1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * FPGA to/from HPS Bridge Driver for Altera SoCFPGA Devices
4 *
5 * Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
6 *
7 * Includes this patch from the mailing list:
8 * fpga: altera-hps2fpga: fix HPS2FPGA bridge visibility to L3 masters
9 * Signed-off-by: Anatolij Gustschin <agust@denx.de>
10 */
11
12 /*
13 * This driver manages bridges on a Altera SOCFPGA between the ARM host
14 * processor system (HPS) and the embedded FPGA.
15 *
16 * This driver supports enabling and disabling of the configured ports, which
17 * allows for safe reprogramming of the FPGA, assuming that the new FPGA image
18 * uses the same port configuration. Bridges must be disabled before
19 * reprogramming the FPGA and re-enabled after the FPGA has been programmed.
20 */
21
22 #include <linux/clk.h>
23 #include <linux/fpga/fpga-bridge.h>
24 #include <linux/kernel.h>
25 #include <linux/mfd/syscon.h>
26 #include <linux/module.h>
27 #include <linux/of_platform.h>
28 #include <linux/regmap.h>
29 #include <linux/reset.h>
30 #include <linux/spinlock.h>
31
32 #define ALT_L3_REMAP_OFST 0x0
33 #define ALT_L3_REMAP_MPUZERO_MSK 0x00000001
34 #define ALT_L3_REMAP_H2F_MSK 0x00000008
35 #define ALT_L3_REMAP_LWH2F_MSK 0x00000010
36
37 #define HPS2FPGA_BRIDGE_NAME "hps2fpga"
38 #define LWHPS2FPGA_BRIDGE_NAME "lwhps2fpga"
39 #define FPGA2HPS_BRIDGE_NAME "fpga2hps"
40
41 struct altera_hps2fpga_data {
42 const char *name;
43 struct reset_control *bridge_reset;
44 struct regmap *l3reg;
45 unsigned int remap_mask;
46 struct clk *clk;
47 };
48
alt_hps2fpga_enable_show(struct fpga_bridge * bridge)49 static int alt_hps2fpga_enable_show(struct fpga_bridge *bridge)
50 {
51 struct altera_hps2fpga_data *priv = bridge->priv;
52
53 return reset_control_status(priv->bridge_reset);
54 }
55
56 /* The L3 REMAP register is write only, so keep a cached value. */
57 static unsigned int l3_remap_shadow;
58 static DEFINE_SPINLOCK(l3_remap_lock);
59
_alt_hps2fpga_enable_set(struct altera_hps2fpga_data * priv,bool enable)60 static int _alt_hps2fpga_enable_set(struct altera_hps2fpga_data *priv,
61 bool enable)
62 {
63 unsigned long flags;
64 int ret;
65
66 /* bring bridge out of reset */
67 if (enable)
68 ret = reset_control_deassert(priv->bridge_reset);
69 else
70 ret = reset_control_assert(priv->bridge_reset);
71 if (ret)
72 return ret;
73
74 /* Allow bridge to be visible to L3 masters or not */
75 if (priv->remap_mask) {
76 spin_lock_irqsave(&l3_remap_lock, flags);
77 l3_remap_shadow |= ALT_L3_REMAP_MPUZERO_MSK;
78
79 if (enable)
80 l3_remap_shadow |= priv->remap_mask;
81 else
82 l3_remap_shadow &= ~priv->remap_mask;
83
84 ret = regmap_write(priv->l3reg, ALT_L3_REMAP_OFST,
85 l3_remap_shadow);
86 spin_unlock_irqrestore(&l3_remap_lock, flags);
87 }
88
89 return ret;
90 }
91
alt_hps2fpga_enable_set(struct fpga_bridge * bridge,bool enable)92 static int alt_hps2fpga_enable_set(struct fpga_bridge *bridge, bool enable)
93 {
94 return _alt_hps2fpga_enable_set(bridge->priv, enable);
95 }
96
97 static const struct fpga_bridge_ops altera_hps2fpga_br_ops = {
98 .enable_set = alt_hps2fpga_enable_set,
99 .enable_show = alt_hps2fpga_enable_show,
100 };
101
102 static struct altera_hps2fpga_data hps2fpga_data = {
103 .name = HPS2FPGA_BRIDGE_NAME,
104 .remap_mask = ALT_L3_REMAP_H2F_MSK,
105 };
106
107 static struct altera_hps2fpga_data lwhps2fpga_data = {
108 .name = LWHPS2FPGA_BRIDGE_NAME,
109 .remap_mask = ALT_L3_REMAP_LWH2F_MSK,
110 };
111
112 static struct altera_hps2fpga_data fpga2hps_data = {
113 .name = FPGA2HPS_BRIDGE_NAME,
114 };
115
116 static const struct of_device_id altera_fpga_of_match[] = {
117 { .compatible = "altr,socfpga-hps2fpga-bridge",
118 .data = &hps2fpga_data },
119 { .compatible = "altr,socfpga-lwhps2fpga-bridge",
120 .data = &lwhps2fpga_data },
121 { .compatible = "altr,socfpga-fpga2hps-bridge",
122 .data = &fpga2hps_data },
123 {},
124 };
125
alt_fpga_bridge_probe(struct platform_device * pdev)126 static int alt_fpga_bridge_probe(struct platform_device *pdev)
127 {
128 struct device *dev = &pdev->dev;
129 struct altera_hps2fpga_data *priv;
130 const struct of_device_id *of_id;
131 struct fpga_bridge *br;
132 u32 enable;
133 int ret;
134
135 of_id = of_match_device(altera_fpga_of_match, dev);
136 if (!of_id) {
137 dev_err(dev, "failed to match device\n");
138 return -ENODEV;
139 }
140
141 priv = (struct altera_hps2fpga_data *)of_id->data;
142
143 priv->bridge_reset = of_reset_control_get_exclusive_by_index(dev->of_node,
144 0);
145 if (IS_ERR(priv->bridge_reset)) {
146 dev_err(dev, "Could not get %s reset control\n", priv->name);
147 return PTR_ERR(priv->bridge_reset);
148 }
149
150 if (priv->remap_mask) {
151 priv->l3reg = syscon_regmap_lookup_by_compatible("altr,l3regs");
152 if (IS_ERR(priv->l3reg)) {
153 dev_err(dev, "regmap for altr,l3regs lookup failed\n");
154 return PTR_ERR(priv->l3reg);
155 }
156 }
157
158 priv->clk = devm_clk_get(dev, NULL);
159 if (IS_ERR(priv->clk)) {
160 dev_err(dev, "no clock specified\n");
161 return PTR_ERR(priv->clk);
162 }
163
164 ret = clk_prepare_enable(priv->clk);
165 if (ret) {
166 dev_err(dev, "could not enable clock\n");
167 return -EBUSY;
168 }
169
170 if (!of_property_read_u32(dev->of_node, "bridge-enable", &enable)) {
171 if (enable > 1) {
172 dev_warn(dev, "invalid bridge-enable %u > 1\n", enable);
173 } else {
174 dev_info(dev, "%s bridge\n",
175 (enable ? "enabling" : "disabling"));
176
177 ret = _alt_hps2fpga_enable_set(priv, enable);
178 if (ret)
179 goto err;
180 }
181 }
182
183 br = devm_fpga_bridge_create(dev, priv->name,
184 &altera_hps2fpga_br_ops, priv);
185 if (!br) {
186 ret = -ENOMEM;
187 goto err;
188 }
189
190 platform_set_drvdata(pdev, br);
191
192 ret = fpga_bridge_register(br);
193 if (ret)
194 goto err;
195
196 return 0;
197
198 err:
199 clk_disable_unprepare(priv->clk);
200
201 return ret;
202 }
203
alt_fpga_bridge_remove(struct platform_device * pdev)204 static int alt_fpga_bridge_remove(struct platform_device *pdev)
205 {
206 struct fpga_bridge *bridge = platform_get_drvdata(pdev);
207 struct altera_hps2fpga_data *priv = bridge->priv;
208
209 fpga_bridge_unregister(bridge);
210
211 clk_disable_unprepare(priv->clk);
212
213 return 0;
214 }
215
216 MODULE_DEVICE_TABLE(of, altera_fpga_of_match);
217
218 static struct platform_driver alt_fpga_bridge_driver = {
219 .probe = alt_fpga_bridge_probe,
220 .remove = alt_fpga_bridge_remove,
221 .driver = {
222 .name = "altera_hps2fpga_bridge",
223 .of_match_table = of_match_ptr(altera_fpga_of_match),
224 },
225 };
226
227 module_platform_driver(alt_fpga_bridge_driver);
228
229 MODULE_DESCRIPTION("Altera SoCFPGA HPS to FPGA Bridge");
230 MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
231 MODULE_LICENSE("GPL v2");
232
