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
28struct sta2x11_ahb_regs { /* saved during suspend */
29	u32 base, pexlbase, pexhbase, crw;
30};
31
32struct sta2x11_mapping {
33	int is_suspended;
34	struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
35};
36
37struct sta2x11_instance {
38	struct list_head list;
39	int bus0;
40	struct sta2x11_mapping map[STA2X11_NR_EP];
41};
42
43static LIST_HEAD(sta2x11_instance_list);
44
45/* At probe time, record new instances of this bridge (likely one only) */
46static 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}
65DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
66
67/*
68 * Utility functions used in this file from below
69 */
70static 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
83static 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 */
95struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
96{
97	return sta2x11_pdev_to_instance(pdev);
98}
99EXPORT_SYMBOL(sta2x11_get_instance);
100
101/* At setup time, we use our own ops if the device is a ConneXt one */
102static 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}
112DECLARE_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 */
131static 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}
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