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-direct.h>
15#include <asm/iommu.h>
16
17#define STA2X11_SWIOTLB_SIZE (4*1024*1024)
18
19/*
20 * We build a list of bus numbers that are under the ConneXt. The
21 * main bridge hosts 4 busses, which are the 4 endpoints, in order.
22 */
23#define STA2X11_NR_EP		4	/* 0..3 included */
24#define STA2X11_NR_FUNCS	8	/* 0..7 included */
25#define STA2X11_AMBA_SIZE	(512 << 20)
26
27struct sta2x11_ahb_regs { /* saved during suspend */
28	u32 base, pexlbase, pexhbase, crw;
29};
30
31struct sta2x11_mapping {
32	int is_suspended;
33	struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
34};
35
36struct sta2x11_instance {
37	struct list_head list;
38	int bus0;
39	struct sta2x11_mapping map[STA2X11_NR_EP];
40};
41
42static LIST_HEAD(sta2x11_instance_list);
43
44/* At probe time, record new instances of this bridge (likely one only) */
45static void sta2x11_new_instance(struct pci_dev *pdev)
46{
47	struct sta2x11_instance *instance;
48
49	instance = kzalloc(sizeof(*instance), GFP_ATOMIC);
50	if (!instance)
51		return;
52	/* This has a subordinate bridge, with 4 more-subordinate ones */
53	instance->bus0 = pdev->subordinate->number + 1;
54
55	if (list_empty(&sta2x11_instance_list)) {
56		int size = STA2X11_SWIOTLB_SIZE;
57		/* First instance: register your own swiotlb area */
58		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
59		if (swiotlb_late_init_with_default_size(size))
60			dev_emerg(&pdev->dev, "init swiotlb failed\n");
61	}
62	list_add(&instance->list, &sta2x11_instance_list);
63}
64DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
65
66/*
67 * Utility functions used in this file from below
68 */
69static struct sta2x11_instance *sta2x11_pdev_to_instance(struct pci_dev *pdev)
70{
71	struct sta2x11_instance *instance;
72	int ep;
73
74	list_for_each_entry(instance, &sta2x11_instance_list, list) {
75		ep = pdev->bus->number - instance->bus0;
76		if (ep >= 0 && ep < STA2X11_NR_EP)
77			return instance;
78	}
79	return NULL;
80}
81
82static int sta2x11_pdev_to_ep(struct pci_dev *pdev)
83{
84	struct sta2x11_instance *instance;
85
86	instance = sta2x11_pdev_to_instance(pdev);
87	if (!instance)
88		return -1;
89
90	return pdev->bus->number - instance->bus0;
91}
92
93/* This is exported, as some devices need to access the MFD registers */
94struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
95{
96	return sta2x11_pdev_to_instance(pdev);
97}
98EXPORT_SYMBOL(sta2x11_get_instance);
99
100/* At setup time, we use our own ops if the device is a ConneXt one */
101static void sta2x11_setup_pdev(struct pci_dev *pdev)
102{
103	struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
104
105	if (!instance) /* either a sta2x11 bridge or another ST device */
106		return;
107
108	/* We must enable all devices as master, for audio DMA to work */
109	pci_set_master(pdev);
110}
111DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_setup_pdev);
112
113/*
114 * At boot we must set up the mappings for the pcie-to-amba bridge.
115 * It involves device access, and the same happens at suspend/resume time
116 */
117
118#define AHB_MAPB		0xCA4
119#define AHB_CRW(i)		(AHB_MAPB + 0  + (i) * 0x10)
120#define AHB_CRW_SZMASK			0xfffffc00UL
121#define AHB_CRW_ENABLE			(1 << 0)
122#define AHB_CRW_WTYPE_MEM		(2 << 1)
123#define AHB_CRW_ROE			(1UL << 3)	/* Relax Order Ena */
124#define AHB_CRW_NSE			(1UL << 4)	/* No Snoop Enable */
125#define AHB_BASE(i)		(AHB_MAPB + 4  + (i) * 0x10)
126#define AHB_PEXLBASE(i)		(AHB_MAPB + 8  + (i) * 0x10)
127#define AHB_PEXHBASE(i)		(AHB_MAPB + 12 + (i) * 0x10)
128
129/* At probe time, enable mapping for each endpoint, using the pdev */
130static void sta2x11_map_ep(struct pci_dev *pdev)
131{
132	struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
133	struct device *dev = &pdev->dev;
134	u32 amba_base, max_amba_addr;
135	int i, ret;
136
137	if (!instance)
138		return;
139
140	pci_read_config_dword(pdev, AHB_BASE(0), &amba_base);
141	max_amba_addr = amba_base + STA2X11_AMBA_SIZE - 1;
142
143	ret = dma_direct_set_offset(dev, 0, amba_base, STA2X11_AMBA_SIZE);
144	if (ret)
145		dev_err(dev, "sta2x11: could not set DMA offset\n");
146
147	dev->bus_dma_limit = max_amba_addr;
148	pci_set_consistent_dma_mask(pdev, max_amba_addr);
149	pci_set_dma_mask(pdev, 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}
165DECLARE_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
169static 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
181static 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), &regs->base);
198		pci_read_config_dword(pdev, AHB_PEXLBASE(i), &regs->pexlbase);
199		pci_read_config_dword(pdev, AHB_PEXHBASE(i), &regs->pexhbase);
200		pci_read_config_dword(pdev, AHB_CRW(i), &regs->crw);
201	}
202}
203DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, suspend_mapping);
204
205static 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	}
227out:
228	pci_set_master(pdev); /* Like at boot, enable master on all devices */
229}
230DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, resume_mapping);
231
232#endif /* CONFIG_PM */
233