;
91
92	return pdev->bus->number - instance->bus0;
93}
94
95/* This is exported, as some devices need to access the MFD registers */
96struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
97{
98	return sta2x11_pdev_to_instance(pdev);
99}
100EXPORT_SYMBOL(sta2x11_get_instance);
101
102/* At setup time, we use our own ops if the device is a ConneXt one */
103static void sta2x11_setup_pdev(struct pci_dev *pdev)
104{
105	struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
106
107	if (!instance) /* either a sta2x11 bridge or another ST device */
108		return;
109
110	/* We must enable all devices as master, for audio DMA to work */
111	pci_set_master(pdev);
112}
113DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_setup_pdev);
114
115/*
116 * At boot we must set up the mappings for the pcie-to-amba bridge.
117 * It involves device access, and the same happens at suspend/resume time
118 */
119
120#define AHB_MAPB		0xCA4
121#define AHB_CRW(i)		(AHB_MAPB + 0  + (i) * 0x10)
122#define AHB_CRW_SZMASK			0xfffffc00UL
123#define AHB_CRW_ENABLE			(1 << 0)
124#define AHB_CRW_WTYPE_MEM		(2 << 1)
125#define AHB_CRW_ROE			(1UL << 3)	/* Relax Order Ena */
126#define AHB_CRW_NSE			(1UL << 4)	/* No Snoop Enable */
127#define AHB_BASE(i)		(AHB_MAPB + 4  + (i) * 0x10)
128#define AHB_PEXLBASE(i)		(AHB_MAPB + 8  + (i) * 0x10)
129#define AHB_PEXHBASE(i)		(AHB_MAPB + 12 + (i) * 0x10)
130
131/* At probe time, enable mapping for each endpoint, using the pdev */
132static void sta2x11_map_ep(struct pci_dev *pdev)
133{
134	struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
135	struct device *dev = &pdev->dev;
136	u32 amba_base, max_amba_addr;
137	int i, ret;
138
139	if (!instance)
140		return;
141
142	pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
143	max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
144
145	ret = dma_direct_set_offset(dev, 0, amba_base, STA2X11_AMBA_SIZE);
146	if (ret)
147		dev_err(dev, "sta2x11: could not set DMA offset\n");
148
149	dev->bus_dma_limit = max_amba_addr;
150	dma_set_mask_and_coherent(&pdev->dev, max_amba_addr);
151
152	/* Configure AHB mapping */
153	pci_write_config_dword(pdev, AHB_PEXLBASE(0), 0);
154	pci_write_config_dword(pdev, AHB_PEXHBASE(0), 0);
155	pci_write_config_dword(pdev, AHB_CRW(0), STA2X11_AMBA_SIZE |
156			       AHB_CRW_WTYPE_MEM | AHB_CRW_ENABLE);
157
158	/* Disable all the other windows */
159	for (i = 1; i < STA2X11_NR_FUNCS; i++)
160		pci_write_config_dword(pdev, AHB_CRW(i), 0);
161
162	dev_info(&pdev->dev,
163		 "sta2x11: Map EP %i: AMBA address %#8x-%#8x\n",
164		 sta2x11_pdev_to_ep(pdev), amba_base, max_amba_addr);
165}
166DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_map_ep);
167
168#ifdef CONFIG_PM /* Some register values must be saved and restored */
169
170static struct sta2x11_mapping *sta2x11_pdev_to_mapping(struct pci_dev *pdev)
171{
172	struct sta2x11_instance *instance;
173	int ep;
174
175	instance = sta2x11_pdev_to_instance(pdev);
176	if (!instance)
177		return NULL;
178	ep = sta2x11_pdev_to_ep(pdev);
179	return instance->map + ep;
180}
181
182static void suspend_mapping(struct pci_dev *pdev)
183{
184	struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
185	int i;
186
187	if (!map)
188		return;
189
190	if (map->is_suspended)
191		return;
192	map->is_suspended = 1;
193
194	/* Save all window configs */
195	for (i = 0; i < STA2X11_NR_FUNCS; i++) {
196		struct sta2x11_ahb_regs *regs = map->regs + i;
197
198		pci_read_config_dword(pdev, AHB_BASE(i), &regs->base);
199		pci_read_config_dword(pdev, AHB_PEXLBASE(i), &regs->pexlbase);
200		pci_read_config_dword(pdev, AHB_PEXHBASE(i), &regs->pexhbase);
201		pci_read_config_dword(pdev, AHB_CRW(i), &regs->crw);
202	}
203}
204DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, suspend_mapping);
205
206static void resume_mapping(struct pci_dev *pdev)
207{
208	struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
209	int i;
210
211	if (!map)
212		return;
213
214
215	if (!map->is_suspended)
216		goto out;
217	map->is_suspended = 0;
218
219	/* Restore all window configs */
220	for (i = 0; i < STA2X11_NR_FUNCS; i++) {
221		struct sta2x11_ahb_regs *regs = map->regs + i;
222
223		pci_write_config_dword(pdev, AHB_BASE(i), regs->base);
224		pci_write_config_dword(pdev, AHB_PEXLBASE(i), regs->pexlbase);
225		pci_write_config_dword(pdev, AHB_PEXHBASE(i), regs->pexhbase);
226		pci_write_config_dword(pdev, AHB_CRW(i), regs->crw);
227	}
228out:
229	pci_set_master(pdev); /* Like at boot, enable master on all devices */
230}
231DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, resume_mapping);
232
233#endif /* CONFIG_PM */
234