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 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 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 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 }; 125 126 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 = fpga_bridge_create(dev, priv->name, &altera_hps2fpga_br_ops, priv); 184 if (!br) { 185 ret = -ENOMEM; 186 goto err; 187 } 188 189 platform_set_drvdata(pdev, br); 190 191 ret = fpga_bridge_register(br); 192 if (ret) 193 goto err_free; 194 195 return 0; 196 197 err_free: 198 fpga_bridge_free(br); 199 err: 200 clk_disable_unprepare(priv->clk); 201 202 return ret; 203 } 204 205 static int alt_fpga_bridge_remove(struct platform_device *pdev) 206 { 207 struct fpga_bridge *bridge = platform_get_drvdata(pdev); 208 struct altera_hps2fpga_data *priv = bridge->priv; 209 210 fpga_bridge_unregister(bridge); 211 212 clk_disable_unprepare(priv->clk); 213 214 return 0; 215 } 216 217 MODULE_DEVICE_TABLE(of, altera_fpga_of_match); 218 219 static struct platform_driver alt_fpga_bridge_driver = { 220 .probe = alt_fpga_bridge_probe, 221 .remove = alt_fpga_bridge_remove, 222 .driver = { 223 .name = "altera_hps2fpga_bridge", 224 .of_match_table = of_match_ptr(altera_fpga_of_match), 225 }, 226 }; 227 228 module_platform_driver(alt_fpga_bridge_driver); 229 230 MODULE_DESCRIPTION("Altera SoCFPGA HPS to FPGA Bridge"); 231 MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>"); 232 MODULE_LICENSE("GPL v2"); 233