1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * sun6i_hwspinlock.c - hardware spinlock driver for sun6i compatible Allwinner SoCs 4 * Copyright (C) 2020 Wilken Gottwalt <wilken.gottwalt@posteo.net> 5 */ 6 7 #include <linux/clk.h> 8 #include <linux/debugfs.h> 9 #include <linux/errno.h> 10 #include <linux/hwspinlock.h> 11 #include <linux/io.h> 12 #include <linux/module.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/reset.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/types.h> 19 20 #include "hwspinlock_internal.h" 21 22 #define DRIVER_NAME "sun6i_hwspinlock" 23 24 #define SPINLOCK_BASE_ID 0 /* there is only one hwspinlock device per SoC */ 25 #define SPINLOCK_SYSSTATUS_REG 0x0000 26 #define SPINLOCK_LOCK_REGN 0x0100 27 #define SPINLOCK_NOTTAKEN 0 28 29 struct sun6i_hwspinlock_data { 30 struct hwspinlock_device *bank; 31 struct reset_control *reset; 32 struct clk *ahb_clk; 33 struct dentry *debugfs; 34 int nlocks; 35 }; 36 37 #ifdef CONFIG_DEBUG_FS 38 39 static int hwlocks_supported_show(struct seq_file *seqf, void *unused) 40 { 41 struct sun6i_hwspinlock_data *priv = seqf->private; 42 43 seq_printf(seqf, "%d\n", priv->nlocks); 44 45 return 0; 46 } 47 DEFINE_SHOW_ATTRIBUTE(hwlocks_supported); 48 49 static void sun6i_hwspinlock_debugfs_init(struct sun6i_hwspinlock_data *priv) 50 { 51 priv->debugfs = debugfs_create_dir(DRIVER_NAME, NULL); 52 debugfs_create_file("supported", 0444, priv->debugfs, priv, &hwlocks_supported_fops); 53 } 54 55 #else 56 57 static void sun6i_hwspinlock_debugfs_init(struct sun6i_hwspinlock_data *priv) 58 { 59 } 60 61 #endif 62 63 static int sun6i_hwspinlock_trylock(struct hwspinlock *lock) 64 { 65 void __iomem *lock_addr = lock->priv; 66 67 return (readl(lock_addr) == SPINLOCK_NOTTAKEN); 68 } 69 70 static void sun6i_hwspinlock_unlock(struct hwspinlock *lock) 71 { 72 void __iomem *lock_addr = lock->priv; 73 74 writel(SPINLOCK_NOTTAKEN, lock_addr); 75 } 76 77 static const struct hwspinlock_ops sun6i_hwspinlock_ops = { 78 .trylock = sun6i_hwspinlock_trylock, 79 .unlock = sun6i_hwspinlock_unlock, 80 }; 81 82 static void sun6i_hwspinlock_disable(void *data) 83 { 84 struct sun6i_hwspinlock_data *priv = data; 85 86 debugfs_remove_recursive(priv->debugfs); 87 clk_disable_unprepare(priv->ahb_clk); 88 reset_control_assert(priv->reset); 89 } 90 91 static int sun6i_hwspinlock_probe(struct platform_device *pdev) 92 { 93 struct sun6i_hwspinlock_data *priv; 94 struct hwspinlock *hwlock; 95 void __iomem *io_base; 96 u32 num_banks; 97 int err, i; 98 99 io_base = devm_platform_ioremap_resource(pdev, SPINLOCK_BASE_ID); 100 if (IS_ERR(io_base)) 101 return PTR_ERR(io_base); 102 103 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 104 if (!priv) 105 return -ENOMEM; 106 107 priv->ahb_clk = devm_clk_get(&pdev->dev, "ahb"); 108 if (IS_ERR(priv->ahb_clk)) { 109 err = PTR_ERR(priv->ahb_clk); 110 dev_err(&pdev->dev, "unable to get AHB clock (%d)\n", err); 111 return err; 112 } 113 114 priv->reset = devm_reset_control_get(&pdev->dev, "ahb"); 115 if (IS_ERR(priv->reset)) 116 return dev_err_probe(&pdev->dev, PTR_ERR(priv->reset), 117 "unable to get reset control\n"); 118 119 err = reset_control_deassert(priv->reset); 120 if (err) { 121 dev_err(&pdev->dev, "deassert reset control failure (%d)\n", err); 122 return err; 123 } 124 125 err = clk_prepare_enable(priv->ahb_clk); 126 if (err) { 127 dev_err(&pdev->dev, "unable to prepare AHB clk (%d)\n", err); 128 goto clk_fail; 129 } 130 131 /* 132 * bit 28 and 29 represents the hwspinlock setup 133 * 134 * every datasheet (A64, A80, A83T, H3, H5, H6 ...) says the default value is 0x1 and 0x1 135 * to 0x4 represent 32, 64, 128 and 256 locks 136 * but later datasheets (H5, H6) say 00, 01, 10, 11 represent 32, 64, 128 and 256 locks, 137 * but that would mean H5 and H6 have 64 locks, while their datasheets talk about 32 locks 138 * all the time, not a single mentioning of 64 locks 139 * the 0x4 value is also not representable by 2 bits alone, so some datasheets are not 140 * correct 141 * one thing have all in common, default value of the sysstatus register is 0x10000000, 142 * which results in bit 28 being set 143 * this is the reason 0x1 is considered being 32 locks and bit 30 is taken into account 144 * verified on H2+ (datasheet 0x1 = 32 locks) and H5 (datasheet 01 = 64 locks) 145 */ 146 num_banks = readl(io_base + SPINLOCK_SYSSTATUS_REG) >> 28; 147 switch (num_banks) { 148 case 1 ... 4: 149 priv->nlocks = 1 << (4 + num_banks); 150 break; 151 default: 152 err = -EINVAL; 153 dev_err(&pdev->dev, "unsupported hwspinlock setup (%d)\n", num_banks); 154 goto bank_fail; 155 } 156 157 priv->bank = devm_kzalloc(&pdev->dev, struct_size(priv->bank, lock, priv->nlocks), 158 GFP_KERNEL); 159 if (!priv->bank) { 160 err = -ENOMEM; 161 goto bank_fail; 162 } 163 164 for (i = 0; i < priv->nlocks; ++i) { 165 hwlock = &priv->bank->lock[i]; 166 hwlock->priv = io_base + SPINLOCK_LOCK_REGN + sizeof(u32) * i; 167 } 168 169 /* failure of debugfs is considered non-fatal */ 170 sun6i_hwspinlock_debugfs_init(priv); 171 if (IS_ERR(priv->debugfs)) 172 priv->debugfs = NULL; 173 174 err = devm_add_action_or_reset(&pdev->dev, sun6i_hwspinlock_disable, priv); 175 if (err) { 176 dev_err(&pdev->dev, "failed to add hwspinlock disable action\n"); 177 goto bank_fail; 178 } 179 180 platform_set_drvdata(pdev, priv); 181 182 return devm_hwspin_lock_register(&pdev->dev, priv->bank, &sun6i_hwspinlock_ops, 183 SPINLOCK_BASE_ID, priv->nlocks); 184 185 bank_fail: 186 clk_disable_unprepare(priv->ahb_clk); 187 clk_fail: 188 reset_control_assert(priv->reset); 189 190 return err; 191 } 192 193 static const struct of_device_id sun6i_hwspinlock_ids[] = { 194 { .compatible = "allwinner,sun6i-a31-hwspinlock", }, 195 {}, 196 }; 197 MODULE_DEVICE_TABLE(of, sun6i_hwspinlock_ids); 198 199 static struct platform_driver sun6i_hwspinlock_driver = { 200 .probe = sun6i_hwspinlock_probe, 201 .driver = { 202 .name = DRIVER_NAME, 203 .of_match_table = sun6i_hwspinlock_ids, 204 }, 205 }; 206 module_platform_driver(sun6i_hwspinlock_driver); 207 208 MODULE_LICENSE("GPL"); 209 MODULE_DESCRIPTION("SUN6I hardware spinlock driver"); 210 MODULE_AUTHOR("Wilken Gottwalt <wilken.gottwalt@posteo.net>"); 211